1726099042

Committed 20 Mar 2025 09:41AM UTC coverage: 75.916% (-0.003%) from 75.919%

Build # 1726099042

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push

gitlab-ci

Committed by

web-flow

Commit Message

Merge pull request #1778 from jo-lund/cert-failure

fix: Return an error when certificate fails to load

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87.12

/src/common/http/platform/beast/http.cpp

// Copyright 2023 Northern.tech AS
//
//    Licensed under the Apache License, Version 2.0 (the "License");
//    you may not use this file except in compliance with the License.
//    You may obtain a copy of the License at
//
//        http://www.apache.org/licenses/LICENSE-2.0
//
//    Unless required by applicable law or agreed to in writing, software
//    distributed under the License is distributed on an "AS IS" BASIS,
//    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//    See the License for the specific language governing permissions and
//    limitations under the License.

#include <common/http.hpp>

#include <algorithm>

#include <boost/asio.hpp>
#include <boost/asio/ip/tcp.hpp>
#include <boost/asio/ssl/host_name_verification.hpp>
#include <boost/asio/ssl/verify_mode.hpp>

#include <common/common.hpp>
#include <common/crypto.hpp>

namespace mender {
namespace common {
namespace http {

namespace common = mender::common;
namespace crypto = mender::common::crypto;

// At the time of writing, Beast only supports HTTP/1.1, and is unlikely to support HTTP/2
// according to this discussion: https://github.com/boostorg/beast/issues/1302.
const unsigned int BeastHttpVersion = 11;

namespace asio = boost::asio;
namespace http = boost::beast::http;

const int HTTP_BEAST_BUFFER_SIZE = MENDER_BUFSIZE;

static http::verb MethodToBeastVerb(Method method) {
        switch (method) {
        case Method::GET:
                return http::verb::get;
        case Method::HEAD:
                return http::verb::head;
        case Method::POST:
                return http::verb::post;
        case Method::PUT:
                return http::verb::put;
        case Method::PATCH:
                return http::verb::patch;
        case Method::CONNECT:
                return http::verb::connect;
        case Method::Invalid:
                // Fallthrough to end (no-op).
                break;
        }
        // Don't use "default" case. This should generate a warning if we ever add any methods. But
        // still assert here for safety.
        assert(false);
        return http::verb::get;
}

static expected::expected<Method, error::Error> BeastVerbToMethod(
        http::verb verb, const string &verb_string) {
        switch (verb) {
        case http::verb::get:
                return Method::GET;
        case http::verb::head:
                return Method::HEAD;
        case http::verb::post:
                return Method::POST;
        case http::verb::put:
                return Method::PUT;
        case http::verb::patch:
                return Method::PATCH;
        case http::verb::connect:
                return Method::CONNECT;
        default:
                return expected::unexpected(MakeError(UnsupportedMethodError, verb_string));
        }
}

template <typename StreamType>
class BodyAsyncReader : virtual public io::AsyncReader {
public:
        BodyAsyncReader(StreamType &stream, shared_ptr<bool> cancelled) :
                stream_ {stream},
                cancelled_ {cancelled} {
        }
        ~BodyAsyncReader() {
                Cancel();
        }

        error::Error AsyncRead(
                vector<uint8_t>::iterator start,
                vector<uint8_t>::iterator end,
                io::AsyncIoHandler handler) override {
                if (eof_) {
                        handler(0);
                        return error::NoError;
                }

                if (*cancelled_) {
                        return error::MakeError(
                                error::ProgrammingError,
                                "BodyAsyncReader::AsyncRead called after stream is destroyed");
                }
                stream_.AsyncReadNextBodyPart(start, end, [this, handler](io::ExpectedSize size) {
                        if (size && size.value() == 0) {
                                eof_ = true;
                        }
                        handler(size);
                });
                return error::NoError;
        }

        void Cancel() override {
                if (!*cancelled_) {
                        stream_.Cancel();
                }
        }

private:
        StreamType &stream_;
        shared_ptr<bool> cancelled_;
        bool eof_ {false};

        friend class Client;
        friend class Server;
};

template <typename StreamType>
class RawSocket : virtual public io::AsyncReadWriter {
public:
        RawSocket(shared_ptr<StreamType> stream, shared_ptr<beast::flat_buffer> buffered) :
                destroying_ {make_shared<bool>(false)},
                stream_ {stream},
                buffered_ {buffered} {
                // If there are no buffered bytes, then we don't need it.
                if (buffered_ && buffered_->size() == 0) {
                        buffered_.reset();
                }
        }

        ~RawSocket() {
                *destroying_ = true;
                Cancel();
        }

        error::Error AsyncRead(
                vector<uint8_t>::iterator start,
                vector<uint8_t>::iterator end,
                io::AsyncIoHandler handler) override {
                // If we have prebuffered bytes, which can happen if the HTTP parser read the
                // header and parts of the body in one block, return those first.
                if (buffered_) {
                        return DrainPrebufferedData(start, end, handler);
                }

                read_buffer_ = asio::buffer(&*start, end - start);
                auto &destroying = destroying_;
                stream_->async_read_some(
                        read_buffer_,
                        [destroying, handler](const boost::system::error_code &ec, size_t num_read) {
                                if (*destroying) {
                                        return;
                                }

                                if (ec == asio::error::operation_aborted) {
                                        handler(expected::unexpected(error::Error(
                                                make_error_condition(errc::operation_canceled),
                                                "Could not read from socket")));
                                } else if (ec) {
                                        handler(expected::unexpected(
                                                error::Error(ec.default_error_condition(), "Could not read from socket")));
                                } else {
                                        handler(num_read);
                                }
                        });
                return error::NoError;
        }

        error::Error AsyncWrite(
                vector<uint8_t>::const_iterator start,
                vector<uint8_t>::const_iterator end,
                io::AsyncIoHandler handler) override {
                write_buffer_ = asio::buffer(&*start, end - start);
                auto &destroying = destroying_;
                stream_->async_write_some(
                        write_buffer_,
                        [destroying, handler](const boost::system::error_code &ec, size_t num_written) {
                                if (*destroying) {
                                        return;
                                }

                                if (ec == asio::error::operation_aborted) {
                                        handler(expected::unexpected(error::Error(
                                                make_error_condition(errc::operation_canceled),
                                                "Could not write to socket")));
                                } else if (ec) {
                                        handler(expected::unexpected(
                                                error::Error(ec.default_error_condition(), "Could not write to socket")));
                                } else {
                                        handler(num_written);
                                }
                        });
                return error::NoError;
        }

        void Cancel() override {
                if (stream_->lowest_layer().is_open()) {
                        stream_->lowest_layer().cancel();
                        stream_->lowest_layer().close();
                }
        }

private:
        error::Error DrainPrebufferedData(
                vector<uint8_t>::iterator start,
                vector<uint8_t>::iterator end,
                io::AsyncIoHandler handler) {
                size_t to_copy = min(static_cast<size_t>(end - start), buffered_->size());

                // These two lines are equivalent to:
                //   copy_n(static_cast<const uint8_t *>(buffered_->cdata().data()), to_copy, start);
                // but compatible with Boost 1.67.
                const beast::flat_buffer &cbuffered = *buffered_;
                copy_n(static_cast<const uint8_t *>(cbuffered.data().data()), to_copy, start);
                buffered_->consume(to_copy);
                if (buffered_->size() == 0) {
                        // We don't need it anymore.
                        buffered_.reset();
                }
                handler(to_copy);
                return error::NoError;
        }

        shared_ptr<bool> destroying_;
        shared_ptr<StreamType> stream_;
        shared_ptr<beast::flat_buffer> buffered_;
        asio::mutable_buffer read_buffer_;
        asio::const_buffer write_buffer_;
};

template <typename PARSER>
int64_t GetContentLength(const PARSER &parser) {
        auto content_length = parser.content_length();
        if (content_length) {
                return content_length.value();
        } else {
                return 0;
        }
}

expected::ExpectedBool HasBody(
        const expected::ExpectedString &content_length,
        const expected::ExpectedString &transfer_encoding) {
        if (transfer_encoding) {
                if (transfer_encoding.value() != "chunked") {
                        return expected::unexpected(error::Error(
                                make_error_condition(errc::not_supported),
                                "Unsupported Transfer-Encoding: " + transfer_encoding.value()));
                }
                return true;
        }

        if (content_length) {
                auto length = common::StringToLongLong(content_length.value());
                if (!length || length.value() < 0) {
                        return expected::unexpected(error::Error(
                                length.error().code,
                                "Content-Length contains invalid number: " + content_length.value()));
                }
                return length.value() > 0;
        }

        return false;
}

Client::Client(
        const ClientConfig &client, events::EventLoop &event_loop, const string &logger_name) :
        event_loop_ {event_loop},
        logger_name_ {logger_name},
        client_config_ {client},
        http_proxy_ {client.http_proxy},
        https_proxy_ {client.https_proxy},
        no_proxy_ {client.no_proxy},
        cancelled_ {make_shared<bool>(true)},
        resolver_(GetAsioIoContext(event_loop)),
        body_buffer_(HTTP_BEAST_BUFFER_SIZE) {
}

Client::~Client() {
        if (!*cancelled_) {
                logger_.Warning("Client destroyed while request is still active!");
        }
        DoCancel();
}

error::Error Client::Initialize() {
        if (initialized_) {
                return error::NoError;
        }

        for (auto i = 0; i < MENDER_BOOST_BEAST_SSL_CTX_COUNT; i++) {
                ssl_ctx_[i].set_verify_mode(
                        client_config_.skip_verify ? ssl::verify_none : ssl::verify_peer);

                beast::error_code ec {};
                if (client_config_.client_cert_path != "" and client_config_.client_cert_key_path != "") {
                        ssl_ctx_[i].set_options(boost::asio::ssl::context::default_workarounds);
                        ssl_ctx_[i].use_certificate_file(
                                client_config_.client_cert_path, boost::asio::ssl::context_base::pem, ec);
                        if (ec) {
                                return error::Error(
                                        ec.default_error_condition(), "Could not load client certificate");
                        }
                        auto exp_key = crypto::PrivateKey::Load(
                                {client_config_.client_cert_key_path, "", client_config_.ssl_engine});
                        if (!exp_key) {
                                return exp_key.error().WithContext(
                                        "Error loading private key from " + client_config_.client_cert_key_path);
                        }

                        const int ret =
                                SSL_CTX_use_PrivateKey(ssl_ctx_[i].native_handle(), exp_key.value()->Get());
                        if (ret != 1) {
                                return MakeError(
                                        HTTPInitError,
                                        "Failed to add the PrivateKey: " + client_config_.client_cert_key_path
                                                + " to the SSL CTX");
                        }
                } else if (
                        client_config_.client_cert_path != "" or client_config_.client_cert_key_path != "") {
                        return error::Error(
                                make_error_condition(errc::invalid_argument),
                                "Cannot set only one of client certificate, and client certificate private key");
                }

                bool cert_loaded = true;
                ssl_ctx_[i].set_default_verify_paths(ec); // Load the default CAs
                if (ec) {
                        auto err = error::Error(
                                ec.default_error_condition(), "Failed to load the SSL default directory");
                        if (client_config_.server_cert_path == "") {
                                // We aren't going to have any valid certificates then.
                                return err;
                        } else {
                                // We have a dedicated certificate, so this is not fatal.
                                log::Info(err.String());
                                cert_loaded = false;
                        }
                }
                if (client_config_.server_cert_path != "") {
                        ssl_ctx_[i].load_verify_file(client_config_.server_cert_path, ec);
                        if (ec) {
                                log::Warning("Failed to load the server certificate! Falling back to the CA store");
                                if (!cert_loaded) {
                                        return error::Error(
                                                ec.default_error_condition(),
                                                "Failed to load SSL default directory and server certificate");
                                }
                        }
                }
        }

        initialized_ = true;

        return error::NoError;
}

// Create the HOST header according to:
// https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.23
// In short: Add the port-number if it is non-standard HTTP
static string CreateHOSTAddress(OutgoingRequestPtr req) {
        if (req->GetPort() == 80 || req->GetPort() == 443) {
                return req->GetHost();
        }
        return req->GetHost() + ":" + to_string(req->GetPort());
}

error::Error Client::AsyncCall(
        OutgoingRequestPtr req, ResponseHandler header_handler, ResponseHandler body_handler) {
        auto err = Initialize();
        if (err != error::NoError) {
                return err;
        }

        if (!*cancelled_ && status_ != TransactionStatus::Done) {
                return error::Error(
                        make_error_condition(errc::operation_in_progress), "HTTP call already ongoing");
        }

        if (req->address_.protocol == "" || req->address_.host == "" || req->address_.port < 0) {
                return error::MakeError(error::ProgrammingError, "Request is not ready");
        }

        if (!header_handler || !body_handler) {
                return error::MakeError(
                        error::ProgrammingError, "header_handler and body_handler can not be nullptr");
        }

        if (req->address_.protocol != "http" && req->address_.protocol != "https") {
                return error::Error(
                        make_error_condition(errc::protocol_not_supported), req->address_.protocol);
        }

        logger_ = log::Logger(logger_name_).WithFields(log::LogField("url", req->orig_address_));

        request_ = req;

        err = HandleProxySetup();
        if (err != error::NoError) {
                return err;
        }

        // NOTE: The AWS loadbalancer requires that the HOST header always be set, in order for the
        // request to route to our k8s cluster. Set this in all cases.
        const string header_url = CreateHOSTAddress(req);
        req->SetHeader("HOST", header_url);

        log::Trace("Setting HOST address: " + header_url);

        header_handler_ = header_handler;
        body_handler_ = body_handler;
        status_ = TransactionStatus::None;

        cancelled_ = make_shared<bool>(false);

        auto &cancelled = cancelled_;

        resolver_.async_resolve(
                request_->address_.host,
                to_string(request_->address_.port),
                [this, cancelled](
                        const error_code &ec, const asio::ip::tcp::resolver::results_type &results) {
                        if (!*cancelled) {
                                ResolveHandler(ec, results);
                        }
                });

        return error::NoError;
}

static inline error::Error AddProxyAuthHeader(OutgoingRequest &req, BrokenDownUrl &proxy_address) {
        if (proxy_address.username == "") {
                // nothing to do
                return error::NoError;
        }
        auto ex_dec_username = URLDecode(proxy_address.username);
        auto ex_dec_password = URLDecode(proxy_address.password);
        if (!ex_dec_username) {
                return ex_dec_username.error();
        }
        if (!ex_dec_password) {
                return ex_dec_password.error();
        }
        auto creds = ex_dec_username.value() + ":" + ex_dec_password.value();
        auto ex_encoded_creds = crypto::EncodeBase64(common::ByteVectorFromString(creds));
        if (!ex_encoded_creds) {
                return ex_encoded_creds.error();
        }
        req.SetHeader("Proxy-Authorization", "Basic " + ex_encoded_creds.value());
        log::Warning(
                "Avoid using basic authentication if possible, and make sure if it's used, it's through HTTPS");

        return error::NoError;
}

error::Error Client::HandleProxySetup() {
        secondary_req_.reset();

        if (request_->address_.protocol == "http") {
                socket_mode_ = SocketMode::Plain;

                if (http_proxy_ != "" && !HostNameMatchesNoProxy(request_->address_.host, no_proxy_)) {
                        // Make a modified proxy request.
                        BrokenDownUrl proxy_address;
                        auto err = BreakDownUrl(http_proxy_, proxy_address, true);
                        if (err != error::NoError) {
                                return err.WithContext("HTTP proxy URL is invalid");
                        }
                        if (proxy_address.path != "" && proxy_address.path != "/") {
                                return MakeError(
                                        InvalidUrlError, "A URL with a path is not legal for a proxy address");
                        }

                        request_->address_.path = request_->address_.protocol + "://" + request_->address_.host
                                                                          + ":" + to_string(request_->address_.port)
                                                                          + request_->address_.path;
                        request_->address_.host = proxy_address.host;
                        request_->address_.port = proxy_address.port;
                        request_->address_.protocol = proxy_address.protocol;

                        err = AddProxyAuthHeader(*request_, proxy_address);
                        if (err != error::NoError) {
                                return err;
                        }

                        if (proxy_address.protocol == "https") {
                                socket_mode_ = SocketMode::Tls;
                        } else if (proxy_address.protocol == "http") {
                                socket_mode_ = SocketMode::Plain;
                        } else {
                                // Should never get here.
                                assert(false);
                        }
                }
        } else if (request_->address_.protocol == "https") {
                socket_mode_ = SocketMode::Tls;

                if (https_proxy_ != "" && !HostNameMatchesNoProxy(request_->address_.host, no_proxy_)) {
                        // Save the original request for later, so that we can make a new request
                        // over the channel established by CONNECT.
                        secondary_req_ = std::move(request_);

                        request_ = make_shared<OutgoingRequest>();
                        request_->SetMethod(Method::CONNECT);
                        BrokenDownUrl proxy_address;
                        auto err = BreakDownUrl(https_proxy_, proxy_address, true);
                        if (err != error::NoError) {
                                return err.WithContext("HTTPS proxy URL is invalid");
                        }
                        if (proxy_address.path != "" && proxy_address.path != "/") {
                                return MakeError(
                                        InvalidUrlError, "A URL with a path is not legal for a proxy address");
                        }

                        request_->address_.path =
                                secondary_req_->address_.host + ":" + to_string(secondary_req_->address_.port);
                        request_->address_.host = proxy_address.host;
                        request_->address_.port = proxy_address.port;
                        request_->address_.protocol = proxy_address.protocol;

                        err = AddProxyAuthHeader(*request_, proxy_address);
                        if (err != error::NoError) {
                                return err;
                        }

                        if (proxy_address.protocol == "https") {
                                socket_mode_ = SocketMode::Tls;
                        } else if (proxy_address.protocol == "http") {
                                socket_mode_ = SocketMode::Plain;
                        } else {
                                // Should never get here.
                                assert(false);
                        }
                }
        } else {
                // Should never get here
                assert(false);
        }

        return error::NoError;
}

io::ExpectedAsyncReaderPtr Client::MakeBodyAsyncReader(IncomingResponsePtr resp) {
        if (status_ != TransactionStatus::HeaderHandlerCalled) {
                return expected::unexpected(error::Error(
                        make_error_condition(errc::operation_in_progress),
                        "MakeBodyAsyncReader called while reading is in progress"));
        }

        if (GetContentLength(*response_data_.http_response_parser_) == 0
                && !response_data_.http_response_parser_->chunked()) {
                return expected::unexpected(
                        MakeError(BodyMissingError, "Response does not contain a body"));
        }

        status_ = TransactionStatus::ReaderCreated;
        return make_shared<BodyAsyncReader<Client>>(resp->client_.GetHttpClient(), resp->cancelled_);
}

io::ExpectedAsyncReadWriterPtr Client::SwitchProtocol(IncomingResponsePtr req) {
        if (*cancelled_) {
                return expected::unexpected(error::Error(
                        make_error_condition(errc::not_connected),
                        "Cannot switch protocols if endpoint is not connected"));
        }

        // Rest of the connection is done directly on the socket, we are done here.
        status_ = TransactionStatus::Done;
        *cancelled_ = true;
        cancelled_ = make_shared<bool>(false);

        auto stream = stream_;
        // This no longer belongs to us.
        stream_.reset();

        switch (socket_mode_) {
        case SocketMode::TlsTls:
                return make_shared<RawSocket<ssl::stream<ssl::stream<tcp::socket>>>>(
                        stream, response_data_.response_buffer_);
        case SocketMode::Tls:
                return make_shared<RawSocket<ssl::stream<tcp::socket>>>(
                        make_shared<ssl::stream<tcp::socket>>(std::move(stream->next_layer())),
                        response_data_.response_buffer_);
        case SocketMode::Plain:
                return make_shared<RawSocket<tcp::socket>>(
                        make_shared<tcp::socket>(std::move(stream->next_layer().next_layer())),
                        response_data_.response_buffer_);
        }

        AssertOrReturnUnexpected(false);
}

void Client::CallHandler(ResponseHandler handler) {
        // This function exists to make sure we have a copy of the handler we're calling (in the
        // argument list). This is important in case the handler owns the client instance through a
        // capture, and it replaces the handler with a different one (using `AsyncCall`). If it
        // does, then it destroys the final copy of the handler, and therefore also the client,
        // which is why we need to make a copy here, before calling it.
        handler(response_);
}

void Client::CallErrorHandler(
        const error_code &ec, const OutgoingRequestPtr &req, ResponseHandler handler) {
        CallErrorHandler(error::Error(ec.default_error_condition(), ""), req, handler);
}

void Client::CallErrorHandler(
        const error::Error &err, const OutgoingRequestPtr &req, ResponseHandler handler) {
        status_ = TransactionStatus::Done;
        DoCancel();
        handler(expected::unexpected(
                err.WithContext(MethodToString(req->method_) + " " + req->orig_address_)));
}

void Client::ResolveHandler(
        const error_code &ec, const asio::ip::tcp::resolver::results_type &results) {
        if (ec) {
                CallErrorHandler(ec, request_, header_handler_);
                return;
        }

        if (logger_.Level() >= log::LogLevel::Debug) {
                string ips = "[";
                string sep;
                for (auto r : results) {
                        ips += sep;
                        ips += r.endpoint().address().to_string();
                        sep = ", ";
                }
                ips += "]";
                logger_.Debug("Hostname " + request_->address_.host + " resolved to " + ips);
        }

        resolver_results_ = results;

        stream_ = make_shared<ssl::stream<ssl::stream<tcp::socket>>>(
                ssl::stream<tcp::socket>(GetAsioIoContext(event_loop_), ssl_ctx_[0]), ssl_ctx_[1]);

        if (!response_data_.response_buffer_) {
                // We can reuse this if preexisting.
                response_data_.response_buffer_ = make_shared<beast::flat_buffer>();

                // This is equivalent to:
                //   response_data_.response_buffer_.reserve(body_buffer_.size());
                // but compatible with Boost 1.67.
                response_data_.response_buffer_->prepare(
                        body_buffer_.size() - response_data_.response_buffer_->size());
        }

        auto &cancelled = cancelled_;

        asio::async_connect(
                stream_->lowest_layer(),
                resolver_results_,
                [this, cancelled](const error_code &ec, const asio::ip::tcp::endpoint &endpoint) {
                        if (!*cancelled) {
                                switch (socket_mode_) {
                                case SocketMode::TlsTls:
                                        // Should never happen because we always need to handshake
                                        // the innermost Tls first, then the outermost, but the
                                        // latter doesn't happen here.
                                        assert(false);
                                        CallErrorHandler(
                                                error::MakeError(
                                                        error::ProgrammingError, "TlsTls mode is invalid in ResolveHandler"),
                                                request_,
                                                header_handler_);
                                case SocketMode::Tls:
                                        return HandshakeHandler(stream_->next_layer(), ec, endpoint);
                                case SocketMode::Plain:
                                        return ConnectHandler(ec, endpoint);
                                }
                        }
                });
}

template <typename StreamType>
void Client::HandshakeHandler(
        StreamType &stream, const error_code &ec, const asio::ip::tcp::endpoint &endpoint) {
        if (ec) {
                CallErrorHandler(ec, request_, header_handler_);
                return;
        }

        // Enable TCP keepalive
        boost::asio::socket_base::keep_alive option(true);
        stream_->lowest_layer().set_option(option);

        // We can't avoid a C style cast on this next line. The usual method by which system headers
        // are excluded from warnings doesn't work, because `SSL_set_tlsext_host_name` is a macro,
        // containing a cast, which expands here, not in the original file. So just disable the
        // warning here.
#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wold-style-cast"
#else
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wold-style-cast"
#endif
        // Set SNI Hostname (many hosts need this to handshake successfully)
        if (!SSL_set_tlsext_host_name(stream.native_handle(), request_->address_.host.c_str())) {
#ifdef __clang__
#pragma clang diagnostic pop
#else
#pragma GCC diagnostic pop
#endif
                beast::error_code ec2 {
                        static_cast<int>(::ERR_get_error()), asio::error::get_ssl_category()};
                logger_.Error("Failed to set SNI host name: " + ec2.message());
        }

        // Enable host name verification (not done automatically and we don't have
        // enough access to the TLS internals to use X509_VERIFY_PARAM_set1_host(),
        // hence the callback that boost provides).
        boost::system::error_code b_ec;
        stream.set_verify_callback(ssl::host_name_verification(request_->address_.host), b_ec);
        if (b_ec) {
                logger_.Error("Failed to enable host name verification: " + b_ec.message());
                CallErrorHandler(b_ec, request_, header_handler_);
                return;
        }

        auto &cancelled = cancelled_;

        stream.async_handshake(
                ssl::stream_base::client, [this, cancelled, endpoint](const error_code &ec) {
                        if (*cancelled) {
                                return;
                        }
                        if (ec) {
                                logger_.Error("https: Failed to perform the SSL handshake: " + ec.message());
                                CallErrorHandler(ec, request_, header_handler_);
                                return;
                        }
                        logger_.Debug("https: Successful SSL handshake");
                        ConnectHandler(ec, endpoint);
                });
}


void Client::ConnectHandler(const error_code &ec, const asio::ip::tcp::endpoint &endpoint) {
        if (ec) {
                CallErrorHandler(ec, request_, header_handler_);
                return;
        }

        // Enable TCP keepalive
        boost::asio::socket_base::keep_alive option(true);
        stream_->lowest_layer().set_option(option);

        logger_.Debug("Connected to " + endpoint.address().to_string());

        request_data_.http_request_ = make_shared<http::request<http::buffer_body>>(
                MethodToBeastVerb(request_->method_), request_->address_.path, BeastHttpVersion);

        for (const auto &header : request_->headers_) {
                request_data_.http_request_->set(header.first, header.second);
        }

        request_data_.http_request_serializer_ =
                make_shared<http::request_serializer<http::buffer_body>>(*request_data_.http_request_);

        response_data_.http_response_parser_ = make_shared<http::response_parser<http::buffer_body>>();

        // Don't enforce limits. Since we stream everything, limits don't generally apply, and
        // if they do, they should be handled higher up in the application logic.
        //
        // Note: There is a bug in Beast here (tested on 1.74): One is supposed to be able to
        // pass an uninitialized `optional` to mean unlimited, but they do not check for
        // `has_value()` in their code, causing their subsequent comparison operation to
        // misbehave. So pass highest possible value instead.
        response_data_.http_response_parser_->body_limit(numeric_limits<uint64_t>::max());

        auto &cancelled = cancelled_;
        auto &request_data = request_data_;

        auto handler = [this, cancelled, request_data](const error_code &ec, size_t num_written) {
                if (!*cancelled) {
                        WriteHeaderHandler(ec, num_written);
                }
        };

        switch (socket_mode_) {
        case SocketMode::TlsTls:
                http::async_write_header(*stream_, *request_data_.http_request_serializer_, handler);
                break;
        case SocketMode::Tls:
                http::async_write_header(
                        stream_->next_layer(), *request_data_.http_request_serializer_, handler);
                break;
        case SocketMode::Plain:
                http::async_write_header(
                        stream_->next_layer().next_layer(), *request_data_.http_request_serializer_, handler);
                break;
        }
}

void Client::WriteHeaderHandler(const error_code &ec, size_t num_written) {
        if (num_written > 0) {
                logger_.Trace("Wrote " + to_string(num_written) + " bytes of header data to stream.");
        }

        if (ec) {
                CallErrorHandler(ec, request_, header_handler_);
                return;
        }

        auto exp_has_body =
                HasBody(request_->GetHeader("Content-Length"), request_->GetHeader("Transfer-Encoding"));
        if (!exp_has_body) {
                CallErrorHandler(exp_has_body.error(), request_, header_handler_);
                return;
        }
        if (!exp_has_body.value()) {
                ReadHeader();
                return;
        }

        if (!request_->body_gen_ && !request_->async_body_gen_) {
                auto err = MakeError(BodyMissingError, "No body generator");
                CallErrorHandler(err, request_, header_handler_);
                return;
        }

        assert(!(request_->body_gen_ && request_->async_body_gen_));

        if (request_->body_gen_) {
                auto body_reader = request_->body_gen_();
                if (!body_reader) {
                        CallErrorHandler(body_reader.error(), request_, header_handler_);
                        return;
                }
                request_->body_reader_ = body_reader.value();
        } else {
                auto body_reader = request_->async_body_gen_();
                if (!body_reader) {
                        CallErrorHandler(body_reader.error(), request_, header_handler_);
                        return;
                }
                request_->async_body_reader_ = body_reader.value();
        }

        PrepareAndWriteNewBodyBuffer();
}

void Client::WriteBodyHandler(const error_code &ec, size_t num_written) {
        if (num_written > 0) {
                logger_.Trace("Wrote " + to_string(num_written) + " bytes of body data to stream.");
        }

        if (ec == http::make_error_code(http::error::need_buffer)) {
                // Write next block of the body.
                PrepareAndWriteNewBodyBuffer();
        } else if (ec) {
                CallErrorHandler(ec, request_, header_handler_);
        } else if (num_written > 0) {
                // We are still writing the body.
                WriteBody();
        } else {
                // We are ready to receive the response.
                ReadHeader();
        }
}

void Client::PrepareAndWriteNewBodyBuffer() {
        // request_->body_reader_ XOR request_->async_body_reader_
        assert(
                (request_->body_reader_ || request_->async_body_reader_)
                && !(request_->body_reader_ && request_->async_body_reader_));

        auto cancelled = cancelled_;
        auto read_handler = [this, cancelled](io::ExpectedSize read) {
                if (!*cancelled) {
                        if (!read) {
                                CallErrorHandler(read.error(), request_, header_handler_);
                                return;
                        }
                        WriteNewBodyBuffer(read.value());
                }
        };


        if (request_->body_reader_) {
                read_handler(request_->body_reader_->Read(body_buffer_.begin(), body_buffer_.end()));
        } else {
                auto err = request_->async_body_reader_->AsyncRead(
                        body_buffer_.begin(), body_buffer_.end(), read_handler);
                if (err != error::NoError) {
                        CallErrorHandler(err, request_, header_handler_);
                }
        }
}

void Client::WriteNewBodyBuffer(size_t size) {
        request_data_.http_request_->body().data = body_buffer_.data();
        request_data_.http_request_->body().size = size;

        if (size > 0) {
                request_data_.http_request_->body().more = true;
        } else {
                // Release ownership of Body reader.
                request_->body_reader_.reset();
                request_->async_body_reader_.reset();
                request_data_.http_request_->body().more = false;
        }

        WriteBody();
}

void Client::WriteBody() {
        auto &cancelled = cancelled_;
        auto &request_data = request_data_;

        auto handler = [this, cancelled, request_data](const error_code &ec, size_t num_written) {
                if (!*cancelled) {
                        WriteBodyHandler(ec, num_written);
                }
        };

        switch (socket_mode_) {
        case SocketMode::TlsTls:
                http::async_write_some(*stream_, *request_data_.http_request_serializer_, handler);
                break;
        case SocketMode::Tls:
                http::async_write_some(
                        stream_->next_layer(), *request_data_.http_request_serializer_, handler);
                break;
        case SocketMode::Plain:
                http::async_write_some(
                        stream_->next_layer().next_layer(), *request_data_.http_request_serializer_, handler);
                break;
        }
}

void Client::ReadHeader() {
        auto &cancelled = cancelled_;
        auto &response_data = response_data_;

        auto handler = [this, cancelled, response_data](const error_code &ec, size_t num_read) {
                if (!*cancelled) {
                        ReadHeaderHandler(ec, num_read);
                }
        };

        switch (socket_mode_) {
        case SocketMode::TlsTls:
                http::async_read_some(
                        *stream_,
                        *response_data_.response_buffer_,
                        *response_data_.http_response_parser_,
                        handler);
                break;
        case SocketMode::Tls:
                http::async_read_some(
                        stream_->next_layer(),
                        *response_data_.response_buffer_,
                        *response_data_.http_response_parser_,
                        handler);
                break;
        case SocketMode::Plain:
                http::async_read_some(
                        stream_->next_layer().next_layer(),
                        *response_data_.response_buffer_,
                        *response_data_.http_response_parser_,
                        handler);
                break;
        }
}

void Client::ReadHeaderHandler(const error_code &ec, size_t num_read) {
        if (num_read > 0) {
                logger_.Trace("Read " + to_string(num_read) + " bytes of header data from stream.");
        }

        if (ec) {
                CallErrorHandler(ec, request_, header_handler_);
                return;
        }

        if (!response_data_.http_response_parser_->is_header_done()) {
                ReadHeader();
                return;
        }

        if (secondary_req_) {
                HandleSecondaryRequest();
                return;
        }

        response_.reset(new IncomingResponse(*this, cancelled_));
        response_->status_code_ = response_data_.http_response_parser_->get().result_int();
        response_->status_message_ = string {response_data_.http_response_parser_->get().reason()};

        logger_.Debug(
                "Received response: " + to_string(response_->status_code_) + " "
                + response_->status_message_);

        string debug_str;
        for (auto header = response_data_.http_response_parser_->get().cbegin();
                 header != response_data_.http_response_parser_->get().cend();
                 header++) {
                response_->headers_[string {header->name_string()}] = string {header->value()};
                if (logger_.Level() >= log::LogLevel::Debug) {
                        debug_str += string {header->name_string()};
                        debug_str += ": ";
                        debug_str += string {header->value()};
                        debug_str += "\n";
                }
        }

        logger_.Debug("Received headers:\n" + debug_str);
        debug_str.clear();

        if (GetContentLength(*response_data_.http_response_parser_) == 0
                && !response_data_.http_response_parser_->chunked()) {
                auto cancelled = cancelled_;
                status_ = TransactionStatus::HeaderHandlerCalled;
                CallHandler(header_handler_);
                if (!*cancelled) {
                        status_ = TransactionStatus::Done;
                        if (response_->status_code_ != StatusCode::StatusSwitchingProtocols) {
                                // Make an exception for 101 Switching Protocols response, where the TCP connection
                                // is meant to be reused.
                                DoCancel();
                        }
                        CallHandler(body_handler_);
                }
                return;
        }

        auto cancelled = cancelled_;
        status_ = TransactionStatus::HeaderHandlerCalled;
        CallHandler(header_handler_);
        if (*cancelled) {
                return;
        }

        // We know that a body reader is required here, because of the check for body above.
        if (status_ == TransactionStatus::HeaderHandlerCalled) {
                CallErrorHandler(MakeError(BodyIgnoredError, ""), request_, body_handler_);
        }
}

void Client::HandleSecondaryRequest() {
        logger_.Debug(
                "Received proxy response: "
                + to_string(response_data_.http_response_parser_->get().result_int()) + " "
                + string {response_data_.http_response_parser_->get().reason()});

        request_ = std::move(secondary_req_);

        if (response_data_.http_response_parser_->get().result_int() != StatusOK) {
                auto err = MakeError(
                        ProxyError,
                        "Proxy returned unexpected response: "
                                + to_string(response_data_.http_response_parser_->get().result_int()) + " "
                                + string {response_data_.http_response_parser_->get().reason()});
                CallErrorHandler(err, request_, header_handler_);
                return;
        }

        if (GetContentLength(*response_data_.http_response_parser_) != 0
                || response_data_.http_response_parser_->chunked()) {
                auto err = MakeError(ProxyError, "Body not allowed in proxy response");
                CallErrorHandler(err, request_, header_handler_);
                return;
        }

        // We are connected. Now repeat the request cycle with the original request. Pretend
        // we were just connected.

        assert(request_->GetProtocol() == "https");

        // Make sure that no data is "lost" inside the buffering mechanism, since when switching to
        // a different layer, this will get out of sync.
        assert(response_data_.response_buffer_->size() == 0);

        switch (socket_mode_) {
        case SocketMode::TlsTls:
                // Should never get here, because this is the only place where TlsTls mode
                // is supposed to be turned on.
                assert(false);
                CallErrorHandler(
                        error::MakeError(
                                error::ProgrammingError,
                                "Any other mode than Tls is not valid when handling secondary request"),
                        request_,
                        header_handler_);
                break;
        case SocketMode::Tls:
                // Upgrade to TLS inside TLS.
                socket_mode_ = SocketMode::TlsTls;
                HandshakeHandler(*stream_, error_code {}, stream_->lowest_layer().remote_endpoint());
                break;
        case SocketMode::Plain:
                // Upgrade to TLS.
                socket_mode_ = SocketMode::Tls;
                HandshakeHandler(
                        stream_->next_layer(), error_code {}, stream_->lowest_layer().remote_endpoint());
                break;
        }
}

void Client::AsyncReadNextBodyPart(
        vector<uint8_t>::iterator start, vector<uint8_t>::iterator end, io::AsyncIoHandler handler) {
        assert(AtLeast(status_, TransactionStatus::ReaderCreated));

        if (status_ == TransactionStatus::ReaderCreated) {
                status_ = TransactionStatus::BodyReadingInProgress;
        }

        if (AtLeast(status_, TransactionStatus::BodyReadingFinished)) {
                auto cancelled = cancelled_;
                handler(0);
                if (!*cancelled && status_ == TransactionStatus::BodyReadingFinished) {
                        status_ = TransactionStatus::Done;
                        DoCancel();
                        CallHandler(body_handler_);
                }
                return;
        }

        reader_buf_start_ = start;
        reader_buf_end_ = end;
        reader_handler_ = handler;
        size_t read_size = end - start;
        size_t smallest = min(body_buffer_.size(), read_size);

        response_data_.http_response_parser_->get().body().data = body_buffer_.data();
        response_data_.http_response_parser_->get().body().size = smallest;
        response_data_.last_buffer_size_ = smallest;

        auto &cancelled = cancelled_;
        auto &response_data = response_data_;

        auto async_handler = [this, cancelled, response_data](const error_code &ec, size_t num_read) {
                if (!*cancelled) {
                        ReadBodyHandler(ec, num_read);
                }
        };

        switch (socket_mode_) {
        case SocketMode::TlsTls:
                http::async_read_some(
                        *stream_,
                        *response_data_.response_buffer_,
                        *response_data_.http_response_parser_,
                        async_handler);
                break;
        case SocketMode::Tls:
                http::async_read_some(
                        stream_->next_layer(),
                        *response_data_.response_buffer_,
                        *response_data_.http_response_parser_,
                        async_handler);
                break;
        case SocketMode::Plain:
                http::async_read_some(
                        stream_->next_layer().next_layer(),
                        *response_data_.response_buffer_,
                        *response_data_.http_response_parser_,
                        async_handler);
                break;
        }
}

void Client::ReadBodyHandler(error_code ec, size_t num_read) {
        if (num_read > 0) {
                logger_.Trace("Read " + to_string(num_read) + " bytes of body data from stream.");
        }

        if (ec == http::make_error_code(http::error::need_buffer)) {
                // This can be ignored. We always reset the buffer between reads anyway.
                ec = error_code();
        }

        assert(reader_handler_);

        if (response_data_.http_response_parser_->is_done()) {
                status_ = TransactionStatus::BodyReadingFinished;
        }

        auto cancelled = cancelled_;

        if (ec) {
                auto err = error::Error(ec.default_error_condition(), "Could not read body");
                reader_handler_(expected::unexpected(err));
                if (!*cancelled) {
                        CallErrorHandler(ec, request_, body_handler_);
                }
                return;
        }

        // The num_read from above includes out of band payload data, such as chunk headers, which
        // we are not interested in. So we need to calculate the payload size from the remaining
        // buffer space.
        size_t payload_read =
                response_data_.last_buffer_size_ - response_data_.http_response_parser_->get().body().size;

        size_t buf_size = reader_buf_end_ - reader_buf_start_;
        size_t smallest = min(payload_read, buf_size);

        if (smallest == 0) {
                // We read nothing, which can happen if all we read was a chunk header. We cannot
                // return 0 to the handler however, because in `io::Reader` context this means
                // EOF. So just repeat the request instead, until we get actual payload data.
                AsyncReadNextBodyPart(reader_buf_start_, reader_buf_end_, reader_handler_);
        } else {
                copy_n(body_buffer_.begin(), smallest, reader_buf_start_);
                reader_handler_(smallest);
        }
}

void Client::Cancel() {
        auto cancelled = cancelled_;

        if (!*cancelled) {
                auto err =
                        error::Error(make_error_condition(errc::operation_canceled), "HTTP request cancelled");
                switch (status_) {
                case TransactionStatus::None:
                        CallErrorHandler(err, request_, header_handler_);
                        break;
                case TransactionStatus::HeaderHandlerCalled:
                case TransactionStatus::ReaderCreated:
                case TransactionStatus::BodyReadingInProgress:
                case TransactionStatus::BodyReadingFinished:
                        CallErrorHandler(err, request_, body_handler_);
                        break;
                case TransactionStatus::Replying:
                case TransactionStatus::SwitchingProtocol:
                        // Not used by client.
                        assert(false);
                        break;
                case TransactionStatus::BodyHandlerCalled:
                case TransactionStatus::Done:
                        break;
                }
        }

        if (!*cancelled) {
                DoCancel();
        }
}

void Client::DoCancel() {
        resolver_.cancel();
        if (stream_) {
                stream_->lowest_layer().cancel();
                stream_->lowest_layer().close();
                stream_.reset();
        }

        // Reset logger to no connection.
        logger_ = log::Logger(logger_name_);

        // Set cancel state and then make a new one. Those who are interested should have their own
        // pointer to the old one.
        *cancelled_ = true;
        cancelled_ = make_shared<bool>(true);
}

Stream::Stream(Server &server) :
        server_ {server},
        logger_ {"http"},
        cancelled_(make_shared<bool>(true)),
        socket_(server_.GetAsioIoContext(server_.event_loop_)),
        body_buffer_(HTTP_BEAST_BUFFER_SIZE) {
        request_data_.request_buffer_ = make_shared<beast::flat_buffer>();

        // This is equivalent to:
        //   request_data_.request_buffer_.reserve(body_buffer_.size());
        // but compatible with Boost 1.67.
        request_data_.request_buffer_->prepare(
                body_buffer_.size() - request_data_.request_buffer_->size());

        request_data_.http_request_parser_ = make_shared<http::request_parser<http::buffer_body>>();

        // Don't enforce limits. Since we stream everything, limits don't generally apply, and if
        // they do, they should be handled higher up in the application logic.
        //
        // Note: There is a bug in Beast here (tested on 1.74): One is supposed to be able to pass
        // an uninitialized `optional` to mean unlimited, but they do not check for `has_value()` in
        // their code, causing their subsequent comparison operation to misbehave. So pass highest
        // possible value instead.
        request_data_.http_request_parser_->body_limit(numeric_limits<uint64_t>::max());
}

Stream::~Stream() {
        DoCancel();
}

void Stream::Cancel() {
        auto cancelled = cancelled_;

        if (!*cancelled) {
                auto err =
                        error::Error(make_error_condition(errc::operation_canceled), "HTTP response cancelled");
                switch (status_) {
                case TransactionStatus::None:
                        CallErrorHandler(err, request_, server_.header_handler_);
                        break;
                case TransactionStatus::HeaderHandlerCalled:
                case TransactionStatus::ReaderCreated:
                case TransactionStatus::BodyReadingInProgress:
                case TransactionStatus::BodyReadingFinished:
                        CallErrorHandler(err, request_, server_.body_handler_);
                        break;
                case TransactionStatus::BodyHandlerCalled:
                        // In between body handler and reply finished. No one to handle the status
                        // here.
                        server_.RemoveStream(shared_from_this());
                        break;
                case TransactionStatus::Replying:
                        CallErrorHandler(err, request_, reply_finished_handler_);
                        break;
                case TransactionStatus::SwitchingProtocol:
                        CallErrorHandler(err, request_, switch_protocol_handler_);
                        break;
                case TransactionStatus::Done:
                        break;
                }
        }

        if (!*cancelled) {
                DoCancel();
        }
}

void Stream::DoCancel() {
        if (socket_.is_open()) {
                socket_.cancel();
                socket_.close();
        }

        // Set cancel state and then make a new one. Those who are interested should have their own
        // pointer to the old one.
        *cancelled_ = true;
        cancelled_ = make_shared<bool>(true);
}

void Stream::CallErrorHandler(const error_code &ec, const RequestPtr &req, RequestHandler handler) {
        CallErrorHandler(error::Error(ec.default_error_condition(), ""), req, handler);
}

void Stream::CallErrorHandler(
        const error::Error &err, const RequestPtr &req, RequestHandler handler) {
        status_ = TransactionStatus::Done;
        DoCancel();
        handler(expected::unexpected(err.WithContext(
                req->address_.host + ": " + MethodToString(req->method_) + " " + request_->GetPath())));

        server_.RemoveStream(shared_from_this());
}

void Stream::CallErrorHandler(
        const error_code &ec, const IncomingRequestPtr &req, IdentifiedRequestHandler handler) {
        CallErrorHandler(error::Error(ec.default_error_condition(), ""), req, handler);
}

void Stream::CallErrorHandler(
        const error::Error &err, const IncomingRequestPtr &req, IdentifiedRequestHandler handler) {
        status_ = TransactionStatus::Done;
        DoCancel();
        handler(
                req,
                err.WithContext(
                        req->address_.host + ": " + MethodToString(req->method_) + " " + request_->GetPath()));

        server_.RemoveStream(shared_from_this());
}

void Stream::CallErrorHandler(
        const error_code &ec, const RequestPtr &req, ReplyFinishedHandler handler) {
        CallErrorHandler(error::Error(ec.default_error_condition(), ""), req, handler);
}

void Stream::CallErrorHandler(
        const error::Error &err, const RequestPtr &req, ReplyFinishedHandler handler) {
        status_ = TransactionStatus::Done;
        DoCancel();
        handler(err.WithContext(
                req->address_.host + ": " + MethodToString(req->method_) + " " + request_->GetPath()));

        server_.RemoveStream(shared_from_this());
}

void Stream::CallErrorHandler(
        const error_code &ec, const RequestPtr &req, SwitchProtocolHandler handler) {
        CallErrorHandler(error::Error(ec.default_error_condition(), ""), req, handler);
}

void Stream::CallErrorHandler(
        const error::Error &err, const RequestPtr &req, SwitchProtocolHandler handler) {
        status_ = TransactionStatus::Done;
        DoCancel();
        handler(expected::unexpected(err.WithContext(
                req->address_.host + ": " + MethodToString(req->method_) + " " + request_->GetPath())));

        server_.RemoveStream(shared_from_this());
}

void Stream::AcceptHandler(const error_code &ec) {
        if (ec) {
                log::Error("Error while accepting HTTP connection: " + ec.message());
                return;
        }

        auto ip = socket_.remote_endpoint().address().to_string();

        // Use IP as context for logging.
        logger_ = log::Logger("http_server").WithFields(log::LogField("ip", ip));

        logger_.Debug("Accepted connection.");

        request_.reset(new IncomingRequest(*this, cancelled_));

        request_->address_.host = ip;

        *cancelled_ = false;

        ReadHeader();
}

void Stream::ReadHeader() {
        auto &cancelled = cancelled_;
        auto &request_data = request_data_;

        http::async_read_some(
                socket_,
                *request_data_.request_buffer_,
                *request_data_.http_request_parser_,
                [this, cancelled, request_data](const error_code &ec, size_t num_read) {
                        if (!*cancelled) {
                                ReadHeaderHandler(ec, num_read);
                        }
                });
}

void Stream::ReadHeaderHandler(const error_code &ec, size_t num_read) {
        if (num_read > 0) {
                logger_.Trace("Read " + to_string(num_read) + " bytes of header data from stream.");
        }

        if (ec) {
                CallErrorHandler(ec, request_, server_.header_handler_);
                return;
        }

        if (!request_data_.http_request_parser_->is_header_done()) {
                ReadHeader();
                return;
        }

        auto method_result = BeastVerbToMethod(
                request_data_.http_request_parser_->get().base().method(),
                string {request_data_.http_request_parser_->get().base().method_string()});
        if (!method_result) {
                CallErrorHandler(method_result.error(), request_, server_.header_handler_);
                return;
        }
        request_->method_ = method_result.value();
        request_->address_.path = string(request_data_.http_request_parser_->get().base().target());

        logger_ = logger_.WithFields(log::LogField("path", request_->address_.path));

        string debug_str;
        for (auto header = request_data_.http_request_parser_->get().cbegin();
                 header != request_data_.http_request_parser_->get().cend();
                 header++) {
                request_->headers_[string {header->name_string()}] = string {header->value()};
                if (logger_.Level() >= log::LogLevel::Debug) {
                        debug_str += string {header->name_string()};
                        debug_str += ": ";
                        debug_str += string {header->value()};
                        debug_str += "\n";
                }
        }

        logger_.Debug("Received headers:\n" + debug_str);
        debug_str.clear();

        if (GetContentLength(*request_data_.http_request_parser_) == 0
                && !request_data_.http_request_parser_->chunked()) {
                auto cancelled = cancelled_;
                status_ = TransactionStatus::HeaderHandlerCalled;
                server_.header_handler_(request_);
                if (!*cancelled) {
                        status_ = TransactionStatus::BodyHandlerCalled;
                        CallBodyHandler();
                }
                return;
        }

        assert(!request_data_.http_request_parser_->is_done());

        auto cancelled = cancelled_;
        status_ = TransactionStatus::HeaderHandlerCalled;
        server_.header_handler_(request_);
        if (*cancelled) {
                return;
        }

        // We know that a body reader is required here, because of the check for body above.
        if (status_ == TransactionStatus::HeaderHandlerCalled) {
                CallErrorHandler(MakeError(BodyIgnoredError, ""), request_, server_.body_handler_);
        }
}

void Stream::AsyncReadNextBodyPart(
        vector<uint8_t>::iterator start, vector<uint8_t>::iterator end, io::AsyncIoHandler handler) {
        assert(AtLeast(status_, TransactionStatus::ReaderCreated));

        if (status_ == TransactionStatus::ReaderCreated) {
                status_ = TransactionStatus::BodyReadingInProgress;
        }

        if (status_ != TransactionStatus::BodyReadingInProgress) {
                auto cancelled = cancelled_;
                handler(0);
                if (!*cancelled && status_ == TransactionStatus::BodyReadingFinished) {
                        status_ = TransactionStatus::BodyHandlerCalled;
                        CallBodyHandler();
                }
                return;
        }

        reader_buf_start_ = start;
        reader_buf_end_ = end;
        reader_handler_ = handler;
        size_t read_size = end - start;
        size_t smallest = min(body_buffer_.size(), read_size);

        request_data_.http_request_parser_->get().body().data = body_buffer_.data();
        request_data_.http_request_parser_->get().body().size = smallest;
        request_data_.last_buffer_size_ = smallest;

        auto &cancelled = cancelled_;
        auto &request_data = request_data_;

        http::async_read_some(
                socket_,
                *request_data_.request_buffer_,
                *request_data_.http_request_parser_,
                [this, cancelled, request_data](const error_code &ec, size_t num_read) {
                        if (!*cancelled) {
                                ReadBodyHandler(ec, num_read);
                        }
                });
}

void Stream::ReadBodyHandler(error_code ec, size_t num_read) {
        if (num_read > 0) {
                logger_.Trace("Read " + to_string(num_read) + " bytes of body data from stream.");
        }

        if (ec == http::make_error_code(http::error::need_buffer)) {
                // This can be ignored. We always reset the buffer between reads anyway.
                ec = error_code();
        }

        assert(reader_handler_);

        if (request_data_.http_request_parser_->is_done()) {
                status_ = TransactionStatus::BodyReadingFinished;
        }

        auto cancelled = cancelled_;

        if (ec) {
                auto err = error::Error(ec.default_error_condition(), "Could not read body");
                reader_handler_(expected::unexpected(err));
                if (!*cancelled) {
                        CallErrorHandler(ec, request_, server_.body_handler_);
                }
                return;
        }

        // The num_read from above includes out of band payload data, such as chunk headers, which
        // we are not interested in. So we need to calculate the payload size from the remaining
        // buffer space.
        size_t payload_read =
                request_data_.last_buffer_size_ - request_data_.http_request_parser_->get().body().size;

        size_t buf_size = reader_buf_end_ - reader_buf_start_;
        size_t smallest = min(payload_read, buf_size);

        if (smallest == 0) {
                // We read nothing, which can happen if all we read was a chunk header. We cannot
                // return 0 to the handler however, because in `io::Reader` context this means
                // EOF. So just repeat the request instead, until we get actual payload data.
                AsyncReadNextBodyPart(reader_buf_start_, reader_buf_end_, reader_handler_);
        } else {
                copy_n(body_buffer_.begin(), smallest, reader_buf_start_);
                reader_handler_(smallest);
        }
}

void Stream::AsyncReply(ReplyFinishedHandler reply_finished_handler) {
        SetupResponse();

        reply_finished_handler_ = reply_finished_handler;

        auto &cancelled = cancelled_;
        auto &response_data = response_data_;

        http::async_write_header(
                socket_,
                *response_data_.http_response_serializer_,
                [this, cancelled, response_data](const error_code &ec, size_t num_written) {
                        if (!*cancelled) {
                                WriteHeaderHandler(ec, num_written);
                        }
                });
}

void Stream::SetupResponse() {
        auto response = maybe_response_.lock();
        // Only called from existing responses, so this should always be true.
        assert(response);

        assert(status_ == TransactionStatus::BodyHandlerCalled);
        status_ = TransactionStatus::Replying;

        // From here on we take shared ownership.
        response_ = response;

        response_data_.http_response_ = make_shared<http::response<http::buffer_body>>();

        for (const auto &header : response->headers_) {
                response_data_.http_response_->base().set(header.first, header.second);
        }

        response_data_.http_response_->result(response->GetStatusCode());
        response_data_.http_response_->reason(response->GetStatusMessage());

        response_data_.http_response_serializer_ =
                make_shared<http::response_serializer<http::buffer_body>>(*response_data_.http_response_);
}

void Stream::WriteHeaderHandler(const error_code &ec, size_t num_written) {
        if (num_written > 0) {
                logger_.Trace("Wrote " + to_string(num_written) + " bytes of header data to stream.");
        }

        if (ec) {
                CallErrorHandler(ec, request_, reply_finished_handler_);
                return;
        }

        auto exp_has_body =
                HasBody(response_->GetHeader("Content-Length"), response_->GetHeader("Transfer-Encoding"));
        if (!exp_has_body) {
                CallErrorHandler(exp_has_body.error(), request_, reply_finished_handler_);
                return;
        }
        if (!exp_has_body.value()) {
                FinishReply();
                return;
        }

        if (!response_->body_reader_ && !response_->async_body_reader_) {
                auto err = MakeError(BodyMissingError, "No body reader");
                CallErrorHandler(err, request_, reply_finished_handler_);
                return;
        }

        PrepareAndWriteNewBodyBuffer();
}

void Stream::PrepareAndWriteNewBodyBuffer() {
        // response_->body_reader_ XOR response_->async_body_reader_
        assert(
                (response_->body_reader_ || response_->async_body_reader_)
                && !(response_->body_reader_ && response_->async_body_reader_));

        auto read_handler = [this](io::ExpectedSize read) {
                if (!read) {
                        CallErrorHandler(read.error(), request_, reply_finished_handler_);
                        return;
                }
                WriteNewBodyBuffer(read.value());
        };

        if (response_->body_reader_) {
                read_handler(response_->body_reader_->Read(body_buffer_.begin(), body_buffer_.end()));
        } else {
                auto err = response_->async_body_reader_->AsyncRead(
                        body_buffer_.begin(), body_buffer_.end(), read_handler);
                if (err != error::NoError) {
                        CallErrorHandler(err, request_, reply_finished_handler_);
                }
        }
}

void Stream::WriteNewBodyBuffer(size_t size) {
        response_data_.http_response_->body().data = body_buffer_.data();
        response_data_.http_response_->body().size = size;

        if (size > 0) {
                response_data_.http_response_->body().more = true;
        } else {
                response_data_.http_response_->body().more = false;
        }

        WriteBody();
}

void Stream::WriteBody() {
        auto &cancelled = cancelled_;
        auto &response_data = response_data_;

        http::async_write_some(
                socket_,
                *response_data_.http_response_serializer_,
                [this, cancelled, response_data](const error_code &ec, size_t num_written) {
                        if (!*cancelled) {
                                WriteBodyHandler(ec, num_written);
                        }
                });
}

void Stream::WriteBodyHandler(const error_code &ec, size_t num_written) {
        if (num_written > 0) {
                logger_.Trace("Wrote " + to_string(num_written) + " bytes of body data to stream.");
        }

        if (ec == http::make_error_code(http::error::need_buffer)) {
                // Write next body block.
                PrepareAndWriteNewBodyBuffer();
        } else if (ec) {
                CallErrorHandler(ec, request_, reply_finished_handler_);
        } else if (num_written > 0) {
                // We are still writing the body.
                WriteBody();
        } else {
                // We are finished.
                FinishReply();
        }
}

void Stream::FinishReply() {
        // We are done.
        status_ = TransactionStatus::Done;
        DoCancel();
        // Release ownership of Body reader.
        response_->body_reader_.reset();
        response_->async_body_reader_.reset();
        reply_finished_handler_(error::NoError);
        server_.RemoveStream(shared_from_this());
}

error::Error Stream::AsyncSwitchProtocol(SwitchProtocolHandler handler) {
        SetupResponse();

        switch_protocol_handler_ = handler;
        status_ = TransactionStatus::SwitchingProtocol;

        auto &cancelled = cancelled_;
        auto &response_data = response_data_;

        http::async_write_header(
                socket_,
                *response_data_.http_response_serializer_,
                [this, cancelled, response_data](const error_code &ec, size_t num_written) {
                        if (!*cancelled) {
                                SwitchingProtocolHandler(ec, num_written);
                        }
                });

        return error::NoError;
}

void Stream::SwitchingProtocolHandler(error_code ec, size_t num_written) {
        if (num_written > 0) {
                logger_.Trace("Wrote " + to_string(num_written) + " bytes of header data to stream.");
        }

        if (ec) {
                CallErrorHandler(ec, request_, switch_protocol_handler_);
                return;
        }

        auto socket = make_shared<RawSocket<tcp::socket>>(
                make_shared<tcp::socket>(std::move(socket_)), request_data_.request_buffer_);

        auto switch_protocol_handler = switch_protocol_handler_;

        // Rest of the connection is done directly on the socket, set cancelled_ but don't close it.
        *cancelled_ = true;
        cancelled_ = make_shared<bool>(true);
        server_.RemoveStream(shared_from_this());

        switch_protocol_handler(socket);
}

void Stream::CallBodyHandler() {
        // Get a pointer to ourselves. This is just in case the body handler make a response, which
        // it immediately destroys, which would destroy this stream as well. At the end of this
        // function, it's ok to destroy it.
        auto stream_ref = shared_from_this();

        server_.body_handler_(request_, error::NoError);

        // MakeResponse() should have been called inside body handler. It can use this to generate a
        // response, either immediately, or later. Therefore it should still exist, otherwise the
        // request has not been handled correctly.
        auto response = maybe_response_.lock();
        if (!response) {
                logger_.Error("Handler produced no response. Closing stream prematurely.");
                *cancelled_ = true;
                cancelled_ = make_shared<bool>(true);
                server_.RemoveStream(shared_from_this());
        }
}

Server::Server(const ServerConfig &server, events::EventLoop &event_loop) :
        event_loop_ {event_loop},
        acceptor_(GetAsioIoContext(event_loop_)) {
}

Server::~Server() {
        Cancel();
}

error::Error Server::AsyncServeUrl(
        const string &url, RequestHandler header_handler, RequestHandler body_handler) {
        return AsyncServeUrl(
                url, header_handler, [body_handler](IncomingRequestPtr req, error::Error err) {
                        if (err != error::NoError) {
                                body_handler(expected::unexpected(err));
                        } else {
                                body_handler(req);
                        }
                });
}

error::Error Server::AsyncServeUrl(
        const string &url, RequestHandler header_handler, IdentifiedRequestHandler body_handler) {
        auto err = BreakDownUrl(url, address_);
        if (error::NoError != err) {
                return MakeError(InvalidUrlError, "Could not parse URL " + url + ": " + err.String());
        }

        if (address_.protocol != "http") {
                return error::Error(make_error_condition(errc::protocol_not_supported), address_.protocol);
        }

        if (address_.path.size() > 0 && address_.path != "/") {
                return MakeError(InvalidUrlError, "URLs with paths are not supported when listening.");
        }

        boost::system::error_code ec;
        auto address = asio::ip::make_address(address_.host, ec);
        if (ec) {
                return error::Error(
                        ec.default_error_condition(),
                        "Could not construct endpoint from address " + address_.host);
        }

        asio::ip::tcp::endpoint endpoint(address, address_.port);

        ec.clear();
        acceptor_.open(endpoint.protocol(), ec);
        if (ec) {
                return error::Error(ec.default_error_condition(), "Could not open acceptor");
        }

        // Allow address reuse, otherwise we can't re-bind later.
        ec.clear();
        acceptor_.set_option(asio::socket_base::reuse_address(true), ec);
        if (ec) {
                return error::Error(ec.default_error_condition(), "Could not set socket options");
        }

        ec.clear();
        acceptor_.bind(endpoint, ec);
        if (ec) {
                return error::Error(ec.default_error_condition(), "Could not bind socket");
        }

        ec.clear();
        acceptor_.listen(asio::socket_base::max_listen_connections, ec);
        if (ec) {
                return error::Error(ec.default_error_condition(), "Could not start listening");
        }

        header_handler_ = header_handler;
        body_handler_ = body_handler;

        PrepareNewStream();

        return error::NoError;
}

void Server::Cancel() {
        if (acceptor_.is_open()) {
                acceptor_.cancel();
                acceptor_.close();
        }
        streams_.clear();
}

uint16_t Server::GetPort() const {
        return acceptor_.local_endpoint().port();
}

string Server::GetUrl() const {
        return "http://127.0.0.1:" + to_string(GetPort());
}

ExpectedOutgoingResponsePtr Server::MakeResponse(IncomingRequestPtr req) {
        if (*req->cancelled_) {
                return expected::unexpected(MakeError(StreamCancelledError, "Cannot make response"));
        }
        OutgoingResponsePtr response {new OutgoingResponse(req->stream_, req->cancelled_)};
        req->stream_.maybe_response_ = response;
        return response;
}

error::Error Server::AsyncReply(
        OutgoingResponsePtr resp, ReplyFinishedHandler reply_finished_handler) {
        if (*resp->cancelled_) {
                return MakeError(StreamCancelledError, "Cannot send response");
        }

        resp->stream_.AsyncReply(reply_finished_handler);
        return error::NoError;
}

io::ExpectedAsyncReaderPtr Server::MakeBodyAsyncReader(IncomingRequestPtr req) {
        if (*req->cancelled_) {
                return expected::unexpected(MakeError(StreamCancelledError, "Cannot make body reader"));
        }

        auto &stream = req->stream_;
        if (stream.status_ != TransactionStatus::HeaderHandlerCalled) {
                return expected::unexpected(error::Error(
                        make_error_condition(errc::operation_in_progress),
                        "MakeBodyAsyncReader called while reading is in progress"));
        }

        if (GetContentLength(*stream.request_data_.http_request_parser_) == 0
                && !stream.request_data_.http_request_parser_->chunked()) {
                return expected::unexpected(MakeError(BodyMissingError, "Request does not contain a body"));
        }

        stream.status_ = TransactionStatus::ReaderCreated;
        return make_shared<BodyAsyncReader<Stream>>(stream, req->cancelled_);
}

error::Error Server::AsyncSwitchProtocol(OutgoingResponsePtr resp, SwitchProtocolHandler handler) {
        return resp->stream_.AsyncSwitchProtocol(handler);
}

void Server::PrepareNewStream() {
        StreamPtr new_stream {new Stream(*this)};
        streams_.insert(new_stream);
        AsyncAccept(new_stream);
}

void Server::AsyncAccept(StreamPtr stream) {
        acceptor_.async_accept(stream->socket_, [this, stream](const error_code &ec) {
                if (ec) {
                        if (ec != errc::operation_canceled) {
                                log::Error("Could not accept connection: " + ec.message());
                        }
                        return;
                }

                stream->AcceptHandler(ec);

                this->PrepareNewStream();
        });
}

void Server::RemoveStream(StreamPtr stream) {
        streams_.erase(stream);

        stream->DoCancel();
}

} // namespace http
} // namespace common
} // namespace mender

mendersoftware / mender / 1726099042

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