ruby-grape / grape
97%
master: 97%

Repo Added 04 Apr 2013 06:08AM UTC

Committed 29 Aug 2026 12:31PM UTC coverage: 96.998% (+0.01%) from 96.988%

Committed by

Commit Message

Add Grape::PrecompiledJson for bodies that are already JSON

The JSON formatters encode whatever the endpoint returned, so a String holding
pre-rendered JSON -- a blob cached in Redis, a json_agg column read straight
from Postgres, output from another serializer -- comes back encoded a second
time: '{"a":1}' becomes "\"{\\\"a\\\":1}\"".

The workarounds for this were accidents of implementation rather than
documented behaviour: :serializable_hash happens to return a String untouched,
and :binary has no formatter class at all, so it falls through to
DEFAULT_LAMBDA_FORMATTER -- but answers application/octet-stream.

PrecompiledJson marks one body as already rendered:

  get '/cached' do
    body Grape::PrecompiledJson.new(Rails.cache.read('payload'))
  end

Formatter::Json and Formatter::SerializableHash return it verbatim; everything
unwrapped encodes exactly as before. The opt-in is per response rather than per
API on purpose. A formatter that passed every String through could not tell
pre-rendered JSON from an endpoint returning 'hello', and would answer with a
bare hello -- invalid JSON, silently, and not something a type check can catch
since a String is precisely what it is looking for. A marker never has to
guess.

An Array is joined without its members being parsed, which is what makes a
cached collection cheap: N rendered blobs are spliced together rather than
round-tripped. This is load-bearing rather than a convenience -- handing an
encoder an array of wrappers renders them as ordinary objects
([{"value":"..."}]), so the join has to happen here. Array#join calls to_s, so
members may themselves be PrecompiledJson.

For the same reason a wrapper is only valid as the whole body; nesting one
inside a Hash is documented as unsupported, since no encoder knows to unwrap
it. A value that is neither String nor Array raises
Grape::Exceptions::InvalidFormatter, which the formatter middleware already
rescues into a 500, rather than letting a body Rack ca... (continued)

Coverage Stats

1247 of 1338 branches covered (93.2%)

Branch coverage included in aggregate %.

10 of 10 new or added lines in 3 files covered. (100.0%)

3891 of 3959 relevant lines covered (98.28%)

27154.01 hits per line

3959 RELEVANT LINES 3891 COVERED LINES

27154.01 HITS PER LINE

Builds	Branch	Commit	Type	Ran	Committer	Via	Coverage
33252737439	precompiled_json	Add Grape::PrecompiledJson for bodies that are already JSON The JSON formatters encode whatever the endpoint returned, so a String holding pre-rendered JSON -- a blob cached in Redis, a json_agg column read straight from Postgres, output from ano...	Pull #2869	29 Aug 2026 12:32PM UTC	ericproulx	github	97.0
33252712683	precompiled_json	Add Grape::PrecompiledJson for bodies that are already JSON The JSON formatters encode whatever the endpoint returned, so a String holding pre-rendered JSON -- a blob cached in Redis, a json_agg column read straight from Postgres, output from ano...	push	29 Aug 2026 12:31PM UTC	ericproulx	github	97.0

ruby-grape / grape
97%
master: 97%

ruby-grape / grape 97% master: 97%

README BADGES x

Markdown

Textile

RDoc

HTML

Rst

CHANGE BRANCH x

Relevant lines Covered

Source Files on precompiled_json

Recent builds

ruby-grape / grape
97%
master: 97%

README BADGES
x

CHANGE BRANCH
x