51847fda-a900-452b-a861-1f0740800a77

const debug = require('debug')('iiif-processor:main');
const mime = require('mime-types');
const path = require('path');
const sharp = require('sharp');
const { Operations } = require('./transform');
const IIIFError = require('./error');
const IIIFVersions = require('./versions');

const fixupSlashes = (path, leaveOne) => {
  const replacement = leaveOne ? '/' : '';
  return path?.replace(/^\/*/, replacement).replace(/\/*$/, replacement);
};

class Processor {
  constructor (version, url, streamResolver, opts = {}) {
    if (typeof streamResolver !== 'function') {
      throw new IIIFError('streamResolver option must be specified');
    }

    if (opts.max?.height && !opts.max?.width) {
      throw new IIIFError('maxHeight cannot be specified without maxWidth');
    };

    const defaults = {
      pathPrefix: `/iiif/${version}/`,
      dimensionFunction: this.defaultDimensionFunction,
      density: null
    };

    this
      .setOpts({ ...defaults, ...opts })
      .initialize(version, url, streamResolver);
  }

  setOpts (opts) {
    this.errorClass = IIIFError;
    this.dimensionFunction = opts.dimensionFunction;
    this.max = { ...opts.max };
    this.includeMetadata = !!opts.includeMetadata;
    this.density = opts.density;
    this.pathPrefix = fixupSlashes(opts.pathPrefix, true);
    this.sharpOptions = { ...opts.sharpOptions };

    return this;
  }

  parseUrl (url) {
    const parser = new RegExp(`(?<baseUrl>https?://[^/]+${this.pathPrefix})(?<path>.+)$`);
    const { baseUrl, path } = parser.exec(url).groups;
    const result = this.Implementation.Calculator.parsePath(path);
    result.baseUrl = baseUrl;

    return result;
  }

  initialize (version, url, streamResolver) {
    this.version = version;
    this.Implementation = IIIFVersions[this.version];

    const params = this.parseUrl(url);
    debug('Parsed URL: %j', params);
    Object.assign(this, params);
    this.streamResolver = streamResolver;

    if (this.quality && this.format) {
      this.filename = [this.quality, this.format].join('.');
    } else if (this.info) {
      this.filename = 'info.json';
    }
    return this;
  }

  async withStream ({ id, baseUrl }, callback) {
    debug('Requesting stream for %s', id);
    if (this.streamResolver.length === 2) {
      return await this.streamResolver({ id, baseUrl }, callback);
    } else {
      const stream = await this.streamResolver({ id, baseUrl });
      return await callback(stream);
    }
  }

  async defaultDimensionFunction ({ id, baseUrl }) {
    const result = [];
    let page = 0;
    const target = sharp({ page });

    return await this.withStream({ id, baseUrl }, async (stream) => {
      stream.pipe(target);
      const { width, height, pages } = await target.metadata();
      result.push({ width, height });
      for (page += 1; page < pages; page++) {
        const scale = 1 / 2 ** page;
        result.push({ width: Math.floor(width * scale), height: Math.floor(height * scale) });
      }
      return result;
    });
  }

  async dimensions () {
    const fallback = this.dimensionFunction !== this.defaultDimensionFunction;

    if (!this.sizeInfo) {
      debug('Attempting to use dimensionFunction to retrieve dimensions for %j', this.id);
      const params = { id: this.id, baseUrl: this.baseUrl };
      let dims = await this.dimensionFunction(params);
      if (fallback && !dims) {
        const warning =
          'Unable to get dimensions for %s using custom function. Falling back to sharp.metadata().';
        debug(warning, this.id);
        console.warn(warning, this.id);
        dims = await this.defaultDimensionFunction(params);
      }
      if (!Array.isArray(dims)) dims = [dims];
      this.sizeInfo = dims;
    }
    return this.sizeInfo;
  }

  async infoJson () {
    const [dim] = await this.dimensions();
    const sizes = [];
    for (let size = [dim.width, dim.height]; size.every((x) => x >= 64); size = size.map((x) => Math.floor(x / 2))) {
      sizes.push({ width: size[0], height: size[1] });
    }

    const id = [fixupSlashes(this.baseUrl), fixupSlashes(this.id)].join('/');
    const doc = this.Implementation.infoDoc({ id, ...dim, sizes, max: this.max });
    for (const prop in doc) {
      if (doc[prop] === null || doc[prop] === undefined) delete doc[prop];
    }

    // Serialize sets as arrays
    const body = JSON.stringify(doc, (_key, value) =>
      value?.constructor === Set ? [...value] : value
    );
    return { contentType: 'application/json', body };
  }

  operations (dim) {
    const { sharpOptions: sharp, max } = this;
    return new Operations(this.version, dim, { sharp, max })
      .region(this.region)
      .size(this.size)
      .rotation(this.rotation)
      .quality(this.quality)
      .format(this.format, this.density)
      .withMetadata(this.includeMetadata);
  }

  async iiifImage () {
    const dim = await this.dimensions();
    const operations = this.operations(dim);
    const pipeline = await operations.pipeline();

    const result = await this.withStream({ id: this.id, baseUrl: this.baseUrl }, async (stream) => {
      debug('piping stream to pipeline');
      const transformed = await stream.pipe(pipeline);
      debug('converting to buffer');
      return await transformed.toBuffer();
    });
    debug('returning %d bytes', result.length);
    debug('baseUrl', this.baseUrl);

    const canonicalUrl = new URL(path.join(this.id, operations.canonicalPath()), this.baseUrl);
    return {
      canonicalLink: canonicalUrl.toString(),
      profileLink: this.Implementation.profileLink,
      contentType: mime.lookup(this.format),
      body: result
    };
  }

  async execute () {
    if (this.filename === 'info.json') {
      return await this.infoJson();
    } else {
      return await this.iiifImage();
    }
  }
}

module.exports = Processor;

1	const debug = require('debug')('iiif-processor:main');	5✔
2	const mime = require('mime-types');	5✔
3	const path = require('path');	5✔
4	const sharp = require('sharp');	5✔
5	const { Operations } = require('./transform');	5✔
6	const IIIFError = require('./error');	5✔
7	const IIIFVersions = require('./versions');	5✔
8
9	const fixupSlashes = (path, leaveOne) => {	5✔
10	const replacement = leaveOne ? '/' : '';	103✔
11	return path?.replace(/^\//, replacement).replace(/\/$/, replacement);	103✔
12	};
13
14	class Processor {
15	constructor (version, url, streamResolver, opts = {}) {	73✔
16	if (typeof streamResolver !== 'function') {	98✔
17	throw new IIIFError('streamResolver option must be specified');	2✔
18	}
19
20	if (opts.max?.height && !opts.max?.width) {	96✔
21	throw new IIIFError('maxHeight cannot be specified without maxWidth');	1✔
22	};
23
24	const defaults = {	95✔
25	pathPrefix: `/iiif/${version}/`,
26	dimensionFunction: this.defaultDimensionFunction,
27	density: null
28	};
29
30	this	95✔
31	.setOpts({ ...defaults, ...opts })
32	.initialize(version, url, streamResolver);
33	}
34
35	setOpts (opts) {
36	this.errorClass = IIIFError;	95✔
37	this.dimensionFunction = opts.dimensionFunction;	95✔
38	this.max = { ...opts.max };	95✔
39	this.includeMetadata = !!opts.includeMetadata;	95✔
40	this.density = opts.density;	95✔
41	this.pathPrefix = fixupSlashes(opts.pathPrefix, true);	95✔
42	this.sharpOptions = { ...opts.sharpOptions };	95✔
43
44	return this;	95✔
45	}
46
47	parseUrl (url) {
48	const parser = new RegExp(`(?<baseUrl>https?://[^/]+${this.pathPrefix})(?<path>.+)$`);	95✔
49	const { baseUrl, path } = parser.exec(url).groups;	95✔
50	const result = this.Implementation.Calculator.parsePath(path);	95✔
51	result.baseUrl = baseUrl;	93✔
52
53	return result;	93✔
54	}
55
56	initialize (version, url, streamResolver) {
57	this.version = version;	95✔
58	this.Implementation = IIIFVersions[this.version];	95✔
59
60	const params = this.parseUrl(url);	95✔
61	debug('Parsed URL: %j', params);	93✔
62	Object.assign(this, params);	93✔
63	this.streamResolver = streamResolver;	93✔
64
65	if (this.quality && this.format) {	93✔
66	this.filename = [this.quality, this.format].join('.');	89✔
67	} else if (this.info) {	4!
68	this.filename = 'info.json';	4✔
69	}
70	return this;	93✔
71	}
72
73	async withStream ({ id, baseUrl }, callback) {
74	debug('Requesting stream for %s', id);	132✔
75	if (this.streamResolver.length === 2) {	132✔
76	return await this.streamResolver({ id, baseUrl }, callback);	4✔
77	} else {
78	const stream = await this.streamResolver({ id, baseUrl });	128✔
79	return await callback(stream);	128✔
80	}
81	}
82
83	async defaultDimensionFunction ({ id, baseUrl }) {
84	const result = [];	71✔
85	let page = 0;	71✔
86	const target = sharp({ page });	71✔
87
88	return await this.withStream({ id, baseUrl }, async (stream) => {	71✔
89	stream.pipe(target);	71✔
90	const { width, height, pages } = await target.metadata();	71✔
91	result.push({ width, height });	69✔
92	for (page += 1; page < pages; page++) {	69✔
93	const scale = 1 / 2 ** page;	207✔
94	result.push({ width: Math.floor(width * scale), height: Math.floor(height * scale) });	207✔
95	}
96	return result;	69✔
97	});
98	}
99
100	async dimensions () {
101	const fallback = this.dimensionFunction !== this.defaultDimensionFunction;	73✔
102
103	if (!this.sizeInfo) {	73!
104	debug('Attempting to use dimensionFunction to retrieve dimensions for %j', this.id);	73✔
105	const params = { id: this.id, baseUrl: this.baseUrl };	73✔
106	let dims = await this.dimensionFunction(params);	73✔
107	if (fallback && !dims) {	71✔
108	const warning =
109	'Unable to get dimensions for %s using custom function. Falling back to sharp.metadata().';	2✔
110	debug(warning, this.id);	2✔
111	console.warn(warning, this.id);	2✔
112	dims = await this.defaultDimensionFunction(params);	2✔
113	}
114	if (!Array.isArray(dims)) dims = [dims];	71✔
115	this.sizeInfo = dims;	71✔
116	}
117	return this.sizeInfo;	71✔
118	}
119
120	async infoJson () {
121	const [dim] = await this.dimensions();	4✔
122	const sizes = [];	4✔
123	for (let size = [dim.width, dim.height]; size.every((x) => x >= 64); size = size.map((x) => Math.floor(x / 2))) {	32✔
124	sizes.push({ width: size[0], height: size[1] });	12✔
125	}
126
127	const id = [fixupSlashes(this.baseUrl), fixupSlashes(this.id)].join('/');	4✔
128	const doc = this.Implementation.infoDoc({ id, ...dim, sizes, max: this.max });	4✔
129	for (const prop in doc) {	4✔
130	if (doc[prop] === null \|\| doc[prop] === undefined) delete doc[prop];	46✔
131	}
132
133	// Serialize sets as arrays
134	const body = JSON.stringify(doc, (_key, value) =>	4✔
135	value?.constructor === Set ? [...value] : value	215✔
136	);
137	return { contentType: 'application/json', body };	4✔
138	}
139
140	operations (dim) {
141	const { sharpOptions: sharp, max } = this;	83✔
142	return new Operations(this.version, dim, { sharp, max })	83✔
143	.region(this.region)
144	.size(this.size)
145	.rotation(this.rotation)
146	.quality(this.quality)
147	.format(this.format, this.density)
148	.withMetadata(this.includeMetadata);
149	}
150
151	async iiifImage () {
152	const dim = await this.dimensions();	67✔
153	const operations = this.operations(dim);	65✔
154	const pipeline = await operations.pipeline();	61✔
155
156	const result = await this.withStream({ id: this.id, baseUrl: this.baseUrl }, async (stream) => {	61✔
157	debug('piping stream to pipeline');	61✔
158	const transformed = await stream.pipe(pipeline);	61✔
159	debug('converting to buffer');	61✔
160	return await transformed.toBuffer();	61✔
161	});
162	debug('returning %d bytes', result.length);	59✔
163	debug('baseUrl', this.baseUrl);	59✔
164
165	const canonicalUrl = new URL(path.join(this.id, operations.canonicalPath()), this.baseUrl);	59✔
166	return {	59✔
167	canonicalLink: canonicalUrl.toString(),
168	profileLink: this.Implementation.profileLink,
169	contentType: mime.lookup(this.format),
170	body: result
171	};
172	}
173
174	async execute () {
175	if (this.filename === 'info.json') {	71✔
176	return await this.infoJson();	4✔
177	} else {
178	return await this.iiifImage();	67✔
179	}
180	}
181	}
182
183	module.exports = Processor;	5✔

samvera / node-iiif / 51847fda-a900-452b-a861-1f0740800a77

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