buymymojo.net/node_modules/m3u8-parser/src/parser.js
2021-07-02 19:29:34 +10:00

727 lines
26 KiB
JavaScript

/**
* @file m3u8/parser.js
*/
import Stream from '@videojs/vhs-utils/es/stream.js';
import decodeB64ToUint8Array from '@videojs/vhs-utils/es/decode-b64-to-uint8-array.js';
import LineStream from './line-stream';
import ParseStream from './parse-stream';
const camelCase = (str) => str
.toLowerCase()
.replace(/-(\w)/g, (a) => a[1].toUpperCase());
const camelCaseKeys = function(attributes) {
const result = {};
Object.keys(attributes).forEach(function(key) {
result[camelCase(key)] = attributes[key];
});
return result;
};
// set SERVER-CONTROL hold back based upon targetDuration and partTargetDuration
// we need this helper because defaults are based upon targetDuration and
// partTargetDuration being set, but they may not be if SERVER-CONTROL appears before
// target durations are set.
const setHoldBack = function(manifest) {
const {serverControl, targetDuration, partTargetDuration} = manifest;
if (!serverControl) {
return;
}
const tag = '#EXT-X-SERVER-CONTROL';
const hb = 'holdBack';
const phb = 'partHoldBack';
const minTargetDuration = targetDuration && targetDuration * 3;
const minPartDuration = partTargetDuration && partTargetDuration * 2;
if (targetDuration && !serverControl.hasOwnProperty(hb)) {
serverControl[hb] = minTargetDuration;
this.trigger('info', {
message: `${tag} defaulting HOLD-BACK to targetDuration * 3 (${minTargetDuration}).`
});
}
if (minTargetDuration && serverControl[hb] < minTargetDuration) {
this.trigger('warn', {
message: `${tag} clamping HOLD-BACK (${serverControl[hb]}) to targetDuration * 3 (${minTargetDuration})`
});
serverControl[hb] = minTargetDuration;
}
// default no part hold back to part target duration * 3
if (partTargetDuration && !serverControl.hasOwnProperty(phb)) {
serverControl[phb] = partTargetDuration * 3;
this.trigger('info', {
message: `${tag} defaulting PART-HOLD-BACK to partTargetDuration * 3 (${serverControl[phb]}).`
});
}
// if part hold back is too small default it to part target duration * 2
if (partTargetDuration && serverControl[phb] < (minPartDuration)) {
this.trigger('warn', {
message: `${tag} clamping PART-HOLD-BACK (${serverControl[phb]}) to partTargetDuration * 2 (${minPartDuration}).`
});
serverControl[phb] = minPartDuration;
}
};
/**
* A parser for M3U8 files. The current interpretation of the input is
* exposed as a property `manifest` on parser objects. It's just two lines to
* create and parse a manifest once you have the contents available as a string:
*
* ```js
* var parser = new m3u8.Parser();
* parser.push(xhr.responseText);
* ```
*
* New input can later be applied to update the manifest object by calling
* `push` again.
*
* The parser attempts to create a usable manifest object even if the
* underlying input is somewhat nonsensical. It emits `info` and `warning`
* events during the parse if it encounters input that seems invalid or
* requires some property of the manifest object to be defaulted.
*
* @class Parser
* @extends Stream
*/
export default class Parser extends Stream {
constructor() {
super();
this.lineStream = new LineStream();
this.parseStream = new ParseStream();
this.lineStream.pipe(this.parseStream);
/* eslint-disable consistent-this */
const self = this;
/* eslint-enable consistent-this */
const uris = [];
let currentUri = {};
// if specified, the active EXT-X-MAP definition
let currentMap;
// if specified, the active decryption key
let key;
let hasParts = false;
const noop = function() {};
const defaultMediaGroups = {
'AUDIO': {},
'VIDEO': {},
'CLOSED-CAPTIONS': {},
'SUBTITLES': {}
};
// This is the Widevine UUID from DASH IF IOP. The same exact string is
// used in MPDs with Widevine encrypted streams.
const widevineUuid = 'urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed';
// group segments into numbered timelines delineated by discontinuities
let currentTimeline = 0;
// the manifest is empty until the parse stream begins delivering data
this.manifest = {
allowCache: true,
discontinuityStarts: [],
segments: []
};
// keep track of the last seen segment's byte range end, as segments are not required
// to provide the offset, in which case it defaults to the next byte after the
// previous segment
let lastByterangeEnd = 0;
// keep track of the last seen part's byte range end.
let lastPartByterangeEnd = 0;
this.on('end', () => {
// only add preloadSegment if we don't yet have a uri for it.
// and we actually have parts/preloadHints
if (currentUri.uri || (!currentUri.parts && !currentUri.preloadHints)) {
return;
}
if (!currentUri.map && currentMap) {
currentUri.map = currentMap;
}
if (!currentUri.key && key) {
currentUri.key = key;
}
if (!currentUri.timeline && typeof currentTimeline === 'number') {
currentUri.timeline = currentTimeline;
}
this.manifest.preloadSegment = currentUri;
});
// update the manifest with the m3u8 entry from the parse stream
this.parseStream.on('data', function(entry) {
let mediaGroup;
let rendition;
({
tag() {
// switch based on the tag type
(({
version() {
if (entry.version) {
this.manifest.version = entry.version;
}
},
'allow-cache'() {
this.manifest.allowCache = entry.allowed;
if (!('allowed' in entry)) {
this.trigger('info', {
message: 'defaulting allowCache to YES'
});
this.manifest.allowCache = true;
}
},
byterange() {
const byterange = {};
if ('length' in entry) {
currentUri.byterange = byterange;
byterange.length = entry.length;
if (!('offset' in entry)) {
/*
* From the latest spec (as of this writing):
* https://tools.ietf.org/html/draft-pantos-http-live-streaming-23#section-4.3.2.2
*
* Same text since EXT-X-BYTERANGE's introduction in draft 7:
* https://tools.ietf.org/html/draft-pantos-http-live-streaming-07#section-3.3.1)
*
* "If o [offset] is not present, the sub-range begins at the next byte
* following the sub-range of the previous media segment."
*/
entry.offset = lastByterangeEnd;
}
}
if ('offset' in entry) {
currentUri.byterange = byterange;
byterange.offset = entry.offset;
}
lastByterangeEnd = byterange.offset + byterange.length;
},
endlist() {
this.manifest.endList = true;
},
inf() {
if (!('mediaSequence' in this.manifest)) {
this.manifest.mediaSequence = 0;
this.trigger('info', {
message: 'defaulting media sequence to zero'
});
}
if (!('discontinuitySequence' in this.manifest)) {
this.manifest.discontinuitySequence = 0;
this.trigger('info', {
message: 'defaulting discontinuity sequence to zero'
});
}
if (entry.duration > 0) {
currentUri.duration = entry.duration;
}
if (entry.duration === 0) {
currentUri.duration = 0.01;
this.trigger('info', {
message: 'updating zero segment duration to a small value'
});
}
this.manifest.segments = uris;
},
key() {
if (!entry.attributes) {
this.trigger('warn', {
message: 'ignoring key declaration without attribute list'
});
return;
}
// clear the active encryption key
if (entry.attributes.METHOD === 'NONE') {
key = null;
return;
}
if (!entry.attributes.URI) {
this.trigger('warn', {
message: 'ignoring key declaration without URI'
});
return;
}
if (entry.attributes.KEYFORMAT === 'com.apple.streamingkeydelivery') {
this.manifest.contentProtection = this.manifest.contentProtection || {};
// TODO: add full support for this.
this.manifest.contentProtection['com.apple.fps.1_0'] = {
attributes: entry.attributes
};
return;
}
// check if the content is encrypted for Widevine
// Widevine/HLS spec: https://storage.googleapis.com/wvdocs/Widevine_DRM_HLS.pdf
if (entry.attributes.KEYFORMAT === widevineUuid) {
const VALID_METHODS = ['SAMPLE-AES', 'SAMPLE-AES-CTR', 'SAMPLE-AES-CENC'];
if (VALID_METHODS.indexOf(entry.attributes.METHOD) === -1) {
this.trigger('warn', {
message: 'invalid key method provided for Widevine'
});
return;
}
if (entry.attributes.METHOD === 'SAMPLE-AES-CENC') {
this.trigger('warn', {
message: 'SAMPLE-AES-CENC is deprecated, please use SAMPLE-AES-CTR instead'
});
}
if (entry.attributes.URI.substring(0, 23) !== 'data:text/plain;base64,') {
this.trigger('warn', {
message: 'invalid key URI provided for Widevine'
});
return;
}
if (!(entry.attributes.KEYID && entry.attributes.KEYID.substring(0, 2) === '0x')) {
this.trigger('warn', {
message: 'invalid key ID provided for Widevine'
});
return;
}
// if Widevine key attributes are valid, store them as `contentProtection`
// on the manifest to emulate Widevine tag structure in a DASH mpd
this.manifest.contentProtection = this.manifest.contentProtection || {};
this.manifest.contentProtection['com.widevine.alpha'] = {
attributes: {
schemeIdUri: entry.attributes.KEYFORMAT,
// remove '0x' from the key id string
keyId: entry.attributes.KEYID.substring(2)
},
// decode the base64-encoded PSSH box
pssh: decodeB64ToUint8Array(entry.attributes.URI.split(',')[1])
};
return;
}
if (!entry.attributes.METHOD) {
this.trigger('warn', {
message: 'defaulting key method to AES-128'
});
}
// setup an encryption key for upcoming segments
key = {
method: entry.attributes.METHOD || 'AES-128',
uri: entry.attributes.URI
};
if (typeof entry.attributes.IV !== 'undefined') {
key.iv = entry.attributes.IV;
}
},
'media-sequence'() {
if (!isFinite(entry.number)) {
this.trigger('warn', {
message: 'ignoring invalid media sequence: ' + entry.number
});
return;
}
this.manifest.mediaSequence = entry.number;
},
'discontinuity-sequence'() {
if (!isFinite(entry.number)) {
this.trigger('warn', {
message: 'ignoring invalid discontinuity sequence: ' + entry.number
});
return;
}
this.manifest.discontinuitySequence = entry.number;
currentTimeline = entry.number;
},
'playlist-type'() {
if (!(/VOD|EVENT/).test(entry.playlistType)) {
this.trigger('warn', {
message: 'ignoring unknown playlist type: ' + entry.playlist
});
return;
}
this.manifest.playlistType = entry.playlistType;
},
map() {
currentMap = {};
if (entry.uri) {
currentMap.uri = entry.uri;
}
if (entry.byterange) {
currentMap.byterange = entry.byterange;
}
if (key) {
currentMap.key = key;
}
},
'stream-inf'() {
this.manifest.playlists = uris;
this.manifest.mediaGroups =
this.manifest.mediaGroups || defaultMediaGroups;
if (!entry.attributes) {
this.trigger('warn', {
message: 'ignoring empty stream-inf attributes'
});
return;
}
if (!currentUri.attributes) {
currentUri.attributes = {};
}
Object.assign(currentUri.attributes, entry.attributes);
},
media() {
this.manifest.mediaGroups =
this.manifest.mediaGroups || defaultMediaGroups;
if (!(entry.attributes &&
entry.attributes.TYPE &&
entry.attributes['GROUP-ID'] &&
entry.attributes.NAME)) {
this.trigger('warn', {
message: 'ignoring incomplete or missing media group'
});
return;
}
// find the media group, creating defaults as necessary
const mediaGroupType = this.manifest.mediaGroups[entry.attributes.TYPE];
mediaGroupType[entry.attributes['GROUP-ID']] =
mediaGroupType[entry.attributes['GROUP-ID']] || {};
mediaGroup = mediaGroupType[entry.attributes['GROUP-ID']];
// collect the rendition metadata
rendition = {
default: (/yes/i).test(entry.attributes.DEFAULT)
};
if (rendition.default) {
rendition.autoselect = true;
} else {
rendition.autoselect = (/yes/i).test(entry.attributes.AUTOSELECT);
}
if (entry.attributes.LANGUAGE) {
rendition.language = entry.attributes.LANGUAGE;
}
if (entry.attributes.URI) {
rendition.uri = entry.attributes.URI;
}
if (entry.attributes['INSTREAM-ID']) {
rendition.instreamId = entry.attributes['INSTREAM-ID'];
}
if (entry.attributes.CHARACTERISTICS) {
rendition.characteristics = entry.attributes.CHARACTERISTICS;
}
if (entry.attributes.FORCED) {
rendition.forced = (/yes/i).test(entry.attributes.FORCED);
}
// insert the new rendition
mediaGroup[entry.attributes.NAME] = rendition;
},
discontinuity() {
currentTimeline += 1;
currentUri.discontinuity = true;
this.manifest.discontinuityStarts.push(uris.length);
},
'program-date-time'() {
if (typeof this.manifest.dateTimeString === 'undefined') {
// PROGRAM-DATE-TIME is a media-segment tag, but for backwards
// compatibility, we add the first occurence of the PROGRAM-DATE-TIME tag
// to the manifest object
// TODO: Consider removing this in future major version
this.manifest.dateTimeString = entry.dateTimeString;
this.manifest.dateTimeObject = entry.dateTimeObject;
}
currentUri.dateTimeString = entry.dateTimeString;
currentUri.dateTimeObject = entry.dateTimeObject;
},
targetduration() {
if (!isFinite(entry.duration) || entry.duration < 0) {
this.trigger('warn', {
message: 'ignoring invalid target duration: ' + entry.duration
});
return;
}
this.manifest.targetDuration = entry.duration;
setHoldBack.call(this, this.manifest);
},
start() {
if (!entry.attributes || isNaN(entry.attributes['TIME-OFFSET'])) {
this.trigger('warn', {
message: 'ignoring start declaration without appropriate attribute list'
});
return;
}
this.manifest.start = {
timeOffset: entry.attributes['TIME-OFFSET'],
precise: entry.attributes.PRECISE
};
},
'cue-out'() {
currentUri.cueOut = entry.data;
},
'cue-out-cont'() {
currentUri.cueOutCont = entry.data;
},
'cue-in'() {
currentUri.cueIn = entry.data;
},
'skip'() {
this.manifest.skip = camelCaseKeys(entry.attributes);
this.warnOnMissingAttributes_(
'#EXT-X-SKIP',
entry.attributes,
['SKIPPED-SEGMENTS']
);
},
'part'() {
hasParts = true;
// parts are always specifed before a segment
const segmentIndex = this.manifest.segments.length;
const part = camelCaseKeys(entry.attributes);
currentUri.parts = currentUri.parts || [];
currentUri.parts.push(part);
if (part.byterange) {
if (!part.byterange.hasOwnProperty('offset')) {
part.byterange.offset = lastPartByterangeEnd;
}
lastPartByterangeEnd = part.byterange.offset + part.byterange.length;
}
const partIndex = currentUri.parts.length - 1;
this.warnOnMissingAttributes_(
`#EXT-X-PART #${partIndex} for segment #${segmentIndex}`,
entry.attributes,
['URI', 'DURATION']
);
if (this.manifest.renditionReports) {
this.manifest.renditionReports.forEach((r, i) => {
if (!r.hasOwnProperty('lastPart')) {
this.trigger('warn', {
message: `#EXT-X-RENDITION-REPORT #${i} lacks required attribute(s): LAST-PART`
});
}
});
}
},
'server-control'() {
const attrs = this.manifest.serverControl = camelCaseKeys(entry.attributes);
if (!attrs.hasOwnProperty('canBlockReload')) {
attrs.canBlockReload = false;
this.trigger('info', {
message: '#EXT-X-SERVER-CONTROL defaulting CAN-BLOCK-RELOAD to false'
});
}
setHoldBack.call(this, this.manifest);
if (attrs.canSkipDateranges && !attrs.hasOwnProperty('canSkipUntil')) {
this.trigger('warn', {
message: '#EXT-X-SERVER-CONTROL lacks required attribute CAN-SKIP-UNTIL which is required when CAN-SKIP-DATERANGES is set'
});
}
},
'preload-hint'() {
// parts are always specifed before a segment
const segmentIndex = this.manifest.segments.length;
const hint = camelCaseKeys(entry.attributes);
const isPart = hint.type && hint.type === 'PART';
currentUri.preloadHints = currentUri.preloadHints || [];
currentUri.preloadHints.push(hint);
if (hint.byterange) {
if (!hint.byterange.hasOwnProperty('offset')) {
// use last part byterange end or zero if not a part.
hint.byterange.offset = isPart ? lastPartByterangeEnd : 0;
if (isPart) {
lastPartByterangeEnd = hint.byterange.offset + hint.byterange.length;
}
}
}
const index = currentUri.preloadHints.length - 1;
this.warnOnMissingAttributes_(
`#EXT-X-PRELOAD-HINT #${index} for segment #${segmentIndex}`,
entry.attributes,
['TYPE', 'URI']
);
if (!hint.type) {
return;
}
// search through all preload hints except for the current one for
// a duplicate type.
for (let i = 0; i < currentUri.preloadHints.length - 1; i++) {
const otherHint = currentUri.preloadHints[i];
if (!otherHint.type) {
continue;
}
if (otherHint.type === hint.type) {
this.trigger('warn', {
message: `#EXT-X-PRELOAD-HINT #${index} for segment #${segmentIndex} has the same TYPE ${hint.type} as preload hint #${i}`
});
}
}
},
'rendition-report'() {
const report = camelCaseKeys(entry.attributes);
this.manifest.renditionReports = this.manifest.renditionReports || [];
this.manifest.renditionReports.push(report);
const index = this.manifest.renditionReports.length - 1;
const required = ['LAST-MSN', 'URI'];
if (hasParts) {
required.push('LAST-PART');
}
this.warnOnMissingAttributes_(
`#EXT-X-RENDITION-REPORT #${index}`,
entry.attributes,
required
);
},
'part-inf'() {
this.manifest.partInf = camelCaseKeys(entry.attributes);
this.warnOnMissingAttributes_(
'#EXT-X-PART-INF',
entry.attributes,
['PART-TARGET']
);
if (this.manifest.partInf.partTarget) {
this.manifest.partTargetDuration = this.manifest.partInf.partTarget;
}
setHoldBack.call(this, this.manifest);
}
})[entry.tagType] || noop).call(self);
},
uri() {
currentUri.uri = entry.uri;
uris.push(currentUri);
// if no explicit duration was declared, use the target duration
if (this.manifest.targetDuration && !('duration' in currentUri)) {
this.trigger('warn', {
message: 'defaulting segment duration to the target duration'
});
currentUri.duration = this.manifest.targetDuration;
}
// annotate with encryption information, if necessary
if (key) {
currentUri.key = key;
}
currentUri.timeline = currentTimeline;
// annotate with initialization segment information, if necessary
if (currentMap) {
currentUri.map = currentMap;
}
// reset the last byterange end as it needs to be 0 between parts
lastPartByterangeEnd = 0;
// prepare for the next URI
currentUri = {};
},
comment() {
// comments are not important for playback
},
custom() {
// if this is segment-level data attach the output to the segment
if (entry.segment) {
currentUri.custom = currentUri.custom || {};
currentUri.custom[entry.customType] = entry.data;
// if this is manifest-level data attach to the top level manifest object
} else {
this.manifest.custom = this.manifest.custom || {};
this.manifest.custom[entry.customType] = entry.data;
}
}
})[entry.type].call(self);
});
}
warnOnMissingAttributes_(identifier, attributes, required) {
const missing = [];
required.forEach(function(key) {
if (!attributes.hasOwnProperty(key)) {
missing.push(key);
}
});
if (missing.length) {
this.trigger('warn', {message: `${identifier} lacks required attribute(s): ${missing.join(', ')}`});
}
}
/**
* Parse the input string and update the manifest object.
*
* @param {string} chunk a potentially incomplete portion of the manifest
*/
push(chunk) {
this.lineStream.push(chunk);
}
/**
* Flush any remaining input. This can be handy if the last line of an M3U8
* manifest did not contain a trailing newline but the file has been
* completely received.
*/
end() {
// flush any buffered input
this.lineStream.push('\n');
this.trigger('end');
}
/**
* Add an additional parser for non-standard tags
*
* @param {Object} options a map of options for the added parser
* @param {RegExp} options.expression a regular expression to match the custom header
* @param {string} options.type the type to register to the output
* @param {Function} [options.dataParser] function to parse the line into an object
* @param {boolean} [options.segment] should tag data be attached to the segment object
*/
addParser(options) {
this.parseStream.addParser(options);
}
/**
* Add a custom header mapper
*
* @param {Object} options
* @param {RegExp} options.expression a regular expression to match the custom header
* @param {Function} options.map function to translate tag into a different tag
*/
addTagMapper(options) {
this.parseStream.addTagMapper(options);
}
}