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Merge pull request #2107 from itsjamie/fragment-typescript
Apply TypeScript to Fragment & LevelKey
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| import { buildAbsoluteURL } from 'url-toolkit'; | ||
| import { logger } from '../utils/logger'; | ||
| import LevelKey from './level-key'; | ||
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| export enum ElementaryStreamTypes { | ||
| AUDIO = 'audio', | ||
| VIDEO = 'video', | ||
| } | ||
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| export default class Fragment { | ||
| private _url: string | null = null; | ||
| private _byteRange: number[] | null = null; | ||
| private _decryptdata: LevelKey | null = null; | ||
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| // Holds the types of data this fragment supports | ||
| private _elementaryStreams: Record<ElementaryStreamTypes, boolean> = { | ||
| [ElementaryStreamTypes.AUDIO]: false, | ||
| [ElementaryStreamTypes.VIDEO]: false | ||
| }; | ||
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| public rawProgramDateTime: string | null = null; | ||
| public programDateTime: number | null = null; | ||
| public tagList: Array<string[]> = []; | ||
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| // TODO: Move at least baseurl to constructor. | ||
| // Currently we do a two-pass construction as use the Fragment class almost like a object for holding parsing state. | ||
| // It may make more sense to just use a POJO to keep state during the parsing phase. | ||
| // Have Fragment be the representation once we have a known state? | ||
| // Something to think on. | ||
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| // relurl is the portion of the URL that comes from inside the playlist. | ||
| public relurl!: string; | ||
| // baseurl is the URL to the playlist | ||
| public baseurl!: string; | ||
| // EXTINF has to be present for a m3u8 to be considered valid | ||
| public duration!: number; | ||
| // sn notates the sequence number for a segment, and if set to a string can be 'initSegment' | ||
| public sn: number | 'initSegment' = 0; | ||
| // levelkey is the EXT-X-KEY that applies to this segment for decryption | ||
| // core difference from the private field _decryptdata is the lack of the initialized IV | ||
| // _decryptdata will set the IV for this segment based on the segment number in the fragment | ||
| public levelkey?: LevelKey; | ||
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| // setByteRange converts a EXT-X-BYTERANGE attribute into a two element array | ||
| setByteRange (value: string, previousFrag?: Fragment) { | ||
| const params = value.split('@', 2); | ||
| const byteRange: number[] = []; | ||
| if (params.length === 1) { | ||
| byteRange[0] = previousFrag ? previousFrag.byteRangeEndOffset : 0; | ||
| } else { | ||
| byteRange[0] = parseInt(params[1]); | ||
| } | ||
| byteRange[1] = parseInt(params[0]) + byteRange[0]; | ||
| this._byteRange = byteRange; | ||
| } | ||
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| get url () { | ||
| if (!this._url && this.relurl) { | ||
| this._url = buildAbsoluteURL(this.baseurl, this.relurl, { alwaysNormalize: true }); | ||
| } | ||
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| return this._url; | ||
| } | ||
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| set url (value) { | ||
| this._url = value; | ||
| } | ||
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| get byteRange (): number[] { | ||
| if (!this._byteRange) { | ||
| return []; | ||
| } | ||
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| return this._byteRange; | ||
| } | ||
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| /** | ||
| * @type {number} | ||
| */ | ||
| get byteRangeStartOffset () { | ||
| return this.byteRange[0]; | ||
| } | ||
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| get byteRangeEndOffset () { | ||
| return this.byteRange[1]; | ||
| } | ||
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| get decryptdata (): LevelKey | null { | ||
| if (!this.levelkey && !this._decryptdata) { | ||
| return null; | ||
| } | ||
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| if (!this._decryptdata && this.levelkey) { | ||
| let sn = this.sn; | ||
| if (typeof sn !== 'number') { | ||
| // We are fetching decryption data for a initialization segment | ||
| // If the segment was encrypted with AES-128 | ||
| // It must have an IV defined. We cannot substitute the Segment Number in. | ||
| if (this.levelkey && this.levelkey.method === 'AES-128' && !this.levelkey.iv) { | ||
| logger.warn(`missing IV for initialization segment with method="${this.levelkey.method}" - compliance issue`); | ||
| } | ||
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| /* | ||
| Be converted to a Number. | ||
| 'initSegment' will become NaN. | ||
| NaN, which when converted through ToInt32() -> +0. | ||
| --- | ||
| Explicitly set sn to resulting value from implicit conversions 'initSegment' values for IV generation. | ||
| */ | ||
| sn = 0; | ||
| } | ||
| this._decryptdata = this.setDecryptDataFromLevelKey(this.levelkey, sn); | ||
| } | ||
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| return this._decryptdata; | ||
| } | ||
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| get endProgramDateTime () { | ||
| if (this.programDateTime === null) { | ||
| return null; | ||
| } | ||
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| if (!Number.isFinite(this.programDateTime)) { | ||
| return null; | ||
| } | ||
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| let duration = !Number.isFinite(this.duration) ? 0 : this.duration; | ||
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| return this.programDateTime + (duration * 1000); | ||
| } | ||
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| get encrypted () { | ||
| return !!((this.decryptdata && this.decryptdata.uri !== null) && (this.decryptdata.key === null)); | ||
| } | ||
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| /** | ||
| * @param {ElementaryStreamTypes} type | ||
| */ | ||
| addElementaryStream (type: ElementaryStreamTypes) { | ||
| this._elementaryStreams[type] = true; | ||
| } | ||
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| /** | ||
| * @param {ElementaryStreamTypes} type | ||
| */ | ||
| hasElementaryStream (type: ElementaryStreamTypes) { | ||
| return this._elementaryStreams[type] === true; | ||
| } | ||
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| /** | ||
| * Utility method for parseLevelPlaylist to create an initialization vector for a given segment | ||
| * @param {number} segmentNumber - segment number to generate IV with | ||
| * @returns {Uint8Array} | ||
| */ | ||
| createInitializationVector (segmentNumber: number): Uint8Array { | ||
| let uint8View = new Uint8Array(16); | ||
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| for (let i = 12; i < 16; i++) { | ||
| uint8View[i] = (segmentNumber >> 8 * (15 - i)) & 0xff; | ||
| } | ||
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| return uint8View; | ||
| } | ||
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| /** | ||
| * Utility method for parseLevelPlaylist to get a fragment's decryption data from the currently parsed encryption key data | ||
| * @param levelkey - a playlist's encryption info | ||
| * @param segmentNumber - the fragment's segment number | ||
| * @returns {LevelKey} - an object to be applied as a fragment's decryptdata | ||
| */ | ||
| setDecryptDataFromLevelKey (levelkey: LevelKey, segmentNumber: number): LevelKey { | ||
| let decryptdata = levelkey; | ||
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| if (levelkey && levelkey.method && levelkey.uri && !levelkey.iv) { | ||
| decryptdata = new LevelKey(levelkey.baseuri, levelkey.reluri); | ||
| decryptdata.method = levelkey.method; | ||
| decryptdata.iv = this.createInitializationVector(segmentNumber); | ||
| } | ||
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| return decryptdata; | ||
| } | ||
| } |
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