55 lines
1.5 KiB
TypeScript
55 lines
1.5 KiB
TypeScript
import { WriteStream, createWriteStream } from 'fs'
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import { downloadData } from './FileNetworking'
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export class FileDownloader {
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writeStream: WriteStream
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constructor(private chunkSizes: number[], private valetToken: string, private url: string, filePath: string) {
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this.writeStream = createWriteStream(filePath, { flags: 'a' })
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}
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public async run(): Promise<'success' | 'failed'> {
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const result = await this.downloadChunk(0, 0)
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this.writeStream.close()
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return result
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}
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private async downloadChunk(chunkIndex = 0, contentRangeStart: number): Promise<'success' | 'failed'> {
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const pullChunkSize = this.chunkSizes[chunkIndex]
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const headers = {
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'x-valet-token': this.valetToken,
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'x-chunk-size': pullChunkSize.toString(),
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range: `bytes=${contentRangeStart}-`,
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}
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const response = await downloadData(this.writeStream, this.url, headers)
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if (!String(response.status).startsWith('2')) {
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return 'failed'
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}
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const contentRangeHeader = response.headers['content-range'] as string
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if (!contentRangeHeader) {
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return 'failed'
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}
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const matches = contentRangeHeader.match(/(^[a-zA-Z][\w]*)\s+(\d+)\s?-\s?(\d+)?\s?\/?\s?(\d+|\*)?/)
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if (!matches || matches.length !== 5) {
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return 'failed'
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}
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const rangeStart = +matches[2]
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const rangeEnd = +matches[3]
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const totalSize = +matches[4]
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if (rangeEnd < totalSize - 1) {
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return this.downloadChunk(++chunkIndex, rangeStart + pullChunkSize)
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}
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return 'success'
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}
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}
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