* 下载 URL 内容并转为 base64
(url: string)
| 489 | * 下载 URL 内容并转为 base64 |
| 490 | */ |
| 491 | private downloadAsBase64(url: string): Promise<string> { |
| 492 | return new Promise((resolve) => { |
| 493 | const request = net.request(url) |
| 494 | const chunks: Buffer[] = [] |
| 495 | let resolved = false |
| 496 | const done = (value: string): void => { |
| 497 | clearTimeout(timeout) |
| 498 | if (!resolved) { |
| 499 | resolved = true |
| 500 | resolve(value) |
| 501 | } |
| 502 | } |
| 503 | |
| 504 | const timeout = setTimeout(() => { |
| 505 | if (!resolved) { |
| 506 | resolved = true |
| 507 | request.abort() |
| 508 | resolve('') |
| 509 | } |
| 510 | }, 10000) |
| 511 | |
| 512 | request.on('response', (response) => { |
| 513 | response.on('error', () => { |
| 514 | done('') |
| 515 | }) |
| 516 | |
| 517 | // 处理重定向 |
| 518 | if ( |
| 519 | response.statusCode && |
| 520 | response.statusCode >= 300 && |
| 521 | response.statusCode < 400 && |
| 522 | response.headers.location |
| 523 | ) { |
| 524 | clearTimeout(timeout) |
| 525 | resolved = true |
| 526 | const location = Array.isArray(response.headers.location) |
| 527 | ? response.headers.location[0] |
| 528 | : response.headers.location |
| 529 | this.downloadAsBase64(location).then(resolve) |
| 530 | return |
| 531 | } |
| 532 | |
| 533 | if (response.statusCode !== 200) { |
| 534 | done('') |
| 535 | return |
| 536 | } |
| 537 | |
| 538 | const contentType = |
| 539 | (Array.isArray(response.headers['content-type']) |
| 540 | ? response.headers['content-type'][0] |
| 541 | : response.headers['content-type']) || 'image/x-icon' |
| 542 | |
| 543 | response.on('data', (chunk) => { |
| 544 | chunks.push(Buffer.from(chunk)) |
| 545 | }) |
| 546 | response.on('end', () => { |
| 547 | const buffer = Buffer.concat(chunks) |
| 548 | if (buffer.length > 0) { |