feat: add desktop repo (#1071)

packages/desktop/app/javascripts/Main/FileBackups/FileDownloader.ts

@@ -0,0 +1,54 @@
+import { WriteStream, createWriteStream } from 'fs'
+import { downloadData } from './FileNetworking'
+
+export class FileDownloader {
+  writeStream: WriteStream
+
+  constructor(private chunkSizes: number[], private valetToken: string, private url: string, filePath: string) {
+    this.writeStream = createWriteStream(filePath, { flags: 'a' })
+  }
+
+  public async run(): Promise<'success' | 'failed'> {
+    const result = await this.downloadChunk(0, 0)
+
+    this.writeStream.close()
+
+    return result
+  }
+
+  private async downloadChunk(chunkIndex = 0, contentRangeStart: number): Promise<'success' | 'failed'> {
+    const pullChunkSize = this.chunkSizes[chunkIndex]
+
+    const headers = {
+      'x-valet-token': this.valetToken,
+      'x-chunk-size': pullChunkSize.toString(),
+      range: `bytes=${contentRangeStart}-`,
+    }
+
+    const response = await downloadData(this.writeStream, this.url, headers)
+
+    if (!String(response.status).startsWith('2')) {
+      return 'failed'
+    }
+
+    const contentRangeHeader = response.headers['content-range'] as string
+    if (!contentRangeHeader) {
+      return 'failed'
+    }
+
+    const matches = contentRangeHeader.match(/(^[a-zA-Z][\w]*)\s+(\d+)\s?-\s?(\d+)?\s?\/?\s?(\d+|\*)?/)
+    if (!matches || matches.length !== 5) {
+      return 'failed'
+    }
+
+    const rangeStart = +matches[2]
+    const rangeEnd = +matches[3]
+    const totalSize = +matches[4]
+
+    if (rangeEnd < totalSize - 1) {
+      return this.downloadChunk(++chunkIndex, rangeStart + pullChunkSize)
+    }
+
+    return 'success'
+  }
+}