feat(updater): Cache the new blockmap file and allow customization of the old blockmap file base URL.

packages/electron-updater/src/AppUpdater.ts

@@ -15,7 +15,7 @@ import {
 import { randomBytes } from "crypto"
 import { release } from "os"
 import { EventEmitter } from "events"
-import { mkdir, outputFile, readFile, rename, unlink } from "fs-extra"
+import { mkdir, outputFile, readFile, rename, unlink, copyFile, pathExists } from "fs-extra"
 import { OutgoingHttpHeaders } from "http"
 import { load } from "js-yaml"
 import { Lazy } from "lazy-val"
@@ -31,7 +31,7 @@ import { Provider, ProviderPlatform } from "./providers/Provider"
 import type { TypedEmitter } from "tiny-typed-emitter"
 import Session = Electron.Session
 import type { AuthInfo } from "electron"
-import { gunzipSync } from "zlib"
+import { gunzipSync, gzipSync } from "zlib"
 import { blockmapFiles } from "./util"
 import { DifferentialDownloaderOptions } from "./differentialDownloader/DifferentialDownloader"
 import { GenericDifferentialDownloader } from "./differentialDownloader/GenericDifferentialDownloader"
@@ -117,6 +117,12 @@ export abstract class AppUpdater extends (EventEmitter as new () => TypedEmitter
    */
   forceDevUpdateConfig = false
 
+  /**
+   * The base URL of the old block map file.
+   * @default null
+   */
+  private _oldBlockMapFileBaseUrl: string | null = null
+
   /**
    * The current application version.
    */
@@ -133,6 +139,14 @@ export abstract class AppUpdater extends (EventEmitter as new () => TypedEmitter
     return this._channel
   }
 
+  get oldBlockMapFileBaseUrl(): string | null {
+    return this._oldBlockMapFileBaseUrl
+  }
+
+  set oldBlockMapFileBaseUrl(value: string | null) {
+    this._oldBlockMapFileBaseUrl = value
+  }
+
   /**
    * Set the update channel. Overrides `channel` in the update configuration.
    *
@@ -736,6 +750,10 @@ export abstract class AppUpdater extends (EventEmitter as new () => TypedEmitter
         ...updateInfo,
         downloadedFile: updateFile,
       })
+      const currentBlockMapFile = path.join(cacheDir, "current.blockmap")
+      if (await pathExists(currentBlockMapFile)) {
+        await copyFile(currentBlockMapFile, path.join(downloadedUpdateHelper.cacheDir, "current.blockmap"))
+      }
       return packageFile == null ? [updateFile] : [updateFile, packageFile]
     }
 
@@ -790,7 +808,7 @@ export abstract class AppUpdater extends (EventEmitter as new () => TypedEmitter
       if (this._testOnlyOptions != null && !this._testOnlyOptions.isUseDifferentialDownload) {
         return true
       }
-      const blockmapFileUrls = blockmapFiles(fileInfo.url, this.app.version, downloadUpdateOptions.updateInfoAndProvider.info.version)
+      const blockmapFileUrls = blockmapFiles(fileInfo.url, this.app.version, downloadUpdateOptions.updateInfoAndProvider.info.version, this._oldBlockMapFileBaseUrl)
       this._logger.info(`Download block maps (old: "${blockmapFileUrls[0]}", new: ${blockmapFileUrls[1]})`)
 
       const downloadBlockMap = async (url: URL): Promise<BlockMap> => {
@@ -824,8 +842,33 @@ export abstract class AppUpdater extends (EventEmitter as new () => TypedEmitter
         downloadOptions.onProgress = it => this.emit(DOWNLOAD_PROGRESS, it)
       }
 
-      const blockMapDataList = await Promise.all(blockmapFileUrls.map(u => downloadBlockMap(u)))
-      await new GenericDifferentialDownloader(fileInfo.info, this.httpExecutor, downloadOptions).download(blockMapDataList[0], blockMapDataList[1])
+      const saveBlockMapToCacheDir = async (blockMapData: BlockMap, cacheDir: string) => {
+        const blockMapFile = path.join(cacheDir, "current.blockmap")
+        await outputFile(blockMapFile, gzipSync(JSON.stringify(blockMapData)))
+      }
+
+      const getBlockMapFromCacheDir = async (cacheDir: string) => {
+        const blockMapFile = path.join(cacheDir, "current.blockmap")
+        try {
+          if (await pathExists(blockMapFile)) {
+            return JSON.parse(gunzipSync(await readFile(blockMapFile)).toString())
+          }
+        } catch (e: any) {
+          this._logger.warn(`Cannot parse blockmap "${blockMapFile}", error: ${e}`)
+        }
+        return null
+      }
+
+      const newBlockMapData = await downloadBlockMap(blockmapFileUrls[1])
+      await saveBlockMapToCacheDir(newBlockMapData, this.downloadedUpdateHelper!.cacheDirForPendingUpdate)
+
+      // get old blockmap from cache dir first, if not found, download it
+      let oldBlockMapData = await getBlockMapFromCacheDir(this.downloadedUpdateHelper!.cacheDir)
+      if (oldBlockMapData == null) {
+        oldBlockMapData = await downloadBlockMap(blockmapFileUrls[0])
+      }
+
+      await new GenericDifferentialDownloader(fileInfo.info, this.httpExecutor, downloadOptions).download(oldBlockMapData, newBlockMapData)
       return false
     } catch (e: any) {
       this._logger.error(`Cannot download differentially, fallback to full download: ${e.stack || e}`)

packages/electron-updater/src/differentialDownloader/multipleRangeDownloader.ts

@@ -46,7 +46,7 @@ function doExecuteTasks(differentialDownloader: DifferentialDownloader, options:
   for (let i = options.start; i < options.end; i++) {
     const task = options.tasks[i]
     if (task.kind === OperationKind.DOWNLOAD) {
-      ranges += `${task.start}-${task.end - 1}, `
+      ranges += `${task.start}-${task.end - 1},`
       partIndexToTaskIndex.set(partCount, i)
       partCount++
       partIndexToLength.push(task.end - task.start)

packages/electron-updater/src/util.ts

@@ -30,8 +30,12 @@ export function getChannelFilename(channel: string): string {
   return `${channel}.yml`
 }
 
-export function blockmapFiles(baseUrl: URL, oldVersion: string, newVersion: string): URL[] {
+export function blockmapFiles(baseUrl: URL, oldVersion: string, newVersion: string, oldBlockMapFileBaseUrl: string | null = null): URL[] {
   const newBlockMapUrl = newUrlFromBase(`${baseUrl.pathname}.blockmap`, baseUrl)
-  const oldBlockMapUrl = newUrlFromBase(`${baseUrl.pathname.replace(new RegExp(escapeRegExp(newVersion), "g"), oldVersion)}.blockmap`, baseUrl)
+  const oldBlockMapUrl = newUrlFromBase(
+    `${baseUrl.pathname.replace(new RegExp(escapeRegExp(newVersion), "g"), oldVersion)}.blockmap`,
+    oldBlockMapFileBaseUrl ? new URL(oldBlockMapFileBaseUrl) : baseUrl
+  )
+
   return [oldBlockMapUrl, newBlockMapUrl]
 }

test/src/binDownloadTest.ts

@@ -17,7 +17,7 @@ test("download binary from Mirror with custom dir", async ({ expect }) => {
     "linux-tools-mac-10.12.3.7z",
     "SQ8fqIRVXuQVWnVgaMTDWyf2TLAJjJYw3tRSqQJECmgF6qdM7Kogfa6KD49RbGzzMYIFca9Uw3MdsxzOPRWcYw=="
   )
-    delete process.env.ELECTRON_BUILDER_BINARIES_MIRROR
+  delete process.env.ELECTRON_BUILDER_BINARIES_MIRROR
   delete process.env.ELECTRON_BUILDER_BINARIES_CUSTOM_DIR
   expect(bin).toBeTruthy()
 })
@@ -29,7 +29,7 @@ test("download binary from Mirror", async ({ expect }) => {
     "linux-tools-mac-10.12.3.7z",
     "SQ8fqIRVXuQVWnVgaMTDWyf2TLAJjJYw3tRSqQJECmgF6qdM7Kogfa6KD49RbGzzMYIFca9Uw3MdsxzOPRWcYw=="
   )
-    delete process.env.ELECTRON_BUILDER_BINARIES_MIRROR
+  delete process.env.ELECTRON_BUILDER_BINARIES_MIRROR
   expect(bin).toBeTruthy()
 })
 
@@ -40,6 +40,6 @@ test("download binary from Mirror with Url override", async ({ expect }) => {
     "linux-tools-mac-10.12.3.7z",
     "SQ8fqIRVXuQVWnVgaMTDWyf2TLAJjJYw3tRSqQJECmgF6qdM7Kogfa6KD49RbGzzMYIFca9Uw3MdsxzOPRWcYw=="
   )
-    delete process.env.ELECTRON_BUILDER_BINARIES_DOWNLOAD_OVERRIDE_URL
+  delete process.env.ELECTRON_BUILDER_BINARIES_DOWNLOAD_OVERRIDE_URL
   expect(bin).toBeTruthy()
 })