feat: app-plus downloadFile

src/core/service/api/network/download-file.js

+import {
+  invoke
+} from 'uni-core/service/bridge'
+
+import {
+  onMethod,
+  invokeMethod
+} from '../../platform'
+
+class DownloadTask {
+  constructor (downloadTaskId, callbackId) {
+    this.id = downloadTaskId
+    this._callbackId = callbackId
+    this._callbacks = []
+  }
+  abort () {
+    invokeMethod('operateRequestTask', {
+      downloadTaskId: this.id,
+      operationType: 'abort'
+    })
+  }
+  onProgressUpdate (callback) {
+    if (typeof callback !== 'function') {
+      return
+    }
+    this._callbacks.push(callback)
+  }
+  onHeadersReceived () {
+
+  }
+  offProgressUpdate (callback) {
+    const index = this._callbacks.indexOf(callback)
+    if (index >= 0) {
+      this._callbacks.splice(index, 1)
+    }
+  }
+  offHeadersReceived () {
+
+  }
+}
+const downloadTasks = Object.create(null)
+onMethod('onDownloadTaskStateChange', ({
+  downloadTaskId,
+  state,
+  tempFilePath,
+  statusCode,
+  progress,
+  totalBytesWritten,
+  totalBytesExpectedToWrite,
+  errMsg
+}) => {
+  const downloadTask = downloadTasks[downloadTaskId]
+  const callbackId = downloadTask._callbackId
+
+  switch (state) {
+    case 'progressUpdate':
+      downloadTask._callbacks.forEach(callback => {
+        callback({
+          progress,
+          totalBytesWritten,
+          totalBytesExpectedToWrite
+        })
+      })
+      break
+    case 'success':
+      invoke(callbackId, {
+        tempFilePath,
+        statusCode,
+        errMsg: 'request:ok'
+      })
+      // eslint-disable-next-line no-fallthrough
+    case 'fail':
+      invoke(callbackId, {
+        errMsg: 'request:fail ' + errMsg
+      })
+      // eslint-disable-next-line no-fallthrough
+    default:
+      // progressUpdate 可能晚于 success
+      setTimeout(() => {
+        delete downloadTasks[downloadTaskId]
+      }, 100)
+      break
+  }
+})
+export function downloadFile (args, callbackId) {
+  const {
+    downloadTaskId
+  } = invokeMethod('createDownloadTask', args)
+  const task = new DownloadTask(downloadTaskId, callbackId)
+  downloadTasks[downloadTaskId] = task
+  return task
+}