use async and removed jquery from download.js

frontend/src/fileReceiver.js

@@ -2,87 +2,80 @@ import EventEmitter from 'events';
 import { hexToArray } from './utils';
 
 export default class FileReceiver extends EventEmitter {
-  constructor() {
+  constructor(url, k) {
     super();
+    this.key = window.crypto.subtle.importKey(
+      'jwk',
+      {
+        k,
+        kty: 'oct',
+        alg: 'A128GCM',
+        ext: true
+      },
+      {
+        name: 'AES-GCM'
+      },
+      false,
+      ['decrypt']
+    );
+    this.url = url;
   }
 
-  download() {
-    return window.crypto.subtle
-      .importKey(
-        'jwk',
-        {
-          kty: 'oct',
-          k: location.hash.slice(1),
-          alg: 'A128GCM',
-          ext: true
-        },
-        {
-          name: 'AES-GCM'
-        },
-        true,
-        ['encrypt', 'decrypt']
-      )
-      .then(key => {
-        return new Promise((resolve, reject) => {
-          const xhr = new XMLHttpRequest();
+  downloadFile() {
+    return new Promise((resolve, reject) => {
+      const xhr = new XMLHttpRequest();
 
-          xhr.onprogress = event => {
-            if (event.lengthComputable && event.target.status !== 404) {
-              this.emit('progress', [event.loaded, event.total]);
-            }
-          };
+      xhr.onprogress = event => {
+        if (event.lengthComputable && event.target.status !== 404) {
+          this.emit('progress', [event.loaded, event.total]);
+        }
+      };
 
-          xhr.onload = function(event) {
-            if (xhr.status === 404) {
-              reject(new Error('notfound'));
-              return;
-            }
+      xhr.onload = function(event) {
+        if (xhr.status === 404) {
+          reject(new Error('notfound'));
+          return;
+        }
 
-            const blob = new Blob([this.response]);
-            const type = xhr.getResponseHeader('Content-Type');
-            const meta = JSON.parse(xhr.getResponseHeader('X-File-Metadata'));
-            const fileReader = new FileReader();
-            fileReader.onload = function() {
-              resolve([
-                {
-                  data: this.result,
-                  filename: meta.filename,
-                  type,
-                  iv: meta.id
-                },
-                key
-              ]);
-            };
+        const blob = new Blob([this.response]);
+        const type = xhr.getResponseHeader('Content-Type');
+        const meta = JSON.parse(xhr.getResponseHeader('X-File-Metadata'));
+        const fileReader = new FileReader();
+        fileReader.onload = function() {
+          resolve({
+            data: this.result,
+            name: meta.filename,
+            type,
+            iv: meta.id
+          });
+        };
 
-            fileReader.readAsArrayBuffer(blob);
-          };
+        fileReader.readAsArrayBuffer(blob);
+      };
 
-          xhr.open('get', '/assets' + location.pathname.slice(0, -1), true);
-          xhr.responseType = 'blob';
-          xhr.send();
-        });
-      })
-      .then(([fdata, key]) => {
-        this.emit('decrypting');
-        return Promise.all([
-          window.crypto.subtle
-            .decrypt(
-              {
-                name: 'AES-GCM',
-                iv: hexToArray(fdata.iv),
-                tagLength: 128
-              },
-              key,
-              fdata.data
-            )
-            .then(decrypted => {
-              return Promise.resolve(decrypted);
-            }),
-          {
-            name: decodeURIComponent(fdata.filename),
-            type: fdata.type
-          }
-        ]);
-      });
+      xhr.open('get', this.url);
+      xhr.responseType = 'blob';
+      xhr.send();
+    });
+  }
+
+  async download() {
+    const key = await this.key;
+    const file = await this.downloadFile();
+    this.emit('decrypting');
+    const plaintext = await window.crypto.subtle.decrypt(
+      {
+        name: 'AES-GCM',
+        iv: hexToArray(file.iv),
+        tagLength: 128
+      },
+      key,
+      file.data
+    );
+    return {
+      plaintext,
+      name: decodeURIComponent(file.name),
+      type: file.type
+    };
   }
 }