incremental upload refactor

frontend/src/fileSender.js

@@ -0,0 +1,103 @@
+const EventEmitter = require('events');
+const { ivToStr } = require('./utils');
+
+class FileSender extends EventEmitter {
+  constructor(file) {
+    super();
+    this.file = file;
+    this.iv = window.crypto.getRandomValues(new Uint8Array(16));
+  }
+
+  static delete(fileId, token) {
+    return new Promise((resolve, reject) => {
+      if (!fileId || !token) {
+        return resolve();
+      }
+      let xhr = new XMLHttpRequest();
+      xhr.open('post', '/delete/' + fileId, true);
+      xhr.setRequestHeader('Content-Type', 'application/json');
+
+      xhr.onreadystatechange = () => {
+        if (xhr.readyState === XMLHttpRequest.DONE) {
+          resolve();
+        }
+
+        if (xhr.status === 200) {
+          console.log('The file was successfully deleted.');
+        } else {
+          console.log('The file has expired, or has already been deleted.');
+        }
+      };
+
+      xhr.send(JSON.stringify({ delete_token: token }));
+    });
+  }
+
+  upload() {
+    return Promise.all([
+      window.crypto.subtle.generateKey(
+        {
+          name: 'AES-CBC',
+          length: 128
+        },
+        true,
+        ['encrypt', 'decrypt']
+      ),
+      new Promise((resolve, reject) => {
+        const reader = new FileReader();
+        reader.readAsArrayBuffer(this.file);
+        reader.onload = function(event) {
+          resolve(new Uint8Array(this.result));
+        };
+      })
+    ])
+      .then(([secretKey, plaintext]) => {
+        return Promise.all([
+          window.crypto.subtle.encrypt(
+            {
+              name: 'AES-CBC',
+              iv: this.iv
+            },
+            secretKey,
+            plaintext
+          ),
+          window.crypto.subtle.exportKey('jwk', secretKey)
+        ]);
+      })
+      .then(([encrypted, keydata]) => {
+        return new Promise((resolve, reject) => {
+          let file = this.file;
+          let fileId = ivToStr(this.iv);
+          let dataView = new DataView(encrypted);
+          let blob = new Blob([dataView], { type: file.type });
+          let fd = new FormData();
+          fd.append('fname', file.name);
+          fd.append('data', blob, file.name);
+
+          let xhr = new XMLHttpRequest();
+          xhr.open('post', '/upload/' + fileId, true);
+
+          xhr.upload.addEventListener('progress', e => {
+            if (e.lengthComputable) {
+              let percentComplete = Math.floor(e.loaded / e.total * 100);
+              this.emit('progress', percentComplete);
+            }
+          });
+
+          xhr.onreadystatechange = () => {
+            if (xhr.readyState == XMLHttpRequest.DONE) {
+              resolve({
+                fileId: fileId,
+                secretKey: keydata.k,
+                deleteToken: xhr.responseText
+              });
+            }
+          };
+
+          xhr.send(fd);
+        });
+      });
+  }
+}
+
+module.exports = FileSender;