Use Blob messages to encode Blob and ArrayBuffer input

assets/js/phoenix/longpoll.js

@@ -6,11 +6,16 @@ import {
 import Ajax from "./ajax"
 
 let arrayBufferToBase64 = (buffer) => {
-  let binary = ""
-  let bytes = new Uint8Array(buffer)
-  let len = bytes.byteLength
-  for(let i = 0; i < len; i++){ binary += String.fromCharCode(bytes[i]) }
-  return btoa(binary)
+  return new Promise((resolve, reject) => {
+    let reader = new FileReader()
+    let blob = new Blob([buffer])
+    reader.onload = e => {
+      let dataStart = reader.result.indexOf(',')
+      resolve(reader.result.slice(dataStart + 1))
+    }
+    reader.onerror = () => reject()
+    reader.readAsDataURL(blob)
+  })
 }
 
 export default class LongPoll {
@@ -24,6 +29,7 @@ export default class LongPoll {
     this.currentBatch = null
     this.currentBatchTimer = null
     this.batchBuffer = []
+    this.sendResolver = Promise.resolve()
     this.onopen = function (){ } // noop
     this.onerror = function (){ } // noop
     this.onmessage = function (){ } // noop
@@ -118,18 +124,26 @@ export default class LongPoll {
   // pushes against an empty buffer
 
   send(body){
-    if(typeof(body) !== "string"){ body = arrayBufferToBase64(body) }
-    if(this.currentBatch){
-      this.currentBatch.push(body)
-    } else if(this.awaitingBatchAck){
-      this.batchBuffer.push(body)
-    } else {
-      this.currentBatch = [body]
-      this.currentBatchTimer = setTimeout(() => {
-        this.batchSend(this.currentBatch)
-        this.currentBatch = null
-      }, 0)
-    }
+    this.sendResolver =
+      this.sendResolver
+      .then(() => {
+        if(typeof(body) !== "string"){ return arrayBufferToBase64(body) }
+        return body
+      })
+      .then(body => {
+        if(this.currentBatch){
+          this.currentBatch.push(body)
+        } else if(this.awaitingBatchAck){
+          this.batchBuffer.push(body)
+        } else {
+          this.currentBatch = [body]
+          this.currentBatchTimer = setTimeout(() => {
+            this.batchSend(this.currentBatch)
+            this.currentBatch = null
+            this.sendResolver = Promise.resolve()
+          }, 0)
+        }
+      })
   }
 
   batchSend(messages){

assets/js/phoenix/serializer.js

@@ -9,7 +9,7 @@ export default {
   KINDS: {push: 0, reply: 1, broadcast: 2},
 
   encode(msg, callback){
-    if(msg.payload.constructor === ArrayBuffer){
+    if(msg.payload.constructor === ArrayBuffer || msg.payload.constructor === Blob){
       return callback(this.binaryEncode(msg))
     } else {
       let payload = [msg.join_ref, msg.ref, msg.topic, msg.event, msg.payload]
@@ -45,11 +45,7 @@ export default {
     Array.from(topic, char => view.setUint8(offset++, char.charCodeAt(0)))
     Array.from(event, char => view.setUint8(offset++, char.charCodeAt(0)))
 
-    var combined = new Uint8Array(header.byteLength + payload.byteLength)
-    combined.set(new Uint8Array(header), 0)
-    combined.set(new Uint8Array(payload), header.byteLength)
-
-    return combined.buffer
+    return new Blob([header, payload])
   },
 
   binaryDecode(buffer){

assets/test/serializer_test.js

@@ -34,19 +34,23 @@ describe("binary", () => {
     let buffer = binPayload()
     let bin = "\0\x01\x01\x01\x0101te\x01"
     let decoder = new TextDecoder()
-    Serializer.encode({join_ref: "0", ref: "1", topic: "t", event: "e", payload: buffer}, (result) => {
-      expect(decoder.decode(result)).toBe(bin)
-      done()
+    Serializer.encode({join_ref: "0", ref: "1", topic: "t", event: "e", payload: buffer}, (blob) => {
+      blob.arrayBuffer().then(result => {
+        expect(decoder.decode(result)).toBe(bin)
+        done()
+      })
     })
   })
 
   it("encodes variable length segments", (done) => {
     let buffer = binPayload()
     let bin = "\0\x02\x01\x03\x02101topev\x01"
     let decoder = new TextDecoder()
-    Serializer.encode({join_ref: "10", ref: "1", topic: "top", event: "ev", payload: buffer}, (result) => {
-      expect(decoder.decode(result)).toBe(bin)
-      done()
+    Serializer.encode({join_ref: "10", ref: "1", topic: "top", event: "ev", payload: buffer}, (blob) => {
+      blob.arrayBuffer().then(result => {
+        expect(decoder.decode(result)).toBe(bin)
+        done()
+      })
     })
   })