@ably/delta-codec - npm Package Compare versions

Comparing version 1.0.1 to 1.0.2

package.json

 {
   "name": "@ably/delta-codec",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "description": "Utility library supporting those consuming delta streams from Ably without using the official JavaScript client library (e.g. MQTT and SSE applications).",
@@ -5,0 +5,0 @@ "main": "lib/index.js",

README.md

@@ -22,3 +22,3 @@ # Vcdiff Codec Library for JavaScript
 
-```javascript
+```js
 var deltaCodec = require('@ably/delta-codec');
@@ -89,3 +89,3 @@ ```
 
-### Text stream from Ably via SSE (enveloped)
+### Node.js: Text stream from Ably via SSE (enveloped)
 
@@ -96,22 +96,30 @@ By default the event data received from Ably is enveloped in JSON format.
 ```js
-const url = 'https://realtime.ably.io/sse?v=1.1&key=' + API_KEY + '&channels=' + CHANNEL_NAME;
+const deltaCodec = require('@ably/delta-codec');
+const EventSource = require('eventsource');
+
+const prefix = '[?delta=vcdiff]';
+const url = `https://realtime.ably.io/event-stream?channels=${prefix}${CHANNEL_NAME}&v=1.2&key=${APP_KEY}`;
 const eventSource = new EventSource(url);
-const decoder = new DeltaCodec.VcdiffDecoder();
-eventSource.onmessage = (event) => {
-    var message = JSON.parse(event.data);
-    let stringData = message.data;
-    try {
-        if (message.extras.delta) {
-            stringData = decoder.applyBase64Delta(stringData).asUtf8String();
-        } else {
-            decoder.setBase(stringData);
-        }
-    } catch(e) {
-        console.log(e); // TODO: Handle error.
+const decoder = new deltaCodec.CheckedVcdiffDecoder();
+eventSource.onmessage = function onEventSourceMessage(event) {
+  const message = JSON.parse(event.data);
+  let value;
+  const deltaExtras = (message.extras && message.extras.delta) ? message.extras.delta : null;
+  if (deltaExtras) {
+    if (deltaExtras.format !== 'vcdiff') {
+      throw new Error(`Delta format ${deltaExtras.format} not understood.`);
     }
-    console.log(data); // TODO: Process the received value.
+    value = decoder.applyBase64Delta(message.data, message.id, deltaExtras.from).asUtf8String();
+  } else {
+    value = message.data;
+    decoder.setBase(value, message.id);
+  }
+  console.log(`received: ${value}`);
 };
+eventSource.onerror = function onEventSourceError(event) {
+  console.log(`error: ${event.data}`);
+};
 ```
 
-### Text stream from Ably via SSE (not enveloped)
+### Node.js: Text stream from Ably via SSE (not enveloped)
 
@@ -124,42 +132,56 @@ For this example we have subscribed to Ably as our event source and specified that we do not want the inbound event data to be JSON enveloped.
 ```js
-const url = 'https://realtime.ably.io/sse?v=1.1&key=' + API_KEY + '&channels=' + CHANNEL_NAME + '&enveloped=false';
+const deltaCodec = require('@ably/delta-codec');
+const EventSource = require('eventsource');
+
+const prefix = '[?delta=vcdiff]';
+const url = `https://realtime.ably.io/event-stream?channels=${prefix}${CHANNEL_NAME}&v=1.2&key=${APP_KEY}&enveloped=false`;
 const eventSource = new EventSource(url);
-const decoder = new DeltaCodec.VcdiffDecoder();
-eventSource.onmessage = (event) => {
-    let stringData = event.data;
-    try {
-        if (VcdiffDecoder.isBase64Delta(stringData)) {
-            stringData = decoder.applyBase64Delta(stringData).asUtf8String();
-        } else {
-            decoder.setBase(stringData);
-        }
-    } catch(e) {
-        console.log(e); // TODO: Handle error.
-    }
-    console.log(data); // TODO: Process the received value.
+const decoder = new deltaCodec.VcdiffDecoder();
+eventSource.onmessage = function onEventSourceMessage(event) {
+  const stringData = event.data;
+  let value;
+  if (deltaCodec.VcdiffDecoder.isBase64Delta(stringData)) {
+    value = decoder.applyBase64Delta(stringData).asUtf8String();
+  } else {
+    value = stringData;
+    decoder.setBase(value);
+  }
+  console.log(`received: ${value}`);
 };
+eventSource.onerror = function onEventSourceError(event) {
+  console.log(`error: ${event.data}`);
+};
 ```
 
-### Binary stream from Ably via MQTT
+### Node.js: Binary stream from Ably via MQTT
 
 The raw binary data received over MQTT has no encoding or other form of envelope encapsulating it.
 We need to 'sniff' each inbound payload to identify whether it is an absolute value or a delta to be applied to the previously received value.
+In this example we are transporting UTF-8 encoded strings.
 
 ```js
-const client = mqtt.connect(url, options);
-const channelName = 'sample-app-mqtt';
-const decoder = new VcdiffDecoder();
-client.on('message', (_, payload) => {
-    let data = payload;
-    try {
-        if (VcdiffDecoder.isDelta(data)) {
-            data = decoder.applyDelta(data).asUint8Array();
-        } else {
-            decoder.setBase(data);
-        }
-    } catch(e) {
-        console.log(e); // TODO: Handle error.
-    }
-    console.log(data); // TODO: Process the received value.
+const deltaCodec = require('@ably/delta-codec');
+const mqtt = require('mqtt');
+
+const brokerUrl = `mqtts://mqtt.ably.io`;
+const options = {
+  username: APP_KEY_NAME,
+  password: APP_KEY_SECRET,
+};
+const prefix = '[?delta=vcdiff]';
+const client = mqtt.connect(brokerUrl, options);
+client.on('connect', () => {
+  client.subscribe(`${prefix}${CHANNEL_NAME}`);
 });
+const decoder = new deltaCodec.VcdiffDecoder();
+client.on('message', (topic, message) => {
+  let value;
+  if (deltaCodec.VcdiffDecoder.isDelta(message)) {
+    value = decoder.applyDelta(message).asUtf8String();
+  } else {
+    decoder.setBase(message);
+    value = message.toString();
+  }
+  console.log(`received: ${value}`);
+});
 ```
@@ -204,3 +226,4 @@
 2. Release the tagged commit to Github using `git push origin master --follow-tags`
-3. Release to NPM using `npm publish . --access public`
+3. Release to NPM using `npm publish . --access public` ([this package](https://www.npmjs.com/package/@ably/delta-codec) is configured to require that [2FA](https://docs.npmjs.com/configuring-two-factor-authentication) is used by publishers)
+4. Release to Ably's CDN using `npm run grunt -- publish-cdn` (operable by Ably staff only)
 5. Visit [tags](https://github.com/ably/delta-codec-js/tags) and draft new release for the newly created tag

No alert changes

Improved metrics

Total package byte prevSize

263801

increased by0.42%

Number of lines in readme file

225

increased by11.39%

No dependency changes