Refactor kitchensink (#99)

* [kitchensink] Use local version of SDK

* [kitchensink] Add ngrok to deps

* [kitchensink] Add GET /callback to show helper text

* [kitchensink] Handle webhook test requests

The test requests are with a specific format of replyToken, such as
'000000...'.

* [kitchensink] Add build-sdk npm script

SDK should be prepared before being installed from the example.

* [kitchensink] Use ngrok when BASE_URL is not set

* [kitchensink] Update README

Author: Hyunje Jun

examples/kitchensink/README.md

@@ -2,34 +2,75 @@
 
 A kitchen-sink LINE bot example
 
-## How to use
+## Requirements
 
-### Install deps
+Install npm dependencies:
 
-``` shell
+```bash
+npm run build-sdk # build SDK installed from local directory
 npm install
 ```
 
 Also, FFmpeg and ImageMagick should be installed to test image and video
 echoing.
 
-### Configuration
+### About local dependencies
 
-``` shell
+Currently, [`@line/bot-sdk`](package.json) is installed from local directory.
+
+```json
+{
+  "@line/bot-sdk": "../../"
+}
+```
+
+To install `@line/bot-sdk` from npm, please update the line with the following:
+
+```json
+{
+  "@line/bot-sdk": "*"
+}
+```
+
+In the case, `npm run build-sdk` needn't be run before `npm install`.
+
+## Configuration
+
+Configuration can be done via environment variables.
+
+```bash
 export CHANNEL_SECRET=YOUR_CHANNEL_SECRET
 export CHANNEL_ACCESS_TOKEN=YOUR_CHANNEL_ACCESS_TOKEN
 export BASE_URL=https://your.base.url # for static file serving
 export PORT=1234
 ```
 
-## Run
+The code above is an example of Bash. It may differ in other shells.
+
+## Run webhook server
 
-``` shell
-node .
+```bash
+npm start
 ```
 
-## Webhook URL
+With the configuration above, the webhook listens on `https://your.base.url:1234/callback`.
+
+## ngrok usage
+
+[ngrok](https://ngrok.com/) tunnels extenral requests to localhost, helps
+debugging local webhooks.
+
+This example includes ngrok inside, and it just works if no `BASE_URL` is
+set. Make sure that other configurations are set correctly.
 
 ```
-https://your.base.url/callback
+❯ npm start
+
+...
+
+It seems that BASE_URL is not set. Connecting to ngrok...
+listening on https://ffffffff.ngrok.io/callback
 ```
+
+The URL can be directly registered as the webhook URL in LINE Developers
+console.

examples/kitchensink/index.js

@@ -5,6 +5,7 @@ const express = require('express');
 const fs = require('fs');
 const path = require('path');
 const cp = require('child_process');
+const ngrok = require('ngrok');
 
 // create LINE SDK config from env variables
 const config = {
@@ -13,7 +14,7 @@ const config = {
 };
 
 // base URL for webhook server
-const baseURL = process.env.BASE_URL;
+let baseURL = process.env.BASE_URL;
 
 // create LINE SDK client
 const client = new line.Client(config);
@@ -26,6 +27,8 @@ const app = express();
 app.use('/static', express.static('static'));
 app.use('/downloaded', express.static('downloaded'));
 
+app.get('/callback', (req, res) => res.end(`I'm listening. Please access with POST.`));
+
 // webhook callback
 app.post('/callback', line.middleware(config), (req, res) => {
   // req.body.events should be an array of events
@@ -53,6 +56,10 @@ const replyText = (token, texts) => {
 
 // callback function to handle a single event
 function handleEvent(event) {
+  if (event.replyToken.match(/^(.)\1*$/)) {
+    return console.log("Test hook recieved: " + JSON.stringify(event.message));
+  }
+
   switch (event.type) {
     case 'message':
       const message = event.message;
@@ -370,5 +377,15 @@ function handleSticker(message, replyToken) {
 // listen on port
 const port = process.env.PORT || 3000;
 app.listen(port, () => {
-  console.log(`listening on ${port}`);
+  if (baseURL) {
+    console.log(`listening on ${baseURL}:${port}/callback`);
+  } else {
+    console.log("It seems that BASE_URL is not set. Connecting to ngrok...")
+    ngrok.connect(port, (err, url) => {
+      if (err) throw err;
+
+      baseURL = url;
+      console.log(`listening on ${baseURL}/callback`);
+    });
+  }
 });