Allow application to optionally parse messages before being displayed

src/containers/Chat/index.js

@@ -20,10 +20,44 @@ import Input from 'components/Input'
 import './style.scss'
 
 const MAX_GET_MEMORY_TIME = 10 * 1000 // in ms
+const MAX_APP_PARSE_TIME = 3 * 1000 // in ms
 const FAILED_TO_GET_MEMORY = 'Could not get memory from webchatMethods.getMemory :'
+const FAILED_TO_PARSE = 'Application could not parse the response from backend : '
 const WRONG_MEMORY_FORMAT
   = 'Wrong memory format, expecting : { "memory": <json>, "merge": <boolean> }'
 
+const getApplicationParse =  messages  => {
+  return new Promise(resolve => {
+    if (!window.webchatMethods || !window.webchatMethods.applicationParse) {
+      return resolve()
+    }
+    // so that we process the message in all cases
+    setTimeout(resolve, MAX_APP_PARSE_TIME)
+    try {
+      const applicationParseResponse = window.webchatMethods.applicationParse(messages)
+      if (!applicationParseResponse) {
+        return resolve()
+      }
+      if (applicationParseResponse.then && typeof applicationParseResponse.then === 'function') {
+        // the function returned a Promise
+        applicationParseResponse
+          .then(applicationParse => resolve())
+          .catch(err => {
+            console.error(FAILED_TO_PARSE)
+            console.error(err)
+            resolve()
+          })
+      } else {
+        resolve()
+      }
+    } catch (err) {
+      console.error(FAILED_TO_PARSE)
+      console.error(err)
+      resolve()
+    }
+  })
+}
+
 @connect(
   state => ({
     token: state.conversation.token,
@@ -61,6 +95,7 @@ class Chat extends Component {
     const { messages, show } = nextProps
 
     if (messages !== this.state.messages) {
+      getApplicationParse(messages)
       this.setState({ messages }, () => {
         const { getLastMessage } = this.props
         if (getLastMessage) {