fix(body-processor): Observe the db to clear cache. Fixes #1133

Summary:

Test Plan:

Reviewers:

Subscribers:

internal_packages/message-list/lib/message-item-body.cjsx

@@ -22,20 +22,12 @@ class MessageItemBody extends React.Component
       processedBody: undefined
 
   componentWillMount: =>
-    @_prepareBody(@props)
+    @_unsub = MessageBodyProcessor.processAndSubscribe(@props.message, @_onBodyChanged)
 
-  shouldComponentUpdate: (nextProps, nextState) ->
+  componentWillReceiveProps: (nextProps) ->
-    not Utils.isEqualReact(nextProps, @props) or
+    if nextProps.message.id isnt @props.message.id
-    not Utils.isEqualReact(nextState, @state)
+      @_unsub?()
-
+      @_unsub = MessageBodyProcessor.processAndSubscribe(nextProps.message, @_onBodyChanged)
-  componentWillUpdate: (nextProps, nextState) =>
-    if not Utils.isEqualReact(nextProps.message, @props.message)
-      @_prepareBody(nextProps)
-
-  _prepareBody: (props) ->
-    MessageBodyProcessor.resetCache(props.message)
-    @_unsub?()
-    @_unsub = MessageBodyProcessor.processAndSubscribe(props.message, @_onBodyChanged)
 
   componentWillUnmount: =>
     @_unsub?()

src/flux/stores/message-body-processor.coffee

@@ -1,96 +0,0 @@
-_ = require "underscore"
-crypto = require "crypto"
-MessageUtils = require '../models/message-utils'
-MessageStore = require './message-store'
-
-MessageBodyWidth = 740
-
-class MessageBodyProcessor
-
-  constructor: ->
-    @_subscriptions = []
-    @resetCache()
-
-  resetCache: (msg) ->
-    if msg
-      key = @_key(msg)
-      delete @_recentlyProcessedD[key]
-    else
-      # Store an object for recently processed items. Put the item reference into
-      # both data structures so we can access it in O(1) and also delete in O(1)
-      @_recentlyProcessedA = []
-      @_recentlyProcessedD = {}
-      for {message, callback} in @_subscriptions
-        callback(@process(message))
-
-  # It's far safer to key off the hash of the body then the [id, version]
-  # pair. This is because it's theoretically possible for the body to
-  # change without the version updating. When drafts sent N1 used to
-  # optimistically display the message before the latest changes
-  # persisted.
-  _key: (message) ->
-    return message.id + crypto.createHash('md5').update(message.body ? "").digest('hex')
-
-  version: ->
-    @_version
-
-  processAndSubscribe: (message, callback) =>
-    _.defer => callback(@process(message))
-    sub = {message, callback}
-    @_subscriptions.push(sub)
-    return =>
-      @_subscriptions.splice(@_subscriptions.indexOf(sub), 1)
-
-  process: (message) =>
-    body = message.body
-    return "" unless _.isString message.body
-
-    key = @_key(message)
-    if @_recentlyProcessedD[key]
-      return @_recentlyProcessedD[key].body
-
-    # Give each extension the message object to process the body, but don't
-    # allow them to modify anything but the body for the time being.
-    for extension in MessageStore.extensions()
-      continue unless extension.formatMessageBody
-      latestBody = body
-      try
-        virtual = message.clone()
-        virtual.body = body
-        extension.formatMessageBody({message: virtual})
-        body = virtual.body
-      catch err
-        NylasEnv.reportError(err)
-        body = latestBody
-
-    # Find inline images and give them a calculated CSS height based on
-    # html width and height, when available. This means nothing changes size
-    # as the image is loaded, and we can estimate final height correctly.
-    # Note that MessageBodyWidth must be updated if the UI is changed!
-
-    while (result = MessageUtils.cidRegex.exec(body)) isnt null
-      imgstart = body.lastIndexOf('<', result.index)
-      imgend = body.indexOf('/>', result.index)
-
-      if imgstart != -1 and imgend > imgstart
-        imgtag = body.substr(imgstart, imgend - imgstart)
-        width = imgtag.match(/width[ ]?=[ ]?['"]?(\d*)['"]?/)?[1]
-        height = imgtag.match(/height[ ]?=[ ]?['"]?(\d*)['"]?/)?[1]
-        if width and height
-          scale = Math.min(1, MessageBodyWidth / width)
-          style = " style=\"height:#{height * scale}px;\" "
-          body = body.substr(0, imgend) + style + body.substr(imgend)
-
-    @addToCache(key, body)
-    body
-
-  addToCache: (key, body) ->
-    if @_recentlyProcessedA.length > 50
-      removed = @_recentlyProcessedA.pop()
-      delete @_recentlyProcessedD[removed.key]
-    item = {key, body}
-    @_recentlyProcessedA.unshift(item)
-    @_recentlyProcessedD[key] = item
-
-
-module.exports = new MessageBodyProcessor()

src/flux/stores/message-body-processor.es6

@@ -0,0 +1,150 @@
+import _ from 'underscore';
+import Message from '../models/message';
+import MessageUtils from '../models/message-utils';
+import MessageStore from './message-store';
+import DatabaseStore from './database-store';
+
+const MessageBodyWidth = 740;
+
+class MessageBodyProcessor {
+  constructor() {
+    this._subscriptions = [];
+    this.resetCache();
+
+    DatabaseStore.listen((change) => {
+      if (change.objectClass === Message.name) {
+        change.objects.forEach(this.updateCacheForMessage);
+      }
+    });
+  }
+
+  resetCache() {
+    // Store an object for recently processed items. Put the item reference into
+    // both data structures so we can access it in O(1) and also delete in O(1)
+    this._recentlyProcessedA = [];
+    this._recentlyProcessedD = {};
+    for (const {message, callback} of this._subscriptions) {
+      callback(this.process(message));
+    }
+  }
+
+  updateCacheForMessage = (changedMessage) => {
+    // check that the message exists in the cache
+    const changedKey = this._key(changedMessage);
+    if (!this._recentlyProcessedD[changedKey]) {
+      return;
+    }
+
+    // remove the message from the cache
+    delete this._recentlyProcessedD[changedKey];
+    this._recentlyProcessedA = this._recentlyProcessedA.filter(({key}) =>
+      key !== changedKey
+    );
+
+    // reprocess any subscription using the new message data. Note that
+    // changedMessage may not have a loaded body if it wasn't changed. In
+    // that case, we use the previous body.
+    const subscriptions = this._subscriptions.filter(({message}) =>
+      message.id === changedMessage.id
+    );
+
+    if (subscriptions.length > 0) {
+      const updatedMessage = changedMessage.clone();
+      updatedMessage.body = updatedMessage.body || subscriptions[0].message.body;
+      const output = this.process(updatedMessage);
+      for (const subscription of subscriptions) {
+        subscription.callback(output);
+        subscription.message = updatedMessage;
+      }
+    }
+  }
+
+  _key(message) {
+    // It's safe to key off of the message ID alone because we invalidate the
+    // cache whenever the message is persisted to the database.
+    return message.id;
+  }
+
+  version() {
+    return this._version;
+  }
+
+  processAndSubscribe(message, callback) {
+    _.defer(() => callback(this.process(message)));
+    const sub = {message, callback}
+    this._subscriptions.push(sub);
+    return () => {
+      this._subscriptions.splice(this._subscriptions.indexOf(sub), 1);
+    }
+  }
+
+  process(message) {
+    let body = message.body;
+    if (!_.isString(message.body)) {
+      return "";
+    }
+
+    const key = this._key(message);
+    if (this._recentlyProcessedD[key]) {
+      return this._recentlyProcessedD[key].body;
+    }
+
+    // Give each extension the message object to process the body, but don't
+    // allow them to modify anything but the body for the time being.
+    for (const extension of MessageStore.extensions()) {
+      if (!extension.formatMessageBody) {
+        continue;
+      }
+      const previousBody = body;
+      try {
+        const virtual = message.clone();
+        virtual.body = body;
+        extension.formatMessageBody({message: virtual});
+        body = virtual.body;
+      } catch (err) {
+        NylasEnv.reportError(err);
+        body = previousBody;
+      }
+    }
+
+    // Find inline images and give them a calculated CSS height based on
+    // html width and height, when available. This means nothing changes size
+    // as the image is loaded, and we can estimate final height correctly.
+    // Note that MessageBodyWidth must be updated if the UI is changed!
+    let result = MessageUtils.cidRegex.exec(body);
+
+    while (result !== null) {
+      const imgstart = body.lastIndexOf('<', result.index);
+      const imgend = body.indexOf('/>', result.index);
+
+      if ((imgstart !== -1) && (imgend > imgstart)) {
+        const imgtag = body.substr(imgstart, imgend - imgstart);
+        const widthMatch = imgtag.match(/width[ ]?=[ ]?['"]?(\d*)['"]?/);
+        const width = widthMatch ? widthMatch[1] : null;
+        const heightMatch = imgtag.match(/height[ ]?=[ ]?['"]?(\d*)['"]?/);
+        const height = heightMatch ? heightMatch[1] : null;
+        if (width && height) {
+          const scale = Math.min(1, MessageBodyWidth / width);
+          const style = ` style="height:${height * scale}px;" `
+          body = body.substr(0, imgend) + style + body.substr(imgend);
+        }
+      }
+
+      result = MessageUtils.cidRegex.exec(body);
+    }
+    this.addToCache(key, body);
+    return body;
+  }
+
+  addToCache(key, body) {
+    if (this._recentlyProcessedA.length > 50) {
+      const removed = this._recentlyProcessedA.pop()
+      delete this._recentlyProcessedD[removed.key]
+    }
+    const item = {key, body};
+    this._recentlyProcessedA.unshift(item);
+    this._recentlyProcessedD[key] = item;
+  }
+}
+
+module.exports = new MessageBodyProcessor();