This blog post is a contribution from Jaishree Thiyagarajan, an engineer with the SharePoint Developer Support team.
Update: Though this post title says “HOW TO: Create a Remote Event Receiver for a SharePoint Hosted App”, behind the scenes, Visual Studio adds a web project, associates remote event receiver service to the web project and changes the app from SharePoint Hosted App to Autohosted app. We just wanted to call this out to avoid any confusion.
Let’s first create a SharePoint Hosted App.
Choose “SharePoint-Hosted” option for “How do you want to host your app for SharePoint” in VS 2012.
Now right-click the AppManifest.xml and open with XML editor.
Make sure that you have an internal element within the AppPrincipal element (as shown below).
Here’s my complete AppManifest.xml.
Let’s first add a list within the app; so that whenever an item it added, the remote event receiver will be invoked.
Right-click the project and add “New Item”.
Choose List and give it a name, e.g., “MySampleList”.
Now, let’s add a remote event receiver. Right-click solution explorer and click “Add” and then “New Item”. Choose “Remote Event Receiver” and give it a name, e.g., “MyReR” and click “Add”.
Choose the event receiver. For e.g., let’s use “Item was Added” (ItemAdded – Asynchronous) event.
Once you click “Finish”, a web application is created with a web service that contains a code file.
!!IMPORTANT!! At this time, this is not really a SharePoint-hosted app. VS creates a web application behind the scenes, which actually makes this an Auto-hosted app. This is because remote event receivers does not work with SharePoint-hosted apps for the following reasons:
2. Remote events in SharePoint require a WCF service to call back when a remote event occurs. Again in other words, remote events requires server side code.
3. The only way to host a WCF service for SharePoint to call back when a remote event occurs is to host the service in a remote web project.
4. Thus you see a remote web project being added to the project you created above. Your app will now be an Auto-hosted app and NOT SharePoint-hosted.
5. Auto-hosted app means that you do not have to worry about hosting the remote web project as SharePoint will deploy and host the remote project for you (in Windows Azure web sites).
So, if you want to handle events, your app needs to be either an Auto-hosted app or a Provider-hosted app. Remote events (app events and remote event receivers) are NOT supported in SharePoint-hosted apps.
Now, coming back to the walk-through, if you see the code file of the service, you’d see two methods.
1. ProcessEvent(): This is a synchronous event that handles events that occur before an action occurs. Such as when a user adds or deletes a list item. Two way event that can handle current events (“-ing”) that can callback to SharePoint.
2. ProcessOneWayEvent(): This is a asynchronous event that handles events that occur after an action occurs. Such as after a user adds an item to a list or deletes an item from a list. This is one-way event that can handle past events (“-ed”).
Add the following code to “ProcessOneWayEvent” as we chose to implement the “Item was added” event. The below code just appends the string “changed by RER” to the title of a list item.
Now, copy the URL from the properties window of the web application and paste it in the URL section of the elements.xml file of the event receiver of the SharePoint App.
Here’s the URL I see in my properties window.
Your updated XML should look like the one shown below. NOTE: I’ve added the receiver to just one list instance and not to a list template.
Now, last but not the least, add the below XsltListViewWebPart to the default.aspx page of the SharePoint App, so that we can add items to the list that has been created. Make sure to update the ListUrl property correctly.
Now, click F5 and deploy the App. While deploying, you’ll be asked to trust the App. Hit the “Trust It” button.
Try adding items to the list named “MySampleList” and see SharePoint 2013 remote event receivers in action. I’ve added an item “RER is cool”. The remote event receiver changed the title as “RER is cool changed by RER”.
Attaching a sample for you to quickly try SharePoint 2013 remote event receivers Download Zipped SampleSPApp
Here are a few more references on this topic:
If you have not already done so, download and install the Microsoft Office Developer Tools for Visual Studio 2012 tool set for building SharePoint solutions for SharePoint 2010 and SharePoint 2013 using Visual Studio 2012.
Hope this post was helpful!