Salesforce Lightning Connect to integrate with oData providers

Lightning Connect is a great offering from Salesforce that will allow us to integrate our salesforce org with an external data source which can expose oData rest APIs. The beauty of this integration is that it can be setup with just point and click steps in Salesforce. 

The main requirement is that the external data source should expose oDATA services. I will explain what oData is below and then we can talk about the advantages of using this form of integration in Salesforce.

oData 

According to oData.org, oData is the best way to do REST API integration (there may be others who disagree but we wont go there :) ). As you already know REST APIs expose data in json format from a source and are accessed via unique URI end points. oData enables the creation and consumption of REST APIs identified using URLs and defined in a data model, using simple HTTP messages.

It is also called as ODBC for the web sometimes. Following this protocol, it is possible to setup services exposing REST api urls that expose data out of a database. I will write on how I did the same for a POSTGRES database table in a future post.

Now an oData service exposes a metadata url endpoint which describes the structure/schema of the data it is exposing. For an example, please see below metadata endpoint and its xml output for something i created on Heroku -

If you examine the xml carefully, it mentions couple of things. At the very top, it says m:DataServiceVersion="2.0". This indicates the version of the protocol here is oData 2.0 . Salesforce supports both oData 2.0 and oData 4.0 standards.

Next you will see it exposes a schema with two entities - Account and Servicehistory. These are two tables whose data is exposed via the service.

Though the metadata url returns data in xml format, the actual end point for accessing data can return it in different formats like json, etc.

for ex: https://whispering-woodland-8378.herokuapp.com/odata/account.svc/Account

Now why is it so special in Salesforce?

1. we can setup an integration with the oData service using just point and click steps
2. the entities I mentioned above while discussing the metadata service, gets exposed in Salesforce as External Objects. They are just like Custom objects. We can configure salesforce features like object CRUD settings, page layouts, setup relationships with other objects, setup chatter feeds etc on an external object. Remember we are setting up all these on externally integrated data. That is powerful!
3. External objects can be searched in the global search bar as well.

Consider building all that for an external integration source using APEX or Visualforce!

Here is a screenshot of how my oData service sends data back -

Now lets figure out how to setup the external data source and an external data object is Salesforce. 

Now, an important note - I did not configure any authentication for my oData service so this blog will not talk about authentication setup.

Steps to setup an external data source -

• In your Salesforce org, go to Setup -> External Data Stores. Click the New External Data Source button
• Set a name for the External data source. Since our data service is 2.0, we will choose Type as Lightning Connect: OData 2.o.  Set the URL to the endpoint of the odata service. 
• If you want to allow to edit the data in the external system, set "Allow Create, Edit and Delete" to true. I am going to leave it unchecked as I want the integration to be read only.
• I am also setting the Identity Type and Authentication Protocol  as No Authentication since my oData service is setup without authentication for now. (Something i need to work on!). This is how my setup looks like -

• Now click the Validate and Sync button. This will validate the connection to the service. It will also read the metadata endpoint and show the possible entities (external objects) it can create.
• On selecting the tables and proceeding, it will automatically create the external object, its fields based on the columns exposed from the service, its page layout, etc. Its practically everything you need for exposing this to your users :). Here is a screenshot of my external object that got created -

You will notice the object's name ends with __x instead of __c 

• Now you can create a Tab and link it to the external object you just created.
• Expose this tab to required profiles. 

Thats it, now test your integration by accessing the tab you just created. if you setup everything correctly, the data should show up correctly as it is in the external data source - 

Here is my external data source and its data - 

and here is how the data will appear in Salesforce -

Cool, isnt it? Hope you find this post useful.