Build the script class
In this unit, you'll explore how to build your C# script class to implement your transformation logic.
Custom code that's used with a connector must meet the following requirements:
The class name must be Script.
The Script class must implement ScriptBase.
The Script class must implement a method named ExecuteAsync.
Custom code must take fewer than five seconds to run.
Custom code must be less than 1 MB in total.
Only one Script file or class is supported.
Explore ScriptBase
ScriptBase is a class that the custom connector infrastructure provides with supporting helper methods and interfaces. Your Script class needs to use this abstract class as its base class.
public class Script : ScriptBase
{
public override Task<HttpResponseMessage> ExecuteAsync()
{
// Your code here
}
}
In addition to the ExecuteAsync method, this class also has the CreateJsonContent helper method that you use to create a StringContent object from the serialized JSON. For example, in the following code, the CreateJsonContent helper method populates response.Content from the transformed response that was built.
// Wrap the original JSON object into a new JSON object with just one key ('wrapped')
var newResult = new JObject
{
["wrapped"] = result,
};
response.Content = CreateJsonContent(newResult.ToString());
The ScriptBase class also provides a CancellationToken property. If you make calls by using SendAsync, you'll use the CancellationToken property. If the request takes too long or a cancellation is requested, the method signals the CancellationToken that's passed to it.
The ScriptBase class also has a Context public property, which is available to your logic to provide context for the request that's being processed. The Context property is of the type IScriptContext and has the following useful properties and methods:
OperationId - This property is most useful when you need to identify which operation is being processed so that your logic can provide the correct transformations.
Request - This method is the HttpRequestMessage for the operation that's being processed. If you need to transform the request, you modify this method, and then pass it to SendAsync to send the request to the service.
Logger - This method provides you with an instance of an ILogger that you can use to log diagnostic information from your code to the Code Logs for the connector operation.
SendAsync - Use this property to send an HTTP request to the service. You should use this method instead of making your own HttpClient.SendAsync call.
Compile your code locally
Compiling your code locally can help make it easier for you to identify compilation problems. To compile your code locally, you'll need to create a project on your local computer, and then create files for the ScriptBase class and the IScriptContext interface. You'll copy the code for these files from the Definition of supporting classes and interfaces documentation.
The Microsoft/MTC_CustomConnectorCodeProject open-source project on GitHub can also be helpful for local development. This project provides a console project presetup for custom code development.
Supported namespaces
The custom code that you implement is limited to a set of supported namespaces. These namespaces are mostly a collection of common System.* namespaces, including logging and Newtonsoft JSON, to help support the logic in your custom code. For a complete list of the currently supported namespaces, go to Supported namespaces.
Additionally, your custom code might not reference any other .NET assemblies, so it's limited to the logic that you put in your uploaded script.
Other custom code examples
To learn more about different types of transformations that you'll complete by using custom code, you can browse examples of published Microsoft Power Platform connectors. By searching for ScriptBase on the PowerPlatformConnectors public repository, you can view the current connectors that implement custom code.