Developing a C# Event Function Using IDE

Constraints

When calling a function using APIG, isBase64Encoded is valued true by default, indicating that the request body transferred to FunctionGraph is encoded using Base64 and must be decoded for processing.

{
    "isBase64Encoded": true|false,
    "statusCode": httpStatusCode,
    "headers": {"headerName":"headerValue",...},
    "body": "..."
}

Viewing the.NET Version

Run the following command to view the installed .NET version:

dotnet --info

Figure 1 Viewing the.NET Version

Step 1: Creating a Project

1. Open the IDE and create a C# compilation project, as shown in Figure 2. Select net6.0 as the framework.
   Figure 2 Creating a project
   
2. Check the directory after the project is created.
   Figure 3 Project directory structure
   
3. Download the .dll file of the function and decompress the .dll file to the directory shown in Figure 4.
   Figure 4 Decompressing the .dll file to the directory
   
4. Edit the ConsoleApp1.csproj file in the project to enable the project to reference the downloaded .dll file. The following information is added to the file:

   <ItemGroup>
       <Reference Include="HC.Serverless.Function.Common, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null">
           <HintPath>../HC.Serverless.Function.Common.dll</HintPath>
       </Reference>
   </ItemGroup>

   After the editing is complete, the content of the cspoj file is shown in Figure 5.

   Figure 5 csproj file
   
5. Edit the Program.cs file in the project and replace the original code in the file with the following code:

   using HC.Serverless.Function.Common;
   using System;
   using System.IO;
   using System.Text;
   
   namespace src
   {
       class Program
       {
           static void Main(string[] args)
           {
               Console.WriteLine("Hello World!");
           }
           public Stream myFunc(Stream input,IFunctionContext context)
           {
               string payload = "";
               if (input != null && input.Length > 0)
               {
                   byte[] buffer = new byte[input.Length];
                   input.Read(buffer, 0, (int)(input.Length));
                   payload = Encoding.UTF8.GetString(buffer);
               }
               var ms = new MemoryStream();
               using (var sw = new StreamWriter(ms))
               {
                   sw.WriteLine("CSharp runtime test(v1.0.2)");
                   sw.WriteLine("=====================================");
                   sw.WriteLine("Request Id:       {0}", context.RequestId);
                   sw.WriteLine("Function Name:    {0}", context.FunctionName);
                   sw.WriteLine("Function Version: {0}", context.FunctionVersion);
                   sw.WriteLine("Project:          {0}", context.ProjectId);
                   sw.WriteLine("Package:          {0}", context.PackageName);
                   sw.WriteLine("Security Access Key:       {0}", context.SecurityAccessKey);
                   sw.WriteLine("Security Secret Key:       {0}", context.SecuritySecretKey);
                   sw.WriteLine("Security Token:            {0}", context.SecurityToken);
                   sw.WriteLine("Token:            {0}", context.Token);
                   sw.WriteLine("User data(ud-a):  {0}", context.GetUserData("ud-a"));
                   sw.WriteLine("User data(ud-notexist): {0}", context.GetUserData("ud-notexist", ""));
                   sw.WriteLine("User data(ud-notexist-default): {0}", context.GetUserData("ud-notexist", "default value"));
                   sw.WriteLine("=====================================");
   
                   var logger = context.Logger;
                   logger.Logf("Hello CSharp runtime test(v1.0.2)");
                   sw.WriteLine(payload);
               }
               return new MemoryStream(ms.ToArray());
           }
       }
   }

6. As shown in Figure 6, click the compilation button in the IDE to compile the C# project.
   Figure 6 C# compilation button
   
7. Compress all compiled files in the ConsoleApp1\bin\Debug\net6.0 directory into a .zip file, as shown in Figure 7. Do not compress the entire folder. Ensure that files are displayed after the package is decompressed.
   Figure 7 Compressing compiled files
   

Step 2: Testing the Function

1. Log in to the FunctionGraph console and click Create Function in the upper right corner.
2. Create a C# event function from scratch and click Create Now as shown inFigure 8. The function details page is displayed.
   Figure 8 Creating a function
   

3. Upload the ZIP file compressed in 7. After the code package is uploaded, it will be automatically deployed on the FunctionGraph console, as shown in Figure 9.
   Figure 9 Uploading code
   
4. Choose Configuration > Basic Settings, set Handler to ConsoleApp1::src.Program::myFunc, and click Save, as shown in Figure 10.
   

   The file generated after the C# project in the sample project package is compiled is ConsoleApp1.dll. Therefore, the assembly name of the function handler is ConsoleApp1.

   Figure 10 Configuring the function handler
   
5. Return to the Code tab page, click Test to configure a blank test event.
6. Select the created blank test event, as shown in Figure 11, and click Test to view the function execution result.
   Figure 11 Testing the function
   

Execution Result

The execution result consists of the function output, summary, and log output.

{
    "errorMessage": "",
    "errorType": ""
}