Customizing the log file name using IBinder interface

1. Navigate to the code editor of the RegisterUser function.
2. Remove the TextWriter object and replace it with the variable binder of type IBinder. This is the new signature of the Run method with the changes highlighted:

        public static void Run(HttpRequestMessage req, 
                               TraceWriter log,
                               CloudTable objUserProfileTable,
                               out string objUserProfileQueueItem,
                               out Mail message,
                               IBinder binder,
                               out SMSMessage objsmsmessage
                               )

1. Let's grab the data of the new record that's inserted into the Azure Table storage service. We will be using the GUID (RowKey) of the newly created record in the Table storage. Make the changes highlighted in the following piece of code:

        TableResult objTableResult = 
         objUserProfileTable.Execute(objTblOperationInsert);
        UserProfile objInsertedUser = 
        (UserProfile)objTableResult.Result;

1. As we have removed the TextWriter object, the line of code outputBlob.WriteLine(emailContent); will no longer work. Let's replace it with the following piece of code:

        using (var emailLogBloboutput = binder.Bind<TextWriter>(new 
         BlobAttribute($"userregistrationemaillogs/
         {objInsertedUser.RowKey}.log")))    
        {
           emailLogBloboutput.WriteLine(emailContent);
        } 

1. Let's run a test using the same request payload that we have used in the previous recipes.
2. You will see the email log file that is created using the RowKey of the new record stored in the Azure Table storage, as shown in the following screenshot: