AX / Dynamics 365 For Finance and Operations blog

This is a simple example of how to call external web services from D365FO without using any C# DLL files. Just plain X++ code. As sample External Web Service, I have selected Microsoft Flow. Azure Logic Apps will be similar.

Create a test Microsoft Flow

Let’s create a simple Microsoft Flow that will be triggered by a POST method. Receive some JSON as an input parameter. Do nothing. And then, Send a 200 response with some JSON text.

Please find below the full Microsoft Flow text

Please find animated GIF below how to create this Microsoft Flow

X++ code

main() method

Just create an instance of the class and call the makePOST() method.

makePOST() method

Execute all logic inside X++. Please find the main points of interest below.
• URL – the endpoint of our Microsoft Flow. The address that you have copied from Microsoft Flow after saving.
• requestContent – JSON text that we are going to send to Microsoft Flow
• configureHttpClient() – method to configure HTTP call

configureHttpClient() method

Prepare and configure HTTP call
• Enable TLS 1.2 security protocol
• Validate URL
• Create request. The instance of HttpRequestMessage class. With method POST.
• Update header. Add a correct content type to pass JSON as an input parameter.

X++ code

Please find sample X++ code below

using System.Net;

using System.Net.Http;

 

/// <summary>

///     How to call Microsoft Flow / Logic App from X++ code

/// </summary>

class CiePOSTmsFlow

{

    private HttpRequestMessage          request;

    private System.Net.Http.HttpClient  httpClient;

    private str                         requestContent;

 

    /// <summary>

    ///     main method

    /// </summary>

    /// <param name = "_args"></param>

    public static void main(Args _args)

    {

        CiePOSTmsFlow   postClass = new CiePOSTmsFlow();

 

        postClass.makePOST();

    }

 

    /// <summary>

    ///     Make a POST call to specified URL

    /// </summary>

    public void makePOST()

    {

        System.Net.Http.HttpResponseMessage response;

        const str URL = 'https://prod-38.westus.logic.azure.com:443/workflows/92375d07a20f49f0af0c6ef5ecdcd0dc/triggers/manual/paths/invoke?api-version=2016-06-01&sp=%2Ftriggers%2Fmanual%2Frun&sv=1.0&sig=xUL92bTtRiS4bGK0BEscSmpZoryU8UOxL52uNQR_bto'; //Microsoft Flow / Logic App endpoint

 

        try

        {

            requestContent = '{"name" : "JSON parameter1",  "description" : "Test JSON"   }'; //test JSON

            this.ConfigureHttpClient(URL);

 

            if(request != null)

            {

                response = httpClient.SendAsync(request).Result;

 

                if(!response.IsSuccessStatusCode)

                {

                    Info("MS Flow response is not successful. Please find details below.");

                    warning(strFmt(response.Content.ReadAsStringAsync().Result));

                }

                else

                {

                    Info("MS Flow has been called successful");

                    Info(strFmt(response.Content.ReadAsStringAsync().Result));

                }

            }

        }

        catch

        {

            warning("Error in calling MS Flow");

        }

 

    }

 

    /// <summary>

    /// Configure HTTP Client

    /// </summary>

    /// <param name = "_url">URL</param>

    private void ConfigureHttpClient(str _url = '')

    {

        System.Net.ServicePointManager::set_SecurityProtocol(System.Net.SecurityProtocolType::Tls12);

 

        httpClient = new System.Net.Http.HttpClient();

        if(!_url)

        {

            warning("No URL Provided");

        }

        else

        {

            httpClient.BaseAddress = new System.Uri(_url);

            System.Net.Http.Headers.HttpHeaders requestHeaders = httpClient.DefaultRequestHeaders;

 

            request = new HttpRequestMessage(HttpMethod::Post,  httpClient.BaseAddress);

 

            if(requestContent)

            {

                request.Content =  new StringContent(requestContent);

                requestHeaders = request.Content.Headers;

                requestHeaders.Remove("Content-Type");

                //https://www.json.org/index.html

                //A string is a sequence of zero or more Unicode characters, wrapped in double quotes, using backslash escapes. A character is represented as a single character string.

                //The application/json entry in the IANA registry has a note:

                //Note:  No "charset" parameter is defined for this registration.

                //Adding one really has no effect on compliant recipients.

                requestHeaders.Add("Content-Type", "application/json");

                //requestHeaders.Add("Ocp-Apim-Subscription-Key", sKey);

                requestContent = "";

            }

        }

 

    }

 

}

Test run

Let’s compile it and run. First run should be successful. If not, please make sure that you have copied URL address from Microsoft Flow to your X++ code.

Let’s test failure scenarios as well. Switch off Microsoft Flow and run our class again. You should see error message and receive response from Microsoft Flow.