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HttpClient.Get(Text, var HttpResponseMessage) Method

  • Мақала

Version: Available or changed with runtime version 1.0.

Sends a GET request to get the resource identified by the request URL.

Syntax

[Ok := ]  HttpClient.Get(Path: Text, var Response: HttpResponseMessage)

Parameters

HttpClient
 Type: HttpClient
An instance of the HttpClient data type.

Path
 Type: Text
The path the request is sent to.

Response
 Type: HttpResponseMessage
The response received from the remote endpoint.

Return Value

[Optional] Ok
 Type: Boolean
Accessing the HttpContent property of HttpResponseMessage in a case when the request fails will result in an error. If you omit this optional return value and the operation does not execute successfully, a runtime error will occur.

Ways that HttpClient.Get calls can fail

The method HttpClient.Get can fail and return false in the following ways:

  • The requestUri is not an absolute URI.
  • The request failed due to an underlying issue such as network connectivity, DNS failure, server certificate validation or timeout.
  • The request failed due to timeout.

Important

Outbound HTTP calls from apps/extensions are blocked by default and must be approved for each extension, otherwise instead of an external call, the system will display the following error message: The request was blocked by the runtime to prevent accidental use of production services.

To enable outbound HTTP calls, go to the Extension Management page in Business Central, and choose Configure. Then, on the Extension Settings page, make sure that Allow HttpClient Requests is selected. This setting must be enabled for each app/extension, including library apps.

Example (HTTP GET)

A GET request shouldn't send a body and is used (as the method name indicates) to retrieve (or get) data from a resource. To make an HTTP GET request, given an HttpClient and a URI, use the HttpClient.Get method:

    local procedure GetRequest() ResponseText: Text
    var
        Client: HttpClient;
        IsSuccessful: Boolean;
        Response: HttpResponseMessage;
        ResponseText: Text;
    begin
        IsSuccessful := Client.Get('https://jsonplaceholder.typicode.com/todos/3', Response);

        if not IsSuccessful then begin
            // handle the error
        end;

        if not Response.IsSuccessStatusCode() then begin
            HttpStatusCode := response.HttpStatusCode();
            // handle the error (depending on the HTTP status code)
        end;

        Response.Content().ReadAs(ResponseText);

        // Expected output:
        //   GET https://jsonplaceholder.typicode.com/todos/3 HTTP/1.1
        //   {
        //     "userId": 1,
        //     "id": 3,
        //     "title": "fugiat veniam minus",
        //     "completed": false
        //   }
    end;

The preceding code:

  • Makes a GET request to "https://jsonplaceholder.typicode.com/todos/3".
  • Ensures that the response is successful.
  • Reads the response body as a string.

Supported HTTP methods

The HttpClient datatype supports the following HTTP methods:

  • DELETE
  • GET
  • PATCH
  • POST
  • PUT

The following table includes links to help you get started with calling external services using different HTTP methods.

To See
Dynamically set the HTTP method from AL, set it on the HttpRequestMessage datatype and use the HttpClient.Send method to call the service. HttpClient.Send(HttpRequestMessage, var HttpResponseMessage) Method
HttpRequestMessage.Method([Text]) Method
Delete data in a service endpoint using the HTTP DELETE method. HttpClient.Delete(Text, var HttpResponseMessage) Method
Read data from a service endpoint using the HTTP GET method. HttpClient.Get(Text, var HttpResponseMessage) Method
Update data in a service endpoint using the HTTP PATCH method (no specific AL method exists for PATCH, so use HttpClient.Send). HttpClient.Send(Text, HttpContent, var HttpResponseMessage) Method
Send data to a service endpoint using the HTTP POST method. HttpClient.Post(Text, HttpContent, var HttpResponseMessage) Method
Send data to a service endpoint using the HTTP PUT method. HttpClient.Put(Text, HttpContent, var HttpResponseMessage) Method

Call external services with the HttpClient data type
HttpClient Data Type
Get Started with AL
Developing Extensions