Delphi HMRC test-api.service.hmrc.gov.uk/hello/world - json

Question

I'm trying the HMRC Developers HUB tutorials from:
https://developer.service.hmrc.gov.uk/api-documentation/docs/tutorials
I have tried two ways of the "Hello World", but keep getting:
{"code":"ACCEPT_HEADER_INVALID","message":"The accept header is missing or invalid"}
Example 1 REST Client:
procedure TForm1.btnTest_REST_ClientClick(Sender: TObject);
var
jValue: TJSONValue;
begin
RESTClient1.BaseURL := cbHMRC_Test_URLs.Text;
RESTRequest1.Execute;
jValue := RESTResponse1.JSONValue;
MemoContent.Text:= jValue.ToString;
end;
Example 2 TdHTTP:
procedure TForm1.btnTest_HTTPClick(Sender: TObject);
var
get_url: string;
resp: TMemoryStream;
begin
get_url := 'https://test-api.service.hmrc.gov.uk/hello/world';
resp := TMemoryStream.Create;
try
IdHttp1.Request.CustomHeaders.AddValue('Accept', 'application/vnd.hmrc.1.0+json');
IdHTTP1.Get(get_url, resp);
resp.Position := 0; // <-- add this!!
MemoContent.Lines.LoadFromStream(resp);
finally
resp.Free;
end;
end;
Both make the connection, but fail on the Header.
Any ideas about what I'm doing wrong?

Answer 1

I would suggest going with the REST components. I've used them significantly and they work quite well.
On the REST component side, your just missing the Request Accept value:
RESTRequest1.Accept := 'application/vnd.hmrc.1.0+json';
I tested your example to their hello world resource and received:
{"message":"Hello World"}
Looks like it's working.

Answer 2

For those of you struggling like me with how to implement the initial HMRC tutorials in Delphi, try the following.
Create a new application. I chose a Multi-Device / Blank Application option.
On the main form, add the following components:-
TRESTClient
TRESTRequest
TRESTResponse
TMemo
TButton
Add the System.JSON unit to the uses clause.
Set the Button1Click procedure as follows:-
procedure TForm1.Button1Click(Sender: TObject);
var
jValue: TJSONValue;
begin
RESTClient1.BaseURL := 'https://test-api.service.hmrc.gov.uk/hello/world';
RESTRequest1.Accept := 'application/vnd.hmrc.1.0+json';
RESTRequest1.Execute;
jValue := RESTResponse1.JSONValue;
Memo1.Text:= jValue.ToString;
end;
Run the program, click the button and voila!
I hope this helps someone