How to Prevent dialog (Basic Authentication prompt) during call of Webservice

Question

Hi

In a delphi program (running as a service) i need to call some webservices.
The calls works fine if basic Authentications is not requerired. The calls also works fine if Basic Authentication is requerired and username/password is provided (in BeforePost) using:

InternetSetOption(Data, INTERNET_OPTION_USERNAME,...
InternetSetOption(Data, INTERNET_OPTION_PASSWORD,...

But if Basic Authentication is Requeried, and username/password is not provided, the program brings up af prompt for the username/password (thats a NO-GO in a servcice).

So how can I signal that i DON'T want a prompt, but instead an error?

The problem is, as i can se it, in the SOAPHTTPTrans function THTTPReqResp.Send(const ASrc: TStream): Integer; (line 762 (second call to InternetErrorDlg i that method)).

EDIT1:
if i change the Flags in the beginning of the send method (in SOAPHTTPTRANS) to include INTERNET_FLAG_NO_AUTH, it works as i wanted.
But how do i do that without changing the SAOPHTTPTrans (if possible)?

EDIT2:

ws := THTTPRIO.Create(Self);
ws.URL := 'http://excample.com/ws.asmx';
ws.HTTPWebNode.InvokeOptions := [soIgnoreInvalidCerts];
ws.HTTPWebNode.OnBeforePost := WebServiceCallBeforePost;
AvailabilityWebservice := (ws as AvailabilityServiceSoap);
sTemp := AvailabilityWebservice.GetVersion;

Where AvailabilityServiceSoap is the interface generated using the WSDL importer.

Answer 1

You could create a new class which Inherits from THTTPReqResp and override the send method so that you can include your own flags. You should be able to set ws.HTTPWebNode to a new node using the new class.

Something Like

ws := THTTPRIO.Create(Self);
MyNewNode := MyNewClass.Create;
ws.HTTPWebNode := MyNewNode;
ws.URL := 'http://excample.com/ws.asmx';
ws.HTTPWebNode.InvokeOptions := [soIgnoreInvalidCerts];
ws.HTTPWebNode.OnBeforePost := WebServiceCallBeforePost;
AvailabilityWebservice := (ws as AvailabilityServiceSoap);
sTemp := AvailabilityWebservice.GetVersion;

Answer 2

I had this problem when trying to let Windows Live Messenger work through a web filter.

I ended up writing a small program that auto-authenticates every so often.

Hope this helps you too.

uses
  ... IdHTTP ...;

...
var
  httpGetter: TIdHTTP;
...    
httpGetter.Request.Username := username;
httpGetter.Request.Password := password;
httpGetter.HandleRedirects := True;
httpGetter.Request.BasicAuthentication := True;

//custom useragent required to let live messenger work
//this part is probably not necessary for your situation
httpGetter.Request.UserAgent := 'MSN Explorer/9.0 (MSN 8.0; TmstmpExt)';

httpGetter.Get(url,MS);
...

Answer 3

How about checking the servers authentication mode first?

http://en.wikipedia.org/wiki/Basic_access_authentication

• The client asks for a page that requires authentication but does not provide a user name and password. Typically this is because the user simply entered the address or followed a link to the page.
• The server responds with the 401 response code and provides the authentication realm.

So the client service application could send a Get and see if the response has a header like

WW-Authenticate: Basic realm="Secure Area"