Calling a Web service inside sql server

Question

I have a web-service with the following methods (c#):

    [WebMethod]
    public string HelloWorld1(string a)
    {
        return "Hello World - " + a.ToString();
    }

    [WebMethod]
    public string HelloWorld2()
    {
        return "Hello World";
    }

I am trying to use it inside a sql-server procedure with the following code:

...

-- URL 1
set @url = 'http://localhost/ws/ws1.asmx/HelloWorld2'

-- URL 2
--set @url = 'http://localhost/ws/ws1.asmx/HelloWorld1?a=amama'

EXEC msdb.dbo.sp_OACreate 'MSXML2.XMLHTTP', @OBJ OUT    
EXEC msdb.dbo.sp_OAMethod @OBJ, 'Open', NULL, 'post', @URL , false
EXEC msdb.dbo.sp_OAMethod @OBJ, 'send'
EXEC msdb.dbo.sp_OAGetProperty @OBJ, 'responseText', @RESPONSE OUT
SELECT @RESPONSE [response]
EXEC msdb.dbo.sp_OADestroy @OBJ

When I use the first URL 1, I get the desired response. But when I use URL 2, the following error is showed:

 System.InvalidOperationException: Request format is invalid .
   em System.Web.Services.Protocols.HttpServerProtocol.ReadParameters()
   em System.Web.Services.Protocols.WebServiceHandler.CoreProcessRequest()

Could you please tell me what is wrong?

Answer 1

When using the sp_OAMethod use the GET method and as an enhancement you could try parameterising the stored procedure as follows:

CREATE PROCEDURE [dbo].[sp_CallWebService]
@Param varchar(20) = NULL

AS
    DECLARE @obj INT
    DECLARE @sUrl VARCHAR(200)
    DECLARE @response VARCHAR(8000)

    SET @sUrl = 'http://localhost/ws/ws1.asmx/HelloWorld1?a='+ @Param +''

    EXEC sp_OACreate 'MSXML2.ServerXMLHttp', @obj OUT    
    EXEC sp_OAMethod @obj, 'Open', NULL, 'GET', @sUrl , false
    EXEC sp_OAMethod @obj, 'send'
    EXEC sp_OAGetProperty @obj, 'responseText', @response OUT

    SELECT @response [response]
    EXEC sp_OADestroy @obj

RETURN

You can then execute the stored procedure with the argument supplied:

EXEC [dbo].[sp_CallWebService] 'amana'