Question

I’ve got a asmx service that takes a single int parameter. I can open the URL to the service and see the service description screen. From here I can enter the query parameters into a form and invoke the web service.

Is there any way to invoke a web service directly from a URL/query string?

This doesnt work:

http://localhost:4653/MyService.asmx?op=MyWebMethod&intParameter=1

Any ideas? I’d really like to be able to do this from a standard link due to some deployment issues. Am I going to have to wrap the request in a normal aspx page?

Answer 1

You can decorate your method to allow HTTP GET requests, which should in turn do what you’re looking for like so:

[WebMethod]  
[ScriptMethod(UseHttpGet=true)]
public string MyNiftyMethod(int myint)
{
    // ... code here
}

And edit the web.config :

<system.web>
<webServices>
  <protocols>
    <add name="HttpGet"/>
  </protocols>

Then you’ll be able to call this method like so:

http://mysite.com/Service.asmx/MyNiftyMethod?myint=12345

EDIT: Note that this method of performing GET requests does come with some security risks. According to the MSDN documentation for UseHttpGet:

Setting the UseHttpGet property to
true might pose a security risk for
your application if you are working
with sensitive data or transactions.
In GET requests, the message is
encoded by the browser into the URL
and is therefore an easier target for
tampering.