How do I use HttpWebRequest with GET method
Solution 1
This is specified in the documentation. Basically GET requests aren't meant to contain bodies, so there's no sensible reason to call BeginGetRequestStream
.
Solution 2
Does it make sense for a GET request to send a Content-Type? Did you try removing the third line?
Solution 3
BeginGetRequestStream is used to get a stream specifically for writing data to the request. This is not applicable to GET requests.
The documentation for the BeginGetRequestStream method states explicitly that the method will throw a ProtocolViolationException if the Method is GET or HEAD.
Morale: read the docs ;-)
Solution 4
It is specified in the documentation for the GetRequestStream that it will throw a ProtocolViolationException if the method is GET. However, I cannot find anything in the HTTP spec to suggest that this is actually an HTTP protocol violation. Consider this a challenge.
Adam McKee
Updated on August 24, 2020Comments
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Adam McKee almost 4 years
I have the following code which works just fine when the method is "POST", but changing to "GET" doesn't work:
HttpWebRequest request = null; request = HttpWebRequest.Create(uri) as HttpWebRequest; request.ContentType = "application/x-www-form-urlencoded; charset=UTF-8"; request.Method = "POST"; // Doesn't work with "GET" request.BeginGetRequestStream(this.RequestCallback, null);
I get a
ProtocolViolationException
exception with the "GET" method.Edit: After having a look using Reflector, it seems there is an explicit check for the "GET" method, if it's set to that it throws the exception.
Edit2: I've updated my code to the following, but it still throws an exception when I call EndGetResponse()
if (request.Method == "GET") { request.BeginGetResponse(this.ResponseCallback, state); } else { request.BeginGetRequestStream(this.RequestCallback, state); }
In my function, ResponseCallback, I have this:
HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asyncResult);
Which throws the exception as well.
Answer
The above code now works, I had forgotten to take out the Content-Type line which was causing the exception to be thrown at the end. +1 to tweakt & answer to Jon.
The working code is now below:
HttpWebRequest request = null; request = HttpWebRequest.Create(uri) as HttpWebRequest; request.Method = "GET";// Supports POST too if (request.Method == "GET") { request.BeginGetResponse(this.ResponseCallback, state); } else { request.BeginGetRequestStream(this.RequestCallback, state); }