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WebRequest.GetResponse(): read response, even on a 401?

I'm having trouble with the authorization piece of a third-party API. The API is shooting me a 401 in the HTTP Status Code, and more info in the response body.
var req = HttpWebRequest.Create(url);
req.Method = "GET";
var resp = req.GetResponse();
This is the code I typically use, but GetResponse() throws an exception on the 401 and I never get the response body.
Is there another implementation of this request I'm missing, or another way to do this in .NET so that I can get the response even when the request generates a 401?
Thanks.

web exception
The WebException contains a Response object that you can use to read the response body

C# REST client sending data using POST

I'm trying to send a simple POST request to a REST web service and print the response (code is below, mostly taken from Yahoo! developer documentation and the MSDN code snippets provided with some of the documentation). I would expect the client to send:
Request Method: POST (i.e. I expect $_SERVER['REQUEST_METHOD'] == 'POST' in PHP)
Data: foo=bar (i.e. $_POST['foo'] == 'bar' in PHP)
However, it seems to be sending:
Request Method: FOO=BARPOST
Data: (blank)
I know the API works as I've tested it with clients written in Python and PHP, so I'm pretty sure it must be a problem with my C#. I'm not a .NET programmer by trade so would appreciate any comments/pointers on how to figure out what the problem is - I'm sure it's something trivial but I can't spot it myself.
uri, user and password variables are set earlier in the code - they work fine with GET requests.
request = (HttpWebRequest) WebRequest.Create(uri);
request.Credentials = new NetworkCredential(user, password);
request.Method = WebRequestMethods.Http.Post;
request.ContentType = "application/x-www-form-urlencoded";
string postData = "foo=bar";
request.ContentLength = postData.Length;
StreamWriter postStream = new StreamWriter(request.GetRequestStream(), System.Text.Encoding.ASCII);
postStream.Write(postData);
postStream.Close();
response = (HttpWebResponse) request.GetResponse();
The REST API is written in PHP, and the $_POST array is empty on the server when using the C# client.

Eventually found the HttpWebRequest.PreAuthenticate property which seems to solve the problem if the code is edited like so:
request = (HttpWebRequest) WebRequest.Create(uri);
request.PreAuthenticate = true;
request.Credentials = new NetworkCredential(user, password);
request.Method = WebRequestMethods.Http.Post;
From the documentation I presume this forces authentication before the actual POST request is sent. I'm not sure why the class doesn't do this automatically (libraries for other languages make this process transparent, unless you explicitly turn it off), but it has solved the problem for me and may save someone else another 2 days of searching and hair-pulling.
For what it's worth, PreAuthenticate doesn't need to be set for GET requests, only POST, although if you do set it for a GET request everything will still work, but take slightly longer.

Cannot handle redirect from HTTP/HTTPS protocols to other dissimilar ones

Basically, I'm trying to grab an EXE from CNet's Download.com
So i created web parser and so far all is going well.
Here is a sample link pulled directly from their site:
http://dw.com.com/redir?edId=3&siteId=4&oId=3001-20_4-10308491&ontId=20_4&spi=e6323e8d83a8b4374d43d519f1bd6757&lop=txt&tag=idl2&pid=10566981&mfgId=6250549&merId=6250549&pguid=PlvcGQoPjAEAAH5rQL0AAABv&destUrl=ftp%3A%2F%2F202.190.201.108%2Fpub%2Fryl2%2Fclient%2Finstaller-ryl2_v1673.exe
Here is the problem: When you attempt to download, it begins with HTTP, then redirects to an FTP site. I have tried .NET's WebClient and HttpWebRequest Objects, and it looks like Neither can support Redirects.
This Code Fails at GetResponse();
HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://dw.com.com/redir");
WebResponse response = req.GetResponse();
Now, I also tried this:
HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://dw.com.com/redir");
req.AllowAutoRedirect = false;
WebResponse response = req.GetResponse();
string s = new StreamReader(response.GetResponseStream()).ReadToEnd();
And it does not throw the error anymore, however variable s turns out to be an empty string.
I'm at a loss! Can anyone help out?

You can get the value of the "Location" header from the response.headers, and then create a new FtpWebRequest to download that resource.

in your first code snippet you will be redirected to a link using a different protocol (i.e it's no longer Http as in HttpWebRequest) so it fails du to a malformed http response.
In the second part you're no longer redirected and hence you don't receive a FTP response (which is not malform when interpreted as HTTP response).
You need to acquire FTP link,as ferozo wrote you can do this by getting the value of the header "location", and use a FtpWebRequest to access the file

C# - Consuming REST web service over https

What's the best way to consume secure REST web service in C#? Web Service username and password are supplied in URL...

Several options:
HttpWebRequest class. Powerful but sometimes complex to use.
WebClient class. Less features, but should work for simpler web services, and much simpler.
The new HttpClient in the WCF REST Starter Kit. (The Starter Kit is a separate download, not a part of the .NET Framework).

Use WebRequest class to make the request and HttpWebResponse to get the response.
I used following code for consuming webservice.My user name,password and Url are saved in variables UserName,Pwd and Url respectively.
WebRequest Webrequest;
HttpWebResponse response;
Webrequest = WebRequest.Create(Url);
byte[] auth1 = Encoding.UTF8.GetBytes(UserName + ":" + Pwd);
Webrequest.Headers["Authorization"] = "Basic " + System.Convert.ToBase64String(auth1);
Webrequest.Method = "GET";
Webrequest.ContentType = "application/atom+xml";
response = (HttpWebResponse)Webrequest.GetResponse();
Stream streamResponse = response.GetResponseStream();
StreamReader streamReader = new StreamReader(streamResponse);
string Response = streamReader.ReadToEnd();
Response string will be available in variable Response.

I hope the password in the URL is somwhow encrypted :). Maybe this will help you:
http://social.msdn.microsoft.com/forums/en-US/wcf/thread/3c8db0bf-984e-426b-b068-d80165ed1b37/

Based on the little information you provided I would say that using the HttpWebRequest class is your best option.
It is relatively easy to use, there are lots of examples of how to use it and it will work with any media-type the REST interface delivers. You have full access to Http status codes, and Http Headers.
What more can you ask for?

HTTP Post in C# console app doesn't return the same thing as a browser request

I have a C# console app (.NET 2.0 framework) that does an HTTP post using the following code:
StringBuilder postData = new StringBuilder(100);
postData.Append("post.php?");
postData.Append("Key1=");
postData.Append(val1);
postData.Append("&Key2=");
postData.Append(val2);
byte[] dataArray = Encoding.UTF8.GetBytes(postData.ToString());
HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create("http://example.com/");
httpRequest.Method = "POST";
httpRequest.ContentType = "application/x-www-form-urlencoded";
httpRequest.ContentLength = dataArray.Length;
Stream requestStream = httpRequest.GetRequestStream();
requestStream.Write(dataArray, 0, dataArray.Length);
requestStream.Flush();
requestStream.Close();
HttpWebResponse webResponse = (HttpWebResponse)httpRequest.GetResponse();
if (httpRequest.HaveResponse == true) {
Stream responseStream = webResponse.GetResponseStream();
StreamReader responseReader = new System.IO.StreamReader(responseStream, Encoding.UTF8);
String responseString = responseReader.ReadToEnd();
}
The outputs from this are:
webResponse.ContentLength = -1
webResponse.ContentType = text/html
webResponse.ContentEncoding is blank
The responseString is HTML with a title and body.
However, if I post the same URL into a browser (http://example.com/post.php?Key1=some_value&Key2=some_other_value), I get a small XML snippet like:
<?xml version="1.0" ?>
<RESPONSE RESULT="SUCCESS"/>
with none of the same HTML as in the application. Why are the responses so different? I need to parse the returned result which I am not getting in the HTML. Do I have to change how I do the post in the application? I don't have control over the server side code that accepts the post.

If you are indeed supposed to use the POST HTTP method, you have a couple things wrong. First, this line:
postData.Append("post.php?");
is incorrect. You want to post to post.php, you don't want post the value "post.php?" to the page. Just remove this line entirely.
This piece:
... WebRequest.Create("http://example.com/");
needs post.php added to it, so...
... WebRequest.Create("http://example.com/post.php");
Again this is assuming you are actually supposed to be POSTing to the specified page instead of GETing. If you are supposed to be using GET, then the other answers already supplied apply.

You'll want to get an HTTP sniffer tool like Fiddler and compare the headers that are being sent from your app to the ones being sent by the browser. There will be something different that is causing the server to return a different response. When you tweak your app to send the same thing browser is sending you should get the same response. (It could be user-agent, cookies, anything, but something is surely different.)

I've seen this in the past.
When you run from a browser, the "User-Agent" in the header is "Mozilla ...".
When you run from a program, it's different and generally specific to the language used.

I think you need to use a GET request, instead of POST. If the url you're using has querystring values (like ?Key1=some_value&Key2=some_other_value) then it's expecting a GET. Instead of adding post values to your webrequest, just put this data in the querystring.
HttpWebRequest httpRequest = (HttpWebRequest)WebRequest.Create("http://example.com/?val1=" + val1 + "&val2=" + val2);
httpRequest.Method = "GET";
httpRequest.ContentType = "application/x-www-form-urlencoded";
....
So, the result you're getting is different when you POST the data from your app because the server-side code has a different output when it can't read the data it's expecting in the querystring.

In your code you a specify the POST method which sends the data to the PHP file without putting the data in the web address. When you put the information in the address bar, that is not the POST method, that is the GET method. The name may be confusing, but GET just means that the data is being sent to the PHP file through the web address, instead of behind the scenes, not that it is supposed to get any information. When you put the address in the browser it is using a GET.
Create a simple html form and specify POST as the method and your url as the action. You will see that the information is sent without appearing in the address bar.
Then do the same thing but specify GET. You will see the information you sent in the address bar.

I believe the problem has something to do with the way your headers are set up for the WebRequest.
I have seen strange cases where attempting to simulate a browser by changing headers in the request makes a difference to the server.
The short answer is that your console application is not a web browser and the web server of example.com is expecting to interact with a browser.
You might also consider changing the ContentType to be "multipart/form-data".
What I find odd is that you are essentially posting nothing. The work is being done by the query string. Therefore, you probably should be using a GET instead of a POST.

Is the form expecting a cookie? That is another possible reason why it works in the browser and not from the console app.