Develop Reference

web request in asp.net core

I want to do a web request in a asp.net core project. I tried the following but it doesn't seem to send the data in the request:
using System.Net;
...
//encoder
UTF8Encoding enc = new UTF8Encoding();
//data
string data = "[\"some.data\"]";
//Create request
WebRequest request = WebRequest.Create(url);
request.Method = "POST";
request.ContentType = "application/json";
request.Credentials = new NetworkCredential(user, secret);
//Set data in request
Stream dataStream = await request.GetRequestStreamAsync();
dataStream.Write(enc.GetBytes(data), 0, data.Length);
//Get the response
WebResponse wr = await request.GetResponseAsync();
Stream receiveStream = wr.GetResponseStream();
StreamReader reader = new StreamReader(receiveStream, Encoding.UTF8);
string content = reader.ReadToEnd();
I don't get an error, the request was send but it doesn't seem to send the data with the request.
I also can't give the length of the data with the request. Is this a core issue? (ps: The credentials are send correctly)
Can anyone help me?

You may be facing a synchronization context problem.
Try to await the asynchronous methods like GetRequestStreamAsync() and GetResponseAsync() instead of getting the Result property.
//Set data in request
Stream dataStream = await request.GetRequestStreamAsync();
//Get the response
WebResponse wr = await request.GetResponseAsync();

Finally solved it. There was a bug in my external API code where I resolved the API request. The code in my question works (If someone wants to use it).
PS: I edit the code with the remark of ycrumeyrolle

Get Response from HttpWebRequest on Windows Phone 8

I'm trying to do a WebRequest to a site from a Windows Phone Application.
But is vry important for me to also get the response from the server.
Here is my code:
Uri requestUri = new Uri(string.Format("http://localhost:8099/hello/{0}", metodo));
HttpWebRequest httpWebRequest = (HttpWebRequest)WebRequest.Create(requestUri);
httpWebRequest.ContentType = "application/xml; charset=utf-8";
httpWebRequest.Method = "POST";
using (var stream = await Task.Factory.FromAsync<Stream>(httpWebRequest.BeginGetRequestStream,
httpWebRequest.EndGetRequestStream, null))
{
string xml = "<string xmlns=\"http://schemas.microsoft.com/2003/10/Serialization/\">Ahri</string>";
byte[] xmlAsBytes = Encoding.UTF8.GetBytes(xml);
await stream.WriteAsync(xmlAsBytes, 0, xmlAsBytes.Length);
}
Unfortunatelly, I have no idea of how I could get the response from the server.
Does anyone have an idea?
Thanks in advance.
Thanks to #max I found the solution and wanted to share it above.
Here is how my code looks like:
string xml = "<string xmlns=\"http://schemas.microsoft.com/2003/10/Serialization/\">Claor</string>";
Uri requestUri = new Uri(string.Format("http://localhost:8099/hello/{0}", metodo));
string responseFromServer = "no response";
HttpWebRequest httpWebRequest = HttpWebRequest.Create(requestUri) as HttpWebRequest;
httpWebRequest.ContentType = "application/xml; charset=utf-8";
httpWebRequest.Method = "POST";
using (Stream requestStream = await httpWebRequest.GetRequestStreamAsync())
{
byte[] xmlAsBytes = Encoding.UTF8.GetBytes(xml);
await requestStream.WriteAsync(xmlAsBytes, 0, xmlAsBytes.Length);
}
WebResponse webResponse = await httpWebRequest.GetResponseAsync();
using (var reader = new StreamReader(webResponse.GetResponseStream()))
{
responseFromServer = reader.ReadToEnd();
}
I hope it will help someone in the future.

This is very common question for people new in windows phone app
development. There are several sites which gives tutorials for the
same but I would want to give small answer here.
In windows phone 8 xaml/runtime you can do it by using HttpWebRequest or a WebClient.
Basically WebClient is a wraper around HttpWebRequest.
If you have a small request to make then user HttpWebRequest. It goes like this
HttpWebRequest request = HttpWebRequest.Create(requestURI) as HttpWebRequest;
WebResponse response = await request.GetResponseAsync();
using (var reader = new StreamReader(response.GetResponseStream()))
{
string responseContent = reader.ReadToEnd();
// Do anything with you content. Convert it to xml, json or anything.
}
Although this is a get request and i see that you want to do a post request, you have to modify a few steps to achieve that.
Visit this place for post request.
If you want windows phone tutorials, you can go here. He writes awesome tuts.

Omit images from webpage requested through HttpWebRequest

I fetch webpages in order to feed data to my application. However, the pages contain a lot of images which I don't require at all. I only need the text data.
My problem is that the web requests take an unacceptable amount of time. I think the images also are fetch during a web request. Is there any way to eliminate the images and download only the text data?
The following is the code that I am using currently.
var httpWebRequest = HttpWebRequest.Create(url) as HttpWebRequest;
httpWebRequest.Method = "GET";
httpWebRequest.ProtocolVersion = HttpVersion.Version11;
httpWebRequest.Headers.Add(HttpRequestHeader.AcceptEncoding, "gzip,deflate");
httpWebRequest.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
httpWebRequest.Proxy = null;
httpWebRequest.KeepAlive = true;
httpWebRequest.Accept = "text/html";
string responseString = null;
var httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse;
using (var responseStream = httpWebResponse.GetResponseStream())
{
using (var streamReader = new StreamReader(responseStream))
{
responseString = streamReader.ReadToEnd();
}
}
Also, any other optimization suggestions are most welcome.

That is incorrect.
HttpWebRequest does not know anything about HTML or images; it just sends raw HTTP requests.
You can use Fiddler to see exactly what's going on.

C# httpwebrequest blank chars in responsestream

I'm trying to read the reponse from a webserver using httpwebrequests in C#.
I use the following code:
UriBuilder urib = new UriBuilder();
urib.Host = "wikipedia.com";
HttpWebRequest req = WebRequest.CreateHttp(urib.Uri);
req.KeepAlive = false;
req.Host = "wikipedia.com/";
req.Method = "GET";
HttpWebResponse response = (HttpWebResponse) req.GetResponse();
byte[] buffer = new byte[response.ContentLength];
System.IO.Stream stream = response.GetResponseStream();
stream.Read(buffer, 0, buffer.Length);
Console.WriteLine(System.Text.Encoding.ASCII.GetString(buffer, 0, buffer.Length));
The code does indeed retrieve the correct amount of data (I compared the contentlength used to create the buffer, with the length of the console output, they're the same.
My problem is that the last 80% or so of the response is blank chars. They're all 0x00.
I tested this with several pages, including wikipedia.com and it just cuts off mid-file for some reason.
Have I misunderstood/misused the way to use webrequests or can anyone spot an error here?

Try to use this method:
public static String GetResponseString(Uri url, CookieContainer cc)
{
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url);
request.Method = WebRequestMethods.Http.Get;
request.CookieContainer = cc;
request.AutomaticDecompression = DecompressionMethods.GZip;
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
String responseString = reader.ReadToEnd();
response.Close();
return responseString;
}

There are a couple of issues with your code:
Your trying to read the entire response in one go using Stream.Read - that's not what it was designed for. This should be used for more optimal reading e.g. 4KB chunks.
Your reading a HTML response as ASCII encoding - are you sure the page doesn't contain any Unicode characters? I would stick to UTF-8 encoding to be on the safe side (or alternatively read the Content-Type header in the response).
When reading characters from a byte stream (which is what your response is essentially) the recommended approach is to use StreamReader. More specifically, if you want to read the entire stream in one go then use StreamReader.ReadToEnd.
Your code could be shortened to:
HttpWebRequest req = WebRequest.CreateHttp(new Uri("http://wikipedia.org"));
req.Method = WebRequestMethods.Http.Get;
using (var response = (HttpWebResponse)req.GetResponse())
using (var reader = new StreamReader(response.GetResponseStream()))
{
Console.WriteLine(reader.ReadToEnd());
}

HTTP POST in .NET doesn't work

I've got a problem with creating an HTTP post request in .NET. When I do this request in ruby it does work.
When doing the request in .NET I get following error:
<h1>FOXISAPI call failed</h1><p><b>Progid is:</b> carejobs.carejobs
<p><b>Method is:</b> importvacature/
<p><b>Parameters are:</b>
<p><b> parameters are:</b> vacature.deelnemernr=478
</b><p><b>GetIDsOfNames failed with err code 80020006: Unknown name.
</b>
Does anyone knows how to fix this?
Ruby:
require 'net/http'
url = URI.parse('http://www.carejobs.be/scripts/foxisapi.dll/carejobs.carejobs.importvacature')
post_args = {
'vacature.deelnemernr' => '478',
}
resp, data = Net::HTTP.post_form(url, post_args)
print resp
print data
C#:
Uri address = new Uri(url);
// Create the web request
HttpWebRequest request = WebRequest.Create(address) as HttpWebRequest;
// Set type to POST
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
// Create the data we want to send
StringBuilder data = new StringBuilder();
data.Append("vacature.deelnemernr=" + HttpUtility.UrlEncode("478"));
// Create a byte array of the data we want to send
byte[] byteData = UTF8Encoding.UTF8.GetBytes(data.ToString());
// Set the content length in the request headers
request.ContentLength = byteData.Length;
// Write data
using (Stream postStream = request.GetRequestStream())
{
postStream.Write(byteData, 0, byteData.Length);
}
// Get response
using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
// Get the response stream
StreamReader reader = new StreamReader(response.GetResponseStream());
// Console application output
result = reader.ReadToEnd();
}
return result;

Don't you need the ? after the URL in order to do a post with parameters? I think that Ruby hides this behind the scenes.

I found the problem! The url variable in the C# code was "http://www.carejobs.be/scripts/foxisapi.dll/carejobs.carejobs.importvacature/"
It had to be "http://www.carejobs.be/scripts/foxisapi.dll/carejobs.carejobs.importvacature" without the backslash.