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Best way to send HTTP requests in an ASP.NET webforms project c# [duplicate]

This question already has answers here:
How to simulate HTTP POST programmatically in ASP.NET?
(5 answers)
Closed 5 years ago.
Hey guys im a newbie working with HTTP requests in C#/.Net and would love some tips and suggestions of the correct namespaces or classes that would make doing HTTP requests easier. GET,POST,.etc
Ive come across a few such as the HTTPrequest class, and also the HTTP.WebRequest but im lost as to which to actually use and any advice would be welcome!

The short answer is that you have to make use of HttpWebRequest to make the request and HttpWebResponse to get the response. But this will probably not solve your problem as the configurations for making HTTP requests differ from one case to another. For example, headers, content type, and accept are parameters to which you have to pay attention based on your method (GET, POST,PUT,PATCH,DELETE) and the API with which you are communicating.
For example, let's say that you wanna send and receive a text message, you should follow something like this:
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create("URL");
webRequest.ContentType = "text/plain;charset=UTF-8";
webRequest.Accept = "text/plain;charset=UTF-8";
webRequest.Method = "POST";
using (StreamWriter requestStream = new StreamWriter(webRequest.GetRequestStream())) {
requestStream.WriteLine("Hello");
}
HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse();
using (StreamReader responseStream = new StreamReader(webResponse.GetResponseStream())) {
Console.WriteLine(responseStream.ReadToEnd());
}
You have to keep in mind that your request type (ContentType) or your response type (Accept) may be in different formats such as XML or JSON or even Stream and you have to find the correct settings for your case. You may also need to add custom HTML headers in your request.

Make a request to StackExchange Api [duplicate]

This question already has answers here:
.NET: Is it possible to get HttpWebRequest to automatically decompress gzip'd responses?
(3 answers)
Closed 7 years ago.
I'm trying to request list of tags on StackExchange in JSON format by url, but problem is, that I'm getting some broken text instead of JSON, so I can't even parse it.
P.S. Done it with the help of RestSharp.
private void Refresh()
{
var client = new RestClient("http://api.stackexchange.com/2.2/tags?order=desc&sort=popular&site=stackoverflow");
var result = client.Execute(new RestRequest(Method.GET));
var array = JsonConvert.DeserializeObject<Root>(result.Content);
Platforms = array.Platforms;
}

If you make GET request to this URL using Fiddler, you will see that response has a header:
Content-Encoding: gzip
Which means that response is compressed with gzip. Good news is that HttpWebRequest can handle that:
request.AutomaticDecompression = DecompressionMethods.Deflate | DecompressionMethods.GZip;
After you add this row you will get nice and readable JSON.

As #peeskillet mentions, this looks like compressed data. Please have a look at
What is the canonical method for an HTTP client to instruct an HTTP server to disable gzip responses? and especially this answer.
Something like
Accept-Encoding: *;q=0
should help.

Adding Headers and Post data in RESTfull/HTTP Request in C#

I'm having problems with sending POST request in C# and it seems I misunderstood some HTTP basics. So basically I'm implementing RESTfull service client, which work as follows:
Make POST request with username/password and get token
Use this token in header (Authorization:TOKEN) while making other GET/POST/PUT requests
I use WebRequest to make GET requests (with Authorization header) and it's working. But when I use following code to make PUT requests, service is giving "Authentication failed - not logged in" message back:
String url = String.Format("{0}/{1}", AN_SERVER, app);
WebRequest theRequest = WebRequest.Create(url);
theRequest.Method = "POST";
theRequest.ContentType = "text/x-json";
theRequest.ContentLength = json.Length;
Stream requestStream = theRequest.GetRequestStream();
requestStream.Write(Encoding.ASCII.GetBytes(json), 0, json.Length);
requestStream.Close();
theRequest.Headers.Add("Authorization", authToken);
HttpWebResponse response = (HttpWebResponse)theRequest.GetResponse();
I must be making minor mistake (at least I hope so) while sending POST request. So what am I doing wrong?
Thanks.

Moving Headers before the request steam works (as per AI W's comment), because the request stream is adding the body.
The way webrequest is implemented internally, you need to finish the header before writing body, and once its in stream format, its ready to send.
If you look at the implementation of webrequest in reflector or some such decompiling tool, you'll be able to see the logic.
Hope this helps

Generate http post request from controller

Forgive me if this is a stupid question. I am not very experienced with Web programming.
I am implementing the payment component of my .net mvc application. The component interacts with an external payment service. The payment service accepts http post request in the following form
http://somepaymentservice.com/pay.do?MerchantID=xxx&Price=xxx&otherparameters
I know this is dead easy to do by adding a form in View. However, I do not want my views to deal with third party parameters. I would like my view to submit information to my controller, then controller generates the required url and then send out the request. Following is the pseudo code.
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult PayForOrder(OrderForm order)
{
var url = _paymentService.GetUrlFromOrder(order);
SendPostRequest(url);
return View("FinishedPayment");
}
Is it possible to do so? Does c# have built-in library to generate http request?
Thanks in advance.

You'll want to use the HttpWebRequest class. Be sure to set the Method property to post - here's an example.

There certainly is a built in library to generate http requests. Below are two helpful functions that I quickly converted from VB.NET to C#. The first method performs a post the second performs a get. I hope you find them useful.
You'll want to make sure to import the System.Net namespace.
public static HttpWebResponse SendPostRequest(string data, string url)
{
//Data parameter Example
//string data = "name=" + value
HttpWebRequest httpRequest = HttpWebRequest.Create(url);
httpRequest.Method = "POST";
httpRequest.ContentType = "application/x-www-form-urlencoded";
httpRequest.ContentLength = data.Length;
var streamWriter = new StreamWriter(httpRequest.GetRequestStream());
streamWriter.Write(data);
streamWriter.Close();
return httpRequest.GetResponse();
}
public static HttpWebResponse SendGetRequest(string url)
{
HttpWebRequest httpRequest = HttpWebRequest.Create(url);
httpRequest.Method = "GET";
return httpRequest.GetResponse();
}

It realy makes a difference if ASP.NET makes a request or the the client makes a request.
If the documentation of the the provider says that you should use a form with the given action that has to be submited by the client browser then this might be necessary.
In lots of cases the user (the client) posts some values to the provider, enters some data at the providers site and then gets redirected to your site again. You can not do this applicationflow on the serverside.

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.