Code Answer: Remote HTTP Post with CSharp

How do you do a Remote HTTP Post (request) in CSharp?

i really needs this pls. :(

From stackoverflow

HttpWebRequest

You can use WCF or create a WebRequest

var httpRequest = (HttpWebRequest)WebRequest.Create("http://localhost/service.svc");
var httpRequest.Method = "POST";

using (var outputStream = httpRequest.GetRequestStream())
{
    // some complicated logic to create the message
}

var response = httpRequest.GetResponse();
using (var stream = response.GetResponseStream())
{
    // some complicated logic to handle the response message.
}

I use this very simple class:

 public class   RemotePost{
     private  System.Collections.Specialized.NameValueCollection Inputs 
     = new  System.Collections.Specialized.NameValueCollection() ;

    public string  Url  =  "" ;
    public string  Method  =  "post" ;
    public string  FormName  =  "form1" ;

    public void  Add( string  name, string value ){
        Inputs.Add(name, value ) ;
     }

     public void  Post(){
        System.Web.HttpContext.Current.Response.Clear() ;

         System.Web.HttpContext.Current.Response.Write( "<html><head>" ) ;

         System.Web.HttpContext.Current.Response.Write( string .Format( "</head><body onload=\"document.{0}.submit()\">" ,FormName)) ;

         System.Web.HttpContext.Current.Response.Write( string .Format( "<form name=\"{0}\" method=\"{1}\" action=\"{2}\" >" ,

        FormName,Method,Url)) ;
            for ( int  i = 0 ; i< Inputs.Keys.Count ; i++){
            System.Web.HttpContext.Current.Response.Write( string .Format( "<input name=\"{0}\" type=\"hidden\" value=\"{1}\">" ,Inputs.Keys[i],Inputs[Inputs.Keys[i]])) ;
         }
        System.Web.HttpContext.Current.Response.Write( "</form>" ) ;
         System.Web.HttpContext.Current.Response.Write( "</body></html>" ) ;
         System.Web.HttpContext.Current.Response.End() ;
     }
}

And you use it thusly:

RemotePost myremotepost   =  new   RemotePost()  ;
myremotepost.Url  =  "http://www.jigar.net/demo/HttpRequestDemoServer.aspx" ;
myremotepost.Add( "field1" , "Huckleberry" ) ;
myremotepost.Add( "field2" , "Finn" ) ;
myremotepost.Post() ;

Very clean, easy to use and encapsulates all the muck. I prefer this to using the HttpWebRequest and so forth directly.

BobbyShaftoe : Why is this getting downvoted?

David : If I'm reading this correctly, it doesn't actually post a form, but responds with a form that can be posted.

CodeMonkey1 : I downvoted because it only works in the context of a web page response and even in that case it kills whatever else you may have wanted to do in that page. Also it only allows for a fire & forget post, and is a convoluted way to do it.

Use the WebRequest.Create() and set the Method property.

HttpWebRequest HttpWReq = 
(HttpWebRequest)WebRequest.Create("http://www.google.com");

HttpWebResponse HttpWResp = (HttpWebResponse)HttpWReq.GetResponse();
Console.WriteLine(HttpWResp.StatusCode);
HttpWResp.Close();

Should print "OK" (200) if the request was successful

bendewey : Since the OP is doing a POST you should mention the request stream side as well.

Also System.Net.WebClient

This is code from a small app I wrote once to post a form with values to a URL. It should be pretty robust.

_formValues is a Dictionary<string,string> containing the variables to post and their values.


// encode form data
StringBuilder postString = new StringBuilder();
bool first=true;
foreach (KeyValuePair pair in _formValues)
{
    if(first)
     first=false;
    else
     postString.Append("&");
    postString.AppendFormat("{0}={1}", pair.Key, System.Web.HttpUtility.UrlEncode(pair.Value));
}
ASCIIEncoding ascii = new ASCIIEncoding();
byte[] postBytes = ascii.GetBytes(postString.ToString());

// set up request object
HttpWebRequest request;
try
{
    request = WebRequest.Create(url) as HttpWebRequest;
}
catch (UriFormatException)
{
    request = null;
}
if (request == null)
    throw new ApplicationException("Invalid URL: " + url);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = postBytes.Length;

// add post data to request
Stream postStream = request.GetRequestStream();
postStream.Write(postBytes, 0, postBytes.Length);
postStream.Close();

HttpWebResponse response = request.GetResponse as HttpWebResponse;

Liam : Thanks, the details on how to build the POST data really helped!

Im using the following piece of code for calling webservices using the httpwebrequest class:

internal static string CallWebServiceDetail(string url, string soapbody, 
int timeout) {
    return CallWebServiceDetail(url, soapbody, null, null, null, null, 
null, timeout);
}
internal static string CallWebServiceDetail(string url, string soapbody, 
string proxy, string contenttype, string method, string action, 
string accept, int timeoutMilisecs) {
    var req = (HttpWebRequest) WebRequest.Create(url);
    if (action != null) {
     req.Headers.Add("SOAPAction", action);
    }
    req.ContentType = contenttype ?? "text/xml;charset=\"utf-8\"";
    req.Accept = accept ?? "text/xml";
    req.Method = method ?? "POST";
    req.Timeout = timeoutMilisecs;
    if (proxy != null) {
     req.Proxy = new WebProxy(proxy, true);
    }

    using(var stm = req.GetRequestStream()) {
     XmlDocument doc = new XmlDocument();
     doc.LoadXml(soapbody);
     doc.Save(stm);
    }
    using(var resp = req.GetResponse()) {
     using(var responseStream = resp.GetResponseStream()) {
      using(var reader = new StreamReader(responseStream)) {
       return reader.ReadToEnd();
      }
     }
    }
}

This can be easily used to call a webservice

public void TestWebCall() {
    const string url = 
"http://www.ecubicle.net/whois_service.asmx/HelloWorld";
    const string soap = 
@"<soap:Envelope xmlns:soap='about:envelope'>
    <soap:Body><HelloWorld /></soap:Body>
</soap:Envelope>";
    string responseDoc = CallWebServiceDetail(url, soap, 1000);
    XmlDocument doc = new XmlDocument();
    doc.LoadXml(responseDoc);
    string response = doc.DocumentElement.InnerText;
}

The problem when beginning with high-level language like C#, Java or PHP is that people may have never known how simple the underground is in reality. So here’s a short introduction:

http://reboltutorial.com/blog/raw-http-request/

Code Answer

Thursday, March 31, 2011

Remote HTTP Post with CSharp

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