C HttpWebRequest of type application x-www-form-urlencoded - how to send character in content body

Question

I m writing a small API-connected application in C    I connect to a API which has a method that takes a long string  the contents of a calendar ics  file   I m doing it like this   HttpWebRequest request    HttpWebRequest HttpWebRequest Create URL   request Method    POST   request AllowAutoRedirect   false  request CookieContainer   my cookie container  request Accept    text html application xhtml xml application xml q 0 9     q 0 8   request ContentType    application x-www-form-urlencoded    string iCalStr   GetCalendarAsString     string strNew     amp uploadfile true amp file     iCalStr   using  StreamWriter stOut   new StreamWriter request GetRequestStream    System Text Encoding ASCII           stOut Write strNew        stOut Close         This seems to work great  until I add some specific HTML in my calendar   If I have a   amp nbsp  somewhere in my calendar  or similar  the server only gets all the data up to the   amp  -point  so I m assuming the   amp   makes it look like anything after this point belongs to a new parameter   How can I fix this

User · Answer

As long as the server allows the ampresand character to be POSTed (not all do as it can be unsafe), all you should have to do is URL Encode the character. In the case of an ampresand, you should replace the character with %26.

.NET provides a nice way of encoding the entire string for you though:

string strNew = "&uploadfile=true&file=" + HttpUtility.UrlEncode(iCalStr);

User · Answer

First install  Microsoft ASP NET Web API Client  nuget package     PM  gt  Install-Package Microsoft AspNet WebApi Client   Then use the following function to post your data   public static async Task lt TResult gt  PostFormUrlEncoded lt TResult gt  string url  IEnumerable lt KeyValuePair lt string  string gt  gt  postData        using  var httpClient   new HttpClient                  using  var content   new FormUrlEncodedContent postData                         content Headers Clear                content Headers Add  Content-Type    application x-www-form-urlencoded                 HttpResponseMessage response   await httpClient PostAsync url  content                return await response Content ReadAsAsync lt TResult gt                         And this is how to use it   TokenResponse tokenResponse        await PostFormUrlEncoded lt TokenResponse gt  OAuth2Url  OAuth2PostData     or  TokenResponse tokenResponse         Task Run async               gt  await PostFormUrlEncoded lt TokenResponse gt  OAuth2Url  OAuth2PostData             Result   or  not recommended   TokenResponse tokenResponse        PostFormUrlEncoded lt TokenResponse gt  OAuth2Url  OAuth2PostData  Result

User · Answer

Since your content-type is application x-www-form-urlencoded you ll need to encode the POST body  especially if it contains characters like  amp  which have special meaning in a form  Try passing your string through HttpUtility UrlEncode before writing it to the request stream  Here are a couple links for reference   http   en wikipedia org wiki Percent-encoding

[c#] C# HttpWebRequest of type "application/x-www-form-urlencoded" - how to send '&' character in content body?

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