I have a Windows app written in C#. This app will be deployed to my user's desktops. It will interact with a back-end that has already been created. The back-end is written in ASP.NET MVC 3. It exposes a number of GET and POST operations as shown here:
[AcceptVerbs(HttpVerbs.Get)]
public ActionResult GetItem(string id, string caller)
{
// Do stuff
}
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult SaveItem(string p1, string p2, string p3)
{
// Do stuff
}
The web developers on my team are successfully interacting with these operations via JQuery. So I know they work. But I need to figure out how to interact with them from my Windows C# app. I was using the WebClient, but ran into some performance problems so I was consulted to use the WebRequest object. In an honest effort to attempt this, I tried the following:
WebRequest request = HttpWebRequest.Create("http://www.myapp.com/actions/AddItem");
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.BeginGetResponse(new AsyncCallback(AddItem_Completed), request);
My problem is, I'm not sure how to actually send the data (the parameter values) back to my endpoints. How do I send the parameter values back to my GET and POST operations? Can someone give me some help? Thank you!
One way is to write the input to request stream. You need to serialize input to byte array
Please see below sample code
string requestXml = "someinputxml";
byte[] bytes = Encoding.UTF8.GetBytes(requestXml);
var request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "POST";
request.ContentLength = bytes.Length;
request.ContentType = "application/xml";
using (var requestStream = request.GetRequestStream())
{
requestStream.Write(bytes, 0, bytes.Length);
}
using (var response = (HttpWebResponse)request.GetResponse())
{
statusCode = response.StatusCode;
if (statusCode == HttpStatusCode.OK)
{
responseString = new StreamReader(response.GetResponseStream()).ReadToEnd();
}
}
Well, with WebClient the simplest example would be something like this:
NameValueCollection postData = new NameValueCollection();
postData["field-name-one"] = "value-one";
postData["field-name-two"] = "value-two";
WebClient client = new WebClient();
byte[] responsedata = webClient.UploadValues("http://example.com/postform", "POST", postData);
Have you tried this?
Related
This might be an odd question, but I'm ultimately trying to click an "add to cart" button by sending a POST request in C#. I'm currently using Advanced REST Client to try to send the request and I'm having a lot trouble. This is the item I'm trying to add to cart. I am sending the POST request with
http://www.supremenewyork.com/shop/169720/add?authenticity_token=oZ2ZwxDZwEJ%2BUSczNZrhUlNSGw5NnsP%2FvcbxiSnxnSM%3D&commit=add%20to%20cart&size=32377&utf8=%E2%9C%93
but I keep getting 404 not found. I might be putting in the wrong information into the client. I just started learning about POST/GET requests yesterday, so any advice would be greatly appreciated; thank you.
You can use this method to get content using POST request.
public static async Task<byte[]> GetPostContentAsync(string url, string data)
{
var content = new MemoryStream();
var cookies = new CookieContainer();
HttpWebRequest webReq;
webReq = (HttpWebRequest)WebRequest.Create(url);
webReq.CookieContainer = cookies;
webReq.Method = "POST";
webReq.ContentType = "application/x-www-form-urlencoded";
Stream requestStream = await webReq.GetRequestStreamAsync();
using (var writer = new StreamWriter(requestStream))
{
await writer.WriteAsync(data);
}
using (var responseStream = await webReq.GetResponseAsync())
{
using (Stream response = responseStream.GetResponseStream())
{
await response.CopyToAsync(content);
}
}
return content.ToArray();
}
I need to send some data through http post from my windows forms application to a url. I will be sending a string parameter in this post request. In my C# method i will be validating the parameter and send a response Y or N to the forms application.
My problem is I don't know how to invoke the method in website which is called from forms application. So far i can see the data is posted on to the server and in response i am getting the whole web page. I have no idea how to invoke that particular method in C# and get the response in forms application.
Below is my forms application code
public static string HttpPost(string URI, string Parameters)
{
System.Net.WebRequest req = System.Net.WebRequest.Create(URI);
req.ContentType = "application/x-www-form-urlencoded";
req.Method = "POST";
byte[] bytes = System.Text.Encoding.ASCII.GetBytes(Parameters);
req.ContentLength = bytes.Length;
System.IO.Stream os = req.GetRequestStream();
os.Write(bytes, 0, bytes.Length);
os.Close();
System.Net.WebResponse resp = req.GetResponse();
if (resp == null) return null;
System.IO.StreamReader sr = new System.IO.StreamReader(resp.GetResponseStream());
return sr.ReadToEnd().Trim();
}
I am giving call to the above method
String message = HttpPost(#"http://localhost/Home.aspx/postMessageCall","A1234");
postMessageCall is the method which i want to invoke
Now where and how do i need to write the postMessageCall method so that this method gets invoked everytime when i specify the above url.
Please help..
I'm not sure why this PayPal Pay operation is giving me this error even though I seem to have covered all the required fields:
Error Code: 81002 Severity: Error Message: Unspecified Method (Method Specified is not Supported)"
string postData = JsonConvert.SerializeObject(request);
value of postData:
"actionType=PAY
¤cyCode=USD
&cancelUrl=https%3a%2f%2fexample.com%2fcancel
&returnUrl=https%3a%2f%2fexample.com%2freturn
&requestenvelope.errorLanguage=en_US
&receiverList.receiver(0).email=recipientemail%40gmail.com
&receiverList.receiver(0).amount=0.05
&VERSION=94.0
&USER=bizemail-facilitator_api1.gmail.com
&PWD=xxxxx
&SIGNATURE=xxxxxxxxx"
Here's how I do the post:
SendRequest("https://api-3t.sandbox.paypal.com/nvp", postData);
public string SendRequest(string url, string postData)
{
var uri = new Uri(url);
var request = WebRequest.Create(uri);
var encoding = new UTF8Encoding();
var requestData = encoding.GetBytes(postData);
request.ContentType = "application/x-www-form-urlencoded";
request.Method = "POST";
request.Timeout = (300*1000); //TODO: Move timeout to config
request.ContentLength = requestData.Length;
using (var stream = request.GetRequestStream()) {
stream.Write(requestData, 0, requestData.Length);
}
var response = request.GetResponse();
string result;
using (var reader = new StreamReader(response.GetResponseStream(), Encoding.ASCII)) {
result = reader.ReadToEnd();
}
return result;
}
The method PAY doesn't exist on the NVP api. Full list of methods supported by that API is found here.
The PAY method, however, is defined in the Adaptive Payments API. Depending on your needs, you have two options:
Change the endpoint to https://svcs.paypal.com/AdaptivePayments/PAY and modify your values
Use another method, like DoDirectPayment, but I'm not sure it does what you want to.
I assume the value of postData is before you serialize it to a JSON string, instead of after as you say, since it is clearly not a JSON string.
If so, then it is already x-www-form-urlencoded, and you do not need to serialize it to a JSON string at all.
Or if you do after all, then change just this: request.ContentType = "application/json";
i wrote a simple C# function to retrieve trade history from MtGox with following API call:
https://data.mtgox.com/api/1/BTCUSD/trades?since=<trade_id>
documented here: https://en.bitcoin.it/wiki/MtGox/API/HTTP/v1#Multi_currency_trades
here's the function:
string GetTradesOnline(Int64 tid)
{
Thread.Sleep(30000);
// communicate
string url = "https://data.mtgox.com/api/1/BTCUSD/trades?since=" + tid.ToString();
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
StreamReader reader = new StreamReader(response.GetResponseStream());
string json = reader.ReadToEnd();
reader.Close();
reader.Dispose();
response.Close();
return json;
}
i'm starting at tid=0 (trade id) to get the data (from the very beginning). for each request, i receive a response containing 1000 trade details. i always send the trade id from the previous response for the next request. it works fine for exactly 4 requests & responses. but after that, the following line throws a "System.Net.WebException", saying that "The operation has timed out":
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
here are the facts:
catching the exception and retying keeps causing the same exception
the default HttpWebRequest .Timeout and .ReadWriteTimeout are already high enough (over a minute)
changing HttpWebRequest.KeepAlive to false didn't solve anything either
it seems to always work in the browser even while the function is failing
it has no problems retrieveing the response from https://www.google.com
the amount of successful responses before the exceptions varies from day to day (but browser always works)
starting at the trade id that failed last time causes the exception immediately
calling this function from the main thread instead still caused the exception
running it on a different machine didn't work
running it from a different IP didn't work
increasing Thread.Sleep inbetween requests does not help
any ideas of what could be wrong?
I had the very same issue.
For me the fix was as simple as wrapping the HttpWebResponse code in using block.
using (HttpWebResponse response = (HttpWebResponse) request.GetResponse())
{
// Do your processings here....
}
Details: This issue usually happens when several requests are made to the same host, and WebResponse is not disposed properly. That is where using block will properly dispose the WebResponse object properly and thus solving the issue.
There are two kind of timeouts. Client timeout and server timeout. Have you tried doing something like this:
request.Timeout = Timeout.Infinite;
request.KeepAlive = true;
Try something like this...
I just had similar troubles calling a REST Service on a LINUX Server thru ssl. After trying many different configuration scenarios I found out that I had to send a UserAgent in the http head.
Here is my final method for calling the REST API.
private static string RunWebRequest(string url, string json)
{
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
// Header
request.ContentType = "application/json";
request.Method = "POST";
request.AllowAutoRedirect = false;
request.KeepAlive = false;
request.Timeout = 30000;
request.ReadWriteTimeout = 30000;
request.UserAgent = "test.net";
request.Accept = "application/json";
request.ProtocolVersion = HttpVersion.Version11;
request.Headers.Add("Accept-Language","de_DE");
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };
byte[] bytes = Encoding.UTF8.GetBytes(json);
request.ContentLength = bytes.Length;
using (var writer = request.GetRequestStream())
{
writer.Write(bytes, 0, bytes.Length);
writer.Flush();
writer.Close();
}
var httpResponse = (HttpWebResponse)request.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
var jsonReturn = streamReader.ReadToEnd();
return jsonReturn;
}
}
This is not a solution, but just an alternative:
These days i almost only use WebClient instead of HttpWebRequest. Especially WebClient.UploadString for POST and PUT and WebClient.DownloadString. These simply take and return strings. This way i don't have to deal with streams objects, except when i get a WebException. i can also set the content type with WebClient.Headers["Content-type"] if necessary. The using statement also makes life easier by calling Dispose for me.
Rarely for performance, i set System.Net.ServicePointManager.DefaultConnectionLimit high and instead use HttpClient with it's Async methods for simultaneous calls.
This is how i would do it now
string GetTradesOnline(Int64 tid)
{
using (var wc = new WebClient())
{
return wc.DownloadString("https://data.mtgox.com/api/1/BTCUSD/trades?since=" + tid.ToString());
}
}
2 more POST examples
// POST
string SubmitData(string data)
{
string response;
using (var wc = new WebClient())
{
wc.Headers["Content-type"] = "text/plain";
response = wc.UploadString("https://data.mtgox.com/api/1/BTCUSD/trades", "POST", data);
}
return response;
}
// POST: easily url encode multiple parameters
string SubmitForm(string project, string subject, string sender, string message)
{
// url encoded query
NameValueCollection query = HttpUtility.ParseQueryString(string.Empty);
query.Add("project", project);
query.Add("subject", subject);
// url encoded data
NameValueCollection data = HttpUtility.ParseQueryString(string.Empty);
data.Add("sender", sender);
data.Add("message", message);
string response;
using (var wc = new WebClient())
{
wc.Headers[HttpRequestHeader.ContentType] = "application/x-www-form-urlencoded";
response = wc.UploadString( "https://data.mtgox.com/api/1/BTCUSD/trades?"+query.ToString()
, WebRequestMethods.Http.Post
, data.ToString()
);
}
return response;
}
Error handling
try
{
Console.WriteLine(GetTradesOnline(0));
string data = File.ReadAllText(#"C:\mydata.txt");
Console.WriteLine(SubmitData(data));
Console.WriteLine(SubmitForm("The Big Project", "Progress", "John Smith", "almost done"));
}
catch (WebException ex)
{
string msg;
if (ex.Response != null)
{
// read response HTTP body
using (var sr = new StreamReader(ex.Response.GetResponseStream())) msg = sr.ReadToEnd();
}
else
{
msg = ex.Message;
}
Log(msg);
}
For what it's worth, I was experiencing the same issues with timeouts every time I used it, even though calls went through to the server I was calling. The problem in my case was that I had Expect set to application/json, when that wasn't what the server was returning.
This may be a pathetically simple problem, but I cannot seem to format the post webrequest/response to get data from the Wikipedia API. I have posted my code below if anyone can help me see my problem.
string pgTitle = txtPageTitle.Text;
Uri address = new Uri("http://en.wikipedia.org/w/api.php");
HttpWebRequest request = WebRequest.Create(address) as HttpWebRequest;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
string action = "query";
string query = pgTitle;
StringBuilder data = new StringBuilder();
data.Append("action=" + HttpUtility.UrlEncode(action));
data.Append("&query=" + HttpUtility.UrlEncode(query));
byte[] byteData = UTF8Encoding.UTF8.GetBytes(data.ToString());
request.ContentLength = byteData.Length;
using (Stream postStream = request.GetRequestStream())
{
postStream.Write(byteData, 0, byteData.Length);
}
using (HttpWebResponse response = request.GetResponse() as HttpWebResponse)
{
// Get the response stream.
StreamReader reader = new StreamReader(response.GetResponseStream());
divWikiData.InnerText = reader.ReadToEnd();
}
You might want to try a GET request first because it's a little simpler (you will only need to POST for wikipedia login). For example, try to simulate this request:
http://en.wikipedia.org/w/api.php?action=query&prop=images&titles=Main%20Page
Here's the code:
HttpWebRequest myRequest =
(HttpWebRequest)WebRequest.Create("http://en.wikipedia.org/w/api.php?action=query&prop=images&titles=Main%20Page");
using (HttpWebResponse response = (HttpWebResponse)myRequest.GetResponse())
{
string ResponseText;
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
ResponseText = reader.ReadToEnd();
}
}
Edit: The other problem he was experiencing on the POST request was, The exception is : The remote server returned an error: (417) Expectation failed. It can be solved by setting:
System.Net.ServicePointManager.Expect100Continue = false;
(This is from: HTTP POST Returns Error: 417 "Expectation Failed.")
I'm currently in the final stages of implementing an C# MediaWiki API which allows the easy scripting of most MediaWiki viewing and editing actions.
The main API is here: http://o2platform.googlecode.com/svn/trunk/O2%20-%20All%20Active%20Projects/O2_XRules_Database/_Rules/APIs/OwaspAPI.cs and here is an example of the API in use:
var wiki = new O2MediaWikiAPI("http://www.o2platform.com/api.php");
wiki.login(userName, password);
var page = "Test"; // "Main_Page";
wiki.editPage(page,"Test content2");
var rawWikiText = wiki.raw(page);
var htmlText = wiki.html(page);
return rawWikiText.line().line() + htmlText;
You seem to be pushing the input data on HTTP POST, but it seems you should use HTTP GET.
From the MediaWiki API docs:
The API takes its input through
parameters in the query string. Every
module (and every action=query
submodule) has its own set of
parameters, which is listed in the
documentation and in action=help, and
can be retrieved through
action=paraminfo.
http://www.mediawiki.org/wiki/API:Data_formats