I have the following Silverlight code. It uploads a file (postData) to a backend through the given url (url).
public async Task<HttpFileUploadResponse> PostFile(string url, byte[] postData, string fileName, bool isPDF) {
HttpWebRequest request = null;
Uri uri = new Uri(url);
request = (HttpWebRequest)WebRequest.Create(uri);
request.Method = "POST";
request.ContentType = "multipart/form-data";
using (Stream writeStream = await request.GetRequestStreamAsync()) {
await writeStream.WriteAsync(postData, 0, postData.Length);
}
using (HttpWebResponse response = (HttpWebResponse)await request.GetResponseAsync())
using (Stream responseStream = response.GetResponseStream())
using (StreamReader readStream = new StreamReader(responseStream, System.Text.Encoding.UTF8)) {
return ParseServerResponse(await readStream.ReadToEndAsync());
}
}
The problem with this method is that is freezing Internet Explorer when the line await request.GetRequestStreamAsync() is reached.
Although similar questions have been resolved, such as:
Application hangs on GetRequestStream() after first request
Why does HttpWebRequest.GetResponse() hang when trying to update an OData service?
I've followed the suggested steps, like setting the ContentLength, but the result is the same.
Also I've tried to change the URL to another one corresponding to another backend that is currently working with other Silverlight components that we have. These components also have an await request.GetRequestStreamAsync() but they are working perfectly.
I've tried to change the contentType. My workmates have used Fiddler to see the request but apparently nothing is being sent (I suppose it's because it freezes).
Any idea about what's happening here?
EDIT:
I have decompiled the AsynCompatLibExtensions.cs and TaskExtensions.cs to copy the GetRequestStreamAsync code in order to have a custom cloned class with logs among the instructions.
I have recompiled the solution using this class and the strange thing is that I'm not seeing any log. So I suppose it's freezing when it enters GetRequestStreamAsync but before it reaches any code line inside.
Any idea?
Related
We have a program that has been running for years making API calls to a web server using HttpWebRequest and yesterday it started giving an error (something like "connection forcibly closed by remote host"). The request works just fine when made through a web browser so I would love to be able to see the difference in requests. With the Firefox developer console, I can see the raw request that is made through the browser (that works) and I need to compare that to the http request that is made from our program. It seems like it should be simple (and very useful) to stream the request out to a string or a file so I can look at it (but I have not had any luck finding how to do that).
Can you tell me how to modify the below code to store the request that HttpWebRequest would send to a file or a string (instead of a network stream)?
public string Post(string uri, string data, string contentType, string method = "POST")
{
byte[] dataBytes = Encoding.UTF8.GetBytes(data);
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(uri);
request.AutomaticDecompression = DecompressionMethods.GZip | DecompressionMethods.Deflate;
request.ContentLength = dataBytes.Length;
request.ContentType = contentType;
request.Method = method;
using(Stream requestBody = request.GetRequestStream())
{
requestBody.Write(dataBytes, 0, dataBytes.Length);
}
using(HttpWebResponse response = (HttpWebResponse)request.GetResponse())
using(Stream stream = response.GetResponseStream())
using(StreamReader reader = new StreamReader(stream))
{
return reader.ReadToEnd();
}
}
You can't simply log the httprequest. Because you should also consider logging all the headers.
I suggest you to use some http sniffer to log the traffic(if you can't debug or modify your code)
In addition you can catch the exceptions by using WebException and get the raw error message from the server. Maybe it'll give you idea what the problem is.
catch (WebException ex)
{
using (var stream = ex.Response.GetResponseStream())
using (var reader = new StreamReader(stream))
{
var responseString = reader.ReadToEnd();
}
}
I can't insert permission to a file with this code:
string URI = String.Format("https://www.googleapis.com/drive/v2/files/{0}/permissions&access_token={1}", fileId, "token");
var request = (HttpWebRequest)HttpWebRequest.Create(URI);
request.Method = "POST";
request.ContentType = "application/json";
string json = "{\"role\": \"reader\",\"type\": \"anyone\"}";
byte[] byteData = new System.Text.ASCIIEncoding().GetBytes(json);
request.ContentLength = byteData.Length;
using (var dataStream = request.GetRequestStream())
{
dataStream.Write(byteData, 0, byteData.Length);
}
var response = (HttpWebResponse)request.GetResponse();
using (var reader = new StreamReader(response.GetResponseStream()))
{
json = reader.ReadToEnd();
}
I al getting a 404 error. What's the problem?
string URI = String.Format("https://www.googleapis.com/drive/v2/files/{0}/permissions&access_token={1}", fileId, "token");
Access token is not a string "token" it must be a valid access token for the user who owns the file.
Update:
permissions?access_token={1}",
You should be using ? and not & to add a parameter to the url. Not even sure you can do it like that with a HTTP Post.
Added info:
If this is not simply a typo on your part you may want to read up on Authorization a little
I also recommend checking out the Google client library instead of writing this yourself. Google.Apis.Drive.v2 Client Library.
There is a newer version of the Google Drive API you might also be interested in looking at rather then writing new code for an older version of the API. Google Drive API v3.
Here is my code :
public async Task<HttpResponseMessage> Get()
{
var url = "some url here";
string content;
HttpWebRequest request = WebRequest.Create(url) as HttpWebRequest;
/*1*/ using (HttpWebResponse webresponse = await request.GetResponseAsync() as HttpWebResponse)
{
using (StreamReader reader = new StreamReader(webresponse.GetResponseStream()))
{
/*2*/ content = await reader.ReadToEndAsync();
}
}
var response = this.Request.CreateResponse(HttpStatusCode.OK);
response.Content = new StringContent(content, Encoding.UTF8, "text/plain");
return response;
}
and my problem:
When I try to visit this get in my IE, the connect is marked as pending all the time and nothing is shown. And in FireFox, I can read part of the data, and it is likely missing the last a few characters with the tab showing a spinning icon.
I guess it is because the HTTP connection is not closed by my IIS express( and with a few characters not flushed).
I tried to modify my code in line 1 and 2. The result is if I change line 1 into a synchronous call request.GetResponse() as HttpWebResponse, everything works fine as I expect, no mater what is in line 2, the ReadtoEnd(), async or sync .
I can use a workaround that only call request.GetResponse() to make everything works, but I want to know why this happens.
I'm calling an API hosted on Apache server to post data. I'm using HttpWebRequest to perform POST in C#.
API has both normal HTTP and secure layer (HTTPS) PORT on the server. When I call HTTP URL it works perfectly fine. However, when I call HTTPS it gives me time-out exception (at GetRequestStream() function). Any insights? I'm using VS 2010, .Net framework 3.5 and C#. Here is the code block:
string json_value = jsonSerializer.Serialize(data);
HttpWebRequest request = (HttpWebRequest)System.Net.WebRequest.Create("https://server-url-xxxx.com");
request.Method = "POST";
request.ProtocolVersion = System.Net.HttpVersion.Version10;
request.ContentType = "application/x-www-form-urlencoded";
byte[] buffer = Encoding.ASCII.GetBytes(json_value);
request.ContentLength = buffer.Length;
System.IO.Stream reqStream = request.GetRequestStream();
reqStream.Write(buffer, 0, buffer.Length);
reqStream.Close();
EDIT:
The console program suggested by Peter works fine. But when I add data (in JSON format) that needs to be posted to the API, it throws out operation timed out exception. Here is the code that I add to console based application and it throws error.
byte[] buffer = Encoding.ASCII.GetBytes(json_value);
request.ContentLength = buffer.Length;
I ran into the same issue. It seems like it is solved for me. I went through all my code making sure to invoke webResponse.Close() and/or responseStream.Close() for all my HttpWebResponse objects. The documentation indicates that you can close the stream or the HttpWebResponse object. Calling both is not harmful, so I did. Not closing the responses may cause the application to run out of connections for reuse, and this seems to affect the HttpWebRequest.GetRequestStream as far as I can observe in my code.
I don't know if this will help you with your specific problem but you should consider Disposing some of those objects when you are finished with them. I was doing something like this recently and wrapping stuff up in using statements seems to clean up a bunch of timeout exceptions for me.
using (var reqStream = request.GetRequestStream())
{
if (reqStream == null)
{
return;
}
//do whatever
}
also check these things
Is the server serving https in your local dev environment?
Have you set up your bindings *.443 (https) properly?
Do you need to set credentials on the request?
Is it your application pool account accessing the https resources or is it your account being passed through?
Have you thought about using WebClient instead?
using (WebClient client = new WebClient())
{
using (Stream stream = client.OpenRead("https://server-url-xxxx.com"))
using (StreamReader reader = new StreamReader(stream))
{
MessageBox.Show(reader.ReadToEnd());
}
}
EDIT:
make a request from console.
internal class Program
{
private static void Main(string[] args)
{
new Program().Run();
Console.ReadLine();
}
public void Run()
{
var request = (HttpWebRequest)System.Net.WebRequest.Create("https://server-url-xxxx.com");
request.Method = "POST";
request.ProtocolVersion = System.Net.HttpVersion.Version10;
request.ContentType = "application/x-www-form-urlencoded";
using (var reqStream = request.GetRequestStream())
{
using(var response = new StreamReader(reqStream )
{
Console.WriteLine(response.ReadToEnd());
}
}
}
}
Try this:
WebRequest req = WebRequest.Create("https://server-url-xxxx.com");
req.Method = "POST";
string json_value = jsonSerializer.Serialize(data); //Body data
ServicePointManager.Expect100Continue = false;
using (var streamWriter = new StreamWriter(req.GetRequestStream()))
{
streamWriter.Write(json_value);
streamWriter.Flush();
streamWriter.Close();
}
HttpWebResponse resp = req.GetResponse() as HttpWebResponse;
Stream GETResponseStream = resp.GetResponseStream();
StreamReader sr = new StreamReader(GETResponseStream);
var response = sr.ReadToEnd(); //Response
resp.Close(); //Close response
sr.Close(); //Close StreamReader
And review the URI:
Reserved characters. Send reserved characters by the URI can bring
problems ! * ' ( ) ; : # & = + $ , / ? # [ ]
URI Length: You should not exceed 2000 characters
I ran into this, too. I wanted to simulate hundreds of users with a Console app. When simulating only one user, everything was fine. But with more users came the Timeout exception all the time.
Timeout occurs because by default the ConnectionLimit=2 to a ServicePoint (aka website).
Very good article to read: https://venkateshnarayanan.wordpress.com/2013/04/17/httpwebrequest-reuse-of-tcp-connections/
What you can do is:
1) make more ConnectionGroups within a servicePoint, because ConnectionLimit is per ConnectionGroups.
2) or you just simply increase the connection limit.
See my solution:
private HttpWebRequest CreateHttpWebRequest<U>(string userSessionID, string method, string fullUrl, U uploadData)
{
HttpWebRequest req = (HttpWebRequest)HttpWebRequest.Create(fullUrl);
req.Method = method; // GET PUT POST DELETE
req.ConnectionGroupName = userSessionID; // We make separate connection-groups for each user session. Within a group connections can be reused.
req.ServicePoint.ConnectionLimit = 10; // The default value of 2 within a ConnectionGroup caused me always a "Timeout exception" because a user's 1-3 concurrent WebRequests within a second.
req.ServicePoint.MaxIdleTime = 5 * 1000; // (5 sec) default was 100000 (100 sec). Max idle time for a connection within a ConnectionGroup for reuse before closing
Log("Statistics: The sum of connections of all connectiongroups within the ServicePoint: " + req.ServicePoint.CurrentConnections; // just for statistics
if (uploadData != null)
{
req.ContentType = "application/json";
SerializeToJson(uploadData, req.GetRequestStream());
}
return req;
}
/// <summary>Serializes and writes obj to the requestStream and closes the stream. Uses JSON serialization from System.Runtime.Serialization.</summary>
public void SerializeToJson(object obj, Stream requestStream)
{
DataContractJsonSerializer json = new DataContractJsonSerializer(obj.GetType());
json.WriteObject(requestStream, obj);
requestStream.Close();
}
You may want to set timeout property, check it here http://www.codeproject.com/Tips/69637/Setting-timeout-property-for-System-Net-WebClient
I'm developing the client-side of a third party webservice. The purpose is that I send xml-file to the server.
How should I attach the xml-file to the httpwebrequest? What contentType is needed? More suggestions?
I cannot use mtom or dime.ie because I am using httpwebrequest. I am unable to use WCF either.
Here is a very basic method of sending XML structured data using HttpWebRequest (by the way you need to use request.ContentType = "application/xml";) :
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(new Uri(myUrl));
request.Method = "POST";
request.ContentType = "application/xml";
request.Accept = "application/xml";
XElement redmineRequestXML =
new XElement("issue",
new XElement("project_id", 17)
);
byte[] bytes = Encoding.UTF8.GetBytes(redmineRequestXML.ToString());
request.ContentLength = bytes.Length;
using (Stream putStream = request.GetRequestStream())
{
putStream.Write(bytes, 0, bytes.Length);
}
// Log the response from Redmine RESTful service
using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
using (StreamReader reader = new StreamReader(response.GetResponseStream()))
{
Logger.Info("Response from Redmine Issue Tracker: " + reader.ReadToEnd());
}
I use this at one of my projects (NBug) to submit an issue report to my Redmine issue tracker which accepts XML structured data over web requests (via POST). If you need further examples, you can get a couple of fully featured examples here: http://nbug.codeplex.com/SourceControl/list/changesets (click 'Browse' under 'Latest Verion' label on the right then navigate to "NBug\Submit\Tracker\Redmine.cs")