I have a azure website which was running in browser. If I go to a particular page like my.azurewebsites.net/rest/api it's showing response on webpage. But if I used it in my PCL code like this
using (var httpClient = new HttpClient() { MaxResponseContentBufferSize = int.MaxValue })
{
HttpResponseMessage response = await httpClient.GetAsync(url);
response.EnsureSuccessStatusCode();
return await response.Content.ReadAsStringAsync();
}
Than its showing inner exception "The remote name could not be resolved".
Addition information; "An error occurred while sending request"
3 days before it was working fine. Now I don't know what happened and how to fix.
Related
I started an HTTP server in a local area network from C# as:
HttpListener listener = new HttpListener();
listener.Prefixes.Add(url);
listener.Start();
In another thread, it sends response as:
HttpListenerContext context = listener.GetContext();
context.Response.StatusCode = 200;
using (StreamWriter writer = new StreamWriter(context.Response.OutputStream)) {
writer.WriteLine(responseJson);
}
And in my client code, Http request is sent and processed as:
HttpClient client = new HttpClient();
HttpResponseMessage response = await client.GetAsync(url);
response.EnsureSuccessStatusCode();
string result = await response.Content.ReadAsStringAsync();
This server-client application works well in one LAN. But after I copied the application to another machine in another LAN, the last line of client code (await response result) got error " The input was not in a correct format". I really have no idea what it is about. I visited the server url from web browser, the correct response could be retrieved. So this is more likely to be a client-side issue, I guess.
Any help is appreciate.
I am working in an internal corporate environment. We have created a webapi installed on iis on port 85. We call this from another MVC HelperApp on port 86. It all works as expected. Now we want to tighten security and add an SSL cert to iis on port 444 and bind it to our API.
Initially we test it with Postman, SoapUI, and a C# console app and it all works. Now we try calling it from our MVC HelperApp and it returns a 404 sometimes.
Deeper debugging; I put the code into a C# DLL (see below). Using the console app I call the Dll.PostAPI and it works as expected. Now I call that same Dll.PostAPI from the MVC HelperApp and it won't work. When I step through the code I make it as far as this line await client.PostAsync(url, data); and the code bizarrely ends, it doesn't return and it doesn't throw an exception. Same for Post and Get. I figure it makes the call and nothing is returned, no response and no error.
Also, if I change the url to "https://httpbin.org/post" or to the open http port85 on iss it will work. I have concluded that the C# code is not the problem (but I'm open to being wrong).
Therefore I have come to the conclusion that for some reason the port or cert is refusing calls from browsers.
We are looking at:
the "Subject Alternative Name" but all the examples show
WWW.Addresses which we are not using.
the "Friendly Name" on the cert creation.
and CORS Cross-Origin Resource Sharing.
These are all subjects we lack knowledge in.
This is the calling code used exactly the same in the console app and the web app:
var lib = new HttpsLibrary.ApiCaller();
lib.makeHttpsCall();
This is what's in the DLL that gets called:
public async Task<string> makeHttpsCall()
{
try
{
List<Quote> quotes = new List<Quote>();
quotes.Add(CreateDummyQuote());
var json = JsonConvert.SerializeObject(quotes);
var data = new StringContent(json, Encoding.UTF8, "application/json");
var url = "https://httpbin.org/post"; //this works in Browser
//url = "https://thepath:444//api/ProcessQuotes"; //444 DOES NOT WORK in browsers only. OK in console app.
//url = "http://thepath:85/api/ProcessQuotes"; //85 works.
var client = new HttpClient();
var response = await client.PostAsync(url, data); //<<<this line never returns when called from browser.
//var response = await client.GetAsync(url); //same outcome for Get or Post
var result = await response.Content.ReadAsStringAsync();
return result;
}
catch (Exception ex)
{
throw;
}
}
I have a Windows Phone 8 app containing code as follows:
using (var client = new HttpClient())
{
var httpRequest = new HttpRequestMessage(method, uri);
try
{
var response = client.SendAsync(httpRequest);
var httpResponse = await response;
if (httpResponse.IsSuccessStatusCode)
{
var result = await httpResponse.Content.ReadAsStringAsync();
return result;
}
else
{
HandleError(httpResponse);
return null;
}
}
catch (Exception ex)
{
throw;
}
}
If the client successfully connects to the server, I will get the expected results, including all the appropriate HTTP status codes and reason phrases.
If the client is unable to contact the server (e.g. incorrect domain/IP/port in the URL), the awaited task completes after some delay, with a 404 status and no reason phrase. The task never throws an exception. The task (the response variable in the code snippet) has the status of "ran to completion". Nothing about the result is indicative of the actual problem - be it networking failure, unreachable server, etc.
How can I capture more meaningful errors in the case where the URL points to a non-existent or unreachable server, socket connection refused, etc.? Shouldn't SendAsync be throwing specific exceptions for such cases?
FWIW, the client code is built into a PCL library using VS 2013 update 3 and running in the Windows Phone emulator, using System.Net.Http 2.2.28 from NuGet
Windows Phone's implementation of the .NET HttpClient is different from Desktop's implementation (wininet vs. custom stack). This is one of the incompatibilities that you need to be aware of, if there is a semantic difference for you.
In my simple test I do get a ReasonPhrase of "Not Found" on the phone emulator. Also you can see that the Headers collection is empty whereas if the server was found and actually returned a real 404 then there would be headers.
In a Xamarin application (backed by ASP.NET WebApi), I'm having trouble getting [all of] my GET requests to succeed -- they return 404. In fact, when watching network traffic in Fiddler, I don't even see the request happen.
Here is [basically] what I'm doing:
public async Task<bool> ValidateSponsor(string attendeeId, string sponsorId)
{
string address = String.Format("{0}/Sponsors/?attendeeId={1}&sponsorId={2}", BASE_URI, attendeeId, sponsorId);
var response = await client.GetAsync(address);
var content = response.content;
if (!response.IsSuccessStatusCode)
throw new HttpRequestException("Check your network connection and try again.");
string result = await content.ReadAsStringAsync();
return Convert.ToBoolean(result);
}
If I copy out the address variable and paste it into a browser, it succeeds. POST requests (to different methods, of course) succeed. I've also tried using the PCL version RestSharp but get the same results -- POST succeeds and GET fails.
Edit:
This looks like it also may only be a problem when deployed to Azure, it works fine locally.
I'm using this code to download a web page in my Metro Style app:
public static async Task<string> DownloadPageAsync(string url)
{
HttpClientHandler handler = new HttpClientHandler();
handler.UseDefaultCredentials = true;
handler.AllowAutoRedirect = true;
HttpClient client = new HttpClient(handler);
HttpResponseMessage response = await client.GetAsync(url);
response.EnsureSuccessStatusCode();
string responseBody = response.Content.ReadAsString();
return responseBody;
}
the problem is that when the line client.GetAsync(url) runs, it throws an exception that says:
An error occurred while sending the request. From type: HttpRequestException.
EDIT:
I've used the InnerException to get more info. The first exception thrown is SocketException with the message below:
An attempt was made to access a socket in a way forbidden by its access permissions
at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult)
at System.Net.Http.HttpClientHandler.GetResponseCallback(IAsyncResult ar)
EDIT 2:
I've downloaded and ran the sample from Microsoft and I get the same error:
http://code.msdn.microsoft.com/windowsapps/HttpClient-Upload-Sample-f1abcc4e
EDIT 3:
I ran this on another machine and it worked fine. So I guess there's nothing wrong with the code. I copied the solution and it means that there's nothing wrong with the solution either. I'm trying to re-install Windows Developer Preview to see if it fixes my problem.
OK. I found the answer. The exception was because I installed NetLimiter product on Windows 8 Developer Preview and somehow it prevented my app from accessing the internet.
UPDATE:
First of all, this is the code working in EVERY version of Windows 8.
public static async Task<string> DownloadPageAsync(string url)
{
try
{
HttpClientHandler handler = new HttpClientHandler { UseDefaultCredentials = true, AllowAutoRedirect = true };
HttpClient client = new HttpClient(handler);
HttpResponseMessage response = await client.GetAsync(url);
response.EnsureSuccessStatusCode();
string html = await response.Content.ReadAsStringAsync();
return html;
}
catch (Exception)
{
return "";
}
}
Secondly, if this doesn't work, chances are, you have a network-related software preventing your app to access the Internet. One popular case is proxifier. If you have proxifier installed your MetroStyle apps won't be able to access the internet. To make it work, please refer to my blog at:
http://anoori.me/blog/general/use-proxifier-in-windows-8-without-fiddler2
pretty sure netlimiter was running your internet request through a localhost proxy, and your app didn't have the "local network" capability which would allow such access to the local network