Is there a way to extract the text that is being sent back as part of the WebException that occurs can occur with a HttpWebResponse? I can get all of the header information but there is a custom message being returned with the 400 or 401 response that I would like to get if possible. I am currently handling the exception in my test like this:
var ex = Assert.Throws<WebException>(() =>
{
HttpWebResponse response = Utils.GetRawResponse(url);
});
Assert.Contains("401", ex.Message);
Here is how am getting the response:
public static HttpWebResponse GetRawResponse(string requestURL)
{
HttpWebRequest request = WebRequest.Create(requestURL) as HttpWebRequest;
HttpWebResponse response = request.GetResponse() as HttpWebResponse;
return response;
}
And this works, but does not have the custom message.
Top hopefully be a little more clear am am referring to the message text in the bottom of the screenshot.:
With Gusmans reminder I created a method to extract the response from the WebException:
public static string ParseExceptionRespose(WebException exception)
{
string responseContents;
Stream descrption = ((HttpWebResponse)exception.Response).GetResponseStream();
using (StreamReader readStream = new StreamReader(descrption))
{
responseContents = readStream.ReadToEnd();
}
return responseContents;
}
When handling the exception, try something like:
if (ex.Response.ContentLength > 0)
{
string ResponseBody = new StreamReader(ex.Response.GetResponseStream()).ReadToEnd();
// Do whatever you want with ResponseBody
}
Similar to examples in http://msdn.microsoft.com/en-us/library/system.net.httpwebresponse.contentlength(v=vs.110).aspx)
The key point being that WebException had a Response property: http://msdn.microsoft.com/en-us/library/system.net.webexception.response(v=vs.110).aspx
Related
I am using the following code to complete an External API call.
WebResponse response = request.GetResponse();
string JSONResult = null;
var data = response.GetResponseStream();
using (var reader = new StreamReader(data))
{
JSONResult = reader.ReadToEnd();
}
When there is an exception on the external API, the request.GetResponse throws an error. However, I cannot get the message that is displayed, e.g.
{
"Message": "No HTTP resource was found that matches the request URI '<site>/Foo'.",
"MessageDetail": "No type was found that matches the controller named 'Foo'."
}
Whilst this is displayed in Fiddler and Postman, I cannot get this message anywhere when it is thrown as an exception.
How do I get this specific details when an error on an external API's call is made?
You need to catch the exception and then read the response stream of the exception. Reading the exception's response stream is the same as reading the response of the request. Here is how:
WebRequest request =
WebRequest.Create("http://...");
WebResponse response = null;
try
{
response = request.GetResponse();
}
catch (WebException webEx)
{
if (webEx.Response != null)
{
using (var errorResponse = (HttpWebResponse)webEx.Response)
{
using (var reader = new StreamReader(errorResponse.GetResponseStream()))
{
string error = reader.ReadToEnd();
// TODO: use JSON.net to parse this string
}
}
}
}
Do not put all your code inside the above try block because you are only try(ing) and catch(ing) the request.GetResponse(). The rest of your code needs to go outside that try catch block so you can catch the exceptions from that code separately.
I'm trying to get the order book from GDAX (link to documentation of the call) but when doing it from the c# executable I always get Error 400 - Bad request.
When taking the actual URL and pasting it into my browser, it works fine.
String URL = "https://api.gdax.com/products/BTC-USD/book?level=2";
WebRequest request = WebRequest.Create(URL);
WebResponse response = request.GetResponse();
The actual issue with your API call is , the API is expecting a user-agent string while making the request: Below is the code in working condition:
try
{
String URL = "http://api.gdax.com/products/BTC-USD/book?level=2";
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(URL);
request.UserAgent = ".NET Framework Test Client";
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
var encoding = ASCIIEncoding.ASCII;
using (var reader = new System.IO.StreamReader(response.GetResponseStream(), encoding))
{
string responseText = reader.ReadToEnd();
}
}
catch(WebException ex)
{
HttpWebResponse xyz = ex.Response as HttpWebResponse;
var encoding = ASCIIEncoding.ASCII;
using (var reader = new System.IO.StreamReader(xyz.GetResponseStream(), encoding))
{
string responseText = reader.ReadToEnd();
}
}
Basically ProtocolError indicates that you have received the response but there is an error related to protocol, which you can observe, when you read the response content from exception. I have added catch to handle the exception and read ex.Response (which is HttpWebResponse) and could see that the API is asking for user-agent to be suppllied while making the call. I got to see the error as "{"message":"User-Agent header is required."}"
You can ignore the code inside the exception block, I used it only to see what is the actual response message, which contains actual error details
Note: I have boxed WebRequest to HttpWebRequest to have additional http protocol related properties and most importantly "UserAgent" property which is not available with the WebRequest class.
You need to Accept the certificarte, Google for access to a https webrequest.
Like this
I am initiating an HttpWebRequest and then retrieving it's response. Occasionally, I get a 500 (or at least 5##) error, but no description. I have control over both endpoints and would like the receiving end to get a little bit more information. For example, I would like to pass the exception message from server to client. Is this possible using HttpWebRequest and HttpWebResponse?
Code:
try
{
HttpWebRequest webRequest = HttpWebRequest.Create(URL) as HttpWebRequest;
webRequest.Method = WebRequestMethods.Http.Get;
webRequest.Credentials = new NetworkCredential(Username, Password);
webRequest.ContentType = "application/x-www-form-urlencoded";
using(HttpWebResponse response = webRequest.GetResponse() as HttpWebResponse)
{
if(response.StatusCode == HttpStatusCode.OK)
{
// Do stuff with response.GetResponseStream();
}
}
}
catch(Exception ex)
{
ShowError(ex);
// if the server returns a 500 error than the webRequest.GetResponse() method
// throws an exception and all I get is "The remote server returned an error: (500)."
}
Any help with this would be much appreciated.
Is this possible using HttpWebRequest and HttpWebResponse?
You could have your web server simply catch and write the exception text into the body of the response, then set status code to 500. Now the client would throw an exception when it encounters a 500 error but you could read the response stream and fetch the message of the exception.
So you could catch a WebException which is what will be thrown if a non 200 status code is returned from the server and read its body:
catch (WebException ex)
{
using (var stream = ex.Response.GetResponseStream())
using (var reader = new StreamReader(stream))
{
Console.WriteLine(reader.ReadToEnd());
}
}
catch (Exception ex)
{
// Something more serious happened
// like for example you don't have network access
// we cannot talk about a server exception here as
// the server probably was never reached
}
I came across this question when trying to check if a file existed on an FTP site or not. If the file doesn't exist there will be an error when trying to check its timestamp. But I want to make sure the error is not something else, by checking its type.
The Response property on WebException will be of type FtpWebResponse on which you can check its StatusCode property to see which FTP error you have.
Here's the code I ended up with:
public static bool FileExists(string host, string username, string password, string filename)
{
// create FTP request
FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://" + host + "/" + filename);
request.Credentials = new NetworkCredential(username, password);
// we want to get date stamp - to see if the file exists
request.Method = WebRequestMethods.Ftp.GetDateTimestamp;
try
{
FtpWebResponse response = (FtpWebResponse)request.GetResponse();
var lastModified = response.LastModified;
// if we get the last modified date then the file exists
return true;
}
catch (WebException ex)
{
var ftpResponse = (FtpWebResponse)ex.Response;
// if the status code is 'file unavailable' then the file doesn't exist
// may be different depending upon FTP server software
if (ftpResponse.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
{
return false;
}
// some other error - like maybe internet is down
throw;
}
}
I faced a similar situation:
I was trying to read raw response in case of an HTTP error consuming a SOAP service, using BasicHTTPBinding.
However, when reading the response using GetResponseStream(), got the error:
Stream not readable
So, this code worked for me:
try
{
response = basicHTTPBindingClient.CallOperation(request);
}
catch (ProtocolException exception)
{
var webException = exception.InnerException as WebException;
var rawResponse = string.Empty;
var alreadyClosedStream = webException.Response.GetResponseStream() as MemoryStream;
using (var brandNewStream = new MemoryStream(alreadyClosedStream.ToArray()))
using (var reader = new StreamReader(brandNewStream))
rawResponse = reader.ReadToEnd();
}
You can also use this library which wraps HttpWebRequest and Response into simple methods that return objects based on the results. It uses some of the techniques described in these answers and has plenty of code inspired by answers from this and similar threads. It automatically catches any exceptions, seeks to abstract as much boiler plate code needed to make these web requests as possible, and automatically deserializes the response object.
An example of what your code would look like using this wrapper is as simple as
var response = httpClient.Get<SomeResponseObject>(request);
if(response.StatusCode == HttpStatusCode.OK)
{
//do something with the response
console.Writeline(response.Body.Id); //where the body param matches the object you pass in as an anonymous type.
}else {
//do something with the error
console.Writelint(string.Format("{0}: {1}", response.StatusCode.ToString(), response.ErrorMessage);
}
Full disclosure
This library is a free open source wrapper library, and I am the author of said library. I make no money off of this but have found it immensely useful over the years and am sure anyone who is still using the HttpWebRequest / HttpWebResponse classes will too.
It is not a silver bullet but supports get, post, delete with both async and non-async for get and post as well as JSON or XML requests and responses. It is being actively maintained as of 6/21/2020
Sometimes ex.Response also throws NullReferenceException so below is the best way to handle
catch (WebException ex)
{
using (var stream = ex?.Response?.GetResponseStream())
if(stream != null)
using (var reader = new StreamReader(stream))
{
Console.WriteLine(reader.ReadToEnd());
}
// todo...
}
catch (Exception ex)
{
// todo...
}
**Answer Updated on 14-03-2022**
HttpWebRequest myHttprequest = null;
HttpWebResponse myHttpresponse = null;
try
{
myHttpRequest = (HttpWebRequest)WebRequest.Create(URL);
myHttpRequest.Method = "POST";
myHttpRequest.ContentType = "application/x-www-form-urlencoded";
myHttpRequest.ContentLength = urinfo.Length;
StreamWriter writer = new StreamWriter(myHttprequest.GetRequestStream());
writer.Write(urinfo);
writer.Close();
myHttpresponse = (HttpWebResponse)myHttpRequest.GetResponse();
if (myHttpresponse.StatusCode == HttpStatusCode.OK)
{
//Success code flow
}
myHttpresponse.Close();
}
catch(WebException e) {
Console.WriteLine("This program is expected to throw WebException on successful run."+
"\n\nException Message :" + e.Message);
if(e.Status == WebExceptionStatus.ProtocolError) {
Console.WriteLine("Status Code : {0}",
((HttpWebResponse)e.Response).StatusCode);
Console.WriteLine("Status Description : {0}",
((HttpWebResponse)e.Response).StatusDescription);
}
**Updated Answer with try catch block**
[docs.microsoft][1]
i have been trying to find out either provide URL is available or not. Available doesnt mean domain availability i mean either URL is accessible or its not accessible
i have tested code
var webrequest = (HttpWebRequest)WebRequest.Create(
"http://localhost:64519/TestPage.aspx");
webrequest.Method = "HEAD";
HttpWebResponse response = webrequest.GetResponse() as HttpWebResponse;
and there is some code on pageload of Testpage
protected void Page_Load(object sender, EventArgs e)
{
StreamReader stream = new StreamReader(Request.InputStream);
XDocument xmlInput = XDocument.Load(stream);
}
now issue is even i added HEAD in request yet it goes in to PageLoad and throws exception.
Scenario:
i have been trying to send XML to provided URL. in XML case its working fine but when i try to check that either Link is live or not it throws exception because XDocument.Load(stream); dont have XML\
surely i can solve the issue by using
if (stream.BaseStream.Length != 0)
{
XDocument xmlInput = XDocument.Load(stream);
}
but its not appropriate. i just want to know the link is live or not based on my research is just Add headers but even with adding headers my problem is yet there
so please some one can help me out with this or any kind of help will be appreciated
You could use the HttpWebRequest and HttpWebResponse classes and set the request's Method to "HEAD".
List of other possible Methods.
var request = (HttpWebRequest)WebRequest.Create("http://localhost:64519/TestPage.aspx");
request.Method = "HEAD";
var response = (HttpWebResponse)request.GetResponse();
var success = response.StatusCode == HttpStatusCode.OK;
I've made a function on the fly. Hope that it works for you :)
public bool isValid(string url) {
Stream sStream;
HttpWebRequest urlReq;
HttpWebResponse urlRes;
try {
urlReq = (HttpWebRequest) WebRequest.Create(url);
urlRes = (HttpWebResponse) urlReq.GetResponse();
sStream = urlRes.GetResponseStream();
string read = new StreamReader(sStream).ReadToEnd();
return true;
} catch (Exception ex) {
//Url not valid
return false;
}
}
Use the GET method
If the Website Respond your Query then Get the Response Data...
If there is no such URL then it throws the WebException Error...
Yoiu Can catch that and do something on that...
Here i list my idea. I think it solve ur problem
try
{
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create("http://localhost:64519/TestPage.aspx");
webRequest.Method = "GET";
string responseData = string.Empty;
HttpWebResponse httpResponse = (HttpWebResponse)webRequest.GetResponse();
using (StreamReader responseReader = new StreamReader(httpResponse.GetResponseStream()))
{
responseData = responseReader.ReadToEnd();
}
}
catch (System.Net.WebException ex)
{
//Code - If does not Exist
}
I am initiating an HttpWebRequest and then retrieving it's response. Occasionally, I get a 500 (or at least 5##) error, but no description. I have control over both endpoints and would like the receiving end to get a little bit more information. For example, I would like to pass the exception message from server to client. Is this possible using HttpWebRequest and HttpWebResponse?
Code:
try
{
HttpWebRequest webRequest = HttpWebRequest.Create(URL) as HttpWebRequest;
webRequest.Method = WebRequestMethods.Http.Get;
webRequest.Credentials = new NetworkCredential(Username, Password);
webRequest.ContentType = "application/x-www-form-urlencoded";
using(HttpWebResponse response = webRequest.GetResponse() as HttpWebResponse)
{
if(response.StatusCode == HttpStatusCode.OK)
{
// Do stuff with response.GetResponseStream();
}
}
}
catch(Exception ex)
{
ShowError(ex);
// if the server returns a 500 error than the webRequest.GetResponse() method
// throws an exception and all I get is "The remote server returned an error: (500)."
}
Any help with this would be much appreciated.
Is this possible using HttpWebRequest and HttpWebResponse?
You could have your web server simply catch and write the exception text into the body of the response, then set status code to 500. Now the client would throw an exception when it encounters a 500 error but you could read the response stream and fetch the message of the exception.
So you could catch a WebException which is what will be thrown if a non 200 status code is returned from the server and read its body:
catch (WebException ex)
{
using (var stream = ex.Response.GetResponseStream())
using (var reader = new StreamReader(stream))
{
Console.WriteLine(reader.ReadToEnd());
}
}
catch (Exception ex)
{
// Something more serious happened
// like for example you don't have network access
// we cannot talk about a server exception here as
// the server probably was never reached
}
I came across this question when trying to check if a file existed on an FTP site or not. If the file doesn't exist there will be an error when trying to check its timestamp. But I want to make sure the error is not something else, by checking its type.
The Response property on WebException will be of type FtpWebResponse on which you can check its StatusCode property to see which FTP error you have.
Here's the code I ended up with:
public static bool FileExists(string host, string username, string password, string filename)
{
// create FTP request
FtpWebRequest request = (FtpWebRequest)WebRequest.Create("ftp://" + host + "/" + filename);
request.Credentials = new NetworkCredential(username, password);
// we want to get date stamp - to see if the file exists
request.Method = WebRequestMethods.Ftp.GetDateTimestamp;
try
{
FtpWebResponse response = (FtpWebResponse)request.GetResponse();
var lastModified = response.LastModified;
// if we get the last modified date then the file exists
return true;
}
catch (WebException ex)
{
var ftpResponse = (FtpWebResponse)ex.Response;
// if the status code is 'file unavailable' then the file doesn't exist
// may be different depending upon FTP server software
if (ftpResponse.StatusCode == FtpStatusCode.ActionNotTakenFileUnavailable)
{
return false;
}
// some other error - like maybe internet is down
throw;
}
}
I faced a similar situation:
I was trying to read raw response in case of an HTTP error consuming a SOAP service, using BasicHTTPBinding.
However, when reading the response using GetResponseStream(), got the error:
Stream not readable
So, this code worked for me:
try
{
response = basicHTTPBindingClient.CallOperation(request);
}
catch (ProtocolException exception)
{
var webException = exception.InnerException as WebException;
var rawResponse = string.Empty;
var alreadyClosedStream = webException.Response.GetResponseStream() as MemoryStream;
using (var brandNewStream = new MemoryStream(alreadyClosedStream.ToArray()))
using (var reader = new StreamReader(brandNewStream))
rawResponse = reader.ReadToEnd();
}
You can also use this library which wraps HttpWebRequest and Response into simple methods that return objects based on the results. It uses some of the techniques described in these answers and has plenty of code inspired by answers from this and similar threads. It automatically catches any exceptions, seeks to abstract as much boiler plate code needed to make these web requests as possible, and automatically deserializes the response object.
An example of what your code would look like using this wrapper is as simple as
var response = httpClient.Get<SomeResponseObject>(request);
if(response.StatusCode == HttpStatusCode.OK)
{
//do something with the response
console.Writeline(response.Body.Id); //where the body param matches the object you pass in as an anonymous type.
}else {
//do something with the error
console.Writelint(string.Format("{0}: {1}", response.StatusCode.ToString(), response.ErrorMessage);
}
Full disclosure
This library is a free open source wrapper library, and I am the author of said library. I make no money off of this but have found it immensely useful over the years and am sure anyone who is still using the HttpWebRequest / HttpWebResponse classes will too.
It is not a silver bullet but supports get, post, delete with both async and non-async for get and post as well as JSON or XML requests and responses. It is being actively maintained as of 6/21/2020
Sometimes ex.Response also throws NullReferenceException so below is the best way to handle
catch (WebException ex)
{
using (var stream = ex?.Response?.GetResponseStream())
if(stream != null)
using (var reader = new StreamReader(stream))
{
Console.WriteLine(reader.ReadToEnd());
}
// todo...
}
catch (Exception ex)
{
// todo...
}
**Answer Updated on 14-03-2022**
HttpWebRequest myHttprequest = null;
HttpWebResponse myHttpresponse = null;
try
{
myHttpRequest = (HttpWebRequest)WebRequest.Create(URL);
myHttpRequest.Method = "POST";
myHttpRequest.ContentType = "application/x-www-form-urlencoded";
myHttpRequest.ContentLength = urinfo.Length;
StreamWriter writer = new StreamWriter(myHttprequest.GetRequestStream());
writer.Write(urinfo);
writer.Close();
myHttpresponse = (HttpWebResponse)myHttpRequest.GetResponse();
if (myHttpresponse.StatusCode == HttpStatusCode.OK)
{
//Success code flow
}
myHttpresponse.Close();
}
catch(WebException e) {
Console.WriteLine("This program is expected to throw WebException on successful run."+
"\n\nException Message :" + e.Message);
if(e.Status == WebExceptionStatus.ProtocolError) {
Console.WriteLine("Status Code : {0}",
((HttpWebResponse)e.Response).StatusCode);
Console.WriteLine("Status Description : {0}",
((HttpWebResponse)e.Response).StatusDescription);
}
**Updated Answer with try catch block**
[docs.microsoft][1]