I made a c# web api at the the moment . It is working fine until today.
I've tried to convert an image to a base64string, and then send the base64string to the c# server through ajax. When I did the said steps, an error occur.
XMLHttpRequest cannot load http://10.0.10.105:50231/api/hello. No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://10.0.10.201' is therefore not allowed access.
I dont know where the main problem resides but in my observation, the error only occur when passing a very long base64string to the server because when i try to send short test string the problem wont appear and all is working well.
Do you have any idea what is the better remedy to fix this ? Or any other way to perform my needed objective ? my ajax code is something like this.
$.ajax({
type: 'POST', //GET or POST or PUT or DELETE verb
url: 'http://10.0.10.105:50231/api/hello', // Location of the service
contentType: 'application/x-www-form-urlencoded', // content type sent to server
data: { action: "3",pers_guid:"wew",base64image:"this-is-the-base64-image"},
//dataType: 'jsonp', //Expected data format from server
//processdata: true, //True or False
success: function (data) {//On Successfull service call
$scope.pageView = 2;
console.log("THE Data description for match : " + data[0].description);
},
error: function (msg) {// When Service call fails
alert(msg);
}
});
and my c# server is similar to this (this is not the whole code).
public class theHandler : DelegatingHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
{
return base.SendAsync(request, cancellationToken)
.ContinueWith((task) =>
{
HttpResponseMessage response = task.Result;
response.Headers.Add("Access-Control-Allow-Origin", "*");
return response;
});
}
}
public class HelloController : ApiController
{
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
//.... more code here
}
This is the result when I tried to pass a very long string...
Request URL:http://10.0.10.105:50231/api/hello
Request Headers CAUTION: Provisional headers are shown.
Accept:*/*
Content-Type:application/x-www-form-urlencoded
Origin:http://10.0.10.201
Referer:http://10.0.10.201/kiosk/
User-Agent:Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36
Form Dataview sourceview URL encoded
action:3
pers_guid:wew
base64image:the_long_base64_string
but when i pass just a sample string this is the result.
Remote Address:10.0.10.105:50231
Request URL:http://10.0.10.105:50231/api/hello
Request Method:POST
Status Code:200 OK
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Connection:keep-alive
Content-Length:49
Content-Type:application/x-www-form-urlencoded
Host:10.0.10.105:50231
Origin:http://10.0.10.201
Referer:http://10.0.10.201/kiosk/
User-Agent:Mozilla/5.0 (Windows NT 6.1) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/35.0.1916.114 Safari/537.36
Form Dataview sourceview URL encoded
action:3
pers_guid:wew
base64image:sample_string
Response Headersview source
Access-Control-Allow-Origin:*
Content-Length:103
Content-Type:application/json; charset=utf-8
Date:Wed, 04 Jun 2014 01:02:35 GMT
Server:Microsoft-HTTPAPI/2.0
This error shows up because your server listening on '10.0.10.105' does not specify the 'Access-Control-Allow-Origin' header in its HTTP response. This is a common issue with websites that 'talk' to each other, and you may read about it here (or just Google 'CORS').
As a solution, have the server listening on that IP return the following header from the POST response:
Access-Control-Allow-Origin: *
This has some security implications that you might want to read about (in general it's best to not use the "allow-all" star '*' and instead specify the requesting server explicitly).
Update: As explained in that paper under "Preflight requests", non-trivial POST requests require the server to also listen to OPTIONS requests and return these headers in the response:
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: POST, GET, OPTIONS
Can you try having the image server listen to OPTIONS (just like you did for GET, POST, etc.) and return these headers? (The client making the 'POST' request will automatically precede it with an OPTIONS request to the same server, and if the OPTIONS response contains these headers, the subsequent POST will be called.)
Thank you so much for your answers. It gives me lot of ideas about access origin. It seems that my problem is on the configuration. I added this code and all is working fine.
config.MaxReceivedMessageSize = 5000000;
The program will automatically show an access-control-allow-origin when it exceeds the max limit size of the default configuration.
Thank you so much for the ideas.
So, CORS and the Access-Control-Allow-Origin header are awkward. I ran into this one a while back when I had an API that needed to be referenced from JavaScript code running on several different websites. I ended up writing an ActionFilterAttribute to handle it for my API controllers:
[AttributeUsage(AttributeTargets.Method)]
public class AllowReferrerAttribute : System.Web.Http.Filters.ActionFilterAttribute
{
public override void OnActionExecuting(System.Web.Http.Controllers.HttpActionContext actionContext)
{
var ctx = (System.Web.HttpContextWrapper)actionContext.Request.Properties["MS_HttpContext"];
var referrer = ctx.Request.UrlReferrer;
if (referrer != null)
{
string refhost = referrer.Host;
string thishost = ctx.Request.Url.Host;
if (refhost != thishost)
ctx.Response.AddHeader("Access-Control-Allow-Origin", string.Format("{0}://{1}", referrer.Scheme, referrer.Authority));
}
base.OnActionExecuting(actionContext);
}
}
You can decorate your controller's methods with that attribute and it will add the correct Access-Control-Allow-Origin for your caller's website, regardless of what that website is. And assuming that you're using IIS as your host... won't work for OWIN-hosted sites.
Example usage:
public class HelloController : ApiController
{
[AllowReferrer]
public IEnumerable<string> Get()
{
return new string[] { "value1", "value2" };
}
}
Related
I have an AJAX form which post a form-data to a local API url: /api/document. It contains a file and a custom Id. We simply want to take the exact received Request and forward it to a remote API at example.com:8000/document/upload.
Is there a simple way of achieve this "forward" (or proxy?) of the Request to a remote API using Asp.NET Core?
Below we had the idea to simply use Web API Http client to get the request and then resend it (by doing so we want to be able to for example append a private api key from the backend), but it seems not to work properly, the PostAsync doesn't accept the Request.
Raw request sent by Ajax
POST http://localhost:62640/api/document HTTP/1.1
Host: localhost:62640
Connection: keep-alive
Content-Length: 77424
Accept: application/json
Cache-Control: no-cache
User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/55.0.2883.87 Safari/537.36
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryn1BS5IFplQcUklyt
Accept-Encoding: gzip, deflate, br
Accept-Language: en-US,en;q=0.8,fr;q=0.6
------WebKitFormBoundaryn1BS5IFplQcUklyt
Content-Disposition: form-data; name="fileToUpload"; filename="test-document.pdf"
Content-Type: application/pdf
...
------WebKitFormBoundaryn1BS5IFplQcUklyt
Content-Disposition: form-data; name="id"
someid
------WebKitFormBoundaryn1BS5IFplQcUklyt--
Backend Code
Our .NET Core backend has a simple "forward to another API" purpose.
public class DocumentUploadResult
{
public int errorCode;
public string docId;
}
[Route("api/[controller]")]
public class DocumentController : Controller
{
// POST api/document
[HttpPost]
public async Task<DocumentUploadResult> Post()
{
client.BaseAddress = new Uri("http://example.com:8000");
client.DefaultRequestHeaders.Accept.Clear();
HttpResponseMessage response = await client.PostAsync("/document/upload", Request.Form);
if (response.IsSuccessStatusCode)
{
retValue = await response.Content.ReadAsAsync<DocumentUploadResult>();
}
return retValue;
}
}
We have a GET request (not reproduced here) which works just fine. As it doesn't have to fetch data from locally POSTed data.
My question
How to simply pass the incoming local HttpPost request and forwarding it to the remote API?
I searched A LOT on stackoverflow or on the web but all are old resources talking about forwarding Request.Content to the remote.
But on Asp.NET Core 1.0, we don't have access to Content. We only are able to retrieve Request.Form (nor Request.Body) which is then not accepted as an argument of PostAsync method:
Cannot convert from Microsoft.AspNetCore.Http.IformCollection to
System.Net.Http.HttpContent
I had the idea to directly pass the request to the postAsync:
Cannot convert from Microsoft.AspNetCore.Http.HttpRequest to
System.Net.Http.HttpContent
I don't know how to rebuild expected HttpContent from the local request I receive.
Expected response
For information, When we post a valid form-data with the custom Id and the uploaded file, the remote (example.com) API response is:
{
"errorCode": 0
"docId": "585846a1afe8ad12e46a4e60"
}
Ok first create a view model to hold form information. Since file upload is involved, include IFormFile in the model.
public class FormData {
public int id { get; set; }
public IFormFile fileToUpload { get; set; }
}
The model binder should pick up the types and populate the model with the incoming data.
Update controller action to accept the model and proxy the data forward by copying content to new request.
[Route("api/[controller]")]
public class DocumentController : Controller {
// POST api/document
[HttpPost]
public async Task<IActionResult> Post(FormData formData) {
if(formData != null && ModelState.IsValid) {
client.BaseAddress = new Uri("http://example.com:8000");
client.DefaultRequestHeaders.Accept.Clear();
var multiContent = new MultipartFormDataContent();
var file = formData.fileToUpload;
if(file != null) {
var fileStreamContent = new StreamContent(file.OpenReadStream());
multiContent.Add(fileStreamContent, "fileToUpload", file.FileName);
}
multiContent.Add(new StringContent(formData.id.ToString()), "id");
var response = await client.PostAsync("/document/upload", multiContent);
if (response.IsSuccessStatusCode) {
var retValue = await response.Content.ReadAsAsync<DocumentUploadResult>();
return Ok(reyValue);
}
}
//if we get this far something Failed.
return BadRequest();
}
}
You can include the necessary exception handlers as needed but this is a minimal example of how to pass the form data forward.
Edit 1: Other Controller
public class identityController : ApiController
{
[HttpGet]
public async Task<IHttpActionResult> getfullname(string firstName)
{
string name = firstName;
return Ok(name);
}
}
I have created a controller which uses an API from another solution.
Method that i use in the controller looks like below:
public class GetNameController : ApiController
{
[HttpGet]
public async Task<IHttpActionResult> CalculatePrice(string firstName)
{
string _apiUrl = String.Format("api/identity/getfullname?firstName={0}", firstName);
string _baseAddress = "http://testApp.azurewebsites.net/";
using (var client = new HttpClient())
{
client.BaseAddress = new Uri(_baseAddress);
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
HttpResponseMessage response = await client.GetAsync(_apiUrl);
if (response.IsSuccessStatusCode)
{
return Ok(response);
}
}
return NotFound();
}
The result of response.IsSuccessStatusCode is always false. When i check the response values i see this result:
{
StatusCode: 400, ReasonPhrase: 'Bad Request', Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Connection: close
Date: Thu, 21 Jul 2016 12:28:21 GMT
Server: Microsoft-HTTPAPI/2.0
Content-Length: 334
Content-Type: text/html; charset=us-ascii
}
}
What could i be missing?
string _apiUrl = String.Format("api/identity/{0}", firstName);
This is assuming that your url is correct, and your testapp is up and running. Even though when I hit it azure tells me your app is stopped. You will need to get your app started first, then change the string _apiUrl to the suggestion above.
http://testapp.azurewebsites.net/api/identity/getfullname?firstName=steve
Gives me this message
Error 403 - This web app is stopped.
The web app you have attempted to reach is currently stopped and does
not accept any requests. Please try to reload the page or visit it
again soon.
If you are the web app administrator, please find the common 403 error
scenarios and resolution here. For further troubleshooting tools and
recommendations, please visit Azure Portal.
So there are several things in your identity controller that are going on.
the functions name is getFullName. Since the word get is in the name of the function. Any httpget request will be routed to the function automagically. Thus making the [HttpGet] redundant. This only works if there is 1 and only 1 httpget request in your controller. If there are multiple you will need to fully qualify the url like you have done
Since youa re using the [httpget] method attribute I can assume you are using webapi2. That being the case and you are using a
primitive in your controller argument you can do notneed to fully
qualify the parameter name on your call. ?firstname={0} changes to
/{0}
I am developing an C# console application for testing whether a URL is valid or not. It works well for most of URLs. But we found that there are some cases the application always got 404 response from target site but the URLs actually work in the browser. And those URLs also works when I tried them in the tools such as DHC (Dev HTTP Client).
In the beginning, I though that this could be the reason of not adding right headers. But after tried using Fiddler to compose a http request with same headers, it works in Fiddler.
So what's wrong with my code? Is there any bug in .NET HttpClient?
Here are the simplified code of my test application:
class Program
{
static void Main(string[] args)
{
var urlTester = new UrlTester("http://www.hffa.it/short-master-programs/fashion-photography");
Console.WriteLine("Test is started");
Task.WhenAll(urlTester.RunTestAsync());
Console.WriteLine("Test is stoped");
Console.ReadKey();
}
public class UrlTester
{
private HttpClient _httpClient;
private string _url;
public UrlTester(string url)
{
_httpClient = new HttpClient
{
Timeout = TimeSpan.FromMinutes(1)
};
// Add headers
_httpClient.DefaultRequestHeaders.Add("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/46.0.2490.80 Safari/537.36");
_httpClient.DefaultRequestHeaders.Add("Accept-Encoding", "gzip,deflate,sdch");
_httpClient.DefaultRequestHeaders.Add("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8");
_httpClient.DefaultRequestHeaders.Add("Accept-Language", "sv-SE,sv;q=0.8,en-US;q=0.6,en;q=0.4");
_url = url;
}
public async Task RunTestAsync()
{
var httpRequestMsg = new HttpRequestMessage(HttpMethod.Get, _url);
try
{
using (var response = await _httpClient.SendAsync(httpRequestMsg, HttpCompletionOption.ResponseHeadersRead))
{
Console.WriteLine("Response: {0}", response.StatusCode);
}
}
catch (HttpRequestException e)
{
Console.WriteLine(e.InnerException.Message);
}
}
}
}
This appears to be an issue with the accepted languages. I got a 200 response when using the following Accept-Language header value
_httpClient.DefaultRequestHeaders.Add("Accept-Language", "en-GB,en-US;q=0.8,en;q=0.6,ru;q=0.4");
p.s. I assume you know in your example _client should read _httpClient in the urlTester constructor or it wont build.
Another possible cause of this problem is if the url you are sending is over approx 2048 bytes long. At that point the content (almost certainly the query string) can become truncated and this in turn means that it may not be matched correctly with a server side route.
Although these urls were processed correctly in the browser, they also failed using the get command in power shell.
This issue was resolved by using a POST with key value pairs instead of using a GET with a long query string.
I'm working with an HttpSelfHostServer in .Net 4.5 and it seems to only be able to determine the controller and action when I send a request using QueryString. It doesn't work if I use "application/x-www-form-urlencoded".
Here's the HttpSelfHostServer code.
private static HttpSelfHostConfiguration _config;
private static HttpSelfHostServer _server;
public static readonly string SelfHostUrl = "http://localhost:8989";
internal static void Start()
{
_config = new HttpSelfHostConfiguration(SelfHostUrl);
_config.HostNameComparisonMode = HostNameComparisonMode.Exact;
_config.Routes.MapHttpRoute(
name: "API Default",
routeTemplate: "api/{controller}/{action}",
defaults: new { action = RouteParameter.Optional },
constraints: null);
_server = new HttpSelfHostServer(_config);
_server.OpenAsync().Wait();
}
The controller code.
public class SettingsController : ApiController
{
[HttpPost]
public bool Test(bool work)
{
return work;
}
}
Here is the response I get when attempting to access it via REST Console using
Request URL: http://localhost:8989/api/Settings/Test
Request Method:POST
Status Code:404 Not Found
Request Headersview source
Accept:*/*
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Cache-Control:no-cache
Connection:keep-alive
Content-Length:9
Content-Type:application/x-www-form-urlencoded
Host:localhost:8989
Origin:chrome-extension://cokgbflfommojglbmbpenpphppikmonn
Pragma:no-cache
User-Agent:Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36
(KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36
Form Dataview parsed
work=true
Response Headersview source
Content-Length:205
Content-Type:application/json; charset=utf-8
Date:Mon, 23 Dec 2013 22:41:10 GMT
Server:Microsoft-HTTPAPI/2.0
So, if I change my request to a post to the url below, it works.
http://localhost:8989/api/Settings/Test?work=true
Why isn't Content-Type:application/x-www-form-urlencoded working?
Your action method parameter is bool, which is a simple type. By default, ASP.NET Web API populates it from URI path or query string. That is the reason http://localhost:8989/api/Settings/Test?work=true works.
When you send the same in the request body, it does not work because ASP.NET Web API binds body to a complex type (class) by default and hence the body will not be bound to your argument type bool. To ask Web API to bind the simple type from body, change your action method like this.
public bool Test([FromBody]bool work)
Then, you will need to send only the value in the body, like this.
=true.
The problem is not with the Content-Type. The rest console uses AJAX and CORS, see http://en.wikipedia.org/wiki/Cross-origin_resource_sharing. This is indicated by the Origin http header in the request.
The server that contains the SettingsController must support CORS. If it doesn't the AJAX request will always return a 404.
The easiest way for you to support CORS is to always return a Access-Control-Allow-Origin: * in the request HTTP headers.
Scope:
I am developing a C# aplication to simulate queries into this site. I am quite familiar with simulating web requests for achieving the same human steps, but using code instead.
If you want to try yourself, just type this number into the CNPJ box:
08775724000119 and write the captcha and click on Confirmar
I've dealed with the captcha already, so it's not a problem anymore.
Problem:
As soon as i execute the POST request for a "CNPJ", a exception is thrown:
The remote server returned an error: (403) Forbidden.
Fiddler Debugger Output:
Link for Fiddler Download
This is the request generated by my browser, not by my code
POST https://www.sefaz.rr.gov.br/sintegra/servlet/hwsintco HTTP/1.1
Host: www.sefaz.rr.gov.br
Connection: keep-alive
Content-Length: 208
Cache-Control: max-age=0
Origin: https://www.sefaz.rr.gov.br
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.11 (KHTML, like Gecko) Chrome/23.0.1271.97 Safari/537.11
Content-Type: application/x-www-form-urlencoded
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Referer: https://www.sefaz.rr.gov.br/sintegra/servlet/hwsintco
Accept-Encoding: gzip,deflate,sdch
Accept-Language: pt-BR,pt;q=0.8,en-US;q=0.6,en;q=0.4
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie: GX_SESSION_ID=gGUYxyut5XRAijm0Fx9ou7WnXbVGuUYoYTIKtnDydVM%3D; JSESSIONID=OVuuMFCgQv9k2b3fGyHjSZ9a.undefined
// PostData :
_EventName=E%27CONFIRMAR%27.&_EventGridId=&_EventRowId=&_MSG=&_CONINSEST=&_CONINSESTG=08775724000119&cfield=rice&_VALIDATIONRESULT=1&BUTTON1=Confirmar&sCallerURL=http%3A%2F%2Fwww.sintegra.gov.br%2Fnew_bv.html
Code samples and References used:
I'm using a self developed library to handle/wrap the Post and Get requests.
The request object has the same parameters (Host,Origin, Referer, Cookies..) as the one issued by the browser (logged my fiddler up here).
I've also managed to set the ServicePointValidator of certificates by using:
ServicePointManager.ServerCertificateValidationCallback =
new RemoteCertificateValidationCallback (delegate { return true; });
After all that configuration, i stil getting the forbidden exception.
Here is how i simulate the request and the exception is thrown
try
{
this.Referer = Consts.REFERER;
// PARAMETERS: URL, POST DATA, ThrownException (bool)
response = Post (Consts.QUERYURL, postData, true);
}
catch (Exception ex)
{
string s = ex.Message;
}
Thanks in advance for any help / solution to my problem
Update 1:
I was missing the request for the homepage, which generates cookies (Thanks #W0lf for pointing me that out)
Now there's another weird thing. Fiddler is not showing my Cookies on the request, but here they are :
I made a successful request using the browser and recorded it in Fiddler.
The only things that differ from your request are:
my browser sent no value for the sCallerURL parameter (I have sCallerURL= instead of sCallerURL=http%3A%2F%2Fwww....)
the session ids are different (obviously)
I have other Accept-Language: values (I'm pretty sure this is not important)
the Content-Length is different (obviously)
Update
OK, I thought the Fiddler trace was from your application. In case you are not setting cookies on your request, do this:
before posting data, do a GET request to https://www.sefaz.rr.gov.br/sintegra/servlet/hwsintco. If you examine the response, you'll notice the website sends two session cookies.
when you do the POST request, make sure to attach the cookies you got at the previous step
If you don't know how to store the cookies and use them in the other request, take a look here.
Update 2
The problems
OK, I managed to reproduce the 403, figured out what caused it, and found a fix.
What happens in the POST request is that:
the server responds with status 302 (temporary redirect) and the redirect location
the browser redirects (basically does a GET request) to that location, also posting the two cookies.
.NET's HttpWebRequest attempts to do this redirect seamlessly, but in this case there are two issues (that I would consider bugs in the .NET implementation):
the GET request after the POST(redirect) has the same content-type as the POST request (application/x-www-form-urlencoded). For GET requests this shouldn't be specified
cookie handling issue (the most important issue) - The website sends two cookies: GX_SESSION_ID and JSESSIONID. The second has a path specified (/sintegra), while the first does not.
Here's the difference: the browser assigns by default a path of /(root) to the first cookie, while .NET assigns it the request url path (/sintegra/servlet/hwsintco).
Due to this, the last GET request (after redirect) to /sintegra/servlet/hwsintpe... does not get the first cookie passed in, as its path does not correspond.
The fixes
For the redirect problem (GET with content-type), the fix is to do the redirect manually, instead of relying on .NET for this.
To do this, tell it to not follow redirects:
postRequest.AllowAutoRedirect = false
and then read the redirect location from the POST response and manually do a GET request on it.
The cookie problem (that has happened to others as well)
For this, the fix I found was to take the misplaced cookie from the CookieContainer, set it's path correctly and add it back to the container in the correct location.
This is the code to do it:
private void FixMisplacedCookie(CookieContainer cookieContainer)
{
var misplacedCookie = cookieContainer.GetCookies(new Uri(Url))[0];
misplacedCookie.Path = "/"; // instead of "/sintegra/servlet/hwsintco"
//place the cookie in thee right place...
cookieContainer.SetCookies(
new Uri("https://www.sefaz.rr.gov.br/"),
misplacedCookie.ToString());
}
Here's all the code to make it work:
using System;
using System.IO;
using System.Net;
using System.Text;
namespace XYZ
{
public class Crawler
{
const string Url = "https://www.sefaz.rr.gov.br/sintegra/servlet/hwsintco";
public void Crawl()
{
var cookieContainer = new CookieContainer();
/* initial GET Request */
var getRequest = (HttpWebRequest)WebRequest.Create(Url);
getRequest.CookieContainer = cookieContainer;
ReadResponse(getRequest); // nothing to do with this, because captcha is f##%ing dumb :)
/* POST Request */
var postRequest = (HttpWebRequest)WebRequest.Create(Url);
postRequest.AllowAutoRedirect = false; // we'll do the redirect manually; .NET does it badly
postRequest.CookieContainer = cookieContainer;
postRequest.Method = "POST";
postRequest.ContentType = "application/x-www-form-urlencoded";
var postParameters =
"_EventName=E%27CONFIRMAR%27.&_EventGridId=&_EventRowId=&_MSG=&_CONINSEST=&" +
"_CONINSESTG=08775724000119&cfield=much&_VALIDATIONRESULT=1&BUTTON1=Confirmar&" +
"sCallerURL=";
var bytes = Encoding.UTF8.GetBytes(postParameters);
postRequest.ContentLength = bytes.Length;
using (var requestStream = postRequest.GetRequestStream())
requestStream.Write(bytes, 0, bytes.Length);
var webResponse = postRequest.GetResponse();
ReadResponse(postRequest); // not interested in this either
var redirectLocation = webResponse.Headers[HttpResponseHeader.Location];
var finalGetRequest = (HttpWebRequest)WebRequest.Create(redirectLocation);
/* Apply fix for the cookie */
FixMisplacedCookie(cookieContainer);
/* do the final request using the correct cookies. */
finalGetRequest.CookieContainer = cookieContainer;
var responseText = ReadResponse(finalGetRequest);
Console.WriteLine(responseText); // Hooray!
}
private static string ReadResponse(HttpWebRequest getRequest)
{
using (var responseStream = getRequest.GetResponse().GetResponseStream())
using (var sr = new StreamReader(responseStream, Encoding.UTF8))
{
return sr.ReadToEnd();
}
}
private void FixMisplacedCookie(CookieContainer cookieContainer)
{
var misplacedCookie = cookieContainer.GetCookies(new Uri(Url))[0];
misplacedCookie.Path = "/"; // instead of "/sintegra/servlet/hwsintco"
//place the cookie in thee right place...
cookieContainer.SetCookies(
new Uri("https://www.sefaz.rr.gov.br/"),
misplacedCookie.ToString());
}
}
}
Sometimes HttpWebRequest needs proxy initialization:
request.Proxy = new WebProxy();//in my case it doesn't need parameters, but you can set it to your proxy address