Getting HTML from a page behind a login - asp.net

This question is a follow up to my previous question about getting the HTML from an ASPX page. I decided to try using the webclient object, but the problem is that I get the login page's HTML because login is required. I tried "logging in" using the webclient object:
WebClient ww = new WebClient();
ww.DownloadString("Login.aspx?UserName=&Password=");
string html = ww.DownloadString("Internal.aspx");
But I still get the login page all the time. I know that the username info is not stored in a cookie. I must be doing something wrong or leaving out an important part. Does anyone know what it could be?

Try setting the credentials property of the WebClient object
WebClient ww = new WebClient();
ww.Credentials = CredentialCache.DefaultCredentials;
ww.DownloadString("Login.aspx?UserName=&Password=");
string html = ww.DownloadString("Internal.aspx");

Just pass valid login parameters to a given URI. Should help you out.
If you don't have login information you shouldn't be trying to circumvent it.
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();
}

Well does opening the page in a brower with "Login.aspx?UserName=&Password=" normaly work?
Some pages may not allow login using data provided in the url, and that it must be entered in the login form on the page and then submitted.

The only other reason I can think of then is that the web page is intentionally blocking it from loggin in. If you have access to the code, take a look at the loggin system used to see if theres anything designed to block such logins.

Use Fiddler to see the HTTP requests and responses that happen when you do it manually through the browser.

#Fire Lancer: I asked myself that same question during my tests, so I checked, and it does work from a browser.

As the aspx page I was trying to get was in my own projct, I could use the Server.Execute method. More details in my answer to my original question

Use Firefox with the LiveHttpHeaders plugin.
This will allow you to login via an actual browser and see EXACTLY what is being sent to the server. My first question would be to verify that it isn't expecting a POST from the form. The example URL you are loading is sending the info via a querystring GET.

Related

Get string from current URL

I am writing an asp.net MVC Application. I have the application send a request to FreeAgent and if the request is successful a code is returned in the redirect of the URL.
For example this is a copy of a successful URL.
{
http://localhost:3425/FreeAgent/Home?code=144B2ymEKw3JfB9EDPIqCGeWKYLb9IKc-ABI6SZ0o&state=
}
They have added the ?code=144B2ymEKw3JfB9EDPIqCGeWKYLb9IKc-ABI6SZ0o&state= to my URL
I need the bit after the ?code= and before &state=
I can use this to get the URL
string code = Request.Url.AbsoluteUri;
but I need help extracting the code from this
edit:
The code will be different each time it is run
You can use the System.Uri and System.Web.HttpUtility classes
string uri = "http://localhost:3425/FreeAgent/Home?code=144B2ymEKw3JfB9EDPIqCGeWKYLb9IKc-ABI6SZ0o&state=";
string queryString = new System.Uri(uri).Query;
var queryDictionary = System.Web.HttpUtility.ParseQueryString(queryString);
Then the value of the code query parameter will be available in queryDictionary["code"]

WCF Service Call during post

I have given
[WebGet(UriTemplate = "/{year}/{issue}/{article}")]
Article GetArticle(string year, string issue, string article);
[OperationContract]
[WebInvoke(UriTemplate = "/{year}/{issue}",Method="POST")]
Article AddArticle(string year, string issue, Article article);
My URL is http://localhost:1355/Issues.svc/
if I give this I am fetching all data from the database
http://localhost:1355/Issues.svc/2010/June/A
GetArticle method fires for the filtered data to bring from db.
Similarly I have to call the Add Article(WebInvoke) method to insert data in to the database.
How should I call this method in the browser
how my url should be should I give method=post
check this post help you to achieve the task you want :Create REST service with WCF and Consume using jQuery
You won't be able to send an HTTP post from a browser by just modifying the URL. You'll have to have a web page with a HTML form, some Javascript code, some server-side code, or something else that has the ability to make an HTTP POST request to your service URL.
If you are just wanting to test your service while in development, here's a good HTTP debugging tool that you might want to check out: http://fiddler2.com
You can't use post it using browser url.
Try this code
//Creating the Web Request.
HttpWebRequest httpWebRequest = HttpWebRequest.Create("http://localhost/DemoApp/Default.aspx") as HttpWebRequest;
//Specifing the Method
httpWebRequest.Method = "POST";
//Data to Post to the Page, itis key value pairs; separated by "&"
string data = "Username=username&password=password";
//Setting the content type, it is required, otherwise it will not work.
httpWebRequest.ContentType = "application/x-www-form-urlencoded";
//Getting the request stream and writing the post data
using (StreamWriter sw = new StreamWriter(httpWebRequest.GetRequestStream()))
{
sw.Write(data);
}
//Getting the Respose and reading the result.
HttpWebResponse httpWebResponse = httpWebRequest.GetResponse() as HttpWebResponse;
using (StreamReader sr = new StreamReader(httpWebResponse.GetResponseStream()))
{
MessageBox.Show(sr.ReadToEnd());
}
Source : http://www.dotnetthoughts.net/2009/11/10/post-data-using-httpwebrequest-in-c-sharp/

RIA Services, Forms Authentication and extra cookies

I have an Silverlight 4 RIA Services application with custom Forms Authentication. The custom authentication service works like a charm.
The problems is I want to serialize the user object in a cookie which is then sent with each subsequent request.
I create the cookie and add it to the response cookie collection but on the next request the only cookies in the cookie collection are ASPXAUT and ASPX_SESSIONId, of the custom cookie not a trace.
This is the cookie management class:
public class CookieManager:ISessionManager
{
public object this[string key]
{
get
{
var context = getCurrentContext();
var cookie = context.Request.Cookies[key];
if (cookie == null) return null;
return deserialize(cookie.Value);
}
set
{
var context = getCurrentContext();
string cookieValue = serialize(value);
HttpCookie cookie = new HttpCookie(key, cookieValue);
cookie.Expires = DateTime.Now.AddDays(10000);
cookie.HttpOnly = false;
context.Response.Cookies.Remove(key);
context.Response.Cookies.Add(cookie);
}
}
public void Abandon()
{
var context = getCurrentContext();
context.Response.Cookies.Clear();
}
public void Clear()
{
Abandon();
}
private HttpContext getCurrentContext()
{
return HttpContext.Current;
}
private string serialize(object value)
{
MemoryStream stream = new MemoryStream();
BinaryFormatter formatter = new BinaryFormatter();
formatter.Context = new StreamingContext(StreamingContextStates.Clone);
formatter.Serialize(stream, value);
StreamReader reader = new StreamReader(stream);
stream.Position = 0;
string result = reader.ReadToEnd();
reader.Close();
stream.Close();
return HttpUtility.UrlEncodeUnicode(result);
}
public object deserialize(string value)
{
value = HttpUtility.UrlDecode(value);
MemoryStream stream = new MemoryStream();
StreamWriter writer = new StreamWriter(stream);
writer.Write(value);
BinaryFormatter formatter = new BinaryFormatter();
return formatter.Deserialize(stream);
}
}
It reads and saves cookies.
Now my problem is this:
What I need to enable in silverlight or in the ASP.NET (WCF) application in order for extra cookies to be sent with each request along side the authentication cookie.
EDIT:
I've inspected the HTTP request/response stack and those extra cookies are sent from the server with the WCF RIA Services response but not returned by the next service call from the client.
If I understand your edit above correctly, you've already inspected the HTTP requests and found the desired cookie present in the HTTP Set-Cookie header of the response, but missing in the Cookie header of the next request. Is this correct? If not, please clarify.
If so, the problem sounds like one of three things:
the client is not successfully saving the cookie, due to many possible reasons including:
cookie not properly formatted (unlikley)
cookie is too long
there's a client- or server-side policy (e.g. P3P) preventing saving persistent cookies.
The client is saving the cookie OK, but is not sending it back, even without Silverlight. This could be caused by, for example, a security issue where the hostname of the first request is different from the second.
The client is saving the cookie and can send it back over regular HTML pages, but not via HTTP requests sent by Silverlight.
To see if #1 is the problem, look (using your browser's ability to view cookies) at the cookies saved by your browser for that site. Is the expected cookie saved? If it is, then you can eliminate #1 as the problem. If it's not saved, start looking
To see if #2 is the problem, try creating a server-side page with no silverlight on it-- just a simple HTML page. When you visit that page with your browser, is the cookie sent as expected? If yes, then #2 is not your problem.
If #1 and #2 are not the problem, that leaves #3. Silverlight's HTTP handling is complicated, not least because you have to choose between having HTTP client requests handled by the browser or by Silverlight. Read the Silverlight cookies documentation carefully and see if any of the info therein will help you figure out the problem. Consider trying to use the "Client HTTP" setting, or if you're already using this, consider switching back to the "browser HTTP" setting and see if your problem goes away. Note that the Client HTTP setting apparently has a problem with losing new cookies after an HTTP redirect. See this thread for more info. There's a workaround discussed in that thread: using CookieContainer.
BTW, could you edit your question to include all the HTTP headers of the request and the subsequent request? This may help diagnosis.

Retrieving HTML pages from a 3rd party log in website with ASP.NET

Our Situation:
Our team needs to retrieve log information from a 3rd party website (Specifically, this log
information is call logs -- our client rents an 866 number. When calls come in, they assist
people and need to make notes accordingly in our application that will correspond with the
current call). Our client has a web account with the 3rd party that allows them to view the
current call logs (date/time, phone number, amount of time on each call, etc).
I contacted the developer of their website and inquired about API or any other means of syncing
our database with their constantly updating database. They currently DO NOT support API. I
informed them of my situation and they are perfectly fine with any way we can retrieve the
information (bot/crawler). *The 3rd party said that they are working on API but could not give
us a general timeline as to when it will be up... and as with every client, they need to start
production ASAP.
I completely understand that if the 3rd party were to change their HTML layout, it may cause a
slight headache for us (sorting the data from the webpage). That being said, this is a temporary
solution to a long term issue. Once they implement their API, we will switch them over to it.
So my question is this:
What is the best way to log into the 3rd party website (see image: http://i903.photobucket.com/albums/ac239/jreedinc/customtf.jpg)
and retrieve certain HTML pages? We have reviewed source codes of webcrawlers, but none of them
have the capability of storing cookies and posting information back to the website (with log in information). We would prefer to do this in ASP.NET.
Is there another way to accomplish logging on to the website, then retrieving said information?
The classes you'll need to use are in the System.Net namespace. Below is some quick and dirty proof of concept code. To login in to a site that uses form login + cookies for security and then scrape the HTML output of a page.
In order to parse the HTML results you'll need to use an additional tool.
Possible HTML parsing tools.
SgmlReader, can convert HTML to XML. You then use .NET's XML features to extract data from the XML.
http://code.msdn.microsoft.com/SgmlReader
HTML Agility Pack, allows XPath queries against HTML documents.
http://htmlagilitypack.codeplex.com/
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
class WebWorker {
/// <summary>
/// Cookies for use by web worker
/// </summary>
private System.Collections.Generic.List `<System.Net.Cookie` > cookies = new List < System.Net.Cookie > ();
public string GetWebPageContent(string url) {
System.Net.HttpWebRequest request = (System.Net.HttpWebRequest) System.Net.WebRequest.Create(url);
System.Net.CookieContainer cookieContainer = new System.Net.CookieContainer();
request.CookieContainer = cookieContainer;
request.Method = "GET";
//add cookies to maintain session state
foreach(System.Net.Cookie c in this.cookies) {
cookieContainer.Add(c);
}
System.Net.HttpWebResponse response = request.GetResponse() as System.Net.HttpWebResponse;
System.IO.Stream responseStream = response.GetResponseStream();
System.IO.StreamReader sReader = new System.IO.StreamReader(responseStream);
System.Diagnostics.Debug.WriteLine("Content:\n" + sReader.ReadToEnd());
return sReader.ReadToEnd();
}
public string Login(string url, string userIdFormFieldName, string userIdValue, string passwordFormFieldName, string passwordValue) {
System.Net.HttpWebRequest request = (System.Net.HttpWebRequest) System.Net.WebRequest.Create(url);
System.Net.CookieContainer cookieContainer = new System.Net.CookieContainer();
request.CookieContainer = cookieContainer;
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
string postData = System.Web.HttpUtility.UrlEncode(userIdFormFieldName) + "=" + System.Web.HttpUtility.UrlEncode(userIdValue) +
"&" + System.Web.HttpUtility.UrlEncode(passwordFormFieldName) + "=" + System.Web.HttpUtility.UrlEncode(passwordValue);
request.ContentLength = postData.Length;
request.AllowAutoRedirect = false; //allowing redirect seems to loose cookies
byte[] postDataBytes = System.Text.Encoding.UTF8.GetBytes(postData);
System.IO.Stream requestStream = request.GetRequestStream();
requestStream.Write(postDataBytes, 0, postDataBytes.Length);
System.Net.HttpWebResponse response = request.GetResponse() as System.Net.HttpWebResponse;
// System.Diagnostics.Debug.Write(WriteLine(new StreamReader(response.GetResponseStream()).ReadToEnd());
System.IO.Stream responseStream = response.GetResponseStream();
System.IO.StreamReader sReader = new System.IO.StreamReader(responseStream);
System.Diagnostics.Debug.WriteLine("Content:\n" + sReader.ReadToEnd());
this.cookies.Clear();
if (response.Cookies.Count > 0) {
for (int i = 0; i < response.Cookies.Count; i++) {
this.cookies.Add(response.Cookies[i]);
}
}
return "OK";
}
} //end class
//sample to use class
WebWorker worker = new WebWorker();
worker.Login("http://localhost/test/default.aspx", "uid", "bob", "pwd", "secret");
worker.GetWebPageContent("http://localhost/test/default.aspx");
I used a tool recently called WebQL (its a web scraper tool that lets the developer use SQL like syntax to scrape information from web pages.
WebQL on Wikipedia
This is actually a relatively simple operation. What you need to do is get the page that the screenshot posts back to (something like login.php, etc) and then construct a webrequest to that page with the login data you have. You will most likely get back a cookiecontainer that will have your login cookie to use on all subsequent requests.
You can look at this MSDN article for the basics of how to do it, but their write-up is kind of confusing. Look at the community comments at the end for an example of how to post back page variables (like the username and password). You will need to make sure you pass the cookiecontainer around on subsequent requests.
Unfortunately .NET does not natively have something like WWW::Mechanize, but the Webclient does have an "upload value" which might make it easier. You will still have to manually parse the page to figure out what fields you need to pass.

Response.Redirect with POST instead of Get?

We have the requirement to take a form submission and save some data, then redirect the user to a page offsite, but in redirecting, we need to "submit" a form with POST, not GET.
I was hoping there was an easy way to accomplish this, but I'm starting to think there isn't. I think I must now create a simple other page, with just the form that I want, redirect to it, populate the form variables, then do a body.onload call to a script that merely calls document.forms[0].submit();
Can anyone tell me if there is an alternative? We might need to tweak this later in the project, and it might get sort of complicated, so if there was an easy we could do this all non-other page dependent that would be fantastic.
Anyway, thanks for any and all responses.
Doing this requires understanding how HTTP redirects work. When you use Response.Redirect(), you send a response (to the browser that made the request) with HTTP Status Code 302, which tells the browser where to go next. By definition, the browser will make that via a GET request, even if the original request was a POST.
Another option is to use HTTP Status Code 307, which specifies that the browser should make the redirect request in the same way as the original request, but to prompt the user with a security warning. To do that, you would write something like this:
public void PageLoad(object sender, EventArgs e)
{
// Process the post on your side
Response.Status = "307 Temporary Redirect";
Response.AddHeader("Location", "http://example.com/page/to/post.to");
}
Unfortunately, this won't always work. Different browsers implement this differently, since it is not a common status code.
Alas, unlike the Opera and FireFox developers, the IE developers have never read the spec, and even the latest, most secure IE7 will redirect the POST request from domain A to domain B without any warnings or confirmation dialogs! Safari also acts in an interesting manner, while it does not raise a confirmation dialog and performs the redirect, it throws away the POST data, effectively changing 307 redirect into the more common 302.
So, as far as I know, the only way to implement something like this would be to use Javascript. There are two options I can think of off the top of my head:
Create the form and have its action attribute point to the third-party server. Then, add a click event to the submit button that first executes an AJAX request to your server with the data, and then allows the form to be submitted to the third-party server.
Create the form to post to your server. When the form is submitted, show the user a page that has a form in it with all of the data you want to pass on, all in hidden inputs. Just show a message like "Redirecting...". Then, add a javascript event to the page that submits the form to the third-party server.
Of the two, I would choose the second, for two reasons. First, it is more reliable than the first because Javascript is not required for it to work; for those who don't have it enabled, you can always make the submit button for the hidden form visible, and instruct them to press it if it takes more than 5 seconds. Second, you can decide what data gets transmitted to the third-party server; if you use just process the form as it goes by, you will be passing along all of the post data, which is not always what you want. Same for the 307 solution, assuming it worked for all of your users.
You can use this aproach:
Response.Clear();
StringBuilder sb = new StringBuilder();
sb.Append("<html>");
sb.AppendFormat(#"<body onload='document.forms[""form""].submit()'>");
sb.AppendFormat("<form name='form' action='{0}' method='post'>",postbackUrl);
sb.AppendFormat("<input type='hidden' name='id' value='{0}'>", id);
// Other params go here
sb.Append("</form>");
sb.Append("</body>");
sb.Append("</html>");
Response.Write(sb.ToString());
Response.End();
As result right after client will get all html from server the event onload take place that triggers form submit and post all data to defined postbackUrl.
HttpWebRequest is used for this.
On postback, create a HttpWebRequest to your third party and post the form data, then once that is done, you can Response.Redirect wherever you want.
You get the added advantage that you don't have to name all of your server controls to make the 3rd parties form, you can do this translation when building the POST string.
string url = "3rd Party Url";
StringBuilder postData = new StringBuilder();
postData.Append("first_name=" + HttpUtility.UrlEncode(txtFirstName.Text) + "&");
postData.Append("last_name=" + HttpUtility.UrlEncode(txtLastName.Text));
//ETC for all Form Elements
// Now to Send Data.
StreamWriter writer = null;
HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.Method = "POST";
request.ContentType = "application/x-www-form-urlencoded";
request.ContentLength = postData.ToString().Length;
try
{
writer = new StreamWriter(request.GetRequestStream());
writer.Write(postData.ToString());
}
finally
{
if (writer != null)
writer.Close();
}
Response.Redirect("NewPage");
However, if you need the user to see the response page from this form, your only option is to utilize Server.Transfer, and that may or may not work.
Something new in ASP.Net 3.5 is this "PostBackUrl" property of ASP buttons. You can set it to the address of the page you want to post directly to, and when that button is clicked, instead of posting back to the same page like normal, it instead posts to the page you've indicated. Handy. Be sure UseSubmitBehavior is also set to TRUE.
This should make life much easier.
You can simply use Response.RedirectWithData(...) method in your web application easily.
Imports System.Web
Imports System.Runtime.CompilerServices
Module WebExtensions
<Extension()> _
Public Sub RedirectWithData(ByRef aThis As HttpResponse, ByVal aDestination As String, _
ByVal aData As NameValueCollection)
aThis.Clear()
Dim sb As StringBuilder = New StringBuilder()
sb.Append("<html>")
sb.AppendFormat("<body onload='document.forms[""form""].submit()'>")
sb.AppendFormat("<form name='form' action='{0}' method='post'>", aDestination)
For Each key As String In aData
sb.AppendFormat("<input type='hidden' name='{0}' value='{1}' />", key, aData(key))
Next
sb.Append("</form>")
sb.Append("</body>")
sb.Append("</html>")
aThis.Write(sb.ToString())
aThis.End()
End Sub
End Module
Thought it might interesting to share that heroku does this with it's SSO to Add-on providers
An example of how it works can be seen in the source to the "kensa" tool:
https://github.com/heroku/kensa/blob/d4a56d50dcbebc2d26a4950081acda988937ee10/lib/heroku/kensa/post_proxy.rb
And can be seen in practice if you turn of javascript. Example page source:
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Heroku Add-ons SSO</title>
</head>
<body>
<form method="POST" action="https://XXXXXXXX/sso/login">
<input type="hidden" name="email" value="XXXXXXXX" />
<input type="hidden" name="app" value="XXXXXXXXXX" />
<input type="hidden" name="id" value="XXXXXXXX" />
<input type="hidden" name="timestamp" value="1382728968" />
<input type="hidden" name="token" value="XXXXXXX" />
<input type="hidden" name="nav-data" value="XXXXXXXXX" />
</form>
<script type="text/javascript">
document.forms[0].submit();
</script>
</body>
</html>
PostbackUrl can be set on your asp button to post to a different page.
if you need to do it in codebehind, try Server.Transfer.
#Matt,
You can still use the HttpWebRequest, then direct the response you receive to the actual outputstream response, this would serve the response back to the user. The only issue is that any relative urls would be broken.
Still, that may work.
I suggest building an HttpWebRequest to programmatically execute your POST and then redirect after reading the Response if applicable.
Here's what I'd do :
Put the data in a standard form (with no runat="server" attribute) and set the action of the form to post to the target off-site page.
Before submitting I would submit the data to my server using an XmlHttpRequest and analyze the response. If the response means you should go ahead with the offsite POSTing then I (the JavaScript) would proceed with the post otherwise I would redirect to a page on my site
In PHP, you can send POST data with cURL. Is there something comparable for .NET?
Yes, HttpWebRequest, see my post below.
The GET (and HEAD) method should never be used to do anything that has side-effects. A side-effect might be updating the state of a web application, or it might be charging your credit card. If an action has side-effects another method (POST) should be used instead.
So, a user (or their browser) shouldn't be held accountable for something done by a GET. If some harmful or expensive side-effect occurred as the result of a GET, that would be the fault of the web application, not the user. According to the spec, a user agent must not automatically follow a redirect unless it is a response to a GET or HEAD request.
Of course, a lot of GET requests do have some side-effects, even if it's just appending to a log file. The important thing is that the application, not the user, should be held responsible for those effects.
The relevant sections of the HTTP spec are 9.1.1 and 9.1.2, and 10.3.
Typically, all you'll ever need is to carry some state between these two requests. There's actually a really funky way to do this which doesn't rely on JavaScript (think <noscript/>).
Set-Cookie: name=value; Max-Age=120; Path=/redirect.html
With that cookie there, you can in the following request to /redirect.html retrieve the name=value info, you can store any kind of information in this name/value pair string, up to say 4K of data (typical cookie limit). Of course you should avoid this and store status codes and flag bits instead.
Upon receiving this request you in return respond with a delete request for that status code.
Set-Cookie: name=value; Max-Age=0; Path=/redirect.html
My HTTP is a bit rusty I've been going trough RFC2109 and RFC2965 to figure how reliable this really is, preferably I would want the cookie to round trip exactly once but that doesn't seem to be possible, also, third-party cookies might be a problem for you if you are relocating to another domain. This is still possible but not as painless as when you're doing stuff within your own domain.
The problem here is concurrency, if a power user is using multiple tabs and manages to interleave a couple of requests belonging to the same session (this is very unlikely, but not impossible) this may lead to inconsistencies in your application.
It's the <noscript/> way of doing HTTP round trips without meaningless URLs and JavaScript
I provide this code as a prof of concept: If this code is run in a context that you are not familiar with I think you can work out what part is what.
The idea is that you call Relocate with some state when you redirect, and the URL which you relocated calls GetState to get the data (if any).
const string StateCookieName = "state";
static int StateCookieID;
protected void Relocate(string url, object state)
{
var key = "__" + StateCookieName + Interlocked
.Add(ref StateCookieID, 1).ToInvariantString();
var absoluteExpiration = DateTime.Now
.Add(new TimeSpan(120 * TimeSpan.TicksPerSecond));
Context.Cache.Insert(key, state, null, absoluteExpiration,
Cache.NoSlidingExpiration);
var path = Context.Response.ApplyAppPathModifier(url);
Context.Response.Cookies
.Add(new HttpCookie(StateCookieName, key)
{
Path = path,
Expires = absoluteExpiration
});
Context.Response.Redirect(path, false);
}
protected TData GetState<TData>()
where TData : class
{
var cookie = Context.Request.Cookies[StateCookieName];
if (cookie != null)
{
var key = cookie.Value;
if (key.IsNonEmpty())
{
var obj = Context.Cache.Remove(key);
Context.Response.Cookies
.Add(new HttpCookie(StateCookieName)
{
Path = cookie.Path,
Expires = new DateTime(1970, 1, 1)
});
return obj as TData;
}
}
return null;
}
Copy-pasteable code based on Pavlo Neyman's method
RedirectPost(string url, T bodyPayload) and GetPostData() are for those who just want to dump some strongly typed data in the source page and fetch it back in the target one.
The data must be serializeable by NewtonSoft Json.NET and you need to reference the library of course.
Just copy-paste into your page(s) or better yet base class for your pages and use it anywhere in you application.
My heart goes out to all of you who still have to use Web Forms in 2019 for whatever reason.
protected void RedirectPost(string url, IEnumerable<KeyValuePair<string,string>> fields)
{
Response.Clear();
const string template =
#"<html>
<body onload='document.forms[""form""].submit()'>
<form name='form' action='{0}' method='post'>
{1}
</form>
</body>
</html>";
var fieldsSection = string.Join(
Environment.NewLine,
fields.Select(x => $"<input type='hidden' name='{HttpUtility.UrlEncode(x.Key)}' value='{HttpUtility.UrlEncode(x.Value)}'>")
);
var html = string.Format(template, HttpUtility.UrlEncode(url), fieldsSection);
Response.Write(html);
Response.End();
}
private const string JsonDataFieldName = "_jsonData";
protected void RedirectPost<T>(string url, T bodyPayload)
{
var json = JsonConvert.SerializeObject(bodyPayload, Formatting.Indented);
//explicit type declaration to prevent recursion
IEnumerable<KeyValuePair<string, string>> postFields = new List<KeyValuePair<string, string>>()
{new KeyValuePair<string, string>(JsonDataFieldName, json)};
RedirectPost(url, postFields);
}
protected T GetPostData<T>() where T: class
{
var urlEncodedFieldData = Request.Params[JsonDataFieldName];
if (string.IsNullOrEmpty(urlEncodedFieldData))
{
return null;// default(T);
}
var fieldData = HttpUtility.UrlDecode(urlEncodedFieldData);
var result = JsonConvert.DeserializeObject<T>(fieldData);
return result;
}

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