C# HttpClient URI is not escaping properly - c#

I'm trying to get my URL to escape but it's not working properly. Ironically, on my MacBook when I execute this part of code
Uri url = new Uri("http://www.example.com/?i=123%34", true);
// it returns http://www.example.com/?i=123%34 which is exactly what I want.
The problem is that my IDE says it's obsolete and it does not work on my Windows machine. It's the exact same project, and IDE. So I tried to find a solution, which someone suggested
Uri uri = new Uri(Uri.EscapeUriString("http://www.example.com/?i=123%34"));
// this returns http://www.example.com/?i=123%2534 which is what I DONT want.
So how do I approach this issue? I looked all over the web and I can't find any solutions. I need to know how to properly escape this URL. The second method posted above does not work like the first method above.
I verified the GET requests via Fiddler, so everything is indeed happening.
Update:
Again, I need the server to receive the URL exactly how the string is declared. I want the server to handle the conversion. I cannot substitute %25 for the % symbol. It MUST be received exactly how I the string is declared. Additionally, "http://www.example.com/?i=1234" is NOT what I want either.

The problem is with the configuration of your web server on Windows, that allows double escaping. Your original URL is http://www.example.com/?i=123%34, which when unescaped, becomes http://www.example.com/?i=1234.
Your web server on Windows, on the other hand, escapes the % character again instead of unescaping %34. Thus, it turns into http://www.example.com/?i=123%2534.
This is why you should not use characters like % in the URL before it gets escaped.
Edit -
I typed the following two URLs in Firefox to see how the parameters are received on the server.
The value of i in http://www.example.com/?i=123%34 is 1234.
The value of i in http://www.example.com/?i=123%2534 is 123%34
If the server must receive the % character, it must be escaped in order for it to be dispatched over HTTP. There's literally no other way to send it over the wire. If you don't escape the % character, it will be treated as an escape sequence along with 34 and automatically turn into 4 on the server.
If your network inspector shows you unescaped text in the request, it's because it's prettifying the URL before displaying it to you.

If you are okay with the string reading ht tp://www.example.com/?i=1234, you can try
Uri url = new Uri(Uri.UnescapeDataString("http://www.example.com/?i=123%34"));

Related

Decoding querystring values on the server side

I'm running a web service on my server using WCF and .Net 4. The contract type is WebGet. Here is my problem, at one point in time, someone was sending data through the querystring that was URL encoded. So I added HttpUtility.UrlDecode to decode the parameters. I think that fixed my issue at the time. Now, I've sent a URL encoded string to it and I see that the string is being URL decoded coming into the method (before even getting to the HttpUtility.UrlDecode).
So now I'm confused, if the .Net code is decoding it before it gets to my method, why would I need to call on decode explicitly? But for a time it wasn't, so is this a recent change to the underlying .Net framework?
My problem now is that my users are sending data (unencoded), where the data looks like this: "abc%1234" and I'm getting "abc34", the decoding is eating 3 characters. However, if I urlencode the % sign to be "abc%251234", the value coming into the method is "abc%1234" (what I expected) and then the call to HttpUtility.UrlDecode is changing it to "abc34" (which is not what I expected).
I'm not sure how to proceed here. Do I rip out the explicit call to URLDecode until it starts coming across encoded again or is there a better way to handle this?
It's a subtle thing in documentation, easily missed:
HttpRequest.QueryString Property
Property Value
NameValueCollection
The query string variables sent by the client. Keys and values are
URL-decoded.
So if you access the query string via HttpRequest.QueryString (or Params) collection they are already decoded.
You can get to the raw string in RawUrl, QueryString.ToString() (manually that is - re: manipulation, split, etc.).
End of day, %:
Because the percent ("%") character serves as the indicator for
percent-encoded octets, it must be percent-encoded as "%25" for that
octet to be used as data within a URI.
REF: RFC3986
Hth

How can I modify or handle URL special characters in MVC?

I have an MVC web application. The URL for a particular area is coming in as:
http://localhost/General/Bpa%3fapplication%3dTrf%23/GeneralInputs
This causes a "The resource cannot be found." error. However, if I change the URL to
http://localhost/General/Bpa?application=Trf#/GeneralInputs
then everything works. I can see from using some route debugging tricks that the controller in the first case is: "Bpa?application=Trf#", whereas the second one is: "Bpa", which is correct. How can I account for this or substitute for the encoded characters?
The encoding of the first URL is wrong. If you look at RFC 3986 you will find in 2.4 the paragraph
When a URI is dereferenced, the components and subcomponents
significant to the scheme-specific dereferencing process (if any)
must be parsed and separated before the percent-encoded octets within
those components can be safely decoded, as otherwise the data may be
mistaken for component delimiters.
That means the URL is decomposed by unencoded characters (in this case the ? matters). If the encoded string #3f is used, then the framework would have to look for a controller named "Bpa?application=Trf#" and not "Bpa". Thus a 404 / resource not found is returned.
You should not fix it on the server side; you will have to change the place where the wrong url http://localhost/General/Bpa%3fapplication%3dTrf%23/GeneralInputs is generated.
You're going to want to use this on your url:
string fixedUrl = System.Uri.UnescapeDataString(yourUrlHere);
Hope that works out for you!

Web API OData (OData Client v4) forward slash in key

I have created an OData Web API but I am having problems looking up data where the primary key contains a forward slash.
This url returns data as expected:
/api/SalesOrders('12345')
But this one with the forward slash in the key fails:
/api/SalesOrders('12345/1')
Even when encoded:
/api/SalesOrders('12345%2F1')
In the error presented (see below), it looks like the final forward slash is being converted to a backslash as you would expect because it is part of the url and not in the query string:
If I use the following url instead, where the forward slash is in the querystring, then the data is returned correctly:
/api/SalesOrders?$filter=SalesOrderNumber eq 12345/1
If I were generating the urls myself, this wouldn't be much of an issue.
However, I am using the OData v4 Client Code Generator
So the call in code actually looks like this:
var salesOrder = erpClient.SalesOrders.ByKey(worksOrder.SalesOrderNumber).GetValue();
This generates the url which contains the forward slash before the query string and thus fails.
Is this a known issue with the OData v4 Client?
Is there a setting that forces use of querystring over primary key type calls?
I can work around this by forcing the forward slash into the querystring as follows:
var salesOrder = erpClient.SalesOrders.Where(so => so.SalesOrderNumber == "12345/1" && so.SalesOrderNumber == so.SalesOrderNumber).FirstOrDefault();
This forces the forward slash into the querystring:
/api/SalesOrders?$filter=SalesOrderNumber eq '450993/1' and SalesOrderNumber eq SalesOrderNumber
This feels messy and I would like to avoid moving away from the OData v4 Client as we have several apps that already use it.
Is there anything else I can do to make this work a little neater?
Footnote:
I followed the process on this blog to handle special characters, but this does not include advice on how to handle the forward slash:
using-wcf-data-service-with-restricted-characters-as-keys
Take a look at the ODataPathAndSlashEscapeSample on Github. The basic idea is to subclass DefaultODataPathHandler and override the Parse method. Then provide an instance of your custom path handler to the MapODataServiceRoute method in your Web API configuration code.
This might help anyone looking for a similar solution, just under the 'OData Routing' section...
...To prevent this error, your client should use the double escape sequences for slash (%252F) and backslash (%255C)....
Probably odata is messing up because it can be read litraly
even if it is encoded, my opinion is you must send parameters as an object in the request content.
You can see better http://blogs.msdn.com/b/odatateam/archive/2014/12/08/function-amp-action-in-web-api-v2-2-for-odata-v4-0-type-scenario.aspx#gist16957953
Hope this help

C# string.Split() Matching Both Slashes?

I've got a .NET 3.5 web application written in C# doing some URL rewriting that includes a file path, and I'm running into a problem. When I call string.Split('/') it matches both '/' and '\' characters. Is that... supposed to happen? I assumed that it would notice that the ASCII values were different and skip it, but it appears that I'm wrong.
// url = 'someserver.com/user/token/files\subdir\file.jpg
string[] buffer = url.Split('/');
The above code gives a string[] with 6 elements in it... which seems counter intuitive. Is there a way to force Split() to match ONLY the forward slash? Right now I'm lucky, since the offending slashes are at the end of the URL, I can just concatenate the rest of the elements in the string[], but it's a lot of work for what we're doing, and not a great solution to the underlying problem.
Anyone run into this before? Have a simple answer? I appreciate it!
More Code:
url = HttpContext.Current.Request.Path.Replace("http://", "");
string[] buffer = url.Split('/');
Turns out, Request.Path and Request.RawUrl are both changing my slashes, which is ridiculous. So, time to research that a bit more and figure out how to get the URL from a function that doesn't break my formatting. Thanks everyone for playing along with my insanity, sorry it was a misleading question!
When I try the following:
string url = #"someserver.com/user/token/files\subdir\file.jpg";
string[] buffer = url.Split('/');
Console.WriteLine(buffer.Length);
... I get 4. Post more code.
Something else is happening, paste more code.
string str = "a\\b/c\\d";
string[] ts = str.Split('/');
foreach (string t in ts)
{
Console.WriteLine(t);
}
outputs
a\b
c\d
just like it should.
My guess is that you are converting / into \ somewhere.
You could use regex to convert all \ slashes to a temp char, split on /, then regex the temp chars back to \. Pain in the butt, but one option.
I suspect (without seeing your whole application) that the problem lies in the semantics of path delimiters in URLs. It sounds like you are trying to attach a semantic value to backslashes within your application that is contrary to the way HTTP protocols define and use backslashes.
This is just a guess, of course.
The best way to solve this problem might be modifying the application to encode the path in some other way (such as "%5C" for backslashes, maybe?).
those two functions are probably converting \ to / because \ is not a valid character in a URL (see Which characters make a URL invalid?). The browser (NOT C#, as you are inferring) is assuming that when you are using that invalid character, you mean /, so it is "fixing" it for you. If you want \ in your URL, you need to encode it first.
The browsers themselves are actually the ones that make that change in the request, even if it is behind the scenes. To verify this, just turn on fiddler and look at the URLs that are actually getting sent when you go to a URL like this. IE and Chrome actually change the \ to / in the URL field on the browser itself, FireFox doesn't, but the request goes through that way anyways.
Update:
How about this:
Regex.Split(url, "/");

What's wrong with my url encoding?

In my asp.net mvc application I created the following link:
http://localhost:2689/en/Formula.mvc/351702++LYS+GRONN+5G+9%252f2++fds
I get error 400 (bad request).
I think it blocks at the %25 (forward slash).
What am I doing wrong?
--EDIT 3--
I tried not encoding anything at all but rather rely on the default encoding of Url.RouteUrl().
It seems that this doesn't encode the "/" for some reason.
If I encode it myself first, I end up with the doubel encoded %252f. This gives me a bad request for some reason..
Why?!
--EDIT 2--
I generated the last part of the URI as follows:
Take the id.toString
Take the HttpUtility.UrlEncode(name)
Take the HttpUtility.UrlEncode(code)
String.Format("{0}--{1}--{2}") with the values from the previous parts
Add it as a parameter to Url.RouteUrl()
After that my action gets this parameter again, splits it at -- and HttpUtility.Decode() the values back.
I do it this way because the two last parameters are optional, but functional parameters. IF they are defined in a previous step, they have to be carried along to the other pages.
Less abstract: A color can have multiple names, but if a user selected it by a particular name, it should be kept throughout all the other pages.
--EDIT 1--
It also looks like HttpUtility.UrlEncode() and Url.Encode() return different results :S
If I don't encode the "/", it acts as a separator=>no luck there.
If I encode it with Url.Encode() I end up with %2F => Code 400
If I encode it with HttpUtility.UrlEncode() I end up with %25 => code 400
Because 400 doesn't even let it through to asp.net-mvc, the route debugger is of no use :(
I was there a couple of days ago. If you can accept unreadable route-values in the URL try this:
URL-encoded slash in URL
%25 is actually encoded "%", so %252f is encoded "%2f".
%2f (encoded "/") is not allowed in URL unless you explicitly allow it in webserver's configuration.
Have you run the Routing debugger: http://haacked.com/archive/2008/03/13/url-routing-debugger.aspx
I haven't looked too much at the encoding - but note that if this is to be stored somewhere (or acted upon in some way), then a POST would be more appropriate. If the text on the right is actually representative of the data with id 351702 (a vanity url, much like /665354/whats-wrong-with-my-url-encoding), then you should humanize the text. Much as the spaces have been removed from the above. It is also common to have this as a separate level in the route that is simply discarded.
Generally, MVC urls should be comprehensible.
W3Schools works fine: http://www.w3schools.com/TAGS/html_form_submit.asp?text=hello/world
Here's the URL encoding reference: http://www.w3schools.com/TAGS/ref_urlencode.asp
You can't use a forward slash as a value in the URL. Here is a nice post about creating browser and SEO friendly URLS => http://www.dominicpettifer.co.uk/displayBlog.aspx?id=34
[Edit]
Whenever you create a route you associate it with a URL pattern (The default pattern is {controller}/{action}/{id}). And in this url pattern you are supposed to use the forward slash to separate different tokens. Hope that helps

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