Question

I’m writing a REST webservice having a method like this:

[WebGet(
    UriTemplate = "/Test/{p1}/{p2}",
    BodyStyle = WebMessageBodyStyle.Bare,
    ResponseFormat = WebMessageFormat.Xml)]
public string Test(string p1, string p2)
{
    // Do something here
}

So if I call basurl/Test/prova/test my method Test is invoked with p1=”prova” and p2=”test” and everything works fine.
Problem comes when I try to use a param having (for example) % char: even translating it in URL code, when I try to call basurl/Test/prova/te%25st I get a
Errore HTTP 400 – Bad Request.

If I use

[WebGet(
    UriTemplate = "/Test/{p1}?p2={p2}",
    BodyStyle = WebMessageBodyStyle.Bare,
    ResponseFormat = WebMessageFormat.Xml)]
public string Test(string p1, string p2)
{
    // Do something here
}

and call basurl/Test/prova?p2=te%25st it works.
Why? What can I do to let first syntax work?

UPDATE:
Look at my answer with a possible solution.
If someone finds a better one, please post it!!
Thanks

Answer 1

Googling around I’ve just found this link:
http://weblogs.asp.net/imranbaloch/archive/2010/04/23/understanding-400-bad-request-exception.aspx
where they say:

ASP.NET Restrictions:

After passing the restrictions enforced by the kernel mode http.sys then the request is handed off to IIS and then to ASP.NET
engine and then again request has to pass some restriction from
ASP.NET in order to complete it successfully.

ASP.NET only allows URL path lengths to 260 characters(only paths, for example http://a/b/c/d, here path is from a to d). This
means that if you have long paths containing 261 characters then you
will get the Bad Request exception. This is due to NTFS file-path
limit.

Another restriction is that which characters can be used in URL path portion.You can use any characters except some characters
because they are called invalid characters in path. Here are some of
these invalid character in the path portion of a URL, <,>,*,%,&,:,\,?.
For confirming this just right click on your Solution Explorer and Add
New Folder and name this File to any of the above character, you will
get the message. Files or folders cannot be empty strings nor they
contain only ‘.’ or have any of the following characters…..

For checking the above situation i have created a Web Application and put Default.aspx inside A%A folder (created from
windows explorer), then navigate to,
http://localhost:1234/A%25A/Default.aspx, what i get response from
server is the Bad Request exception. The reason is that %25 is the %
character which is invalid URL path character in ASP.NET. However you
can use these characters in query string.

The reason for these restrictions are due to security, for example with the help of % you can double encode the URL path portion
and : is used to get some specific resource from server.

So I’m starting to think that my problem is impossible to solve.
I’m sure that this problem is not present in some REST webservice written in PHP and hosted with Apache, so I think it’s just a IIS/ASP “security” restriction I can’t find a workaround for…

UPDATE WITH FINAL SOLUTION:
I found a solution here: read the article to understand everything.
You should know that it could be risky, so think well before using it.

<system.web>
  <httpRuntime requestPathInvalidCharacters="" />
  <pages validateRequest="false" />
</system.web>