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httpurluri-scheme

Is a URL with only scheme + path valid?

I know absolute path-only URLs (/path/to/resource) are valid, and refer to the same scheme, host, port, etc. as the current resource. Is the URL still valid if the same (or a different!) scheme is added? (http:/path/to/resource or https:/path/to/resource)

If it is valid according to the letter of the spec, how well do browsers handle it? How well do developers that may come across the code in the future handle it?

Addendum:

Here's a simple test case I set up on an Apache server:

resource/number/one/index.html:

<a href="http:/resource/number/two/">link</a>

resource/number/two/index.html:

two

Testing in Chrome 43 on OS X: The URL displayed when hovering over the link looks correct. Clicking the link works as expected. Looking at the DOM in the web inspector, hovering over the a href URL displays an incorrect location (/resource/number/one/http:/resource/number/two/).

Firefox 38 appears to also handle the click correctly. Weird.

Solution

  • No, it’s not valid. From RFC 3986:

    4.2.  Relative Reference

   A relative reference takes advantage of the hierarchical syntax
   (Section 1.2.3) to express a URI reference relative to the name space
   of another hierarchical URI.

      relative-ref  = relative-part [ "?" query ] [ "#" fragment ]

      relative-part = "//" authority path-abempty
                    / path-absolute
                    / path-noscheme
                    / path-empty

   The URI referred to by a relative reference, also known as the target
   URI, is obtained by applying the reference resolution algorithm of
   Section 5.

   A relative reference that begins with two slash characters is termed
   a network-path reference; such references are rarely used.  A
   relative reference that begins with a single slash character is
   termed an absolute-path reference.  A relative reference that does
   not begin with a slash character is termed a relative-path reference.

   A path segment that contains a colon character (e.g., "this:that")
   cannot be used as the first segment of a relative-path reference, as
   it would be mistaken for a scheme name.  Such a segment must be
   preceded by a dot-segment (e.g., "./this:that") to make a relative-
   path reference.

    where path-noscheme is specifically a path that doesn’t start with / whose first segment does not contain a colon, which addresses your question pretty specifically.