Absolute VS Relative Urls

Absolute vs relative URLs

In general, it is considered best-practice to use relative URLs, so that your website will not be bound to the base URL of where it is currently deployed. For example, it will be able to work on localhost, as well as on your public domain, without modifications.

Absolute urls, relative urls, and...?

Here are the URL components:

http://www.example.com/en/public/img/logo.gif
\__/   \_____________/\_____________________/
 #1     #2             #3

scheme/protocol
host
path

A URL is called an absolute URL if it begins with the scheme and scheme specific part (here // after http:). Anything else is a relative URL.

A URL path is called an absolute URL path if it begins with a /. Any other URL path is called a relative URL path.

Thus:

http://www.example.com/en/public/img/logo.gif is a absolute URL,
../../public/img/logo.gif is a relative URL with a relative URL path and
/en/public/img/logo.gif is a relative URL with an absolute URL path.

Note: The current definition of URI (RFC 3986) is different from the old URL definition (RFC 1738 and RFC 1808).

The three examples with URI terms:

http://www.example.com/en/public/img/logo.gif is a URI,
../../public/img/logo.gif is a relative reference with just a relative path and
/en/public/img/logo.gif is a relative reference with just an absolute path.

Absolute vs relative vs slash URL?

Your first example is a URL. Your second and third examples are not URLs, they're paths. If the path begins with / then it's an absolute path, otherwise it's a relative path.

Web browsers generally understand how to interpret a path in relation to the "current" host and path.

Javascript – absolute or relative URL in history.pushState

Reading Mdn history.pushState() reference

the last parameter, the URL, can be relative or absolute (with the same origin).
If you use relative Url is more Comfortable:
For example if your starting page is:

https://www.google.com/bar.html

and you do:

history.pushState(null,null,"foo.html");

you will get
https://www.google.com/foo.html

Note that this does not make a request to the server but it changes the url in the location address bar and in location.href

But you can use also an absolute URL according to the documentation

relative url and absolute url difference

Absolute URL is : http://stackoverflow.com/questions/3591899/relative-url-and-absolute-url-difference

and a relative URL is: /questions/3591899/relative-url-and-absolute-url-difference

Also, a relative URL can be just: ../questions/3591899/relative-url-and-absolute-url-difference depending where is the linking page located...

Or ./3591899/relative-url-and-absolute-url-difference if the linking page is located on the questions folder

I will suggest to always use Relative URL... and it goes hard, keep trying to use them...

One question, why your JSPs are in the WEB-INF/ folder?

You don't have access to JSP under the WEB-INF folder, if you try to access it the server will throw a 404 error. J2EE only looks for classes and libraries under this folder.

HATEOAS: absolute or relative URLs?

There is a subtle conceptual ambiguity when people say "relative URI".

By RFC3986's definition, a generic URI contains:

  URI         = scheme ":" hier-part [ "?" query ] [ "#" fragment ]

  hier-part   = "//" authority path-abempty
              / path-absolute
              / path-rootless
              / path-empty

     foo://example.com:8042/over/there?name=ferret#nose
     \_/   \______________/\_________/ \_________/ \__/
      |           |            |            |        |
   scheme     authority       path        query   fragment

The tricky thing is, when scheme and authority are omitted, the "path" part itself can be either an absolute path (starts with /) or a "rootless" relative path. Examples:

An absolute URI or a full URI: "http://example.com:8042/over/there?name=ferret"
And this is a relative uri, with absolute path: /over/there
And this is a relative uri, with relative path: here or ./here or ../here or etc.

So, if the question was "whether a server should produce relative path in restful response", the answer is "No" and the detail reason is available here.
I think most people (include me) against "relative URI" are actually against "relative path".

And in practice, most server-side MVC framework can easily generate relative URI with absolute path such as /absolute/path/to/the/controller, and the question becomes "whether the server implementation should prefix a scheme://hostname:port in front of the absolute path". Like the OP's question. I am not quite sure about this one.

On the one hand, I still think server returning a full uri is recommended. However, the server should never hardcode the hostname:port thing inside source code like this (otherwise I would rather fallback to relative uri with absolute path). Solution is server-side always obtaining that prefix from HTTP request's "Host" header. Not sure whether this works for every situations though.

On the other hand, it seems not very troublesome for the client to concatenate the http://example.com:8042 and the absolute path. After all, the client already know that scheme and domain name when it send the request to the server right?

All in all, I would say, recommend to use absolute URI, possibly fallback to relative URI with absolute path, never use relative path.

Absolute or Relative URL if my website may not be at the root folder?

I think you should use relative urls, and concentrate your searchs on how to use relative urls in templates, that would be resolved relatively to the final page.

I don't know the technology you are using for templating, but I see two common solutions :

declare a "relative path" variable in the template, and then override it in the different pages, with the new relative path. Use this relative path as a prefix for all urls
delegate urls construction to a service that would know the final page. Somethinkg like resolveUrl(..)

Are protocol-relative URLs relative URLs?

Every relative URL is an unambiguous URL given the URL it is relative to. So if your page is http://mypage.com/some/folder/ then you know the relative URL this/that corresponds to http://mypage.com/some/folder/this/that and you know the relative URL //otherpage.com/ resolves to http://otherpage.com/. Importantly, it cannot be resolved without knowing the page URL it is relative to.

A relative URL is any URL that is relative to something and cannot be resolved by itself. An aboslute URL does not require any context whatsoever to resolve.

Absolute VS Relative Urls