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URL

A URL is used to point to loctions on the Internet. Traditionally, these locations were a single computer. But over time, it has become common for these locations to be groups of computers, structured in specific ways, and necessarily always a single computer.

It is possible for there to be alternative technologies that point to locations. So, the special thing about URLs is that there are a very very popular form of this technology.

URL” is an acronym for “Uniform Resource Locator”. Although it seems to have been originally an acronym for “Universal Resource Locator”. And thus URLs were renamed.

Example URLs

Here are some example URLs:…

  • http://www.example.com/
  • https://www.example.com/apple/banana/cherry.html
  • ftp://example.com/path/to/file.txt
  • finger://example.com/joeblow
  • rsync://example.com/it/is/here/

Internet Domain Names & URLs

URLs are by definition bound to the Internet domain name system. And thus URLs come with the problems that using Internet domain names bring with them.

An example Internet domain name is: example.com

One of the problems with the Internet domain name system is that it is susceptible to political activities, such as: censorship, seizures, suspensions, etc.

Another problem with the Internet domain name sytem is that it is not necessarily that they cost money to keep them, but that people do not always pay the money to renew them. And this causes truely useful content, and websites disappear forever.

Origin of URLs

The URL evolved from a pattern seen with Unix CLI programs. For example:…


telnet 207.241.233.214
			

telnet example.com
			

scp joeblow@example.com:/path/to/file.txt .
			

The command (such as “scp”, and “telnet”) were mapped to the URL scheme.

Protocol Relative URLs

A protocol relative URLs is one in which to URLs scheme omitted.

For example: //example.com/path/to/file.txt

I think I first time I used a protocol relative URLs in software I created was back in about 2003.

We were giving our partners HTML code that would link to our site to pull JavaScript code. So, something such as:


<script src="http://example.com/path/to/script.js"></script>
			

The problem is that, we didn't know whether the partner was going to put our code on an HTTP based website, or a (secure) HTTP based website.

That means were weren't sure if our code should be:


<script src="http://example.com/path/to/script.js"></script>
			

Or (secure):


<script src="https://example.com/path/to/script.js"></script>
			

We needed to match these, or our partner's user's web browser would complain.

-- Mirza Charles Iliya Krempeaux
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