4 ms·

Difference Between URL and URI

97 points by carlsednaoui 15y ago

danellis 15y ago
My favourite example to give for this distinction is 'news' vs 'nntp'. An 'nntp' URL specifies a specific message in a specific group on a specific server, hence it always has an authority part. It's also indicating to use the NNTP protocol to retrieve the message. A 'news' URI, on the other hand, identifies a specific message by its message ID, and leaves it to the user agent to choose a protocol and server. (The distinction isn't quite that clear cut, as 'news' URIs can specify a server, making them more like URLs, but I think it conveys the difference.)
- mapgrep 15y ago
  I hope one of the top two Stackoverflow answers steals this example and appends it. It is better than any of the examples in the thread.
finin 15y ago
For completeness, IRIs should be mentioned as well.
- deleted 15y ago
  [deleted]
- alexchamberlain 15y ago
  Which are?
  - ElliotH 15y ago
    Internationalized URIs
binarycrusader 15y ago
On a somewhat related note: http://www.rfc-editor.org/rfc/rfc3986.txt http://www.rfc-editor.org/rfc/rfc3986.txt From section 1.1.3: An individual scheme does not have to be classified as being just one of "name" or "locator". Instances of URIs from any given scheme may have the characteristics of names or locators or both, often depending on the persistence and care in the assignment of identifiers by the naming authority, rather than on any quality of the scheme. Future specifications and related documentation should use the general term "URI" rather than the more restrictive terms "URL" and "URN" [RFC3305].
- gojomo 15y ago
  That's a very related note! The classic hierarchy ("URLs and URNs are distinct subsets of URIs") wasn't as neat and useful as originally thought, so "it's just URIs now, with their own scheme-specific qualities" is the modern thinking, as reflected by this passage from RFC3986. The modern answer to "What's the difference between a URI and URL?" is thus very nearly 'Mu.'
- deleted 15y ago
  [deleted]
eblackburn 15y ago
I've met Jon Skeet and he sincerely is a really smashing chap. The cult of Skeet on SO is getting a tad much. (I find sycophantic behaviour a terrible trait)
deleted 15y ago
[deleted]
tingletech 15y ago
Multiple times I've called a URL a "URL" only to have some linked data enthusiast "correct" you by saying "you mean URI".
deleted 15y ago
[deleted]

97 points by carlsednaoui 15y ago

My favourite example to give for this distinction is 'news' vs 'nntp'. An 'nntp' URL specifies a specific message in a specific group on a specific server, hence it always has an authority part. It's also indicating to use the NNTP protocol to retrieve the message. A 'news' URI, on the other hand, identifies a specific message by its message ID, and leaves it to the user agent to choose a protocol and server. (The distinction isn't quite that clear cut, as 'news' URIs can specify a server, making them more like URLs, but I think it conveys the difference.)

mapgrep 15y ago
I hope one of the top two Stackoverflow answers steals this example and appends it. It is better than any of the examples in the thread.

finin 15y ago

For completeness, IRIs should be mentioned as well.

deleted 15y ago
[deleted]
alexchamberlain 15y ago
Which are?
- ElliotH 15y ago
  Internationalized URIs

binarycrusader 15y ago

On a somewhat related note: http://www.rfc-editor.org/rfc/rfc3986.txt http://www.rfc-editor.org/rfc/rfc3986.txt From section 1.1.3: An individual scheme does not have to be classified as being just one of "name" or "locator". Instances of URIs from any given scheme may have the characteristics of names or locators or both, often depending on the persistence and care in the assignment of identifiers by the naming authority, rather than on any quality of the scheme. Future specifications and related documentation should use the general term "URI" rather than the more restrictive terms "URL" and "URN" [RFC3305].

gojomo 15y ago
That's a very related note! The classic hierarchy ("URLs and URNs are distinct subsets of URIs") wasn't as neat and useful as originally thought, so "it's just URIs now, with their own scheme-specific qualities" is the modern thinking, as reflected by this passage from RFC3986. The modern answer to "What's the difference between a URI and URL?" is thus very nearly 'Mu.'
deleted 15y ago
[deleted]

eblackburn 15y ago

I've met Jon Skeet and he sincerely is a really smashing chap. The cult of Skeet on SO is getting a tad much. (I find sycophantic behaviour a terrible trait)

deleted 15y ago

[deleted]

tingletech 15y ago

Multiple times I've called a URL a "URL" only to have some linked data enthusiast "correct" you by saying "you mean URI".

deleted 15y ago

[deleted]