When are and aren't two URLs the same? (ports)

[OHTSUKA Ko-hei]

I think
   http://joe.example.com/
   http://joe.example.com:80/
   http://joe.example.com
should be different identity.

Reasons are three points:

1.Many web server products can assume these accesses as different one,
   using environment variable.
   So, if want, people can provide different contents to every ways of
   access.
   It is not good for "identification".

2.If thinking them same one, forces little more efforts to both Yadis
   services and relying parties.
   They may manage users profile or so by hash or DB using identity URL
   as key, so if allow these another way of expression, have to add one
   more process to canonicalize URL.
   It is poor effort, I think.

3.Having multiple expression is not suit for "identification".
   I think identity must be have one-to-one correspondence with
   expression.
   # Needless to say, I think OK that one people uses multiple
   # identities.
   # But, each identity should have only one expression.

Any comments?

Joaquin Miller wrote:
> This argument applies to the special cases mentioned, Port 80 and the 
> trailing slash.
> 
> We also need to consider the general case.
> 
>> > Do these URLs:
>> >     http://example.com/joe
>> >     http://example.com:80/joe <http://example.com/joe>
>> > represent the same identity?
>>
>> I say yes. Not only from a practical standpoint, but also a technical
>> one. My interpretation of the HTTP spec is that this is a perfectly
>> valid translation to make, based on the following:
>>
>> >From 3.2.2, regarding URLs: If the port is empty or not given, port 80
>> is assumed.
>>
>> >From 14.23, regarding the Host header: A "host" without any trailing
>> port information implies the default port for the service requested
>> (e.g., "80" for an HTTP URL)
>>
>> http://www.w3.org/Protocols/rfc2616/rfc2616.html
>>
>> To me, this is no different than assuming that the identity
>> " http://joe.example.com <http://joe.example.com/>" and " 
>> http://joe.example.com/" are identical.
>> The trailing slash, identifying the root path as part of the identity,
>> is optional and assumed.
>>
>> (Helps to actually send this to the list address :)
>>
>> - K.Howe