Re: [Uri-review] Is TCP a URI scheme?

[Martin J. Dürst <[e-mail]>]

Hello Graham, others,

On 2019/02/22 20:19, Graham Klyne wrote:
> I have a couple of comments prompted by this thread..
> 
> 
> 1. I propose that it is quite possible to use a string that conforms to 
> URI syntax (explicitly or otherwise) without it being a URI.  So what 
> makes it a URI?  Two touchstones that I apply are: (a) "what does it 
> identify", and (b) "does it make sense to use it in a context where 
> other URI schemes might equally be used" (e.g., as an href in an HTML 
> document, or as a link relation type on an HTTP Link: header field).

I agree. My main point was that URIs and URI schemes have been 
spreading, so href in an HTML document and link relation type in an HTTP 
Link: header field are only the top of the iceberg nowadays.

> 2. Registration of *provisional* URI schemes is now first-come, 
> first-served, without formal review, subject to satisfying some simple 
> administrative requirements (cf. [1]).
> 
>     Permanent registration is a different matter, and does involve 
> stricter requirements and formal review [2], which in turn involves some 
> judgement by the reviewer about whether the requirements are satisfied.  
> As the current reviewer, I will typically look for indications of 
> working group approval, similar from other recognized bodies like W3C, 
> or "IETF review" (formerly "IETF consensus") [3] to inform that judgement.
> 
> 
> [1] https://tools.ietf.org/html/rfc7595#section-4
> 
> [2] https://tools.ietf.org/html/rfc7595#section-3
> 
> [3] https://tools.ietf.org/html/rfc8126#section-4.8
> 
> #g
> -- 
> 
> 
> PS: since [4], I've personally come to further downplay the URI/URL 
> distinction. I regard it as more to do with context of use than 
> something inherent to the actual string form used, in that *any* 
> identifier can be a locator given the right infrastructure (e.g,. DOIs), 
> and any locator can potentially be used as an identifier.
> 
> [4] https://www.w3.org/TR/uri-clarification/

For those who haven't been involved in that effort, and who haven't 
bothered to click on the link and check the data, it's from 2001, so 
really already quite a while ago. But it still very much (or even more 
so) applies at present.

Regards,   Martin.

> 
> 
> On 22/02/2019 04:54, Martin J. Dürst wrote:
>> Hello Eric, others,
>>
>> On 2019/02/22 09:49, Eric Johnson wrote:
>>
>>> Speaking somewhat on behalf of TIBCO, I'm not sure that the use of a 
>>> string
>>> that begins "tcp:" means that what is contained is necessarily a URL. 
>>> I did
>>> a small amount of very informal questioning of some of my fellow 
>>> employees,
>>> and didn't get the impression that the use of "tcp:" was anything other
>>> than a signal for the type of thing that followed the prefix, and not
>>> strictly speaking a "resource" locator.
>>
>> This overlaps quite a bit with what I'd have written as an answer to the
>> original question if I had had some spare time when that comes up.
>>
>> One of the core points of URIs is that they unify syntax at a very high
>> level (the level of foo:). That makes them very useful for pointing at
>> various things, from various places. The original place was the href
>> attribute of the <a> element in HTML. There, the main schemes were
>> http:, https:, ftp:, mailto:, and so on.
>>
>> Other places where there was a need to point to something reused URIs,
>> but once in a while, there was a need to point to something that didn't
>> yet have an URI scheme. With the use of URIs expanding, such things got
>> more and more diverse. That somebody somewhere wanted to point to a
>> (potential) tcp connection, and would used tcp: for that, was just a
>> matter of time.
>>
>> For quite a while, registration of URI schemes was handled rather
>> strictly. It's supposed to be easier today, but it's still some work,
>> some discussion, and some wait. Also, the documents describing URIs are
>> not necessarily an easy read for everyone, because they use general
>> terms that can easily be misunderstood.
>>
>> Also, please note that we are talking about URIs here, not URLs, so it's
>> resource Resource Identifier, not Locator. And "resource" is really
>> extremely general, even if for some schemes (e.g. mailto:), some care is
>> needed when describing what exactly it stands for.
>>
>>   > On Fri, Feb 1, 2019 at 9:18 AM Ted Hardie <[e-mail]> wrote:
>>   >
>>   >> I don't believe it has ever been registered, even provisionally, 
>> but you
>>   >> can find example syntax in both IBM and TIBCO documentation of their
>>   >> usage.  See, for example:
>>   >>
>>   >>
>>   >>
>> https://docs.tibco.com/pub/activespaces/2.1.6/doc/html/GUID-CAE482DF-C20D-46C4-AD2D-337535551423.html 
>>
>>
>> Looking at that page, it says "TCP Discovery URL Format". I'm not
>> familiar with this "discovery" part, but it may have been better to use
>> something like "tcp-disc:" or so as a prefix.
>>
>> Regards,   Martin.