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Date: Sun, 10 Apr 2005 23:45:17 +1200
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CC: Sara Golemon <pollita@php.net>, Wez Furlong <kingwez@gmail.com>
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Subject: Re: [PHP-DEV] Scheme identification in stream wrappers: (Partial)
	disambiguation?
From: packrat@nznet.gen.nz ("Morgan L. Owens")

Wez Furlong wrote:
> On Apr 9, 2005 6:07 AM, Morgan L. Owens <packrat@nznet.gen.nz> wrote:
> 
>> > Really?
>> > Can you guarantee that your user-space code to sniff out the path is
>> > going to work 100% of the time on all platforms?
>> >
>>Who said user-space? I meant in the implementation of fopen().
> 
> 
> fopen() is implemented in user-space, meaning, not kernel-space.
> Only the kernel knows what logic it will really really use to resolve
> a valid path.
> Emulating that code for each supported platform on which PHP runs is
> plain stupid.
>  
I still don't see why emulation code would be necessary. What happens
when fopen() is passed an invalid file path now? It's obviously capable
of coping with failure. What is so unimplementable with it coping with
its initial failure by going "Drat. Okay, might it be a URL? Looks like
it has a scheme... let's try it". If you insist, you could wrap that in
#ifdefs so that the code is only compiled on platforms where 'foo:'
might validly appear at the start of a file path.

if(the string might be a URL)
{
#ifdef FILEPATHS_CAN_START_WITH_SCHEMELIKE_SEQUENCE
	if(attempt to open as local file succeeds)
		return handle
	else
#endif
	if(scheme is registered && attempt to open as stream succeeds)
		return handle
	else
		return fail
}
else
{
	if(attempt to open as local file succeeds)
		return handle
	else
		return fail
}

> 
> I suggest that you go and re-read RFC 1738, section 3.1, Common
> Internet Scheme Syntax.  We support that, because the original
> wrappers implementation was solely for "URL schemes that involve the
> direct use of an IP-based protocol to a specified host on the
> Internet".
> 
> ...
> 
> In other words, there is no defined mapping to a streaming data
> source, which is what the wrappers layer in PHP is built for.
> 
Sorry, I didn't see any mention of that in the documentation. Just saw
"URL" and assumed that it referred to RFC 2396, which IIRC would have 
been the current standard at the time. Nothing about direct use of an 
IP-based protocol to a specified host (like a local variable or a 
gzip'ed file?). If I could search back through the development 
discussion list over the relevant time period I'd've found this?

In short, what you're talking about supporting is (what is now) Section 
3.2 of RFC 3986. Thanks for clearing that up.

> 
> Do you think that by trying to insult PHP you'll motivate the
> developers to try and change it to the way you think it should work?
> 
Just characterising the sort of response I can imagine people not
married to PHP making when they first run into this. Hey, none of this 
is the result of any decision of mine. So I wasn't aware of which 
interpretation of "URL" you had chosen to use. Now that you've gotten 
around to saying which (to me, if not to those other users I mentioned), 
I've got my answer.

MLO