Re: CERN httpd and libwww 2.14 released
Rob McCool (robm@ncsa.uiuc.edu)
Wed, 17 Nov 1993 15:12:03 -0600
/*
* Re: CERN httpd and libwww 2.14 released by Ari Luotonen (luotonen@ptsun00.cern.ch)
* written on Nov 17, 9:21pm.
*
*
* > For simple scripts, escaping and parsing is what you want and it
* > does make sense. For complex scripts, you really want the server
* > to touch the URL as little as possible. It doesn't know what your
* > escaping scheme is and it shouldn't know because your script will
* > have to be responsible for escaping URLs in the HTML output.
* > Moreover, your escaping scheme may not be the "standard" one
* > (for http: scheme URLs, there's no requirement you use % hex escapes).
* > I often do escaping which keeps the URLs smaller and more human
* > decodable (e.g., translating ' ' -> '_').
*
* ??? I thought HTTP doc specifies how to escape illegal characters
* in URL?
*
* Tony's private message, however, pointed out that in future my current
* _parsing_ scheme can lose information. I still would like casual
* script programmers have a very clear and easy interface that is not
* burdened with the ability of coping every possible future feature.
*
* So what I was thinking of just this afternoon was that the _script_
* should be able to request the server to call it in the way it (script)
* wants, and not vice versa. This could be done e.g. by filename extensions.
* This way the script could, at it's own will, be called with raw URL,
* or with pre-parsed URL (which is very nice for 90% of the cases).
* Script could also ask URL to be passed to it from stdin instead of
* command line.
File name extensions may work. My approach has been to provide C code and an
externally callable program to unescape the URL's.
* By the way, I must admit I was very busy with AA when the original
* /htbin discussion went on. Was there a strong opposition to having
* scripts just anywhere and not only in bindir directory; and was there
* any reason for having the URL start with /htbin/ (I know that can
* be configured for NCSA server, but it is still constant once it's
* defined)?
It used to be, now it isn't. See below.
As far as the background of server scripts, there was never a discussion.
Nor was there any particular reason to pick /htbin. The script interface was
something I put together because I saw the gateway capabilities in Plexus
and thought it would be great to have them in our daemon. So I designed an
interface, implemented it, and released it. It was never intended as a
standard, it was just a feature.
* I've been thinking of having an exec rule that would, when URL
* matches a given template, execute a given script. Just for
* an example current htbin field in our rule file:
*
* htbin /x/y/z
*
* (which gives the physical bindirectory to CERN daemon) could be
* expressed as:
*
* exec /htbin/* /x/y/z/*
*
* This would free us from /htbin/ being translated specially in URL,
* and would introduce more flexibility and power to scripts.
*/
The ScriptAlias directive does that in 1.0a5. It's exactly like what you
describe above.
--Rob