Re: Possible problems with Brookhaven Mirror

Murray-Rust Dr P (
Mon, 26 Feb 1996 15:39:16 +0000 (GMT)

On Mon, 26 Feb 1996, John Walshaw wrote:

> There are a number of solutions-
> 3) Use a different extension for the PDB files, e.g. '.ent' , '.pps' etc,
> which is not currently present on any files on the Brookhaven Web server,
> and ask Dave Stampf to configure the server to deliver these with the
> chemical MIME type (and use relative URLs). But my gut feeling is that
> filename extensions are quite important, and preferably, the '.pdb' extension
> should be used for PDB files.
We raised the 'ent' question with B'haven about 18 months ago, I think.
Just in case people are not clear what happens...

For server->client transmission:

1. server determines the MIME type for a file from the extension (on the
server). This mapping is in mime.types on the *server*

2. server stamps the file with Content-type as (say) chemical/x-pdb.

3. client receives file. It looks *only* at the stamp to determine the
MIME type; the extension on the remote machine is irrelevant.

4. client looks in .mailcap (or netscape.ini, or whatever) to see what
application has been mapped onto this *type*, and invokes that. If none,
it assumes text/plain (this can be a menace for binary files :-)

For *local* files. (if you are using a browser with the Load File, rather
than Load URL option).

1. client determines extension and uses .mime.types (sic) to determine MIME
type. (There may be a communal .mime.types). PC have other *.INI files and
it's configurable on many browsers.

2. client invokes application.

(It's possible, therefore, to access a file by two methods - through a
server, and locally and to have it stamped with different file types.
This could, for example, apply to anyone working at BBK or at BNL).

I am strongly of the opinion that the MIME type of a file should be
closely related to its extension if possible. General names (e.g. .ent,
.dat, .pps (which could be confused with *.ps) should be discouraged.
Note, however, that some MIME types are more than 3 chars, e.g.
*.MDL maps onto x-mdl-molfile


Peter Murray-Rust 44-181-9662554 T "Nothing exists except atoms and empty 44-181-9662109 F space; all else is opinion" Democritos.
Biomolecular Structure, Glaxo Wellcome, Greenford, Middx, UB6 0HE, UK
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