Re: Multiple people touching the same file with ange-ftp

[Kevin Rodgers <kevin.d.rodgers@gmail.com>]

rgb wrote:
> Kevin Rodgers wrote:
>> rgb wrote:
>>> I see the command MDTM being attempted and the response
>>> 'command not understood' coming back.
>>> If I could intercept this, the DIR command does show the modification
>>> time so I should be able to find and return it.
>> Searching for MDTM in ange-ftp.el leads one to ange-ftp-file-modtime.
>>
> 
> Yes I did notice that.  Thanks
> As yet I don't see an obvious way to override or intercept that
> function on a  host by host basis.
> I see examples of host specific calls being set up like this.
> (add-to-list 'ange-ftp-parse-list-func-alist
> 	     '(vms . ange-ftp-parse-vms-listing))
> But it doesn't work for this function.
> I'm sure, with some further study
> I'll find a way.  It's been a slow process so far.  Perhaps putting
> advice around it is the only way.
> There seems to be lots of essoteric knowledge needed to
> retrieve the data needed to compute the time too.
> I'm continuing to plug away at it and will keep my eye here
> for shortcuts or advise on the best way to proceed.

You could start by making ange-ftp-file-modtime extensible, the same way
ange-ftp-parse-listing is extensible via the ange-ftp-parse-list-func-alist
variable:

(defvar ange-ftp-file-modtime-func-alist nil
   "Alist saying how to return modification time of remote file.
Association list of \( TYPE \. FUNC \) pairs, where FUNC is a
routine which returns the modification time of a remote file from
a host of type TYPE.")

(defadvice ange-ftp-file-modtime (around func-alist activate)
   "If `ange-ftp-file-modtime-func-alist' has an entry for FILE's host type,
return the result of calling that function."
   (let* ((ftp-name (ange-ftp-ftp-name file))
	 (host (nth 0 ftp-name))
	 (user (nth 1 ftp-name))
	 (name (nth 2 ftp-name))
	 (func (assq (ange-ftp-host-type host)
		     ange-ftp-file-modtime-func-alist)))
     (if func
	(funcall func file)
       ad-do-it)))

Now you just have to implement ange-ftp-file-modtime-for-FOO and add
(FOO . ange-ftp-file-modtime-for-FOO) to ange-ftp-file-modtime-func-alist,
assuming ange-ftp-host-type returns FOO for file's on your server. :-)

-- 
Kevin Rodgers
Denver, Colorado, USA