Posted by Edward Vermillion on 09/04/05 01:16

Dan Trainor wrote:
> Dan Trainor wrote:
>
>> Hello, all -
>>
>> This is a question that could depend on a completely different (yet,
>> relayed) subject, so I'm sending this email to both php-general@ and
>> httpd@users.apache.org. I thank you in advance for your understanding.
>>
>> I am currently generating some images on the fly using some of PHP's
>> image generation and rendering functions. I'm having loads of
>> success, and like the results that I see.
>>
>> What I'd like this script to do is, to create symlinks to the
>> origional image, and then when the script is done running, the
>> symlinks are deleted. Basically trying to make it so that the
>> origional image is not known to the client or browser.
>>
>> So I'm taking, say, image1.jpg. I'm creating a symlink via:
>>
>> $linkname = md5(rand());
>>
>> or something similar. I'd then like to return $linkname to the client
>> or browser. Then, when the browser has completed rendering the page
>> to the client or browser, the symlink is then deleted.
>>
>> What I'm curious as to right now is if I do this, the client will see
>> the link to $linkname via HTML's "img src=" specification. What
>> happens if this is sent to the client or browser, and the symlink is
>> deleted immediately after the name is sent to the client or browser?
>> Would the web server (in this case, Apache) cache the image in memory
>> until the client has downloaded said image, and then delete it from
>> memory when the page is done rendering or being sent? Will PHP
>> totally disregard the web server's request to "hold" the image, and
>> render nothing to the browser? This is something I'm confused about.
>>
>> Thanks!
>> -dant
>>
>
> Hello -
>
> Don't suppose anyone has any pointers for me with this one, do ya?
>
> Thanks!
> -dant
>

I tried something similar to this a while back, although not with
symlinks. I was writing a copy of the image to a "temporary" directory,
sending that out to the browser in an <img> tag, then removing the copy.
It worked like a charm in IE, but Netscaape/Mozilla/Firebird/Safari
would give me a "corrupted image" or some-such error.

The only thing I could figure out from it was the browsers that do a
"look ahead" on the links to the image wouldn't see an image at the link
before it was clicked, and would cache that result. Eventually I just
gave up on that idea.

You might look for the recent threads that deal with dynamic image
generation that sends the image directly to the browser. There's been a
few reciently and you might be able to do something with that.

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