Re: Serving graphics from a database
From: Steve (ThisOne_at_Aint.valid)
Date: 08/18/04
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Date: Wed, 18 Aug 2004 22:47:13 +1200
Margaret MacDonald wrote:
> Andy Hassall wrote:
>
>
>>On Sat, 14 Aug 2004 13:28:17 GMT, Margaret MacDonald
>><scratch65536@att.not.invalid> wrote:
>>
>>
>>>I want to store frequently-used graphic elements in a db and serve
>>>them from there rather than from the filesystem.
>>>
>>>Is there a better/faster way to do that than this? (error checking
>>>etc not shown)
>>>
>>>The relevant piece of the page:
>>><?php
>>> echo
>>> '<table><tr><td>
>>> <img src="ImageFromDB.php?Image=ImageIdentifer">
>>> </td></tr></table>' ;
>>>?>
>>>
>>>ImageFromDB.php:
>>><?php
>>> $imgname = $_GET['Image'] ;
>>> $dset = mysql_query( 'SELECT imagebits FROM graphics_table
>>> WHERE name="' . $imgname . '"' ) ;
>>> $rec = mysql_fetch_row($dset) ;
>>> $browser = fopen( 'php://output', 'w') ;
>>> header( 'Content-Type: image/png' ) ;
>>> fwrite( $browser, $rec[0] ) ;
>>>?>
>>>
>>>I fingered through the docs and did some googling, but didn't find
>>>anything obviously helpful. Many thanks for any insights.
>>
>>Looks OK to me. A plain 'print' would likely do just as well as opening the
>>output stream as you've done, but there's nothing wrong with that. You might
>>want to change the mode to 'wb' though to indicate binary mode.
>>
>>If these images are frequently accessed then it might be worth considering
>>using a filesystem-based cache if the database queries take noticable amounts
>>of resources.
>>
>>General opinion on this group is to not store images in a database and instead
>>just store a filesystem path. However, I believe that if the images are
>>
>>(a) user data rather than static source code of the site
>>(b) have relationships with data in the database
>>(c) have any sort of value with regards to the end-user
>>
>>... then it's worth considering storing them in full in the database so you
>>can include them consistently in the database backups, and have the same
>>transaction guarantees as all the other data on them.
>
>
> Thanks, Andy. I didn't even experiment with print() since I presumed
> it would do gratuitous interpretation. And thanks for catching the
> 'b'--I seem to have a habit of missing that out.
>
> Your articulation of when/why it can be good to store images in the db
> fits for me.
>
> Margaret
The only real downside on storing images s a database is if you're using
a system-based backup procidure. Then, every time oyu change an image,
then the whole data file needs to be saved again, and images tend not to
be small.
So why not apply the same logic above to the file name, and then store
the images somewhere else. That way they can be backed up individually
when they change, not en masse.
$0.02
Steve
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