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how can i know if a photo is available  or not before puting it?

Posted on 2008-10-14
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Last Modified: 2009-07-29
i have 30 photo links that some of them dont work the photo is not there so when i try to see it like this

  <img src="<?php echo $photo[$p];?>"/></br>
i get a x on the photo like its unavailable

so how can i know that its unavailable before and not showing it?
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Question by:mgtm3
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8 Comments
 
LVL 24

Accepted Solution

by:
glcummins earned 350 total points
ID: 22716190
You can use get_headers() to determine if a URL returns a valid response before using it:

<?php
 
list($response_code) = get_headers($photo[$p]);
 
if (stristr($response_code, '200 OK'))
{
   // The photo exists
   echo $photo[$p];
}
else
{
   // Take whatever action is necessary, like outputting a placeholder image URL.
}
?>

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0
 

Author Comment

by:mgtm3
ID: 22716318
is there any faster code?
0
 
LVL 39

Assisted Solution

by:Roger Baklund
Roger Baklund earned 150 total points
ID: 22716452
If the images are on the local server, you can use file_exists().

You can use a placeholder image, like glcummins suggests, or remove the image completely, i.e. only display the image element if the image actually exists:
<?php if(file_exists($photo[$p]))
  echo '<img src="'.$photo[$p].'"/></br>';
?>

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Author Comment

by:mgtm3
ID: 22716538
but the image is not on the sever and the command that glucummis takes for ever
0
 
LVL 39

Expert Comment

by:Roger Baklund
ID: 22716605
It's probably the network and/or the remote server that is slowing you down. There is no way around this. Some packets have to travel across the network to determine if the file exists, and the remote server will use some time to respond. You should of course remove links to non-existing photos from your page, that would solve the problem.
0
 

Author Comment

by:mgtm3
ID: 22716660
how can i remove the links? you mean not showing the image
0
 
LVL 39

Expert Comment

by:Roger Baklund
ID: 22716741
With links I meant "photo links" or image URLs. How did they get into $photo[$p] ? They are probably read from some database table? You should delete or otherwise 'block' these records from that table.
0
 
LVL 24

Expert Comment

by:glcummins
ID: 22717176
I run a large server with many millions of image references to other servers. I run a process in the background that periodically checks for the existence of those images, and updated a database record if they do not exist.

When the customer loads the website, my front-end scripts instantly know if the remote image is available, and do not need to run the slow get_headers() command in real-time.

Perhaps a similar system will work for you?
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