caching external content

dougholt

I have several affiliate programs that pull information from external servers to generate updated code that appears on my website, to show products or services available from that affiliate. But if their servers are unavailable then the code breaks and my page turns ugly. Can anyone point me towards any tutorials or code snippets that would help me eliminate this problem by cacheing the most recent good information, or checking to see if a script fails and then falling back to the most recent good info? If anyone has any questions about what I mean please contact me for more info.

batman

Well...since your pulling stuff from other servers, I assume that you are pulling it straight from the url?
EXAMPLE: http://www.server.com/folder/file.htm
Or what have you.

If this is true, then you should be able to use something like this:


//Put sql query to get the file for the desired affiliate.

$sql = mysql_query("SELECT * FROM table WHERE afid='$afid'");
$result = mysql_fetch_array($sql);
$file = $result["name of field that stores file"];

if(file_exists($file))
{
whatevr here
}
else
{
echo "This affiliate's site is temporarily down, and will be up soon.";
}

Hope that helps at all,
-Blake

dougholt

Actually the primary affiliate I am speaking of is TemplateMonster.com and their content is pulled into an IFRAME with the source listed as such

but then this generates valid html just like template.html would right? In your example I didn't see where it was pulling the info from the external server, checking to see if it was valid html (not 404 or other error) then reverting back to last previous good code. Could you elaborate?

batman

Oh, my bad. I was setting it up as to where you were using a database to store the files, and not using an iframe.

Try something like this then:

$file = "http://www.mytemplatestorage.com/banner.php";

if(file_exists($file))
{
echo "<IFRAME src='http://www.mytemplatestorage.com/banner.php?aff=dougholt&cols=3&rows=1&skin=19&sp=0&type=wt&category=11' width='540' height='240' align='center' frameborder='0'></IFRAME>";
}
else
{
echo "Site temporarily down. Sorry for the inconvienance.";
}

The reason that $file only equals up to the banner.php, is because all the variables that follow are, I'm sure, due to change.
As long as the banner.php page exists, then you should be fine.
You can modify that code if you want.

-Blake

dougholt

Cool. I think this is the right direction, but I have a couple of questions. Even if http://www.mytemplatestorage.com/banner.php is not available, it will return a 404 error page that the $file variable would interpret as valid, even though it weren't, or am I wrong?

batman

I don't believe so. Even though it stays on the page you tried to visit, I believe a 404 error doesn't count as an actual page. Try putting it up and see if the basics of the code works. Of course you won't be able to test all of it unless their server is down.

-Blake

dougholt

Nope. tried it at http://www.watchthisinteractive.com/testBanner.php and doesn't seem to work. Tried this code.

 
<?php
$file = "http://www.mytemplatestorage.com/banner.php";

if(file_exists($file))
{
echo "<IFRAME src='http://www.mytemplatestorage.com/banner.php?aff=dougholt&cols=3&rows=1&skin=19&sp=0&type=wt&category=11' width='540' height='240' align='center' frameborder='0'></IFRAME>";
}
else
{
echo "Site temporarily down. Sorry for the inconvienance.";
}
?>

batman

Ok, well I think I'll change it around a little bit. I will also make the iframe to something more noticable.

<?php
$file = "http://www.mytemplatestorage.com/banner.php";

if(!file_exists($file))
{
echo "Site temporarily down. Sorry for the inconvienance.";
}
else
{
echo "<IFRAME src='http://www.yahoo.com'></IFRAME>";
}
?>

Let me know,
-Blake

dougholt

No, the page is available right now. try http://www.mytemplatestorage.com/banner.php and you'll get a valid page. I think we need another piece of code to check to see if the page exists.

batman

Ok, I guess the file_exists only works on files remotely hosted.
Try using this:

<?php
$file = fopen ("http://www.mytemplatestorage.com/banner.php", "r");
if (!$file) 
{
echo "Site temporarily down. Sorry for the inconvienance.";
}
else
{
echo "<IFRAME src='http://www.yahoo.com'></IFRAME>";
}
?>

This should give you an error if the site is down, but set the iframe to yahoo.com if it does exist.

Hope this one works,
-Blake