Cache fopen

[daq]

I created an online rss reader using lastRSS http://lastrss.oslab.net/.

Basically, all it does is read the xml from rss feed using fopen and then parses it.

 

It works great but occasionally, it gets stuck on rss items from several months ago and refuses to update.

I don't use caching of any kind so I have no idea where old data comes from.

 

Since I'm out of ideas I'm coming up with insane theories to justify this behavior. Is it possible my web host is caching fopen requests? Is that even possible?

 

Any help appreciated.

[premiso]

You can set the page to not cache using header.

 

<?php
header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past

?>

 

So each time the page is loaded it must be refreshed....

[rhodesa]

it is possible that they are caching requests. try adding a unique value to the end:

 

<?php
  $url = "http://hostname.com/feed.rss";
  //Try to stop caching
  $url  = $url . '?_='.time();
  fopen($url,'r');
  //etc
?>

[daq]

You can set the page to not cache using header.

 

<?php
header("Cache-Control: no-cache, must-revalidate"); // HTTP/1.1
header("Expires: Sat, 26 Jul 1997 05:00:00 GMT"); // Date in the past

?>

 

So each time the page is loaded it must be refreshed....

 

Sorry, I guess I wasn't specific enough. I didn't mean browser cache. I meant server side cache for fopen.

[daq]

it is possible that they are caching requests. try adding a unique value to the end:

 

<?php
  $url = "http://hostname.com/feed.rss";
  //Try to stop caching
  $url  = $url . '?_='.time();
  fopen($url,'r');
  //etc
?>

 

This is a great solution that should've worked, but I'm still getting outdated data.

[premiso]

Why not try curl or for a simpler route, file_get_contents

 

Curl is quicker, but file_get_contents is easier =)

[rhodesa]

it is possible that they are caching requests. try adding a unique value to the end:

 

<?php
  $url = "http://hostname.com/feed.rss";
  //Try to stop caching
  $url  = $url . '?_='.time();
  fopen($url,'r');
  //etc
?>

 

This is a great solution that should've worked, but I'm still getting outdated data.

 

then their server is doing something wrong. if you load the RSS feed into a browser, does it not show the old data?

[daq]

then their server is doing something wrong. if you load the RSS feed into a browser, does it not show the old data?

 

No, it shows updated information.

[rhodesa]

is it a public link i can look at?

[daq]

Why not try curl or for a simpler route, file_get_contents

 

Curl is quicker, but file_get_contents is easier =)

 

Interesting. Using curl, the feeds that showed old content, don't show any data at all. I wonder if a timeout or something similar causes web host to use cache?

[daq]

is it a public link i can look at?

 

Its a closed site, but the problem is not reproducible 100% of the time and my host, 1&1, completely blocks all error messages so you wouldn't see much more than outdated rss feeds.

[daq]

OK, I figured it out with the help of Curl. Both RSS feeds that were showing old data changed address and were returning a 301, page moved permanently. I'm surprised the script worked at all. And I still don't know where the old data came from.

 

At least the problem is gone.

Thanks to everyone for the help!

[daq]

Wow. I was wrong. Even after I updated the links, I'm still getting old data even with curl. Where the hell can it be coming from?

[daq]

I'm sorry for posting a million things, but this simple test script, seems to work without problems:

<?php
$rss_url = "http://feedproxy.google.com/Explosm";

$f = curl_init();
curl_setopt($f, CURLOPT_URL,$rss_url);
curl_setopt($f, CURLOPT_CONNECTTIMEOUT, 2);
curl_setopt($f, CURLOPT_RETURNTRANSFER, true);
curl_setopt($f, CURLOPT_VERBOSE, true);


if ($rss_content = curl_exec($f))
{
echo $rss_content;
}
curl_close($f);

?>

 

This is the same code I use in my RSS reader which is showing old data.