[Plugin: WP Super Cache] wp super cache Warning: strpos() [function.strpos]: Offset not contained in

cherty
(@cherty)

11 years, 10 months ago

I upgraded to Version 3.4 on our multiuser/networked WordPress site. The root WordPress installation is in a subfolder in public_html, and the networked blogs are in subfolders (not subdomains). Then I upgraded to WP Super Cache 1.1. Then I got several wp-super-cache warning messages. So I duplicated our site on a test xampp on my laptop (which I’ve done many times). I get the same warning/notice messages:

Warning: strpos() [function.strpos]: Offset not contained in string in C:\xampp\htdocs\wp\wp-content\plugins\wp-super-cache\wp-cache-base.php on line 26

Notice: Undefined variable: cache_wptouch in C:\xampp\htdocs\wp\wp-content\plugins\wp-super-cache\plugins\wptouch.php on line 109

I googled the strpos() phrase and found a large number of active websites with the same warning messages. This is worrisome. So I disabled wp super cache on our live website.

On my test xampp, I added a space between the ” on line 26 of wp-cache-base.php and this got rid of the Warning message.
Here is the original code:
$blogcacheid = str_replace( $base, '', $request_uri );
Here is my edited code:
$blogcacheid = str_replace( $base, ' ', $request_uri );

I also added a similar space on line 49 of wp-cache-config.php and got rid of that warning message.
Here is the original code:
$blogcacheid = str_replace( $base, '', $request_uri );
Here is my edited code:
$blogcacheid = str_replace( $base, ' ', $request_uri );

I would like to know if this is a safe hack for my site, and is adding a space between the ” assigned to $blogcacheid a possible remedy for the many websites found in my google search. I have never changed any of the core code.

Thank you in advance for any help.

http://wordpress.org/extend/plugins/wp-super-cache/

Viewing 11 replies - 1 through 11 (of 11 total)

Plugin Author Donncha O Caoimh (a11n)
(@donncha)

11 years, 10 months ago

No, it’s the next line that causes the problem. I’ll add some code that checks the length of $blogcacheid.

Can you restore the code to what it was before for me and debug it? I’d like to know what $blogcacheid was before line 26. Something like this will log that to the file /tmp/err.txt but you could put it in whatever file you want.

error_log( $_SERVER[ 'REQUEST_URI' ] . " $blogcacheid\n", 3, "/tmp/err.txt" );

Put that on the line just before the str_replace. Thanks!
Thread Starter cherty
(@cherty)

11 years, 10 months ago
Thank you for your quick reply. Sorry it’s taken so long to get back.

I reinstalled the WordPress site on my test xampp server, then network activated WP Super Cache. With debug on from the wp-config.php file, these two messages displayed in the browser:

Warning: strpos() [function.strpos]: Offset not contained in string in C:\xampp\htdocs\wp\wp-content\plugins\wp-super-cache\wp-cache-base.php on line 26

Notice: Undefined variable: cache_wptouch in C:\xampp\htdocs\wp\wp-content\plugins\wp-super-cache\plugins\wptouch.php on line 109

After setting caching on and using mod_rewrite, I added your error_log code to the plugins/wp-super-cache/wp-cache-base.php file (lines 19 through 28, sorry about indents below):
```
} else {
		$request_uri = preg_replace('/[ <>\'\"\r\n\t]/', '', str_replace( '..', '', $_SERVER['REQUEST_URI'] ) );
		if( strpos( $request_uri, '/', 1 ) ) {
			if( $base == '/' ) {
				$blogcacheid = substr( $request_uri, 1, strpos( $request_uri, '/', 1 ) - 1 );
			} else {
			  error_log( $_SERVER[ 'REQUEST_URI' ] . " $blogcacheid\n", 3, "err.txt" );  // test code added 6-20-12
				$blogcacheid = str_replace( $base, '', $request_uri );
				$blogcacheid = substr( $blogcacheid, 0, strpos( $blogcacheid, '/', 1 ) );
			}
```
I visited these pages:
1. Homepage
2. Homepage Dashboard
3. Network Dashboard
4. Homepage
5. Blog Site
6. Blog site Dashboard
7. Homepage

Here is the err.txt output for the pages I visited:

/wp/ blog
/wp/bcc-news/ blog
/wp/ blog
/wp/bcc-news/ blog
/wp/ztest/ blog
/wp/ztest/page-1/ blog
/wp/ blog
/wp/bcc-news/ blog

Thanks.
Thread Starter cherty
(@cherty)

11 years, 10 months ago

Plugin Author Donncha O Caoimh (a11n)
(@donncha)

11 years, 10 months ago

Thanks, I appreciate that. Can you change the error_log so it records $base and $request_uri too? Something like this should be enough:
`error_log( “$request_uri $base $blogcacheid\n”, 3, “/tmp/err.txt” );

Thanks!
Thread Starter cherty
(@cherty)

11 years, 10 months ago
Thanks. Here is what I added (lines 19 through 29):
```
} else {
		$request_uri = preg_replace('/[ <>\'\"\r\n\t]/', '', str_replace( '..', '', $_SERVER['REQUEST_URI'] ) );
		if( strpos( $request_uri, '/', 1 ) ) {
			if( $base == '/' ) {
				$blogcacheid = substr( $request_uri, 1, strpos( $request_uri, '/', 1 ) - 1 );
			} else {
			  //error_log( $_SERVER[ 'REQUEST_URI' ] . " $blogcacheid\n", 3, "err.txt" );  // test code added 6-20-12
				error_log( "$request_uri $base $blogcacheid\n", 3, "err.txt" ); // test code added 6-21-12
				$blogcacheid = str_replace( $base, '', $request_uri );
				$blogcacheid = substr( $blogcacheid, 0, strpos( $blogcacheid, '/', 1 ) );
			}
```
Here is how I navigated:
Login, Homepage, Homepage Dashboard, Network Dashboard, Homepage, Blog Site, Blog Site Dashboard, Homepage

Here is the output to err.txt:
```
/wp/wp-login.php /wp/ blog
/wp/wp-login.php /wp/ blog
/wp/wp-login.php /wp/ blog
/wp/wp-login.php /wp/ blog
/wp/ /wp/ blog
/wp/ /wp/ blog
/wp/bcc-news/ /wp/ blog
/wp/bcc-news/ /wp/ blog
/wp/ /wp/ blog
/wp/bcc-news/ /wp/ blog
/wp/ztest/ /wp/ blog
/wp/ztest/ /wp/ blog
/wp/ztest/page-1/ /wp/ blog
/wp/ztest/page-1/ /wp/ blog
/wp/ /wp/ blog
/wp/bcc-news/ /wp/ blog
```
Note – The Test Cache works fine, and the two lines of cache code appear at the bottom of web pages using View Source.

Not sure if I am giving you what you want to see.
Thanks for all your help.
Thread Starter cherty
(@cherty)

11 years, 10 months ago
I just tried the development version and it seemed to work well on my test website. The if statement on Line 28 seems to have solved my problem:
```
if ( $blogcacheid != '' )
    $blogcacheid = substr( $blogcacheid, 0, strpos( $blogcacheid, '/', 1 ) );
```
The dev version is at http://downloads.wordpress.org/plugin/wp-super-cache.zip and was referenced on another forum item that you posted (http://wordpress.org/support/topic/plugin-wp-super-cache-issue-with-scheduled-posts-not-showing-up).

Debug on and php_error_log showed no errors. Test cache works fine and the two statements at the bottom of View Source pages display fine.

Thanks so much, Donncha.
AllyV4
(@allyv4)

11 years, 10 months ago

I’ve got the same error on line 109:

Undefined variable: cache_wptouch in /MYDOMAIN/wp-content/plugins/wp-super-cache/plugins/wptouch.php on line 109

What should I do?

It also seems to have a conflict with WP super cache but both plugin leave me a blank page on their own page.

Thanks for the help.

Plugin Author Donncha O Caoimh (a11n)
(@donncha)

11 years, 10 months ago

AllyV4 – it’s a harmless warning but it’s fixed in the development version.

You can install it from this zip file:

http://downloads.wordpress.org/plugin/wp-super-cache.zip

AllyV4
(@allyv4)

11 years, 10 months ago

Thank you 🙂

Andreas
(@anec)

11 years, 7 months ago

I also have this issue, but I would like to avoid using development versions. Do you maybe know when you will release the next official version of WP Super Cache?

Plugin Author Donncha O Caoimh (a11n)
(@donncha)

11 years, 7 months ago

anec – just try the dev version. I haven’t changed anything in it in weeks and it’s very stable. It’ll possibly be the new stable version soon, but I just need to find time to release it.

Viewing 11 replies - 1 through 11 (of 11 total)

The topic ‘[Plugin: WP Super Cache] wp super cache Warning: strpos() [function.strpos]: Offset not contained in’ is closed to new replies.