[core] Implemented MemcachedCache

[em92]

In my bridge instance to reduce usage of file system, MemcachedCache was implemented to use memcached server as feed items cache.

To turn it on I made hardcode edit:

diff --git a/index.php b/index.php
index a95302a..7c78f83 100644
--- a/index.php
+++ b/index.php
@@ -202,7 +202,7 @@ try {
                );
 
                // Initialize cache
-               $cache = Cache::create('FileCache');
+               $cache = Cache::create('MemcachedCache');
                $cache->setPath(PATH_CACHE);
                $cache->purgeCache(86400); // 24 hours
                $cache->setParameters($cache_params);

It would be cool, if user could use some other cache just by editing config. But in current implementation, there is no such config. So for this, we need next config items:

• which cache to use (FileCache or MemcachedCache)
• params for caches themselves (directory or list for servers)

Here we discuss, how to implement MemcachedCache to bridge instance in normal way

[logmanoriginal]

Nice work 🥇

Just to be sure, Memcached is some sort of external service?

To turn it on I made hardcode edit

It would be cool, if user could use some other cache just by editing config.

Good point, this clearly needs to be fixed. I've added the Code-Investigation-Needed label for that reason.

to reduce usage of file system

Out of curiosity, would compressing files do any good?

[em92]

Memcached is some sort of external service?

Yes. https://memcached.org/

Out of curiosity, would compressing files do any good?

It will slow down bridge instance itself 'cos of decompressing and compressing. Feed items cached data in my instance was less than 5 mb, AFAIK

[logmanoriginal]

I'm gonna merge #1002 in a minute, which breaks this PR because the code from index.php moves to /actions/DisplayAction.php#L88.

Would it be okay for you to merge this PR without changes to index.php? (assuming it is stable)
The cache type needs a configuration option, which is a separate topic anyway.

[em92]

No problem. I will fix this PR

[logmanoriginal]

Thanks, support for custom cache names will follow in a minute...

[logmanoriginal]

Adding

; Defines the cache type used by RSS-Bridge
; "file" = FileCache (default)
; "memcache" = MemcacheCache
type = "memcache"

to config.ini.php should now work (actually might not work because it ends on 'cache' which is filtered by lib/Cache.php!?).

[em92]

actually might not work because it ends on 'cache' which is filtered by lib/Cache.php!?

Fixed with:

diff --git a/lib/Cache.php b/lib/Cache.php
index 6826d4c..6c2943a 100644
--- a/lib/Cache.php
+++ b/lib/Cache.php
@@ -193,7 +193,7 @@ class Cache {
                        }
 
                        // Trim trailing 'Cache' if exists
-                       if(preg_match('/(.+)(?:Cache)/i', $name, $matches)) {
+                       if(preg_match('/(.+)(?:Cache)$/i', $name, $matches)) {
                                $name = $matches[1];
                        }
 

[logmanoriginal]

I've added your fix to master. Hope it works now. Regarding Travis, here is a rather new discussion regarding memcached support which could be of help: https://travis-ci.community/t/unable-to-load-dynamic-library-memcached-so/2232

[logmanoriginal]

Can this be merged?

[logmanoriginal]

Please test if this still works on current master. #1060 introduced a few changes.

[em92]

Please test if this still works on current master

It does not. I will make changes for it to work.

[em92]

Looks fine on first minutes on my instance. I will comment here tomorrow morning (YEKT) if everything is fine.

[em92]

Works fine. It can be merged now

[teromene]

Thanks for the hard work !