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Use the ldap_memcache functions to maintain an in-memory client side cache to store search requests. Caching improves performance and reduces network bandwidth when a client makes repeated requests. The cache uses search criteria as the key to the cached
items. When you send a search request, the cache checks the search criteria to determine if that request has been previously stored . If the request was stored, the search results are read from the cache.
Make a call to ldap_memcache_init() to create the in-memory client side cache. The function passes back a pointer to an LDAPMemCache structure, which represents the cache. Make a call to the ldap_memcache_set() function to associate this cache with an LDAP connection handle, an LDAP structure. ttl is the the maximum amount of time (in seconds) that an item can be cached. If a ttl value of 0 is passed, there is no limit to the
amount of time that an item can be cached. size is the maximum amount of memory (in bytes) that the cache will consume. A zero value of size means the cache has no size limit. baseDNS is an array of the base DN strings representing
the base DNs of the search requests you want cached. If baseDNS is not NULL, only the search requests with the specified base DNs will be cached. If baseDNS is NULL, all search requests are cached.
The thread_fns parameter takes an ldap_thread_fns structure specifying the functions that you want used to ensure that the cache is thread-safe. You should specify this if you have multiple threads that are using the same connection handle and cache. If
you are not using multiple threads, pass NULL for this parameter.
ldap_memcache_set() associates an in-memory cache that you have already created by calling the ldap_memcache_init() function with an LDAP connection handle. The ld parameter should be the result of a successful
call to ldap_open(3LDAP). The cache parameter should be the result of a cache created by the ldap_memcache_init() call.
After you call this function, search requests made over the specified LDAP connection will use this cache. To disassociate the cache from the LDAP connection handle, make a call to the ldap_unbind(3LDAP) or ldap_unbind_ext(3LDAP) function. Make a call to ldap_memcache_set() if you want to associate a cache with multiple LDAP connection handles.
For example, call the ldap_memcache_get() function to get the cache associated with one connection, then you can call this function and associate the cache with another connection.
The ldap_memcache_get() function gets the cache associated with the specified connection handle (LDAP structure). This cache is used by all search requests made through that connection. When you call this function, the function sets
the cachep parameter as a pointer to the LDAPMemCache structure that is associated with the connection handle.
ldap_memcache_flush() flushes search requests from the cache. If the base DN of a search request is within the scope specified by the dn and scope arguments, the search request is flushed from the cache. If no DN is specified, the entire cache is flushed. The scope parameter, along with the dn parameter, identifies the search requests that you want flushed from the cache. This argument can have one of the following
values:
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LDAP_SCOPE_BASE
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LDAP_SCOPE_ONELEVEL
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LDAP_SCOPE_SUBTREE
ldap_memcache_destroy() frees the specified LDAPMemCache structure pointed to by cache from memory. Call this function after you are done working with a cache.
ldap_memcache_update() checks the cache for items that have expired and removes them. This check is typically done as part of the way the cache normally works. You do not need to call this function unless you want to update the cache
at this point in time. This function is only useful in a multithreaded application, since it will not return until the cache is destroyed.
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