Sun Java System Web Server 6.1 SP11 NSAPI Programmer's Guide


The dr_cache_refresh function provides a way of refreshing a cache entry when the plug-in requires it. This can be achieved by passing NULL for the ref parameter in dr_cache_init and by passing DR_CHECK in a dr_net_write call. If DR_CHECK is passed to dr_net_write and it returns with DR_EXPIR, the plug-in should generate new content in the entry and call dr_cache_refresh with that entry before calling dr_net_write again to send the response.

The plug-in may simply decide to replace the cached entry even if it has not expired (based on some other business logic). The dr_cache_refresh function is useful in this case. This way the plug-in does the cache refresh management actively by itself.


PRInt32 dr_cache_refresh(DrHdl hdl, const char *key, PRUint32 klen,
PRIntervalTime timeout, Entry *entry, Request *rq, Session *sn);


1 if successful.

0 if an error occurs.


The following table describes parameters for the dr_cache_refresh function.

Table 11–2 dr_cache_refresh parameters



DrHdl hdl

Persistent handle created by the dr_cache_init function.

const char *key

Key to cache, search, or refresh. 

PRUint32 klen

Length of the key in bytes. 

PRIntervalTime timeout

Expiration time of this entry. If a value of 0 is passed, the maxAge value passed to dr_cache_init is used.

Entry *entry

The not NULL entry to be cached. 

Request *rq

Pointer to the request. 

Session *sn

Pointer to the session. 


Entry entry;
char *key = "MOVIES"
GenNewMovieList(&, &entry.dataLen);  // Implemented by
                                               // plugin developer
if(!dr_cache_refresh(hdl, key, strlen(key), 0, &entry, rq, sn))
    ereport(LOG_FAILURE, "dr_cache_refresh() failed");
    return REQ_ABORTED;