mod_proxy.h

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 * @return      proxy_worker or NULL if not found
 */
PROXY_DECLARE(proxy_worker *) ap_proxy_get_worker(apr_pool_t *p,
                                                  proxy_server_conf *conf,
                                                  const char *url);
/**
 * Add the worker to proxy configuration
 * @param worker the new worker
 * @param p      memory pool to allocate worker from 
 * @param conf   current proxy server configuration
 * @param url    url containing worker name
 * @return       error message or NULL if successfull
 */
PROXY_DECLARE(const char *) ap_proxy_add_worker(proxy_worker **worker,
                                                apr_pool_t *p,
                                                proxy_server_conf *conf,
                                                const char *url);

/**
 * Create new worker
 * @param p      memory pool to allocate worker from 
 * @return       new worker
 */
PROXY_DECLARE(proxy_worker *) ap_proxy_create_worker(apr_pool_t *p);

/**
 * Initize the worker's shared data
 * @param conf   current proxy server configuration
 * @param worker worker to initialize
 * @param s      current server record
 * @param worker worker to initialize
 */
PROXY_DECLARE(void) ap_proxy_initialize_worker_share(proxy_server_conf *conf,
                                                     proxy_worker *worker,
                                                     server_rec *s);


/**
 * Initize the worker
 * @param worker worker to initialize
 * @param s      current server record
 * @return       APR_SUCCESS or error code
 */
PROXY_DECLARE(apr_status_t) ap_proxy_initialize_worker(proxy_worker *worker,
                                                       server_rec *s);
/**
 * Get the balancer from proxy configuration
 * @param p     memory pool used for finding balancer
 * @param conf  current proxy server configuration
 * @param url   url to find the worker from. Has to have balancer:// prefix
 * @return      proxy_balancer or NULL if not found
 */
PROXY_DECLARE(proxy_balancer *) ap_proxy_get_balancer(apr_pool_t *p,
                                                      proxy_server_conf *conf,
                                                      const char *url);
/**
 * Add the balancer to proxy configuration
 * @param balancer the new balancer
 * @param p      memory pool to allocate balancer from 
 * @param conf   current proxy server configuration
 * @param url    url containing balancer name
 * @return       error message or NULL if successfull
 */
PROXY_DECLARE(const char *) ap_proxy_add_balancer(proxy_balancer **balancer,
                                                  apr_pool_t *p,
                                                  proxy_server_conf *conf,
                                                  const char *url);

/**
 * Add the worker to the balancer
 * @param pool     memory pool for adding worker 
 * @param balancer balancer to add to
 * @param balancer worker to add
 * @note Single worker can be added to multiple balancers.
 */
PROXY_DECLARE(void) ap_proxy_add_worker_to_balancer(apr_pool_t *pool,
                                                    proxy_balancer *balancer,
                                                    proxy_worker *worker);
/**
 * Get the most suitable worker and(or) balancer for the request
 * @param worker   worker used for processing request
 * @param balancer balancer used for processing request
 * @param r        current request
 * @param conf     current proxy server configuration
 * @param url      request url that balancer can rewrite.
 * @return         OK or  HTTP_XXX error 
 * @note It calls balancer pre_request hook if the url starts with balancer://
 * The balancer then rewrites the url to particular worker, like http://host:port
 */
PROXY_DECLARE(int) ap_proxy_pre_request(proxy_worker **worker,
                                        proxy_balancer **balancer,
                                        request_rec *r,
                                        proxy_server_conf *conf,
                                        char **url);
/**
 * Post request worker and balancer cleanup
 * @param worker   worker used for processing request
 * @param balancer balancer used for processing request
 * @param r        current request
 * @param conf     current proxy server configuration
 * @return         OK or  HTTP_XXX error
 * @note When ever the pre_request is called, the post_request has to be
 * called too. 
 */
PROXY_DECLARE(int) ap_proxy_post_request(proxy_worker *worker,
                                         proxy_balancer *balancer,
                                         request_rec *r,
                                         proxy_server_conf *conf);

/**
 * Request status function
 * @param status   status of proxy request
 * @return         OK or DECLINED
 */
 PROXY_DECLARE(int) ap_proxy_request_status(int *status, request_rec *r);

/**
 * Deternime backend hostname and port
 * @param p       memory pool used for processing
 * @param r       current request
 * @param conf    current proxy server configuration
 * @param worker  worker used for processing request
 * @param conn    proxy connection struct
 * @param uri     processed uri
 * @param url     request url
 * @param proxyname are we connecting directly or via s proxy
 * @param proxyport proxy host port
 * @param server_portstr Via headers server port
 * @param server_portstr_size size of the server_portstr buffer
 * @return         OK or HTTP_XXX error
 */                                         
PROXY_DECLARE(int) ap_proxy_determine_connection(apr_pool_t *p, request_rec *r,
                                                 proxy_server_conf *conf,
                                                 proxy_worker *worker,
                                                 proxy_conn_rec *conn,
                                                 apr_uri_t *uri,
                                                 char **url,
                                                 const char *proxyname,
                                                 apr_port_t proxyport,
                                                 char *server_portstr,
                                                 int server_portstr_size);
/**
 * Mark a worker for retry
 * @param proxy_function calling proxy scheme (http, ajp, ...)
 * @param conf    current proxy server configuration
 * @param worker  worker used for retrying
 * @param s       current server record
 * @return        OK if marked for retry, DECLINED otherwise
 * @note Worker will be marker for retry if the time of the last retry
 * has been ellapsed. In case there is no retry option set, defaults to
 * number_of_retries seconds.
 */                                         
PROXY_DECLARE(int) ap_proxy_retry_worker(const char *proxy_function,
                                         proxy_worker *worker,
                                         server_rec *s);
/**
 * Acquire a connection from workers connection pool
 * @param proxy_function calling proxy scheme (http, ajp, ...)
 * @param conn    acquired connection
 * @param worker  worker used for obtaining connection
 * @param s       current server record
 * @return        OK or HTTP_XXX error
 * @note If the number of connections is exhaused the function will
 * block untill the timeout is reached.
 */                                         
PROXY_DECLARE(int) ap_proxy_acquire_connection(const char *proxy_function,
                                               proxy_conn_rec **conn,
                                               proxy_worker *worker,
                                               server_rec *s);
/**
 * Release a connection back to worker connection pool
 * @param proxy_function calling proxy scheme (http, ajp, ...)
 * @param conn    acquired connection
 * @param s       current server record
 * @return        OK or HTTP_XXX error
 * @note The connection will be closed if conn->close_on_release is set
 */                                         
PROXY_DECLARE(int) ap_proxy_release_connection(const char *proxy_function,
                                               proxy_conn_rec *conn,
                                               server_rec *s);
/**
 * Make a connection to the backend
 * @param proxy_function calling proxy scheme (http, ajp, ...)
 * @param conn    acquired connection
 * @param worker  connection worker
 * @param s       current server record
 * @return        OK or HTTP_XXX error
 * @note In case the socket already exists for conn, just check the link
 * status.
 */                                         
PROXY_DECLARE(int) ap_proxy_connect_backend(const char *proxy_function,
                                            proxy_conn_rec *conn,
                                            proxy_worker *worker,
                                            server_rec *s);
/**
 * Make a connection record for backend connection
 * @param proxy_function calling proxy scheme (http, ajp, ...)
 * @param conn    acquired connection
 * @param c       client connection record
 * @param s       current server record
 * @return        OK or HTTP_XXX error
 */                                         
PROXY_DECLARE(int) ap_proxy_connection_create(const char *proxy_function,
                                              proxy_conn_rec *conn,
                                              conn_rec *c, server_rec *s);
/**
 * Signal the upstream chain that the connection to the backend broke in the
 * middle of the response. This is done by sending an error bucket with
 * status HTTP_BAD_GATEWAY and an EOS bucket up the filter chain.
 * @param r       current request record of client request
 * @param brigade The brigade that is sent through the output filter chain
 */
PROXY_DECLARE(void) ap_proxy_backend_broke(request_rec *r,
                                           apr_bucket_brigade *brigade);

/* Scoreboard */
#if MODULE_MAGIC_NUMBER_MAJOR > 20020903
#define PROXY_HAS_SCOREBOARD 1
#else
#define PROXY_HAS_SCOREBOARD 0
#endif

/**
 * Transform buckets from one bucket allocator to another one by creating a
 * transient bucket for each data bucket and let it use the data read from
 * the old bucket. Metabuckets are transformed by just recreating them.
 * Attention: Currently only the following bucket types are handled:
 *
 * All data buckets
 * FLUSH
 * EOS
 *
 * If an other bucket type is found its type is logged as a debug message
 * and APR_EGENERAL is returned.
 * @param r    current request record of client request. Only used for logging
 *             purposes
 * @param from the brigade that contains the buckets to transform
 * @param to   the brigade that will receive the transformed buckets
 * @return     APR_SUCCESS if all buckets could be transformed APR_EGENERAL
 *             otherwise
 */
PROXY_DECLARE(apr_status_t)
ap_proxy_buckets_lifetime_transform(request_rec *r, apr_bucket_brigade *from,
                                        apr_bucket_brigade *to);

#define PROXY_LBMETHOD "proxylbmethod"

/* The number of dynamic workers that can be added when reconfiguring.
 * If this limit is reached you must stop and restart the server.
 */
#define PROXY_DYNAMIC_BALANCER_LIMIT    16
/**
 * Calculate number of maximum number of workers in scoreboard.
 * @return  number of workers to allocate in the scoreboard
 */
int ap_proxy_lb_workers(void);

/* For proxy_util */
extern module PROXY_DECLARE_DATA proxy_module;

extern int PROXY_DECLARE_DATA proxy_lb_workers;

#endif /*MOD_PROXY_H*/
/** @} */