redisx-sub.c File Reference

Functions
int	redisxAddSubscriber (Redis *redis, const char *channelStem, RedisSubscriberCall f)
int	redisxClearSubscribers (Redis *redis)
int	redisxEndSubscription (Redis *redis)
int	redisxNotify (Redis *redis, const char *channel, const char *message)
int	redisxPublish (Redis *redis, const char *channel, const char *data, int length)
int	redisxPublishAsync (Redis *redis, const char *channel, const char *data, int length)
int	redisxRemoveSubscribers (Redis *redis, RedisSubscriberCall f)
int	redisxSubscribe (Redis *redis, const char *pattern)
int	redisxUnsubscribe (Redis *redis, const char *pattern)

Detailed Description

Date

Created on Aug 26, 2024

Author

Attila Kovacs

PUB/SUB functions for the RedisX library.

Function Documentation

redisxAddSubscriber()

int redisxAddSubscriber	(	Redis *	redis,
		const char *	channelStem,
		RedisSubscriberCall	f
	)

Add a targeted subscriber processing function to the list of functions that process Redis PUB/SUB responses. You will still have to subscribe the relevant PUB/SUB messages from redis separately, using redisxSubscribe() before any messages are delivered to this client. If the subscriber with the same callback function and channel stem is already added, this call simply return and will NOT create a duplicate enry. However, the same callback may be added multiple times with different channel stems (which pre-filter what messages each of the callbacks may get).

Parameters

redis	Pointer to a Redis instance.
channelStem	If NULL, the consumer will receive all Redis messages published to the given channel. Otherwise, the consumer will be notified only if the incoming channel begins with the specified stem.
f	A function that consumes subscription messages.

See also

redisxRemoveSubscribers()

redisxSubscribe()

References X_SUCCESS, x_warn(), xStringCopyOf(), and xvprintf.

redisxClearSubscribers()

int redisxClearSubscribers

(

Redis *

redis

)

Stops the custom consumption of PUB/SUB messages from Redis.

Parameters

redis

Pointer to a Redis instance.

Returns

X_SUCCESS (0) if successful, or X_NULL if the redis instance is NULL.

References xvprintf.

redisxEndSubscription()

int redisxEndSubscription

(

Redis *

redis

)

Unsubscribes from all channels, stops the subscription listener thread, and closes the subscription client connection.

Parameters

redis

Pointer to a Redis instance.

Returns

X_SUCCESS (0) if successful or else an error code (<0).

See also

redisxUnsubscribe()

References X_SUCCESS.

redisxNotify()

int redisxNotify	(	Redis *	redis,
		const char *	channel,
		const char *	message
	)

Sends a regular string terminated Redis PUB/SUB message on the specified channel. Same as redisxPublish() with the length argument set to the length of the string message. Redis must be connected before attempting to send messages.

Parameters

redis	Pointer to a Redis instance.
channel	Redis PUB/SUB channel on which to notify
message	Message to send.

Returns

X_SUCCESS if the message was successfullt sent. X_NO_INIT if the Redis library was not initialized via initRedis(). X_NO_SERVICE if there was a connection problem. PARSE_ERROR if the Redis response could not be confirmed.

See also

redisxPublish()

redisxPublishAsync()

redisxSubscribe()

References redisxPublish(), and X_SUCCESS.

redisxPublish()

int redisxPublish	(	Redis *	redis,
		const char *	channel,
		const char *	data,
		int	length
	)

Sends a generic Redis PUB/SUB message on the specified channel. Redis must be connected before attempting to send messages. It will send the message over the pipeline client if it is avaiable, or else over the interactive client.

Parameters

redis	Pointer to a Redis instance.
channel	Redis PUB/SUB channel on which to notify
data	Data to send.
length	Bytes of data to send, or 0 to determine automatically with strlen().

Returns

X_SUCCESS if the message was successfullt sent. X_NO_INIT if the Redis library was not initialized via initRedis(). X_NO_SERVICE if there was a connection problem. PARSE_ERROR if the Redis response could not be confirmed.

See also

redisxNotify()

redisxPublishAsync()

redisxSubscribe()

References Redis::id, Redis::interactive, redisxCheckValid(), redisxLockConnected(), redisxPublishAsync(), redisxUnlockClient(), X_SUCCESS, and xvprintf.

redisxPublishAsync()

int redisxPublishAsync	(	Redis *	redis,
		const char *	channel,
		const char *	data,
		int	length
	)

Sends a Redis notification asynchronously using the Redis "PUBLISH" command. The caller should have an exclusive lock on the interactive Redis channel before calling this.

Parameters

redis	Pointer to a Redis instance.
channel	Redis PUB/SUB channel on which to notify
data	Message body data.
length	Bytes of message data to send, ot 0 to determine automatically with strlen().

Returns

X_SUCCESS (0) if successful, or else X_NULL if the redis instance is NULL X_NAME_INVALID if the PUB/SUB channel is null or empty or an error code (<0) returned by redisxSendArrayRequestAsync().

See also

redisxPublish()

redisxNotify()

References Redis::interactive, redisxCheckValid(), redisxSendArrayRequestAsync(), redisxSkipReplyAsync(), x_error(), X_NULL, and X_SUCCESS.

redisxRemoveSubscribers()

int redisxRemoveSubscribers	(	Redis *	redis,
		RedisSubscriberCall	f
	)

Removes all instances of a subscribe consumer function from the current list of consumers. This calls only deactivates the specified processing callback function(s), without stopping the delivery of associated messages. To stop Redis sending messages that are no longer being processed, you should also call redisxUnsubscribe() as appropriate.

Parameters

redis	Pointer to a Redis instance.
f	The consumer function to remove from the list of active subscribers.

Returns

The number of instances of f() that have been removed from the list of subscribers.

See also

redisxAddSubscriber()

redisxClearSubscribers()

redisxUnsubscrive()

References x_error(), X_NULL, and xvprintf.

redisxSubscribe()

int redisxSubscribe	(	Redis *	redis,
		const char *	pattern
	)

Subscribe to a specific Redis channel. The call will also start the subscription listener thread to processing incoming subscription messages. Subscribing only enabled the delivery of the messages to this client without any actions on these messages. In order to process the messages for your subscriptons, you will also want to call redisxAddSubscriber() to add your custom processor function(s).

Parameters

redis	Pointer to a Redis instance.
pattern	The Channel pattern to subscribe to, e.g. 'acc1', or 'acc*'...

Returns

X_SUCCESS if successfully subscribed to the Redis distribution channel. X_NO_SERVICE if there is no active connection to the Redis server. X_NULL if the channel argument is NULL

See also

redisxAddSubscriber()

redisxUnsubscribe()

redisxNotify()

redisxPublish()

redisxPublishAsync()

References redisxIsGlobPattern(), redisxLockConnected(), redisxSendRequestAsync(), redisxUnlockClient(), Redis::subscription, x_error(), X_NULL, and X_SUCCESS.

redisxUnsubscribe()

int redisxUnsubscribe	(	Redis *	redis,
		const char *	pattern
	)

Unsubscribe from one or all Redis PUB/SUB channel(s). If there are no active subscriptions when Redis confirms the unsubscrive command, the subscription listener thread will also conclude automatically. Unsubscribing will stop delivery of mesasages for the affected channels but any associated processing callbacks remain registered, until redisxRemovesubscribers() is called to deactive them as appropriate.

Parameters

redis	Pointer to a Redis instance.
pattern	The channel pattern, or NULL to unsubscribe all channels and patterns.

Returns

X_SUCCESS if successfully subscribed to the Redis distribution channel. X_NO_SERVICE if there is no active connection to the Redis server.

See also

redisxSubscribe()

redisxEndSubscribe()

redisxRemoveSubscribers()

References redisxCheckValid(), redisxIsGlobPattern(), redisxLockConnected(), redisxSendRequestAsync(), redisxUnlockClient(), Redis::subscription, and X_SUCCESS.