Detailed Description

Collaboration diagram for C API:

Macros
#define	SMQ_setCtx(o, ctx) SOCKET_constructor(&(o)->sock, ctx)
	Bare metal configuration. More...

#define	SMQ_getMsgSize(o) ((o)->frameLen-15)
	Returns the message size, which is SMQ::frameLen - 15. More...

Functions
void	SMQ_constructor (SMQ o, U8 buf, U16 bufLen)
	Create a SimpleMQ client instance. More...

int	SMQ_init (SMQ o, const char url, U32 *rnd)
	Initiate the SMQ server connection. More...

int	SMQ_connect (SMQ o, const char uid, int uidLen, const char credentials, U8 credLen, const char info, int infoLen)
	Connect/establish a persistent SimpleMQ connection. More...

void	SMQ_disconnect (SMQ *o)
	Gracefully close the connection. More...

void	SMQ_destructor (SMQ *o)
	Terminate a SimpleMQ instance. More...

int	SMQ_create (SMQ o, const char topic)
	Create a topic an fetch the topic ID (tid). More...

int	SMQ_createsub (SMQ o, const char subtopic)
	Create a sub-topic and fetch the subtopic ID. More...

int	SMQ_subscribe (SMQ o, const char topic)
	The response to SMQ_subscribe is asynchronous and returned as status SMQ_SUBACK via SMQ_getMessage. More...

int	SMQ_unsubscribe (SMQ *o, U32 tid)
	Requests the broker to unsubscribe the server from a topic. More...

int	SMQ_publish (SMQ o, const void data, int len, U32 tid, U32 subtid)
	Publish messages to a topic and optionally to a sub-topic. More...

int	SMQ_wrtstr (SMQ o, const char str)
	Publish a message in chunks and request the broker to assemble the message before publishing to the subscriber(s). More...

int	SMQ_write (SMQ o, const void data, int len)
	Publish a message in chunks and request the broker to assemble the message before publishing to the subscriber(s). More...

int	SMQ_pubflush (SMQ *o, U32 tid, U32 subtid)
	Flush the internal buffer and request the broker to assemble all stored fragments as one message. More...

int	SMQ_observe (SMQ *o, U32 tid)
	Request the broker to provide change notification events when the number of subscribers to a specific topic changes. More...

int	SMQ_unobserve (SMQ *o, U32 tid)
	Stop receiving change notifications for a topic ID or ephemeral topic ID. More...

int	SMQ_getMessage (SMQ o, U8 *msg)
	Wait for messages sent from the broker. More...

Macro Definition Documentation

◆ SMQ_getMsgSize

#define SMQ_getMsgSize ( o ) ((o)->frameLen-15)

Returns the message size, which is SMQ::frameLen - 15.

Parameters

o	the SMQ instance.

◆ SMQ_setCtx

#define SMQ_setCtx	(	o,
		ctx
	)	SOCKET_constructor(&(o)->sock, ctx)

Bare metal configuration.

This macro must be called immediately after calling the constructor on bare metal systems.

Parameters

o	the SMQ instance.
ctx	an SeCtx instance.

Function Documentation

◆ SMQ_connect()

int SMQ_connect	(	SMQ *	o,
		const char *	uid,
		int	uidLen,
		const char *	credentials,
		U8	credLen,
		const char *	info,
		int	infoLen
	)

Connect/establish a persistent SimpleMQ connection.

The connection phase is divided into two steps: (1) initiating via SMQ_init and (2) connecting.

Parameters

o	the SMQ instance.
uid	a universally unique client identifier (uid) must be unique across all clients connecting to the same broker instance. The uid is preferably a stringified version of the client's Ethernet MAC address.
uidLen	the uid length.
credentials	provide credentials if required by the broker instance.
credLen	credentials length.
info	a string that provides information to optional server code interacting with the broker. This string is also passed into the optional broker's authentication callback function.
infoLen	length of info.

Returns: 0 on success, error code from TCP/IP stack, SimpleMQ error code, or one of the following error codes from the broker:

0x01 Connection Refused: unacceptable protocol version
0x02 Connection Refused: server unavailable
0x03 Connection Refused: Incorrect credentials
0x04 Connection Refused: Client certificate required
0x05 Connection Refused: Client certificate not accepted
0x06 Connection Refused: Access denied

The broker may optionally send a human readable string in addition to the above broker produced error codes. This string is avaiable via SMQ::buf.

◆ SMQ_constructor()

void SMQ_constructor	(	SMQ *	o,
		U8 *	buf,
		U16	bufLen
	)

Create a SimpleMQ client instance.

Parameters

o	Uninitialized data of size sizeof(SMQ).
buf	is used for internal management and must not be less than 127 bytes and not smaller than the largest control frame. Function SMQ_getMessage will return SMQE_BUF_OVERFLOW if the buffer is not sufficiently large.
bufLen	buffer length.

◆ SMQ_create()

int SMQ_create	(	SMQ *	o,
		const char *	topic
	)

Create a topic an fetch the topic ID (tid).

The SMQ protocol is optimized and does not directly use a string when publishing, but a number. The server randomly a creates 32 bit number and persistently stores the topic name and number.

The response to SMQ_create is asynchronous and returned as status SMQ_CREATEACK via SMQ_getMessage.

Parameters

o	the SMQ instance.
topic	the topic name where you plan on publishing messages.

◆ SMQ_createsub()

int SMQ_createsub	(	SMQ *	o,
		const char *	subtopic
	)

Create a sub-topic and fetch the subtopic ID.

The response to SMQ_subscribe is asynchronous and returned as status SMQ_CREATESUBACK via SMQ_getMessage.

Parameters

o	the SMQ instance.
subtopic	the sub-topic name you want registered.

◆ SMQ_destructor()

void SMQ_destructor ( SMQ * o )

Terminate a SimpleMQ instance.

Parameters

o	the SMQ instance.

◆ SMQ_disconnect()

void SMQ_disconnect ( SMQ * o )

Gracefully close the connection.

You cannot publish any messages after calling this method.

Parameters

o	the SMQ instance.

◆ SMQ_getMessage()

int SMQ_getMessage	(	SMQ *	o,
		U8 **	msg
	)

Wait for messages sent from the broker.

Parameters

o	the SMQ instance.
msg	a pointer to the response data (out param)

Returns

a negative value signals an error code or an asynchronous response code.
zero signals timeout.
a value greater than zero signals the reception of a full message or a message fragment. See receiving large frames for details.

Receiving large frames:
The SimpleMQ protocol is frame based, but the function can return a fragment before the complete SimpleMQ frame is received if the frame sent by the peer is larger than the provided buffer. The frame length is returned in SMQ::frameLen and the data consumed thus far is returned in SMQ::bytesRead. The complete frame is consumed when frameLen == bytesRead.

Note: the default timeout value is set to one minute. You can set the timeout value by setting SharkMQ::timeout to the number of milliseconds you want to wait for incoming messages before the timeout triggers. Note: Setting a long timeout may interfere with the built in PING timer.

Returns

< 0: An error or a control message such as SMQ_SUBACK
>= 0: An SMQ message with this length

◆ SMQ_init()

int SMQ_init	(	SMQ *	o,
		const char *	url,
		U32 *	rnd
	)

Initiate the SMQ server connection.

The connection phase is divided into two steps: (1) initiating and (2) connecting via SMQ_connect.

Parameters

o	the SMQ instance.
url	is a URL that starts with http:// and this URL must be to a server resource that initiates a SimpleMQ connection.
rnd	(out param) a random number created by the server. This number can be used for securing hash based password encryption.

Returns: 0 on success, error code from TCP/IP stack, or SimpleMQ error code. SMQ::buf is set to the IP address of the client as seen by the broker.

◆ SMQ_observe()

int SMQ_observe	(	SMQ *	o,
		U32	tid
	)

Request the broker to provide change notification events when the number of subscribers to a specific topic changes.

Ephemeral topic IDs can also be observed. The number of connected subscribers for an ephemeral ID can only be one, which means the client is connected. Receiving a change notification for an ephemeral ID means the client has disconnected and that you no longer will get any change notifications for the observed topic ID.

Change notification events are received as SMQ_SUBCHANGE via SMQ_getMessage.

Parameters

o	the SMQ instance.
tid	the Topic ID you which to observe.

◆ SMQ_pubflush()

int SMQ_pubflush	(	SMQ *	o,
		U32	tid,
		U32	subtid
	)

Flush the internal buffer and request the broker to assemble all stored fragments as one message.

This message is then published to topic 'tid', and sub-topic 'subtid'.

Parameters

o	the SMQ instance.
tid	the topic ID (created with SMQ_create).
subtid	optional sub-topic ID preferably created with SMQ_createsub.

Example:

SMQ_wrtstr(smq, "Hello");
SMQ_wrtstr(smq, " ");
SMQ_wrtstr(smq, "World");
SMQ_pubflush(smq,tid,subtid);

◆ SMQ_publish()

int SMQ_publish	(	SMQ *	o,
		const void *	data,
		int	len,
		U32	tid,
		U32	subtid
	)

Publish messages to a topic and optionally to a sub-topic.

Topic name must have previosly been been resolved by SMQ_create and sub-topic should preferably have been created by SMQ_createsub.

Parameters

o	the SMQ instance.
data	message payload.
len	payload length.
tid	the topic ID (created with SMQ_create).
subtid	optional sub-topic ID preferably created with SMQ_createsub.

◆ SMQ_subscribe()

int SMQ_subscribe	(	SMQ *	o,
		const char *	topic
	)

The response to SMQ_subscribe is asynchronous and returned as status SMQ_SUBACK via SMQ_getMessage.

Parameters

o	the SMQ instance.
topic	the topic name to subscribe to.

◆ SMQ_unobserve()

int SMQ_unobserve	(	SMQ *	o,
		U32	tid
	)

Stop receiving change notifications for a topic ID or ephemeral topic ID.

Parameters

o	the SMQ instance.
tid	the Topic ID you no longer want to observe.

◆ SMQ_unsubscribe()

int SMQ_unsubscribe	(	SMQ *	o,
		U32	tid
	)

Requests the broker to unsubscribe the server from a topic.

Parameters

o	the SMQ instance.
tid	the topic name's Topic ID.

◆ SMQ_write()

int SMQ_write	(	SMQ *	o,
		const void *	data,
		int	len
	)

Publish a message in chunks and request the broker to assemble the message before publishing to the subscriber(s).

This method uses the internal buffer (SMQ::buf) and sends the message as a chunk when the internal buffer is full, thus sending the message as an incomplete message to the broker. The message is assembled by the broker when you flush the remaining bytes in the buffer by calling SMQ_pubflush.

Parameters

o	the SMQ instance.
data	message payload.
len	payload length.

◆ SMQ_wrtstr()

int SMQ_wrtstr	(	SMQ *	o,
		const char *	str
	)

Publish a message in chunks and request the broker to assemble the message before publishing to the subscriber(s).

This method uses the internal buffer (SMQ::buf) and sends the message as a chunk when the internal buffer is full, thus sending the message as an incomplete message to the broker. The message is assembled by the broker when you flush the remaining bytes in the buffer by calling SMQ_pubflush.

Parameters

o	the SMQ instance.
str	a string.

Detailed Description

Macros

Functions

Macro Definition Documentation

◆ SMQ_getMsgSize

◆ SMQ_setCtx

Function Documentation

◆ SMQ_connect()

◆ SMQ_constructor()

◆ SMQ_create()

◆ SMQ_createsub()

◆ SMQ_destructor()

◆ SMQ_disconnect()

◆ SMQ_getMessage()

◆ SMQ_init()

◆ SMQ_observe()

◆ SMQ_pubflush()

◆ SMQ_publish()

◆ SMQ_subscribe()

◆ SMQ_unobserve()

◆ SMQ_unsubscribe()

◆ SMQ_write()

◆ SMQ_wrtstr()