Simple Message Queue (SMQ) More...
Modules | |
Error codes returned by function SMQ_getMessage | |
Response codes returned by function SMQ_getMessage | |
Data Structures | |
struct | SMQ |
SimpleMQ structure. More... | |
Macros | |
#define | INFINITE_TMO (~((U32)0)) |
Infinite wait time option for socket read functions. | |
#define | SOCKET int |
The SOCKET object/handle is an 'int' when using a BSD compatible TCP/IP stack. More... | |
#define | SMQ_setCtx(o, ctx) SOCKET_constructor(&(o)->sock, ctx) |
Bare metal configuration. More... | |
#define | SMQ_getMsgSize(o) |
Returns the message size, which is SMQ::frameLen - 15. More... | |
Functions | |
int | se_connect (int *sock, const char *address, U16 port) |
Initializes a SOCKET object connected to a remote host/address at a given port. More... | |
int | se_bind (int *sock, U16 port) |
Initializes a SOCKET object bound to a local port, ready to accept client connections. More... | |
int | se_accept (int **listenSock, U32 timeout, int **outSock) |
Waits for remote connections on the server SOCKET object 'listenSock', initialized by function se_bind, and initializes socket object 'outSock' to represent the new connection. More... | |
void | se_close (int *sock) |
Close a connected socket connection. | |
int | se_sockValid (int *sock) |
Returns TRUE if socket is valid (connected). | |
S32 | se_send (int *sock, const void *buf, U32 len) |
Sends data to the connected peer. | |
S32 | se_recv (int *sock, void *buf, U32 len, U32 timeout) |
Waits for data sent by peer. More... | |
void | mainTask (void *ctx) |
Main entry for all example programs. | |
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... | |
Detailed Description
Simple Message Queue (SMQ)
SMQ is an easy to use IoT (M2M) publish subscribe protocol designed and optimized for embedded systems providing instantaneous Edge Node connectivity. The solution allows resource contrained real-time control, analysis, and updates.
See SMQ Website for more information.
Macro Definition Documentation
#define SMQ_getMsgSize | ( | o | ) |
Returns the message size, which is SMQ::frameLen - 15.
- Parameters
-
o
the SMQ instance.
#define SMQ_setCtx | ( | o, |
|
ctx |
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) | 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.
#define SOCKET int |
The SOCKET object/handle is an 'int' when using a BSD compatible TCP/IP stack.
Non BSD compatible TCP IP stacks must set the macro NO_BSD_SOCK and define the SOCKET object. See the header file selib.h for details.
Function Documentation
int se_accept | ( | int ** | listenSock, |
U32 | timeout, |
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int ** | outSock |
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) |
Waits for remote connections on the server SOCKET object 'listenSock', initialized by function se_bind, and initializes socket object 'outSock' to represent the new connection.
- Returns
1
Success0
timeout-1
error
int se_bind | ( | int * | sock, |
U16 | port |
||
) |
Initializes a SOCKET object bound to a local port, ready to accept client connections.
- Returns
- Zero on success. Error codes returned:
-1
Cannot create socket: Fatal-2
Cannot listen: Fatal-3
Cannot bind: socket in use
int se_connect | ( | int * | sock, |
const char * | address, |
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U16 | port |
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) |
Initializes a SOCKET object connected to a remote host/address at a given port.
- Returns
- Zero on success. Error codes returned:
-1
Cannot create socket: Fatal-2
Cannot resolve 'address'-3
Cannot connect
S32 se_recv | ( | int * | sock, |
void * | buf, |
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U32 | len, |
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U32 | timeout |
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) |
Waits for data sent by peer.
- Parameters
-
sock
the SOCKET object. buf
is the data to send. len
is the 'buf' length. timeout
in milliseconds. The timeout can be set to INFINITE_TMO.
- Returns
- the length of the data read, zero on timeout, or a negative value on error.
int SMQ_connect | ( | SMQ * | o, |
const char * | uid, |
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int | uidLen, |
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const char * | credentials, |
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U8 | credLen, |
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const char * | info, |
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int | infoLen |
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) |
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.
void SMQ_constructor | ( | SMQ * | o, |
U8 * | buf, |
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U16 | bufLen |
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) |
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.
int SMQ_create | ( | SMQ * | o, |
const char * | topic |
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) |
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.
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.
void SMQ_disconnect | ( | SMQ * | o | ) |
Gracefully close the connection.
You cannot publish any messages after calling this method.
- Parameters
-
o
the SMQ instance.
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.
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.
int SMQ_init | ( | SMQ * | o, |
const char * | url, |
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U32 * | rnd |
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) |
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.
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.
int SMQ_pubflush | ( | SMQ * | o, |
U32 | tid, |
||
U32 | subtid |
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) |
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:
int SMQ_publish | ( | SMQ * | o, |
const void * | data, |
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int | len, |
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U32 | tid, |
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U32 | subtid |
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) |
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.
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.
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.
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.
int SMQ_write | ( | SMQ * | o, |
const void * | data, |
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int | len |
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) |
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.
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.