一、MQTT简介
1.1 实现方式
实现MQTT协议需要客户端和服务器端通讯完成，在通讯过程中，MQTT协议中有三种身份：发布者（Publish）、代理（Broker）（服务器）、订阅者（Subscribe）。其中，消息的发布者和订阅者都是客户端，消息代理是服务器，消息发布者可以同时是订阅者。
MQTT传输的消息分为：主题（Topic）和负载（payload）两部分：
Topic，可以理解为消息的类型，订阅者订阅（Subscribe）后，就会收到该主题的消息内容（payload）；
payload，可以理解为消息的内容，是指订阅者具体要使用的内容。
- MQTT服务器的主要工作是数据分发，没有数据保存功能。
- 可以订阅自己发布的主题，服务器就是回发测试。
- MQTT让逻辑变得更清晰，需要什么订阅什么。
- 走标准化流程，解放了私有协议制定、实现、调试、测试一整套复杂的流程。
1.2 Paho MQTT
Eclipse Paho项目是IBM在2011年建立的Eclipse开源项目，该项目包含以C、Java、Python、Javascript等语言编写的可用客户端。
二、移植Paho MQTT
2.1 下载源码
嵌入式C语言客户端开源地址：https://github.com/eclipse/paho.mqtt.embedded-c
下载之后解压，会得到这么一个文件夹：
- MQTTClient： 封装MQTTPacket生成的高级别C++客户端程序。
- MQTTClient-C： 封装MQTTPacket生成的高级别C客户端程序
- samples目录提供FreeRTOS和Linux两个例程，分别支持FreeRTOS和Linux系统。
- src目录提供MQTTClient的代码实现能力，以及用于移植到对应平台的网络驱动。
- MQTTPacket： 提供MQTT数据包的序列化与反序列化，以及部分辅助函数。
2.2 新建BUILD.gn
在鸿蒙系统源码的 third_party 文件夹下创建一个 paho_mqtt 文件夹，然后把解压后的所有文件都拷贝到 paho_mqtt 文件夹下
下一步，我们在 paho_mqtt 文件夹下面新建 BUILD.gn 文件，用来构建编译。
其内容如下：
# Copyright (c) 2020 Huawei Device Co., Ltd.
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import("//build/lite/config/component/lite_component.gni")
import("//build/lite/ndk/ndk.gni")
config("pahomqtt_config") {
include_dirs = [
"MQTTPacket/src",
"MQTTClient-C/src",
"MQTTClient-C/src/liteOS",
"//third_party/iot_link/network/mqtt/mqtt_al",
"//third_party/iot_link/inc",
"//vendor/hisi/hi3861/hi3861/third_party/lwip_sack/include",
"//kernel/liteos_m/components/cmsis/2.0",
]
}
cflags = [ "-Wno-unused-variable" ]
cflags += [ "-Wno-unused-but-set-variable" ]
cflags += [ "-Wno-unused-parameter" ]
cflags += [ "-Wno-sign-compare" ]
cflags += [ "-Wno-unused-function" ]
cflags += [ "-Wno-return-type" ]
pahomqtt_sources = [
"MQTTClient-C/src/liteOS/MQTTLiteOS.c",
"MQTTClient-C/src/MQTTClient.c",
"MQTTPacket/src/MQTTConnectClient.c",
"MQTTPacket/src/MQTTConnectServer.c",
"MQTTPacket/src/MQTTDeserializePublish.c",
"MQTTPacket/src/MQTTFormat.c",
"MQTTPacket/src/MQTTPacket.c",
"MQTTPacket/src/MQTTSerializePublish.c",
"MQTTPacket/src/MQTTSubscribeClient.c",
"MQTTPacket/src/MQTTSubscribeServer.c",
"MQTTPacket/src/MQTTUnsubscribeClient.c",
"MQTTPacket/src/MQTTUnsubscribeServer.c",
"MQTTPacket/samples/transport.c",
]
lite_library("pahomqtt_static") {
target_type = "static_library"
sources = pahomqtt_sources
public_configs = [ ":pahomqtt_config" ]
}
lite_library("pahomqtt_shared") {
target_type = "shared_library"
sources = pahomqtt_sources
public_configs = [ ":pahomqtt_config" ]
}
ndk_lib("pahomqtt_ndk") {
if (board_name != "hi3861v100") {
lib_extension = ".so"
deps = [
":pahomqtt_shared"
]
} else {
deps = [
":pahomqtt_static"
]
}
head_files = [
"//third_party/paho_mqtt"
]
}
2.3 创建LiteOS文件夹
MQTT 已经提供了 Linux 和 Freertos 的移植，这里我们参考，新建文件夹：
third_party\paho_mqtt\MQTTClient-C\src\liteOS 里面存放两个文件：
MQTTLiteOS.c 和 MQTTLiteOS.h
内容如下：
2.3.1 MQTTLiteOS.c
/*******************************************************************************
* Copyright (c) 2014, 2015 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v1.0 which accompany this distribution.
*
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Allan Stockdill-Mander - initial API and implementation and/or initial documentation
* Ian Craggs - convert to FreeRTOS
*******************************************************************************/
#include "MQTTLiteOS.h"
int ThreadStart(Thread* thread, void (*fn)(void*), void* arg)
{
int rc = 0;
thread = thread;
osThreadAttr_t attr;
attr.name = "MQTTTask";
attr.attr_bits = 0U;
attr.cb_mem = NULL;
attr.cb_size = 0U;
attr.stack_mem = NULL;
attr.stack_size = 2048;
attr.priority = osThreadGetPriority(osThreadGetId());
rc = (int)osThreadNew((osThreadFunc_t)fn, arg, &attr);
return rc;
}
void TimerInit(Timer* timer)
{
timer->end_time = (struct timeval){0, 0};
}
char TimerIsExpired(Timer* timer)
{
struct timeval now, res;
gettimeofday(&now, NULL);
timersub(&timer->end_time, &now, &res);
return res.tv_sec < 0 || (res.tv_sec == 0 && res.tv_usec <= 0);
}
void TimerCountdownMS(Timer* timer, unsigned int timeout)
{
struct timeval now;
gettimeofday(&now, NULL);
struct timeval interval = {timeout / 1000, (timeout % 1000) * 1000};
timeradd(&now, &interval, &timer->end_time);
}
void TimerCountdown(Timer* timer, unsigned int timeout)
{
struct timeval now;
gettimeofday(&now, NULL);
struct timeval interval = {timeout, 0};
timeradd(&now, &interval, &timer->end_time);
}
int TimerLeftMS(Timer* timer)
{
struct timeval now, res;
gettimeofday(&now, NULL);
timersub(&timer->end_time, &now, &res);
//printf("left %d ms\n", (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000);
return (res.tv_sec < 0) ? 0 : res.tv_sec * 1000 + res.tv_usec / 1000;
}
void MutexInit(Mutex* mutex)
{
mutex->sem = osSemaphoreNew(1, 1, NULL);
}
int MutexLock(Mutex* mutex)
{
return osSemaphoreAcquire(mutex->sem, LOS_WAIT_FOREVER);
}
int MutexUnlock(Mutex* mutex)
{
return osSemaphoreRelease(mutex->sem);
}
int linux_read(Network* n, unsigned char* buffer, int len, int timeout_ms)
{
struct timeval interval = {timeout_ms / 1000, (timeout_ms % 1000) * 1000};
if (interval.tv_sec < 0 || (interval.tv_sec == 0 && interval.tv_usec <= 0))
{
interval.tv_sec = 0;
interval.tv_usec = 100;
}
setsockopt(n->my_socket, SOL_SOCKET, SO_RCVTIMEO, (char *)&interval, sizeof(struct timeval));
int bytes = 0;
while (bytes < len)
{
int rc = recv(n->my_socket, &buffer[bytes], (size_t)(len - bytes), 0);
if (rc == -1)
{
if (errno != EAGAIN && errno != EWOULDBLOCK)
bytes = -1;
break;
}
else if (rc == 0)
{
bytes = 0;
break;
}
else
bytes += rc;
}
return bytes;
}
int linux_write(Network* n, unsigned char* buffer, int len, int timeout_ms)
{
struct timeval tv;
tv.tv_sec = 0; /* 30 Secs Timeout */
tv.tv_usec = timeout_ms * 1000; // Not init'ing this can cause strange errors
setsockopt(n->my_socket, SOL_SOCKET, SO_SNDTIMEO, (char *)&tv,sizeof(struct timeval));
int rc = send(n->my_socket, buffer, len, 0);
return rc;
}
void NetworkInit(Network* n)
{
n->my_socket = 0;
n->mqttread = linux_read;
n->mqttwrite = linux_write;
}
int NetworkConnect(Network* n, char* addr, int port)
{
int type = SOCK_STREAM;
struct sockaddr_in address;
int rc = -1;
sa_family_t family = AF_INET;
struct addrinfo *result = NULL;
struct addrinfo hints = {0, AF_UNSPEC, SOCK_STREAM, IPPROTO_TCP, 0, NULL, NULL, NULL};
if ((rc = getaddrinfo(addr, NULL, &hints, &result)) == 0)
{
struct addrinfo* res = result;
/* prefer ip4 addresses */
while (res)
{
if (res->ai_family == AF_INET)
{
result = res;
break;
}
res = res->ai_next;
}
if (result->ai_family == AF_INET)
{
address.sin_port = htons(port);
address.sin_family = family = AF_INET;
address.sin_addr = ((struct sockaddr_in*)(result->ai_addr))->sin_addr;
}
else
rc = -1;
freeaddrinfo(result);
}
if (rc == 0)
{
n->my_socket = socket(family, type, 0);
if (n->my_socket != -1)
rc = connect(n->my_socket, (struct sockaddr*)&address, sizeof(address));
else
rc = -1;
}
return rc;
}
void NetworkDisconnect(Network* n)
{
close(n->my_socket);
}
2.3.2 MQTTLiteOS.h
/*******************************************************************************
* Copyright (c) 2014, 2015 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v1.0 which accompany this distribution.
*
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Allan Stockdill-Mander - initial API and implementation and/or initial documentation
*******************************************************************************/
#if !defined(MQTTLiteOS_H)
#define MQTTLiteOS_H
#include
#if !defined(SOCKET_ERROR)
/** error in socket operation */
#define SOCKET_ERROR -1
#endif
#if defined(WIN32)
/* default on Windows is 64 - increase to make Linux and Windows the same */
#define FD_SETSIZE 1024
#include
#include
#define MAXHOSTNAMELEN 256
#define EAGAIN WSAEWOULDBLOCK
#define EINTR WSAEINTR
#define EINVAL WSAEINVAL
#define EINPROGRESS WSAEINPROGRESS
#define EWOULDBLOCK WSAEWOULDBLOCK
#define ENOTCONN WSAENOTCONN
#define ECONNRESET WSAECONNRESET
#define ioctl ioctlsocket
#define socklen_t int
#else
#define INVALID_SOCKET SOCKET_ERROR
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#include
#endif
#if defined(WIN32)
#include
#else
#include
#include
#endif
#include "ohos_init.h"
#include "cmsis_os2.h"
#include "lwip/ip_addr.h"
#include "lwip/netifapi.h"
#include "lwip/sockets.h"
#define MQTT_TASK
typedef struct Thread
{
osThreadId_t task;
} Thread;
int ThreadStart(Thread*, void (*fn)(void*), void* arg);
typedef struct Timer
{
struct timeval end_time;
} Timer;
typedef struct Mutex
{
osSemaphoreId_t sem;
} Mutex;
void MutexInit(Mutex*);
int MutexLock(Mutex*);
int MutexUnlock(Mutex*);
void TimerInit(Timer*);
char TimerIsExpired(Timer*);
void TimerCountdownMS(Timer*, unsigned int);
void TimerCountdown(Timer*, unsigned int);
int TimerLeftMS(Timer*);
typedef struct Network
{
int my_socket;
int (*mqttread) (struct Network*, unsigned char*, int, int);
int (*mqttwrite) (struct Network*, unsigned char*, int, int);
} Network;
int linux_read(Network*, unsigned char*, int, int);
int linux_write(Network*, unsigned char*, int, int);
void NetworkInit(Network*);
int NetworkConnect(Network*, char*, int);
void NetworkDisconnect(Network*);
#endif
2.4 修改MQTTClient.c和MQTTClient.h
打开 third_party\paho_mqtt\MQTTClient-C\src\MQTTClient.c 文件，这个文件也是我们主要移植的文件，我们需要实现 socket 相关的操作，包括发送、接收数据。
2.4.1 MQTTClient.c
/*******************************************************************************
* Copyright (c) 2014, 2017 IBM Corp.
*
* All rights reserved. This prog/*******************************************************************************
* Copyright (c) 2014, 2017 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v1.0 which accompany this distribution.
*
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Allan Stockdill-Mander/Ian Craggs - initial API and implementation and/or initial documentation
* Ian Craggs - fix for #96 - check rem_len in readPacket
* Ian Craggs - add ability to set message handler separately #6
*******************************************************************************/
#include "MQTTClient.h"
#include
#include
static void NewMessageData(MessageData* md, MQTTString* aTopicName, MQTTMessage* aMessage) {
md->topicName = aTopicName;
md->message = aMessage;
}
static int getNextPacketId(MQTTClient *c) {
return c->next_packetid = (c->next_packetid == MAX_PACKET_ID) ? 1 : c->next_packetid + 1;
}
static int sendPacket(MQTTClient* c, int length, Timer* timer)
{
int rc = FAILURE,
sent = 0;
while (sent < length && !TimerIsExpired(timer))
{
rc = c->ipstack->mqttwrite(c->ipstack, &c->buf[sent], length, TimerLeftMS(timer));
if (rc < 0) // there was an error writing the data
break;
sent += rc;
}
if (sent == length)
{
TimerCountdown(&c->last_sent, c->keepAliveInterval); // record the fact that we have successfully sent the packet
rc = SUCCESS;
}
else
rc = FAILURE;
return rc;
}
void MQTTClientInit(MQTTClient* c, Network* network, unsigned int command_timeout_ms,
unsigned char* sendbuf, size_t sendbuf_size, unsigned char* readbuf, size_t readbuf_size)
{
int i;
c->ipstack = network;
for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
c->messageHandlers[i].topicFilter = 0;
c->command_timeout_ms = command_timeout_ms;
c->buf = sendbuf;
c->buf_size = sendbuf_size;
c->readbuf = readbuf;
c->readbuf_size = readbuf_size;
c->isconnected = 0;
c->cleansession = 0;
c->ping_outstanding = 0;
c->defaultMessageHandler = NULL;
c->next_packetid = 1;
TimerInit(&c->last_sent);
TimerInit(&c->last_received);
#if defined(MQTT_TASK)
MutexInit(&c->mutex);
#endif
}
static int decodePacket(MQTTClient* c, int* value, int timeout)
{
unsigned char i;
int multiplier = 1;
int len = 0;
const int MAX_NO_OF_REMAINING_LENGTH_BYTES = 4;
*value = 0;
do
{
int rc = MQTTPACKET_READ_ERROR;
if (++len > MAX_NO_OF_REMAINING_LENGTH_BYTES)
{
rc = MQTTPACKET_READ_ERROR; /* bad data */
goto exit;
}
rc = c->ipstack->mqttread(c->ipstack, &i, 1, timeout);
if (rc != 1)
goto exit;
*value += (i & 127) * multiplier;
multiplier *= 128;
} while ((i & 128) != 0);
exit:
return len;
}
static int readPacket(MQTTClient* c, Timer* timer)
{
MQTTHeader header = {0};
int len = 0;
int rem_len = 0;
/* 1. read the header byte. This has the packet type in it */
int rc = c->ipstack->mqttread(c->ipstack, c->readbuf, 1, TimerLeftMS(timer));
if (rc != 1)
goto exit;
len = 1;
/* 2. read the remaining length. This is variable in itself */
decodePacket(c, &rem_len, TimerLeftMS(timer));
len += MQTTPacket_encode(c->readbuf + 1, rem_len); /* put the original remaining length back into the buffer */
if ((unsigned int)rem_len > (c->readbuf_size - len))
{
rc = BUFFER_OVERFLOW;
goto exit;
}
/* 3. read the rest of the buffer using a callback to supply the rest of the data */
if (rem_len > 0 && (rc = c->ipstack->mqttread(c->ipstack, c->readbuf + len, rem_len, TimerLeftMS(timer)) != rem_len)) {
rc = 0;
goto exit;
}
header.byte = c->readbuf[0];
rc = header.bits.type;
if (c->keepAliveInterval > 0)
TimerCountdown(&c->last_received, c->keepAliveInterval); // record the fact that we have successfully received a packet
exit:
return rc;
}
// assume topic filter and name is in correct format
// # can only be at end
// + and # can only be next to separator
static char isTopicMatched(char* topicFilter, MQTTString* topicName)
{
char* curf = topicFilter;
char* curn = topicName->lenstring.data;
char* curn_end = curn + topicName->lenstring.len;
while (*curf && curn < curn_end)
{
if (*curn == '/' && *curf != '/')
break;
if (*curf != '+' && *curf != '#' && *curf != *curn)
break;
if (*curf == '+')
{ // skip until we meet the next separator, or end of string
char* nextpos = curn + 1;
while (nextpos < curn_end && *nextpos != '/')
nextpos = ++curn + 1;
}
else if (*curf == '#')
curn = curn_end - 1; // skip until end of string
curf++;
curn++;
};
return (curn == curn_end) && (*curf == '\0');
}
int deliverMessage(MQTTClient* c, MQTTString* topicName, MQTTMessage* message)
{
int i;
int rc = FAILURE;
// we have to find the right message handler - indexed by topic
for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
{
if (c->messageHandlers[i].topicFilter != 0 && (MQTTPacket_equals(topicName, (char*)c->messageHandlers[i].topicFilter) ||
isTopicMatched((char*)c->messageHandlers[i].topicFilter, topicName)))
{
if (c->messageHandlers[i].fp != NULL)
{
MessageData md;
NewMessageData(&md, topicName, message);
c->messageHandlers[i].fp(&md);
rc = SUCCESS;
}
}
}
if (rc == FAILURE && c->defaultMessageHandler != NULL)
{
MessageData md;
NewMessageData(&md, topicName, message);
c->defaultMessageHandler(&md);
rc = SUCCESS;
}
return rc;
}
int keepalive(MQTTClient* c)
{
int rc = SUCCESS;
if (c->keepAliveInterval == 0)
goto exit;
// If we are waiting for a ping response, check if it has been too long
if ( c->ping_outstanding == 1 ){
if ( TimerIsExpired(&c->pingresp_timer) ){
rc = FAILURE; /* PINGRESP not received in keepalive interval */
goto exit;
}
}
else{
// If we have not sent or received anything in the timeout period,
// send out a ping request
if ( TimerIsExpired(&c->last_sent) || TimerIsExpired(&c->last_received) )
{
Timer timer;
TimerInit(&timer);
TimerCountdownMS(&timer, 1000);
int len = MQTTSerialize_pingreq(c->buf, c->buf_size);
if (len > 0 && (rc = sendPacket(c, len, &timer)) == SUCCESS){ // send the ping packet
// send the ping packet
// Expect the PINGRESP within 2 seconds of the PINGREQ
// being sent
TimerCountdownMS(&c->pingresp_timer, 2000 );
c->ping_outstanding = 1;
}
}
}
exit:
return rc;
}
void MQTTCleanSession(MQTTClient* c)
{
int i = 0;
for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
c->messageHandlers[i].topicFilter = NULL;
}
void MQTTCloseSession(MQTTClient* c)
{
c->ping_outstanding = 0;
c->isconnected = 0;
if (c->cleansession)
MQTTCleanSession(c);
}
int cycle(MQTTClient* c, Timer* timer)
{
int len = 0,
rc = SUCCESS;
int packet_type = readPacket(c, timer); /* read the socket, see what work is due */
switch (packet_type)
{
default:
/* no more data to read, unrecoverable. Or read packet fails due to unexpected network error */
rc = packet_type;
goto exit;
case 0: /* timed out reading packet */
break;
case CONNACK:
case PUBACK:
case SUBACK:
case UNSUBACK:
break;
case PUBLISH:
{
MQTTString topicName;
MQTTMessage msg;
int intQoS;
msg.payloadlen = 0; /* this is a size_t, but deserialize publish sets this as int */
if (MQTTDeserialize_publish(&msg.dup, &intQoS, &msg.retained, &msg.id, &topicName,
(unsigned char**)&msg.payload, (int*)&msg.payloadlen, c->readbuf, c->readbuf_size) != 1)
goto exit;
msg.qos = (enum QoS)intQoS;
deliverMessage(c, &topicName, &msg);
if (msg.qos != QOS0)
{
if (msg.qos == QOS1)
len = MQTTSerialize_ack(c->buf, c->buf_size, PUBACK, 0, msg.id);
else if (msg.qos == QOS2)
len = MQTTSerialize_ack(c->buf, c->buf_size, PUBREC, 0, msg.id);
if (len <= 0)
rc = FAILURE;
else
rc = sendPacket(c, len, timer);
if (rc == FAILURE)
goto exit; // there was a problem
}
break;
}
case PUBREC:
case PUBREL:
{
unsigned short mypacketid;
unsigned char dup, type;
if (MQTTDeserialize_ack(&type, &dup, &mypacketid, c->readbuf, c->readbuf_size) != 1)
rc = FAILURE;
else if ((len = MQTTSerialize_ack(c->buf, c->buf_size,
(packet_type == PUBREC) ? PUBREL : PUBCOMP, 0, mypacketid)) <= 0)
rc = FAILURE;
else if ((rc = sendPacket(c, len, timer)) != SUCCESS) // send the PUBREL packet
rc = FAILURE; // there was a problem
if (rc == FAILURE)
goto exit; // there was a problem
break;
}
case PUBCOMP:
break;
case PINGRESP:
c->ping_outstanding = 0;
break;
}
if (keepalive(c) != SUCCESS) {
//check only keepalive FAILURE status so that previous FAILURE status can be considered as FAULT
rc = FAILURE;
}
exit:
if (rc == SUCCESS)
rc = packet_type;
else if (c->isconnected)
MQTTCloseSession(c);
return rc;
}
int MQTTYield(MQTTClient* c, int timeout_ms)
{
int rc = SUCCESS;
Timer timer;
TimerInit(&timer);
TimerCountdownMS(&timer, timeout_ms);
do
{
if (cycle(c, &timer) < 0)
{
rc = FAILURE;
break;
}
} while (!TimerIsExpired(&timer));
return rc;
}
int MQTTIsConnected(MQTTClient* client)
{
return client->isconnected;
}
void MQTTRun(void* parm)
{
Timer timer;
MQTTClient* c = (MQTTClient*)parm;
TimerInit(&timer);
while (1)
{
#if defined(MQTT_TASK)
MutexLock(&c->mutex);
#endif
TimerCountdownMS(&timer, 500); /* Don't wait too long if no traffic is incoming */
cycle(c, &timer);
#if defined(MQTT_TASK)
MutexUnlock(&c->mutex);
#endif
}
}
#if defined(MQTT_TASK)
int MQTTStartTask(MQTTClient* client)
{
return ThreadStart(&client->thread, &MQTTRun, client);
}
#endif
int waitfor(MQTTClient* c, int packet_type, Timer* timer)
{
int rc = FAILURE;
do
{
if (TimerIsExpired(timer))
break; // we timed out
rc = cycle(c, timer);
}
while (rc != packet_type && rc >= 0);
return rc;
}
int MQTTConnectWithResults(MQTTClient* c, MQTTPacket_connectData* options, MQTTConnackData* data)
{
Timer connect_timer;
int rc = FAILURE;
MQTTPacket_connectData default_options = MQTTPacket_connectData_initializer;
int len = 0;
#if defined(MQTT_TASK)
MutexLock(&c->mutex);
#endif
if (c->isconnected) /* don't send connect packet again if we are already connected */
goto exit;
TimerInit(&connect_timer);
TimerCountdownMS(&connect_timer, c->command_timeout_ms);
if (options == 0)
options = &default_options; /* set default options if none were supplied */
c->keepAliveInterval = options->keepAliveInterval;
c->cleansession = options->cleansession;
TimerCountdown(&c->last_received, c->keepAliveInterval);
if ((len = MQTTSerialize_connect(c->buf, c->buf_size, options)) <= 0)
goto exit;
if ((rc = sendPacket(c, len, &connect_timer)) != SUCCESS) // send the connect packet
goto exit; // there was a problem
// this will be a blocking call, wait for the connack
if (waitfor(c, CONNACK, &connect_timer) == CONNACK)
{
data->rc = 0;
data->sessionPresent = 0;
if (MQTTDeserialize_connack(&data->sessionPresent, &data->rc, c->readbuf, c->readbuf_size) == 1)
rc = data->rc;
else
rc = FAILURE;
}
else
rc = FAILURE;
exit:
if (rc == SUCCESS)
{
c->isconnected = 1;
c->ping_outstanding = 0;
}
#if defined(MQTT_TASK)
MutexUnlock(&c->mutex);
#endif
return rc;
}
int MQTTConnect(MQTTClient* c, MQTTPacket_connectData* options)
{
MQTTConnackData data;
return MQTTConnectWithResults(c, options, &data);
}
int MQTTSetMessageHandler(MQTTClient* c, const char* topicFilter, messageHandler messageHandler)
{
int rc = FAILURE;
int i = -1;
/* first check for an existing matching slot */
for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
{
if (c->messageHandlers[i].topicFilter != NULL && strcmp(c->messageHandlers[i].topicFilter, topicFilter) == 0)
{
if (messageHandler == NULL) /* remove existing */
{
c->messageHandlers[i].topicFilter = NULL;
c->messageHandlers[i].fp = NULL;
}
rc = SUCCESS; /* return i when adding new subscription */
break;
}
}
/* if no existing, look for empty slot (unless we are removing) */
if (messageHandler != NULL) {
if (rc == FAILURE)
{
for (i = 0; i < MAX_MESSAGE_HANDLERS; ++i)
{
if (c->messageHandlers[i].topicFilter == NULL)
{
rc = SUCCESS;
break;
}
}
}
if (i < MAX_MESSAGE_HANDLERS)
{
c->messageHandlers[i].topicFilter = topicFilter;
c->messageHandlers[i].fp = messageHandler;
}
}
return rc;
}
int MQTTSubscribeWithResults(MQTTClient* c, const char* topicFilter, enum QoS qos,
messageHandler messageHandler, MQTTSubackData* data)
{
int rc = FAILURE;
Timer timer;
int len = 0;
MQTTString topic = MQTTString_initializer;
topic.cstring = (char *)topicFilter;
#if defined(MQTT_TASK)
MutexLock(&c->mutex);
#endif
if (!c->isconnected)
goto exit;
TimerInit(&timer);
TimerCountdownMS(&timer, c->command_timeout_ms);
len = MQTTSerialize_subscribe(c->buf, c->buf_size, 0, getNextPacketId(c), 1, &topic, (int*)&qos);
if (len <= 0)
goto exit;
if ((rc = sendPacket(c, len, &timer)) != SUCCESS) // send the subscribe packet
goto exit; // there was a problem
if (waitfor(c, SUBACK, &timer) == SUBACK) // wait for suback
{
int count = 0;
unsigned short mypacketid;
data->grantedQoS = QOS0;
if (MQTTDeserialize_suback(&mypacketid, 1, &count, (int*)&data->grantedQoS, c->readbuf, c->readbuf_size) == 1)
{
if (data->grantedQoS != 0x80)
rc = MQTTSetMessageHandler(c, topicFilter, messageHandler);
}
}
else
rc = FAILURE;
exit:
if (rc == FAILURE)
MQTTCloseSession(c);
#if defined(MQTT_TASK)
MutexUnlock(&c->mutex);
#endif
return rc;
}
int MQTTSubscribe(MQTTClient* c, const char* topicFilter, enum QoS qos,
messageHandler messageHandler)
{
MQTTSubackData data;
return MQTTSubscribeWithResults(c, topicFilter, qos, messageHandler, &data);
}
int MQTTUnsubscribe(MQTTClient* c, const char* topicFilter)
{
int rc = FAILURE;
Timer timer;
MQTTString topic = MQTTString_initializer;
topic.cstring = (char *)topicFilter;
int len = 0;
#if defined(MQTT_TASK)
MutexLock(&c->mutex);
#endif
if (!c->isconnected)
goto exit;
TimerInit(&timer);
TimerCountdownMS(&timer, c->command_timeout_ms);
if ((len = MQTTSerialize_unsubscribe(c->buf, c->buf_size, 0, getNextPacketId(c), 1, &topic)) <= 0)
goto exit;
if ((rc = sendPacket(c, len, &timer)) != SUCCESS) // send the subscribe packet
goto exit; // there was a problem
if (waitfor(c, UNSUBACK, &timer) == UNSUBACK)
{
unsigned short mypacketid; // should be the same as the packetid above
if (MQTTDeserialize_unsuback(&mypacketid, c->readbuf, c->readbuf_size) == 1)
{
/* remove the subscription message handler associated with this topic, if there is one */
MQTTSetMessageHandler(c, topicFilter, NULL);
}
}
else
rc = FAILURE;
exit:
if (rc == FAILURE)
MQTTCloseSession(c);
#if defined(MQTT_TASK)
MutexUnlock(&c->mutex);
#endif
return rc;
}
int MQTTPublish(MQTTClient* c, const char* topicName, MQTTMessage* message)
{
int rc = FAILURE;
Timer timer;
MQTTString topic = MQTTString_initializer;
topic.cstring = (char *)topicName;
int len = 0;
#if defined(MQTT_TASK)
MutexLock(&c->mutex);
#endif
if (!c->isconnected)
goto exit;
TimerInit(&timer);
TimerCountdownMS(&timer, c->command_timeout_ms);
if (message->qos == QOS1 || message->qos == QOS2)
message->id = getNextPacketId(c);
len = MQTTSerialize_publish(c->buf, c->buf_size, 0, message->qos, message->retained, message->id,
topic, (unsigned char*)message->payload, message->payloadlen);
if (len <= 0)
goto exit;
if ((rc = sendPacket(c, len, &timer)) != SUCCESS) // send the subscribe packet
goto exit; // there was a problem
if (message->qos == QOS1)
{
if (waitfor(c, PUBACK, &timer) == PUBACK)
{
unsigned short mypacketid;
unsigned char dup, type;
if (MQTTDeserialize_ack(&type, &dup, &mypacketid, c->readbuf, c->readbuf_size) != 1)
rc = FAILURE;
}
else
rc = FAILURE;
}
else if (message->qos == QOS2)
{
if (waitfor(c, PUBCOMP, &timer) == PUBCOMP)
{
unsigned short mypacketid;
unsigned char dup, type;
if (MQTTDeserialize_ack(&type, &dup, &mypacketid, c->readbuf, c->readbuf_size) != 1)
rc = FAILURE;
}
else
rc = FAILURE;
}
exit:
if (rc == FAILURE)
MQTTCloseSession(c);
#if defined(MQTT_TASK)
MutexUnlock(&c->mutex);
#endif
return rc;
}
int MQTTDisconnect(MQTTClient* c)
{
int rc = FAILURE;
Timer timer; // we might wait for incomplete incoming publishes to complete
int len = 0;
#if defined(MQTT_TASK)
MutexLock(&c->mutex);
#endif
TimerInit(&timer);
TimerCountdownMS(&timer, c->command_timeout_ms);
len = MQTTSerialize_disconnect(c->buf, c->buf_size);
if (len > 0)
rc = sendPacket(c, len, &timer); // send the disconnect packet
MQTTCloseSession(c);
#if defined(MQTT_TASK)
MutexUnlock(&c->mutex);
#endif
return rc;
}
2.4.2 MQTTClient.h
/*******************************************************************************
* Copyright (c) 2014, 2017 IBM Corp.
*
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* and Eclipse Distribution License v1.0 which accompany this distribution.
*
* The Eclipse Public License is available at
* http://www.eclipse.org/legal/epl-v10.html
* and the Eclipse Distribution License is available at
* http://www.eclipse.org/org/documents/edl-v10.php.
*
* Contributors:
* Allan Stockdill-Mander/Ian Craggs - initial API and implementation and/or initial documentation
* Ian Craggs - documentation and platform specific header
* Ian Craggs - add setMessageHandler function
*******************************************************************************/
#if !defined(MQTT_CLIENT_H)
#define MQTT_CLIENT_H
#if defined(__cplusplus)
extern "C" {
#endif
#if defined(WIN32_DLL) || defined(WIN64_DLL)
#define DLLImport __declspec(dllimport)
#define DLLExport __declspec(dllexport)
#elif defined(LINUX_SO)
#define DLLImport extern
#define DLLExport __attribute__ ((visibility ("default")))
#else
#define DLLImport
#define DLLExport
#endif
#include "liteOS/MQTTLiteOS.h"
#include "MQTTPacket.h"
#if defined(MQTTCLIENT_PLATFORM_HEADER)
/* The following sequence of macros converts the MQTTCLIENT_PLATFORM_HEADER value
* into a string constant suitable for use with include.
*/
#define xstr(s) str(s)
#define str(s) #s
#include xstr(MQTTCLIENT_PLATFORM_HEADER)
#endif
#define MAX_PACKET_ID 65535 /* according to the MQTT specification - do not change! */
#if !defined(MAX_MESSAGE_HANDLERS)
#define MAX_MESSAGE_HANDLERS 5 /* redefinable - how many subscriptions do you want? */
#endif
enum QoS { QOS0, QOS1, QOS2, SUBFAIL=0x80 };
/* all failure return codes must be negative */
enum returnCode { BUFFER_OVERFLOW = -2, FAILURE = -1, SUCCESS = 0 };
/* The Platform specific header must define the Network and Timer structures and functions
* which operate on them.
*
typedef struct Network
{
int (*mqttread)(Network*, unsigned char* read_buffer, int, int);
int (*mqttwrite)(Network*, unsigned char* send_buffer, int, int);
} Network;*/
/* The Timer structure must be defined in the platform specific header,
* and have the following functions to operate on it. */
extern void TimerInit(Timer*);
extern char TimerIsExpired(Timer*);
extern void TimerCountdownMS(Timer*, unsigned int);
extern void TimerCountdown(Timer*, unsigned int);
extern int TimerLeftMS(Timer*);
typedef struct MQTTMessage
{
enum QoS qos;
unsigned char retained;
unsigned char dup;
unsigned short id;
void *payload;
size_t payloadlen;
} MQTTMessage;
typedef struct MessageData
{
MQTTMessage* message;
MQTTString* topicName;
} MessageData;
typedef struct MQTTConnackData
{
unsigned char rc;
unsigned char sessionPresent;
} MQTTConnackData;
typedef struct MQTTSubackData
{
enum QoS grantedQoS;
} MQTTSubackData;
typedef void (*messageHandler)(MessageData*);
typedef struct MQTTClient
{
unsigned int next_packetid,
command_timeout_ms;
size_t buf_size,
readbuf_size;
unsigned char *buf,
*readbuf;
unsigned int keepAliveInterval;
char ping_outstanding;
int isconnected;
int cleansession;
struct MessageHandlers
{
const char* topicFilter;
void (*fp) (MessageData*);
} messageHandlers[MAX_MESSAGE_HANDLERS]; /* Message handlers are indexed by subscription topic */
void (*defaultMessageHandler) (MessageData*);
Network* ipstack;
Timer last_sent, last_received, pingresp_timer;
#if defined(MQTT_TASK)
Mutex mutex;
Thread thread;
#endif
} MQTTClient;
#define DefaultClient {0, 0, 0, 0, NULL, NULL, 0, 0, 0}
/**
* Create an MQTT client object
* @param client
* @param network
* @param command_timeout_ms
* @param
*/
DLLExport void MQTTClientInit(MQTTClient* client, Network* network, unsigned int command_timeout_ms,
unsigned char* sendbuf, size_t sendbuf_size, unsigned char* readbuf, size_t readbuf_size);
/** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack
* The nework object must be connected to the network endpoint before calling this
* @param options - connect options
* @return success code
*/
DLLExport int MQTTConnectWithResults(MQTTClient* client, MQTTPacket_connectData* options,
MQTTConnackData* data);
/** MQTT Connect - send an MQTT connect packet down the network and wait for a Connack
* The nework object must be connected to the network endpoint before calling this
* @param options - connect options
* @return success code
*/
DLLExport int MQTTConnect(MQTTClient* client, MQTTPacket_connectData* options);
/** MQTT Publish - send an MQTT publish packet and wait for all acks to complete for all QoSs
* @param client - the client object to use
* @param topic - the topic to publish to
* @param message - the message to send
* @return success code
*/
DLLExport int MQTTPublish(MQTTClient* client, const char*, MQTTMessage*);
/** MQTT SetMessageHandler - set or remove a per topic message handler
* @param client - the client object to use
* @param topicFilter - the topic filter set the message handler for
* @param messageHandler - pointer to the message handler function or NULL to remove
* @return success code
*/
DLLExport int MQTTSetMessageHandler(MQTTClient* c, const char* topicFilter, messageHandler messageHandler);
/** MQTT Subscribe - send an MQTT subscribe packet and wait for suback before returning.
* @param client - the client object to use
* @param topicFilter - the topic filter to subscribe to
* @param message - the message to send
* @return success code
*/
DLLExport int MQTTSubscribe(MQTTClient* client, const char* topicFilter, enum QoS, messageHandler);
/** MQTT Subscribe - send an MQTT subscribe packet and wait for suback before returning.
* @param client - the client object to use
* @param topicFilter - the topic filter to subscribe to
* @param message - the message to send
* @param data - suback granted QoS returned
* @return success code
*/
DLLExport int MQTTSubscribeWithResults(MQTTClient* client, const char* topicFilter, enum QoS, messageHandler, MQTTSubackData* data);
/** MQTT Subscribe - send an MQTT unsubscribe packet and wait for unsuback before returning.
* @param client - the client object to use
* @param topicFilter - the topic filter to unsubscribe from
* @return success code
*/
DLLExport int MQTTUnsubscribe(MQTTClient* client, const char* topicFilter);
/** MQTT Disconnect - send an MQTT disconnect packet and close the connection
* @param client - the client object to use
* @return success code
*/
DLLExport int MQTTDisconnect(MQTTClient* client);
/** MQTT Yield - MQTT background
* @param client - the client object to use
* @param time - the time, in milliseconds, to yield for
* @return success code
*/
DLLExport int MQTTYield(MQTTClient* client, int time);
/** MQTT isConnected
* @param client - the client object to use
* @return truth value indicating whether the client is connected to the server
*/
DLLExport int MQTTIsConnected(MQTTClient* client);
#if defined(MQTT_TASK)
/** MQTT start background thread for a client. After this, MQTTYield should not be called.
* @param client - the client object to use
* @return success code
*/
DLLExport int MQTTStartTask(MQTTClient* client);
#endif
#if defined(__cplusplus)
}
#endif
#endif
三、API说明
业务BUILD.gn中包含路径
include_dirs = [
"//utils/native/lite/include",
"//kernel/liteos_m/components/cmsis/2.0",
"//base/iot_hardware/interfaces/kits/wifiiot_lite",
"//foundation/communication/interfaces/kits/wifi_lite/wifiservice",
"//vendor/hisi/hi3861/hi3861/third_party/lwip_sack/include/",
"//third_party/paho_mqtt/MQTTPacket/src",
"//third_party/paho_mqtt/MQTTClient-C/src",
]
以下网络接口位于 third_party\paho_mqtt\MQTTClient-C\src\liteOS\MQTTLiteOS.h。
3.1 NetworkInit
| 功能 | 初始化网络结构体，socket描述符、socket发送和接收函数 |
|---|---|
| 函数定义 | void NetworkInit(Network* n) |
| 参数 | n：网络结构体 |
| 返回 | 无 |
3.2 NetworkConnect
| 功能 | 连接到指定的MQTT服务器IP、端口号 |
|---|---|
| 函数定义 | int NetworkConnect(Network* n, char* addr, int port) |
| 参数 | n：网络结构体 addr：IP地址 port：端口 |
| 返回 | 0 - 成功，-1 - 失败 |
3.3 NetworkDisconnect
| 功能 | 关闭网络连接 |
|---|---|
| 函数定义 | void NetworkDisconnect(Network* n) |
| 参数 | n：网络结构体 |
| 返回 | 无 |
以下 MQTT 接口位于 third_party\paho_mqtt\MQTTClient-C\src\liteOS\MQTTLiteOS.h。
3.4 MQTTClientInit
| 功能 | 创建一个MQTT客户端对象 |
|---|---|
| 函数定义 | void MQTTClientInit(MQTTClient* c, Network* network, unsigned int command_timeout_ms, unsigned char* sendbuf, size_t sendbuf_size, unsigned char* readbuf, size_t readbuf_size) |
| 参数 | c：MQTT客户端 network：网络结构体 command_timeout_ms：超时时间 sendbuf：发送缓冲区 sendbuf_size：发送缓冲区大小 readbuf：接收缓冲区 readbuf_size：接收缓冲区大小 |
| 返回 | 无 |
3.5 MQTTConnect
| 功能 | 发送MQTT连接数据包 |
|---|---|
| 函数定义 | int MQTTConnect(MQTTClient* c, MQTTPacket_connectData* options) |
| 参数 | c：MQTT客户端 options：连接参数 |
| 返回 | 错误码 |
3.6 MQTTPublish
| 功能 | 发送MQTT发布数据包 |
|---|---|
| 函数定义 | int MQTTPublish(MQTTClient* c, const char* topicName, MQTTMessage* message) |
| 参数 | c：MQTT客户端 topicName：主题 message：消息 |
| 返回 | 错误码 |
3.7 MQTTSubscribe
| 功能 | 发送MQTT订阅数据包 |
|---|---|
| 函数定义 | int MQTTSubscribe(MQTTClient* c, const char* topicFilter, enum QoS qos, messageHandler messageHandler) |
| 参数 | c：MQTT客户端 topicFilter：主题 qos：服务质量 messageHandler：消息处理函数 |
| 返回 | 错误码 |
3.8 MQTTDisconnect
| 功能 | 发送MQTT断开连接数据包并关闭连接 |
|---|---|
| 函数定义 | int MQTTDisconnect(MQTTClient* c) |
| 参数 | c：MQTT客户端 |
| 返回 | 错误码 |
四、MQTT客户端
4.1 配置SSID和密码连接WIFI
wifi_connect.c
#include
#include
#include
#include "lwip/netif.h"
#include "lwip/netifapi.h"
#include "lwip/ip4_addr.h"
#include "lwip/api_shell.h"
#include "cmsis_os2.h"
#include "hos_types.h"
#include "wifi_device.h"
#include "wifiiot_errno.h"
#include "ohos_init.h"
#define DEF_TIMEOUT 15
#define ONE_SECOND 1
#define SELECT_WIFI_SECURITYTYPE WIFI_SEC_TYPE_PSK
static void WiFiInit(void);
static void WaitSacnResult(void);
static int WaitConnectResult(void);
static void OnWifiScanStateChangedHandler(int state, int size);
static void OnWifiConnectionChangedHandler(int state, WifiLinkedInfo *info);
static void OnHotspotStaJoinHandler(StationInfo *info);
static void OnHotspotStateChangedHandler(int state);
static void OnHotspotStaLeaveHandler(StationInfo *info);
static int g_staScanSuccess = 0;
static int g_ConnectSuccess = 0;
static int ssid_count = 0;
WifiEvent g_wifiEventHandler = {0};
WifiErrorCode error;
#define SELECT_WLAN_PORT "wlan0"
int WifiConnect(const char *ssid, const char *psk)
{
WifiScanInfo *info = NULL;
unsigned int size = WIFI_SCAN_HOTSPOT_LIMIT;
static struct netif *g_lwip_netif = NULL;
osDelay(200);
printf("<--System Init-->\r\n");
//初始化WIFI
WiFiInit();
//使能WIFI
if (EnableWifi() != WIFI_SUCCESS)
{
printf("EnableWifi failed, error = %d\r\n", error);
return -1;
}
//判断WIFI是否激活
if (IsWifiActive() == 0)
{
printf("Wifi station is not actived.\r\n");
return -1;
}
//分配空间，保存WiFi信息
info = malloc(sizeof(WifiScanInfo) * WIFI_SCAN_HOTSPOT_LIMIT);
if (info == NULL)
{
return -1;
}
//轮询查找WiFi列表
do{
//重置标志位
ssid_count = 0;
g_staScanSuccess = 0;
//开始扫描
Scan();
//等待扫描结果
WaitSacnResult();
//获取扫描列表
error = GetScanInfoList(info, &size);
}while(g_staScanSuccess != 1);
//打印WiFi列表
printf("********************\r\n");
for(uint8_t i = 0; i < ssid_count; i++)
{
printf("no:%03d, ssid:%-30s, rssi:%5d\r\n", i+1, info[i].ssid, info[i].rssi/100);
}
printf("********************\r\n");
//连接指定的WiFi热点
for(uint8_t i = 0; i < ssid_count; i++)
{
if (strcmp(ssid, info[i].ssid) == 0)
{
int result;
printf("Select:%3d wireless, Waiting...\r\n", i+1);
//拷贝要连接的热点信息
WifiDeviceConfig select_ap_config = {0};
strcpy(select_ap_config.ssid, info[i].ssid);
strcpy(select_ap_config.preSharedKey, psk);
select_ap_config.securityType = SELECT_WIFI_SECURITYTYPE;
if (AddDeviceConfig(&select_ap_config, &result) == WIFI_SUCCESS)
{
if (ConnectTo(result) == WIFI_SUCCESS && WaitConnectResult() == 1)
{
printf("WiFi connect succeed!\r\n");
g_lwip_netif = netifapi_netif_find(SELECT_WLAN_PORT);
break;
}
}
}
if(i == ssid_count-1)
{
printf("ERROR: No wifi as expected\r\n");
while(1) osDelay(100);
}
}
//启动DHCP
if (g_lwip_netif)
{
dhcp_start(g_lwip_netif);
printf("begain to dhcp\r\n");
}
//等待DHCP
for(;;)
{
if(dhcp_is_bound(g_lwip_netif) == ERR_OK)
{
printf("<-- DHCP state:OK -->\r\n");
//打印获取到的IP信息
netifapi_netif_common(g_lwip_netif, dhcp_clients_info_show, NULL);
break;
}
printf("<-- DHCP state:Inprogress -->\r\n");
osDelay(100);
}
osDelay(100);
return 0;
}
static void WiFiInit(void)
{
printf("<--Wifi Init-->\r\n");
g_wifiEventHandler.OnWifiScanStateChanged = OnWifiScanStateChangedHandler;
g_wifiEventHandler.OnWifiConnectionChanged = OnWifiConnectionChangedHandler;
g_wifiEventHandler.OnHotspotStaJoin = OnHotspotStaJoinHandler;
g_wifiEventHandler.OnHotspotStaLeave = OnHotspotStaLeaveHandler;
g_wifiEventHandler.OnHotspotStateChanged = OnHotspotStateChangedHandler;
error = RegisterWifiEvent(&g_wifiEventHandler);
if (error != WIFI_SUCCESS)
{
printf("register wifi event fail!\r\n");
}
else
{
printf("register wifi event succeed!\r\n");
}
}
static void OnWifiScanStateChangedHandler(int state, int size)
{
if (size > 0)
{
ssid_count = size;
g_staScanSuccess = 1;
}
printf("callback function for wifi scan:%d, %d\r\n", state, size);
return;
}
static void OnWifiConnectionChangedHandler(int state, WifiLinkedInfo *info)
{
if (info == NULL)
{
printf("WifiConnectionChanged:info is null, stat is %d.\n", state);
}
else
{
if (state == WIFI_STATE_AVALIABLE)
{
g_ConnectSuccess = 1;
}
else
{
g_ConnectSuccess = 0;
}
}
}
static void OnHotspotStaJoinHandler(StationInfo *info)
{
(void)info;
printf("STA join AP\n");
return;
}
static void OnHotspotStaLeaveHandler(StationInfo *info)
{
(void)info;
printf("HotspotStaLeave:info is null.\n");
return;
}
static void OnHotspotStateChangedHandler(int state)
{
printf("HotspotStateChanged:state is %d.\n", state);
return;
}
static void WaitSacnResult(void)
{
int scanTimeout = DEF_TIMEOUT;
while (scanTimeout > 0)
{
sleep(ONE_SECOND);
scanTimeout--;
if (g_staScanSuccess == 1)
{
printf("WaitSacnResult:wait success[%d]s\n", (DEF_TIMEOUT - scanTimeout));
break;
}
}
if (scanTimeout <= 0)
{
printf("WaitSacnResult:timeout!\n");
}
}
static int WaitConnectResult(void)
{
int ConnectTimeout = DEF_TIMEOUT;
while (ConnectTimeout > 0)
{
sleep(ONE_SECOND);
ConnectTimeout--;
if (g_ConnectSuccess == 1)
{
printf("WaitConnectResult:wait success[%d]s\n", (DEF_TIMEOUT - ConnectTimeout));
break;
}
}
if (ConnectTimeout <= 0)
{
printf("WaitConnectResult:timeout!\n");
return 0;
}
return 1;
}
wifi_connect.h
#ifndef __WIFI_CONNECT_H__
#define __WIFI_CONNECT_H__
int WifiConnect(const char *ssid,const char *psk);
#endif /* __WIFI_CONNECT_H__ */
4.2 网络初始化
Network network;
//初始化结构体
NetworkInit(&network);
//连接到指定的MQTT服务器IP、端口号
NetworkConnect(&network, "192.168.31.225", 1883); // 修改为要连接的电脑IP
4.3 设置MQTT缓存
static unsigned char sendBuf[1000];
static unsigned char readBuf[1000];
MQTTClient client;
MQTTClientInit(&client, &network, 2000, sendBuf, sizeof(sendBuf), readBuf, sizeof(readBuf));
4.4 设置MQTT相关参数并连接MQTT服务器
MQTTString clientId = MQTTString_initializer;
clientId.cstring = "bearpi";
MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
data.clientID = clientId;
data.willFlag = 0;
data.MQTTVersion = 3;
data.keepAliveInterval = 0;
data.cleansession = 1;
printf("MQTTConnect ...\n");
rc = MQTTConnect(&client, &data);
4.5 订阅主题和接收消息
void messageArrived(MessageData* data)
{
printf("Message arrived on topic %.*s: %.*s\n", data->topicName->lenstring.len, data->topicName->lenstring.data,
data->message->payloadlen, data->message->payload);
}
printf("MQTTSubscribe ...\n");
rc = MQTTSubscribe(&client, "substopic", 2, messageArrived);
4.6 发送消息
MQTTMessage message;
char payload[30];
message.qos = 2;
message.retained = 0;
message.payload = payload;
sprintf(payload, "message number %d", count);
message.payloadlen = strlen(payload);
rc = MQTTPublish(&client, "pubtopic", &message);
4.7 完整代码
#include
#include
#include
#include "ohos_init.h"
#include "cmsis_os2.h"
#include "wifi_connect.h"
#include "MQTTClient.h"
static unsigned char sendBuf[1000];
static unsigned char readBuf[1000];
Network network;
void messageArrived(MessageData* data)
{
printf("Message arrived on topic %.*s: %.*s\n", data->topicName->lenstring.len, data->topicName->lenstring.data,
data->message->payloadlen, data->message->payload);
}
/* */
static void MQTT_DemoTask(void)
{
WifiConnect("test","12345678"); // 修改为要连接的WIFI
printf("Starting ...\n");
int rc, count = 0;
MQTTClient client;
NetworkInit(&network);
printf("NetworkConnect ...\n");
begin:
NetworkConnect(&network, "192.168.31.225", 1883);// 修改为要连接的电脑IP
printf("MQTTClientInit ...\n");
MQTTClientInit(&client, &network, 2000, sendBuf, sizeof(sendBuf), readBuf, sizeof(readBuf));
MQTTString clientId = MQTTString_initializer;
clientId.cstring = "bearpi";
MQTTPacket_connectData data = MQTTPacket_connectData_initializer;
data.clientID = clientId;
data.willFlag = 0;
data.MQTTVersion = 3;
data.keepAliveInterval = 0;
data.cleansession = 1;
printf("MQTTConnect ...\n");
rc = MQTTConnect(&client, &data);
if (rc != 0) {
printf("MQTTConnect: %d\n", rc);
NetworkDisconnect(&network);
MQTTDisconnect(&client);
osDelay(200);
goto begin;
}
printf("MQTTSubscribe ...\n");
rc = MQTTSubscribe(&client, "substopic", 2, messageArrived);
if (rc != 0) {
printf("MQTTSubscribe: %d\n", rc);
osDelay(200);
goto begin;
}
while (++count)
{
MQTTMessage message;
char payload[30];
message.qos = 2;
message.retained = 0;
message.payload = payload;
sprintf(payload, "message number %d", count);
message.payloadlen = strlen(payload);
if ((rc = MQTTPublish(&client, "pubtopic", &message)) != 0){
printf("Return code from MQTT publish is %d\n", rc);
NetworkDisconnect(&network);
MQTTDisconnect(&client);
goto begin;
}
osDelay(50);
}
}
static void MQTT_Demo(void)
{
osThreadAttr_t attr;
attr.name = "MQTT_DemoTask";
attr.attr_bits = 0U;
attr.cb_mem = NULL;
attr.cb_size = 0U;
attr.stack_mem = NULL;
attr.stack_size = 10240;
attr.priority = osPriorityNormal;
if (osThreadNew((osThreadFunc_t)MQTT_DemoTask, NULL, &attr) == NULL) {
printf("[MQTT_Demo] Falied to create MQTT_DemoTask!\n");
}
}
APP_FEATURE_INIT(MQTT_Demo);
五、搭建本地MQTT服务器
EMQ官网下载：https://www.emqx.com/zh/downloads?product=broker
-
下载EMQ X开源版
- 解压后进入
emqx-windows-4.3.8\emqx\bin目录（路径不要带有空格或中文）
- Shift+右键在此处打开 Powershell 窗口，输入命令
emqx start
- 打开浏览器，输入
http://127.0.0.1:18083/，账号admin，密码public，进入管理界面
-
工具 - Websocket，选择连接
-
订阅主题和发布消息
六、运行测试
调试打印：
服务器查看：
• 由 Leung 写于 2021 年 4 月 4 日
• 参考：【鸿蒙2.0设备开发教程】小熊派HarmonyOS 鸿蒙·季 开发教程
OpenHarmony轻量系统开发【11】移植MQTT
在鸿蒙系统上使用MQTT编程