libnsq编译、使用记录

官方介绍libnsq是nsq的c库，尼玛还真是c库，如果用g++编译还真编译不过。这篇文章就是说一下怎么在c++中使用libnsq。

为什么用g++编译不过libnsq呢，因为其头文件中默认全是c函数，没有对c++编译器做处理。

为了保持libnsq的完整性，不对libnsq代码作任何修改。

libnsq默认编译输出libnsq.a，个人不太喜欢使用静态库，所以自行编译为动态库:

gcc -o libnsq.so command.c http.c json.c message.c nsqd_connection.c nsqlookupd.c reader.c -fPIC -shared -lev -levbuffsock -lcurl -ljson-c

随后封装了c调研libnsq，代码如下

brd_nsq_consumer.h

#ifndef __BRD_NSQ_CONSUMER_H__
#define __BRD_NSQ_CONSUMER_H__
#ifdef __cplusplus
extern "C" {
#endif
typedef void (*HANDLER)(const char *msg);
HANDLER callback;

void init_nsq_consumer(const char *topic,const char *channel,const char *nsqlookupdDomain,int nsqlookupdPort,HANDLER handle);

#ifdef __cplusplus
}
#endif
#endif

brd_nsq_consumer.c

#include "brd_nsq_consumer.h"
#include "nsq.h"

void message_handler(struct NSQReader *rdr, struct NSQDConnection *conn, struct NSQMessage *msg, void *ctx);

void init_nsq_consumer(const char *topic,const char *channel,const char *nsqlookupdDomain,int nsqlookupdPort,HANDLER handle)
{
callback = handle;
struct NSQReader *rdr;
struct ev_loop *loop;
void *ctx = NULL; //(void *)(new TestNsqMsgContext());

loop = ev_default_loop(0);
rdr = new_nsq_reader(loop, topic, channel, (void *)ctx,
NULL, NULL, NULL, message_handler);

nsq_reader_connect_to_nsqd(rdr, "127.0.0.1", 4150);
//nsq_reader_add_nsqlookupd_endpoint(rdr, nsqlookupdDomain, 4161);
nsq_run(loop);
}

void message_handler(struct NSQReader *rdr, struct NSQDConnection *conn, struct NSQMessage *msg, void *ctx)
{
if(callback!=NULL)
callback(msg->body);
buffer_reset(conn->command_buf);

nsq_finish(conn->command_buf, msg->id);

buffered_socket_write_buffer(conn->bs, conn->command_buf);

buffer_reset(conn->command_buf);
nsq_ready(conn->command_buf, rdr->max_in_flight);
buffered_socket_write_buffer(conn->bs, conn->command_buf);

free_nsq_message(msg);
}

编译：

gcc -shared -fPIC -o libnsqconsumer.so brd_nsq_consumer.c -lnsq

然后在c++中调用，代码如下:

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include "brd_nsq_consumer.h"

class CMainModule
{
public:
CMainModule();
~CMainModule();
static void handler(const char *msg);
int procMSg(const char *msg);
};

static CMainModule *g_pModule;

int main()
{
CMainModule *pModule = new CMainModule;
g_pModule=pModule;

init_nsq_consumer("test","ch","127.0.0.1",4161,CMainModule::handler);
sleep(1000);
delete pModule;
}

CMainModule::CMainModule(){

}
CMainModule::~CMainModule(){

}
void CMainModule::handler(const char *msg){
g_pModule->procMSg(msg);
}
int CMainModule::procMSg(const char *msg){
printf("====main=========%s
",msg );
return 0;
}

编译:

g++ main.cpp -o a.out -lnsqconsumer -L./