message PMessage {required int32 id = 1;optional int32 num = 2;optional string str = 3;
}

protoc -I=proto --cpp_out=src proto/message.proto

#include <netinet/in.h>
#include <sys/socket.h>
#include <unistd.h>#include <stdio.h>
#include <string.h>#include <event.h>
#include <event2/listener.h>
#include <event2/bufferevent.h>
#include <event2/thread.h>#include "message.pb.h"using namespace std;void listener_cb(evconnlistener *listener, evutil_socket_t fd,sockaddr *sock, int socklen, void *arg);void socket_read_cb(bufferevent *bev, void *arg);void socket_event_cb(bufferevent *bev, short events, void *arg);int main(int argc, char **argv) {sockaddr_in sin;memset(&sin, 0, sizeof(sockaddr_in));sin.sin_family = AF_INET;sin.sin_port = htons(8899);event_base *base = event_base_new();evconnlistener *listener= evconnlistener_new_bind(base,listener_cb, base,LEV_OPT_REUSEABLE|LEV_OPT_CLOSE_ON_FREE,10, (sockaddr*)&sin, sizeof(sockaddr_in));event_base_dispatch(base);evconnlistener_free(listener);event_base_free(base);}void listener_cb(evconnlistener *listener, evutil_socket_t fd,sockaddr *sock, int socklen, void *arg) {printf("accept a client %d\n", fd);event_base *base = (event_base *)arg;bufferevent *bev = bufferevent_socket_new(base, fd, BEV_OPT_CLOSE_ON_FREE);bufferevent_setcb(bev, socket_read_cb, NULL, socket_event_cb, NULL);bufferevent_enable(bev, EV_READ|EV_PERSIST);}void socket_read_cb(bufferevent *bev, void *arg) {char msg[4096];size_t len = bufferevent_read(bev, msg, sizeof(msg)-1);msg[len] = '\0';PMessage pmsg;pmsg.ParseFromArray((const void*)msg, len);printf("Server read the data:%i, %i, %s\n", pmsg.id(), pmsg.num(), pmsg.str().c_str());pmsg.set_str("I have read your data.");string sendbuf;pmsg.SerializeToString(&sendbuf);bufferevent_write(bev, sendbuf.c_str(), sendbuf.length());}void socket_event_cb(bufferevent *bev, short events, void *arg) {if (events & BEV_EVENT_EOF) {printf("connection close\n");}else if (events & BEV_EVENT_ERROR) {printf("some other error\n");}bufferevent_free(bev);
}

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <errno.h>
#include <unistd.h>#include <stdio.h>
#include <string.h>
#include <stdlib.h>#include <event.h>
#include <event2/bufferevent.h>
#include <event2/buffer.h>
#include <event2/util.h>#include "message.pb.h"using namespace std;void cmd_msg_cb(int fd, short events, void *arg);void server_msg_cb(bufferevent *bev, void *arg);void event_cb(bufferevent *bev, short event, void *arg);static int gid = 1;int main(int argc, char **argv) {if (argc < 3) {printf("please input IP and port\n");return 1;}event_base *base = event_base_new();bufferevent *bev = bufferevent_socket_new(base, -1, BEV_OPT_CLOSE_ON_FREE);event *ev_cmd = event_new(base, STDIN_FILENO,EV_READ|EV_PERSIST,cmd_msg_cb, (void *)bev);event_add(ev_cmd, NULL);sockaddr_in server_addr;memset(&server_addr, 0, sizeof(server_addr));server_addr.sin_family = AF_INET;server_addr.sin_port = htons(atoi(argv[2]));inet_aton(argv[1], &server_addr.sin_addr);bufferevent_socket_connect(bev, (sockaddr*)&server_addr, sizeof(server_addr));bufferevent_setcb(bev, server_msg_cb, NULL, event_cb, (void*)ev_cmd);bufferevent_enable(bev, EV_READ|EV_PERSIST);event_base_dispatch(base);printf("Finish\n");return 0;}void cmd_msg_cb(int fd, short events, void *arg) {char msg[1024];int ret = read(fd, msg, sizeof(msg));if (ret < 0) {perror("read error.\n");exit(1);}// protobuf
        PMessage pmsg;pmsg.set_id(gid++);pmsg.set_num(rand());pmsg.set_str(msg);string sendbuf;pmsg.SerializeToString(&sendbuf);// processing network transferbufferevent *bev = (bufferevent *)arg;bufferevent_write(bev, sendbuf.c_str(), sendbuf.length());
}void server_msg_cb(bufferevent *bev, void *arg) {char msg[1024];size_t len = bufferevent_read(bev, msg, sizeof(msg)-1);msg[len] = '\0';PMessage pmsg;pmsg.ParseFromArray((const void*)msg, len);printf("Recv %d, %d, %s from server.\n", pmsg.id(), pmsg.num(), pmsg.str().c_str());
}void event_cb(bufferevent *bev, short eventid, void *arg) {if (eventid & BEV_EVENT_EOF) {printf("Connection closed.\n");}else if (eventid & BEV_EVENT_ERROR) {printf("Some other error.\n");}else if (eventid & BEV_EVENT_CONNECTED) {printf("Client has successfully connected.\n");return;}bufferevent_free(bev);event *ev = (event *)arg;event_free(ev);
}

CXX=/opt/compiler/gcc-4.8.2/bin/g++INCPATH= \/home/work/.jumbo/include/DEP_LDFLAGS= \-L/home/work/.jumbo/lib/DEP_LDLIBS= \-levent \-lprotobuf \-lpthreadTARGET= lserver lclientall : $(TARGET)lserver : lserver.cc message.pb.cc$(CXX) -o $@ $^ -I$(INCPATH) $(DEP_LDFLAGS) $(DEP_LDLIBS)lclient : lclient.cc message.pb.cc$(CXX) -o $@ $^ -I$(INCPATH) $(DEP_LDFLAGS) $(DEP_LDLIBS).PHONY : all cleanclean :rm -rf $(TARGET)

src]$ ./lserver
accept a client 7
Server read the data:1, 1804289383, aaaaaaaaaaaaaaaaaaaaaaaaaServer read the data:2, 846930886, aaServer read the data:3, 1681692777, bbServer read the data:4, 1714636915, abcdefgServer read the data:5, 1957747793, connection close
accept a client 7
Server read the data:1, 1804289383, 2aaServer read the data:2, 846930886, 2bbServer read the data:3, 1681692777, 111111111111111111111222222222222222222222223333333333333333333333333Server read the data:4, 1714636915, ^C

src]$ ./lclient localhost 8899
Client has successfully connected.
aaaaaaaaaaaaaaaaaaaaaaaaa
Recv 1, 1804289383, I have read your data. from server.
aa
Recv 2, 846930886, I have read your data. from server.
bb
Recv 3, 1681692777, I have read your data. from server.
abcdefg
Recv 4, 1714636915, I have read your data. from server.Recv 5, 1957747793, I have read your data. from server.
^C
[src]$ ./lclient localhost 8899
Client has successfully connected.
2aa
Recv 1, 1804289383, I have read your data. from server.
2bb
Recv 2, 846930886, I have read your data. from server.
111111111111111111111222222222222222222222223333333333333333333333333
Recv 3, 1681692777, I have read your data. from server.Recv 4, 1714636915, I have read your data. from server.
Connection closed.
Finish

[libprotobuf ERROR google/protobuf/wire_format.cc:1053] String field contains invalid UTF-8 data when serializing a protocol buffer. Use the 'bytes' type if you intend to send raw bytes.