学习libuv库，写TCP echo-server
大部分代码都来自libuv源码test目录下echo-server.c文件。
我自己添加了一点代码，通过uv_read_start函数更改read_cb函数
使得第奇数次客户端输入一行文字后，服务端原样返回，
偶数次输入一行文字，服务端将输入的一行文字逆序后返回
结果如下：
cheng@debian:~$ telnet 127.0.0.1 7890
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is ‘^]‘.
helo
helo
helo
oleh
00000111111
00000111111
00000111111
11111100000
---------------------------------------------------------总结的分割线---------------------------------------------------------------------------------
通过echo-server这个程序，可以学习怎么利用libuv，像完成原始socket网络编程那样，
创建socket, bind, listen, accept过程。
只是在异步，非阻塞的方式编程时，需要通过事先为某个事件发生时应该调用的回调
在echo-server程序中，通过uv_listen函数注册连接回调函数
uv_read_start注册读函数
uv_write注册写函数
在头文件uv.h看这三个函数的函数原型，可以很清楚的知道每个参数的意义
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修改过的echo-server.c代码：
/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <uv.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#define ASSERT assert
#define TEST_PORT 7890
static void reversed(char *s, int len)
{
char c;
char *end;
end = s + len - 1;
while (*end == ‘\r‘ || *end == ‘\n‘) {
end--;
}
while (end > s) {
c = *end;
*end = *s;
*s = c;
end--;
s++;
}
}
typedef struct {
uv_write_t req;
uv_buf_t buf;
} write_req_t;
#define FATAL(msg) do { fprintf(stderr, "Fatal error in %s on line %d: %s\n", __FILE__, __LINE__, msg); fflush(stderr); abort(); } while (0)
typedef enum {
TCP = 0,
UDP,
PIPE
} stream_type;
static uv_loop_t* loop;
static int server_closed;
static stream_type serverType;
static uv_tcp_t tcpServer;
static uv_udp_t udpServer;
static uv_pipe_t pipeServer;
static uv_handle_t* server;
static void after_write(uv_write_t* req, int status);
static void after_read(uv_stream_t*, ssize_t nread, uv_buf_t buf);
static void on_close(uv_handle_t* peer);
static void on_server_close(uv_handle_t* handle);
static void on_connection(uv_stream_t*, int status);
static uv_buf_t echo_alloc(uv_handle_t* handle, size_t suggested_size);
static void after_read(uv_stream_t* handle, ssize_t nread, uv_buf_t buf);
static void after_read_2(uv_stream_t* handle, ssize_t nread, uv_buf_t buf);
static void after_write(uv_write_t* req, int status) {
write_req_t* wr;
uv_err_t err;
/* Free the read/write buffer and the request */
wr = (write_req_t*) req;
free(wr->buf.base);
free(wr);
if (status == 0)
return;
err = uv_last_error(loop);
fprintf(stderr, "uv_write error: %s\n", uv_strerror(err));
if (err.code == UV_ECANCELED)
return;
ASSERT(err.code == UV_EPIPE);
uv_close((uv_handle_t*)req->handle, on_close);
}
static void after_shutdown(uv_shutdown_t* req, int status) {
uv_close((uv_handle_t*)req->handle, on_close);
free(req);
}
static void after_read(uv_stream_t* handle, ssize_t nread, uv_buf_t buf) {
int i;
write_req_t *wr;
uv_shutdown_t* req;
int r;
if (nread < 0) {
/* Error or EOF */
ASSERT (uv_last_error(loop).code == UV_EOF);
if (buf.base) {
free(buf.base);
}
req = (uv_shutdown_t*) malloc(sizeof *req);
uv_shutdown(req, handle, after_shutdown);
return;
}
if (nread == 0) {
/* Everything OK, but nothing read. */
free(buf.base);
return;
}
/*
* Scan for the letter Q which signals that we should quit the server.
* If we get QS it means close the stream.
*/
if (!server_closed) {
for (i = 0; i < nread; i++) {
if (buf.base[i] == ‘Q‘) {
if (i + 1 < nread && buf.base[i + 1] == ‘S‘) {
free(buf.base);
uv_close((uv_handle_t*)handle, on_close);
return;
} else {
uv_close(server, on_server_close);
server_closed = 1;
}
}
}
}
wr = (write_req_t*) malloc(sizeof *wr);
wr->buf = uv_buf_init(buf.base, nread);
if (uv_write(&wr->req, handle, &wr->buf, 1, after_write)) {
FATAL("uv_write failed");
}
r = uv_read_start(handle, echo_alloc, after_read_2);
ASSERT(r == 0);
}
static void after_read_2(uv_stream_t* handle, ssize_t nread, uv_buf_t buf) {
int i;
write_req_t *wr;
uv_shutdown_t* req;
int r;
if (nread < 0) {
/* Error or EOF */
ASSERT (uv_last_error(loop).code == UV_EOF);
if (buf.base) {
free(buf.base);
}
req = (uv_shutdown_t*) malloc(sizeof *req);
uv_shutdown(req, handle, after_shutdown);
return;
}
if (nread == 0) {
/* Everything OK, but nothing read. */
free(buf.base);
return;
}
/*
* Scan for the letter Q which signals that we should quit the server.
* If we get QS it means close the stream.
*/
if (!server_closed) {
for (i = 0; i < nread; i++) {
if (buf.base[i] == ‘Q‘) {
if (i + 1 < nread && buf.base[i + 1] == ‘S‘) {
free(buf.base);
uv_close((uv_handle_t*)handle, on_close);
return;
} else {
uv_close(server, on_server_close);
server_closed = 1;
}
}
}
}
wr = (write_req_t*) malloc(sizeof *wr);
reversed(buf.base, nread);
wr->buf = uv_buf_init(buf.base, nread);
if (uv_write(&wr->req, handle, &wr->buf, 1, after_write)) {
FATAL("uv_write failed");
}
r = uv_read_start(handle, echo_alloc, after_read);
ASSERT(r == 0);
}
static void on_close(uv_handle_t* peer) {
free(peer);
}
static uv_buf_t echo_alloc(uv_handle_t* handle, size_t suggested_size) {
return uv_buf_init(malloc(suggested_size), suggested_size);
}
static void on_connection(uv_stream_t* server, int status) {
uv_stream_t* stream;
int r;
if (status != 0) {
fprintf(stderr, "Connect error %d\n",
uv_last_error(loop).code);
}
ASSERT(status == 0);
switch (serverType) {
case TCP:
stream = malloc(sizeof(uv_tcp_t));
ASSERT(stream != NULL);
r = uv_tcp_init(loop, (uv_tcp_t*)stream);
ASSERT(r == 0);
break;
case PIPE:
stream = malloc(sizeof(uv_pipe_t));
ASSERT(stream != NULL);
r = uv_pipe_init(loop, (uv_pipe_t*)stream, 0);
ASSERT(r == 0);
break;
default:
ASSERT(0 && "Bad serverType");
abort();
}
/* associate server with stream */
stream->data = server;
r = uv_accept(server, stream);
ASSERT(r == 0);
r = uv_read_start(stream, echo_alloc, after_read);
ASSERT(r == 0);
}
static void on_server_close(uv_handle_t* handle) {
ASSERT(handle == server);
}
static void on_send(uv_udp_send_t* req, int status);
static void on_recv(uv_udp_t* handle,
ssize_t nread,
uv_buf_t buf,
struct sockaddr* addr,
unsigned flags) {
uv_udp_send_t* req;
int r;
ASSERT(nread > 0);
ASSERT(addr->sa_family == AF_INET);
req = malloc(sizeof(*req));
ASSERT(req != NULL);
r = uv_udp_send(req, handle, &buf, 1, *(struct sockaddr_in*)addr, on_send);
ASSERT(r == 0);
}
static void on_send(uv_udp_send_t* req, int status) {
ASSERT(status == 0);
free(req);
}
static int tcp4_echo_start(int port) {
struct sockaddr_in addr = uv_ip4_addr("0.0.0.0", port);
int r;
server = (uv_handle_t*)&tcpServer;
serverType = TCP;
r = uv_tcp_init(loop, &tcpServer);
if (r) {
/* TODO: Error codes */
fprintf(stderr, "Socket creation error\n");
return 1;
}
r = uv_tcp_bind(&tcpServer, addr);
if (r) {
/* TODO: Error codes */
fprintf(stderr, "Bind error\n");
return 1;
}
r = uv_listen((uv_stream_t*)&tcpServer, SOMAXCONN, on_connection);
if (r) {
/* TODO: Error codes */
fprintf(stderr, "Listen error %s\n",
uv_err_name(uv_last_error(loop)));
return 1;
}
return 0;
}
int main()
{
loop = uv_default_loop();
if (tcp4_echo_start(TEST_PORT))
return 1;
uv_run(loop, UV_RUN_DEFAULT);
return 0;
}
基于libuv的TCP echo-server,布布扣,bubuko.com
原文：http://blog.csdn.net/gamesofsailing/article/details/20382175