libuv库TCP echo-server

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：

[cpp] view
plaincopy





/* 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;

}