nginx模块开发入门（一）快速编写一个模块

ginkgodia

2013-09-04

1.首先按照nginx

参考http://running.iteye.com/blog/326873

2.创建新模块目录

#mkdir ngx_module_echo

3.创建编译相关文件(config)

#vim ngx_module_echo/config

其内容为:

ngx_addon_name=ngx_module_echo
HTTP_MODULES="$HTTP_MODULES ngx_module_echo"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_module_echo.c"
CORE_LIBS="$CORE_LIBS "
#CORE_LIBS="$CORE_LIBS -lm"

ngx_addon_name一般设置为模块名称

HTTP_MODULES保持所有的HTTP模块名称，以空格符相连。用法有点类似于linux中得path，先给出之前的$HTTP_MODULES，然后在加上新增的MODULES

NGX_ADDON_SRCS指定新增模块的源代码，注意：如果使用了$ngx_addon_dir，它等价于在configure执行时--add-module=PATH中的PATH参数

4.创建源文件ngx_module_echo.c

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>

static char* ngx_echo_readconf(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static void* ngx_echo_create_loc_conf(ngx_conf_t *cf);
static char* ngx_echo_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child);

typedef struct {
    ngx_str_t ecdata;
    ngx_flag_t           enable;
} ngx_echo_loc_conf_t;

static ngx_command_t  ngx_echo_commands[] = {
    { ngx_string("echo"),
      NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1,
      ngx_echo_readconf,
      NGX_HTTP_LOC_CONF_OFFSET,
      offsetof(ngx_echo_loc_conf_t, ecdata),
      NULL },
      ngx_null_command
};


static ngx_http_module_t  ngx_echo_module_ctx = {
    NULL,                          /* preconfiguration */
    NULL,           /* postconfiguration */

    NULL,                          /* create main configuration */
    NULL,                          /* init main configuration */

    NULL,                          /* create server configuration */
    NULL,                          /* merge server configuration */

    ngx_echo_create_loc_conf,  /* create location configuration */
    ngx_echo_merge_loc_conf /* merge location configuration */
};


ngx_module_t  ngx_module_echo = {
    NGX_MODULE_V1,
    &ngx_echo_module_ctx, /* module context */
    ngx_echo_commands,   /* module directives */
    NGX_HTTP_MODULE,               /* module type */
    NULL,                          /* init master */
    NULL,                          /* init module */
    NULL,                          /* init process */
    NULL,                          /* init thread */
    NULL,                          /* exit thread */
    NULL,                          /* exit process */
    NULL,                          /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_int_t
ngx_echo_handler(ngx_http_request_t *r)
{
    printf("called:ngx_echo_handler\n");
    ngx_int_t     rc;
    ngx_buf_t    *b;
    ngx_chain_t   out;

    ngx_echo_loc_conf_t  *cglcf;
    cglcf = ngx_http_get_module_loc_conf(r, ngx_module_echo);

    if (!(r->method & (NGX_HTTP_GET|NGX_HTTP_HEAD))) {
        return NGX_HTTP_NOT_ALLOWED;
    }
    if (r->headers_in.if_modified_since) {
        return NGX_HTTP_NOT_MODIFIED;
    }

    r->headers_out.content_type.len = sizeof("text/html") - 1;
    r->headers_out.content_type.data = (u_char *) "text/html";



    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = cglcf->ecdata.len;

    if (r->method == NGX_HTTP_HEAD) {
        rc = ngx_http_send_header(r);

        if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
            return rc;
        }
    }

    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
    if (b == NULL) {
        ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "Failed to allocate response buffer.");
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }

    out.buf = b;
    out.next = NULL;


    b->pos = cglcf->ecdata.data;
    b->last = cglcf->ecdata.data+(cglcf->ecdata.len);

    b->memory = 1;
    b->last_buf = 1;
    rc = ngx_http_send_header(r);

    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
        return rc;
    }
    return ngx_http_output_filter(r, &out);
}
static char *
ngx_echo_readconf(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    printf("called:ngx_echo_readconf\n");
    ngx_http_core_loc_conf_t  *clcf;

    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    clcf->handler = ngx_echo_handler;
    ngx_conf_set_str_slot(cf,cmd,conf);
    return NGX_CONF_OK;
}


static void *
ngx_echo_create_loc_conf(ngx_conf_t *cf)
{
    printf("called:ngx_echo_create_loc_conf\n");
    ngx_echo_loc_conf_t  *conf;

    conf = ngx_pcalloc(cf->pool, sizeof(ngx_echo_loc_conf_t));
    if (conf == NULL) {
        return NGX_CONF_ERROR;
    }

    conf->ecdata.len=0;
    conf->ecdata.data=NULL;
    conf->enable = NGX_CONF_UNSET;
    return conf;
}
static char *
ngx_echo_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
{
    printf("called:ngx_echo_merge_loc_conf\n");
    ngx_echo_loc_conf_t *prev = parent;
    ngx_echo_loc_conf_t *conf = child;

    ngx_conf_merge_str_value(conf->ecdata, prev->ecdata, 10);
    ngx_conf_merge_value(conf->enable, prev->enable, 0);
/**
    if(conf->enable)
        ngx_echo_init(conf);
        */
    return NGX_CONF_OK;
    return NGX_CONF_OK;
}

5.编译nginx

./configure --prefix=/usr/local/nginx --with-pcre=/root/pcre-8.33/ --with-http_stub_status_module  --with-http_realip_module  --add-module=/root/ngx_module_echo/ --with-debug
make
make install

6.修改nginx.conf

worker_processes  1;
daemon off;
master_process  off;
error_log  /tmp/error.log debug;
pid /tmp/nginx_demo.pid;
events {
    worker_connections  1024;
}
http {
    include         mime.types;
    sendfile        on;
    keepalive_timeout  65;
    tcp_nodelay        on;
    server {
        listen   8100;
        server_name  localhost;

        access_log  /tmp/access.log;
        error_log  /tmp/error.log debug;

        location /hello {
            echo "Hi,this is a demo module";
        }
    }
}

7.测试

#/usr/local/nginx/sbin/nginx -t
called:ngx_echo_create_loc_conf
called:ngx_echo_create_loc_conf
called:ngx_echo_create_loc_conf
called:ngx_echo_readconf
called:ngx_echo_merge_loc_conf
called:ngx_echo_merge_loc_conf
nginx: the configuration file /usr/local/nginx/conf/nginx.conf syntax is ok
nginx: configuration file /usr/local/nginx/conf/nginx.conf test is successful

8.运行

测试没有问题以后，我们就可以开始运行了