nginx模块开发(一)

决定重新整理nginx模块开发
helloworld

config

ngx_addon_name=ngx_http_mytest_module
HTTP_MODULES="$HTTP_MODULES ngx_http_mytest_module"
NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_mytest_module.c"

ngx_http_mytest_module.c

#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_http.h>
#define HELLO 42
static char * ngx_http_mytest(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);
static ngx_int_t ngx_http_mytest_handler(ngx_http_request_t *r);
static ngx_command_t  ngx_http_mytest_commands[] =
{
    {
        ngx_string("mytest"),
        NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_HTTP_LMT_CONF | NGX_CONF_NOARGS,
        ngx_http_mytest,
        NGX_HTTP_LOC_CONF_OFFSET,
        0,
        NULL
    },
    ngx_null_command
};
static ngx_http_module_t  ngx_http_mytest_module_ctx =
{
    NULL,/* preconfiguration */
    NULL,/* postconfiguration */

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

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

    NULL,/* create location configuration */
    NULL /* merge location configuration */
};
ngx_module_t  ngx_http_mytest_module =
{
    NGX_MODULE_V1,
    &ngx_http_mytest_module_ctx,/* module context */
    ngx_http_mytest_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 char * ngx_http_mytest(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
{
    ngx_http_core_loc_conf_t  *clcf;
    //首先找到mytest配置项所属的配置块，clcf貌似是location块内的数据
    //结构，其实不然，它可以是main、srv或者loc级别配置项，也就是说在每个
    //http{}和server{}内也都有一个ngx_http_core_loc_conf_t结构体
    clcf = ngx_http_conf_get_module_loc_conf(cf, ngx_http_core_module);
    //http框架在处理用户请求进行到NGX_HTTP_CONTENT_PHASE阶段时，如果
    //请求的主机域名、URI与mytest配置项所在的配置块相匹配，就将调用我们
    //实现的ngx_http_mytest_handler方法处理这个请求
    clcf->handler = ngx_http_mytest_handler;
    return NGX_CONF_OK;
}
static ngx_int_t ngx_http_mytest_handler(ngx_http_request_t *r)
{
    int watchpoint = 12;
    printf("this is ngx_hello %d \n",HELLO);
    ngx_log_error(NGX_LOG_ERR, r->connection->log, 0," haoning error \n");
    //必须是GET或者HEAD方法，否则返回405 Not Allowed
    if (!(r->method & (NGX_HTTP_GET | NGX_HTTP_HEAD)))
    {
        return NGX_HTTP_NOT_ALLOWED;
    }
    //丢弃请求中的包体
    ngx_int_t rc = ngx_http_discard_request_body(r);
    if (rc != NGX_OK)
    {
        return rc;
    }
    //设置返回的Content-Type。注意，ngx_str_t有一个很方便的初始化宏
    //ngx_string，它可以把ngx_str_t的data和len成员都设置好
    ngx_str_t type = ngx_string("text/plain");
    //返回的包体内容
    ngx_str_t response = ngx_string("Hello World!");
    //设置返回状态码
    r->headers_out.status = NGX_HTTP_OK;
    //响应包是有包体内容的，所以需要设置Content-Length长度
    r->headers_out.content_length_n = response.len;
    //设置Content-Type
    r->headers_out.content_type = type;
    //发送http头部
    rc = ngx_http_send_header(r);
    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only)
    {
        return rc;
    }
    //构造ngx_buf_t结构准备发送包体
    ngx_buf_t                 *b;
    b = ngx_create_temp_buf(r->pool, response.len);
    watchpoint = 42;
    if (b == NULL)
    {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    //将Hello World拷贝到ngx_buf_t指向的内存中
    ngx_memcpy(b->pos, response.data, response.len);
    //注意，一定要设置好last指针
    b->last = b->pos + response.len;
    //声明这是最后一块缓冲区
    b->last_buf = 1;
    //构造发送时的ngx_chain_t结构体
    ngx_chain_t     out;
    //赋值ngx_buf_t
    out.buf = b;
    //设置next为NULL
    out.next = NULL;
    //最后一步发送包体，http框架会调用ngx_http_finalize_request方法
    //结束请求
    return ngx_http_output_filter(r, &out);
}

./configure --prefix=/usr/local/nginx --add-module=/opt/chapter3/helloworld
make
./configure --prefix=/usr/local/nginx --add-module=/opt/chapter3/helloworld
#./configure --with-debug --prefix=/usr/local/nginx --add-module=/opt/chapter3/helloworld
#CFLAGS="-g3 -O0" ./configure --prefix=/usr/local/nginx --with-debug --add-module=/opt/chapter3/helloworld
#./configure --with-cc-opt='-ggdb3 -O0' --prefix=/usr/local/nginx --with-debug
make
#make CFLAGS="-ggdb3 -O0"
grep -nR hello *


/opt/nginx-1.13.3/objs/addon/helloworld

vim /usr/local/nginx/conf/nginx.conf
location /hello {
mytest;
}
###########
curl localhost/hello


如果带-ggdb3 或-g3
info macro
如果没有需要l一下

gdb /usr/local/nginx/sbin/nginx
或gdb -p `nginx的worker进程`

set args -c /usr/local/nginx/conf/nginx.conf
b ngx_cycle.c:1264
b ngx_http_mytest_module.c:63
set follow-fork-mode child

切换到子进程

r

info macro


找nginx的worker进程
gdb -q -p `pidof nginx`