Nginx 모듈 개발 및 확장 메커니즘의 기본 구현 원리를 해석합니다.

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

static ngx_int_t ngx_http_example_handler(ngx_http_request_t *r);

static ngx_http_module_t ngx_http_example_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_example_module = {
    NGX_MODULE_V1,
    &ngx_http_example_module_ctx,  /* module context */
    NULL,                          /* 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_command_t ngx_http_example_commands[] = {
    { ngx_string("example"),
      NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_NOARGS,
      ngx_http_example_command,
      NGX_HTTP_LOC_CONF_OFFSET,
      0,
      NULL },
    
    ngx_null_command
};

static ngx_http_module_t ngx_http_example_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_example_module = {
    NGX_MODULE_V1,
    &ngx_http_example_module_ctx,  /* module context */
    ngx_http_example_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_http_example_handler(ngx_http_request_t *r)
{
    ngx_int_t rc;
    ngx_buf_t *b;
    ngx_chain_t out;

    /* 创建一个输出缓冲区 */
    b = ngx_pcalloc(r->pool, sizeof(ngx_buf_t));
    if (b == NULL) {
        return NGX_HTTP_INTERNAL_SERVER_ERROR;
    }
    out.buf = b;
    out.next = NULL;

    /* 设置输出缓冲区的内容 */
    b->pos = (u_char *) "Hello, Nginx!";
    b->last = b->pos + sizeof("Hello, Nginx!") - 1;
    b->memory = 1;
    b->last_buf = 1;

    /* 设置响应头部 */
    r->headers_out.status = NGX_HTTP_OK;
    r->headers_out.content_length_n = sizeof("Hello, Nginx!") - 1;
    rc = ngx_http_send_header(r);

    /* 发送响应内容 */
    if (rc == NGX_ERROR || rc > NGX_OK || r->header_only) {
        return rc;
    }
    return ngx_http_output_filter(r, &out);
}

static ngx_int_t ngx_http_example_init(ngx_conf_t *cf)
{
    /* 获取http模块的ngx_http_core_module上下文 */
    ngx_http_core_main_conf_t *cmcf;
    cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);

    /* 在ngx_http_core_module的处理请求的回调函数数组handlers中加入自定义回调函数 */
    ngx_http_handler_pt *h;
    h = ngx_array_push(&cmcf->phases[NGX_HTTP_CONTENT_PHASE].handlers);
    if (h == NULL) {
        return NGX_ERROR;
    }
    *h = ngx_http_example_handler;

    return NGX_OK;
}

load_module /path/to/module.so;