手把手教你开发Nginx模块

手把手教你开发Nginx模块前面的哪些话关于Nginx模块开发的博客资料，网上很多，很多。

但是，每篇博客都只提要点，无法"step by step"照着做，对于初次接触Nginx开发的同学，只能像只盲目的蚂蚁瞎燥急！该篇文章没有太多技术深度，只是一步一步说明白Nginx模块的开发过程。

开发环境搭建工欲善其事，必先利其器。

个人推荐Eclipse CDT 作为IDE，原因很简单，代码提示与补全功能很全，完胜Codeblock这类...相信与否，试过就知道。

在ubuntu下搭建开发环境：安装GCC编译器apt-get install build-essential安装pcre/openssl/zlib开发库apt-get install libpcre3-devapt-get install libssl-devapt-get install libzip-dev必需安装nginx核心模块依赖的pcre,openssl,zilib开发库安装JRE/Eclipse CDTapt-get install openjdk-8-jrewget http://ftp.yz.yamagata-u.ac.jp/pub/eclipse//technology/epp/downloads/release/neon/R/eclipse-cpp-neon-R-linux-gtk-x86_64.tar.gz && tzr -xzvf eclipse-cpp-neon-R-linux-gtk-x86_64.tar.gz下载nginx源码wget /download/nginx-1.10.1.tar.gz && tar -xzvf nginx-1.10.1.tar.gz配置CDT Build Environment添加变量，值Nginx src下各模块路径，用冒号分隔，例如：/root/Workspace/nginx-1.10.1/src/core:/root/Workspace/nginx-1.10.1/src/event:/root/Workspace/nginx-1.10.1/src/http:/root/Workspace/nginx-1.10.1/src/mail:/root/Workspace/n ginx-1.10.1/src/stream:/root/Workspace/nginx-1.10.1/src/os/unix添加环境变量，创建C项目时自动作为-I选项imageimageNginx模块编译流程Nginx使用configure脚本分析环境，自动生成objs结果。

哪么configure如何编译第三方模块？答案是--add-module指定第三方模块目录，并将目录存为$ngx_addon_dir环境变量。

执行$ngx_addon_dir/config脚本，读取模块配置。

在config中的环境变量分为2种：小写的本地环境变量，大写的全局环境变量。

例如：ngx_addon_name=ngx_http_mytest_moduleHTTP_MODULES="$HTTP_MODULES ngx_http_mytest_module"NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_mytest_moudle.c"CORE_LIBS="$CORE_LIBS -lpcre"HTTP_MODULES中的ngx_http_mytest_module就是NGX_ADDON_SRCS中源码(如果有多个，都要写上)ngx_http_mytest_module.c中定义的ngx_module_t类型的全局变量。

可见，第三方模块的入口点就是ngx_module_t类型全局变量，该变量又关联ngx_http_module_t类型static变量，与ngx_command_t类型static数组。

在ngx_http_module_t中定义上下文配置nginx.conf解析的回调方法。

在ngx_command_t中定义配置项处理的set回调方法。

Nginx的全部操作都是异步的。

在上述的方法中根据需要又会使用其他handler方法。

以上可以看成Nginx第三方模块的起式。

Upstream例子源码configngx_addon_name=ngx_http_mytest_moduleHTTP_MODULES="$HTTP_MODULES ngx_http_mytest_module"NGX_ADDON_SRCS="$NGX_ADDON_SRCS $ngx_addon_dir/ngx_http_mytest_module.c"源代码#include <ngx_config.h>#include <ngx_core.h>#include <ngx_http.h>#include <ngx_stream.h>typedef struct {ngx_http_upstream_conf_t upstream;} mytest_conf_t;typedef struct {ngx_http_status_t status;ngx_str_t backendServer;} mytest_ctx_t;static void *mytest_create_loc_conf(ngx_conf_t *cf);static char *mytest_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child);static ngx_int_t mytest_upstream_create_request(ngx_http_request_t *r);static ngx_int_t mytest_upstream_process_status_line(ngx_http_request_t *r);static ngx_int_t mytest_upstream_process_header(ngx_http_request_t *r);static void mytest_upstream_finalize_request(ngx_http_request_t *r,ngx_int_t rc);static ngx_int_t mytest_handler(ngx_http_request_t *r);static char *mytest(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);static ngx_http_module_t mytest_ctx = {NULL,NULL,NULL,NULL,NULL,NULL,mytest_create_loc_conf,mytest_merge_loc_conf};static ngx_command_t mytest_commands[] = {{ngx_string("mytest"),NGX_HTTP_MAIN_CONF | NGX_HTTP_SRV_CONF | NGX_HTTP_LOC_CONF | NGX_HTTP_LMT_CONF | NGX_CONF_NOARGS, mytest,NGX_HTTP_LOC_CONF_OFFSET,0,NULL},ngx_null_command};ngx_module_t ngx_http_mytest_module = {NGX_MODULE_V1,&mytest_ctx,mytest_commands,NGX_HTTP_MODULE,NULL,NULL,NULL,NULL,NULL,NULL,NULL,NGX_MODULE_V1_PADDING};static ngx_str_t mytest_upstream_hide_headers[] ={ngx_string("Date"),ngx_string("Server"),ngx_string("X-Pad"),ngx_string("X-Accel-Expires"),ngx_string("X-Accel-Redirect"),ngx_string("X-Accel-Limit-Rate"),ngx_string("X-Accel-Buffering"),ngx_string("X-Accel-Charset"),ngx_null_string};static void *mytest_create_loc_conf(ngx_conf_t *cf){mytest_conf_t *mycf;mycf = (mytest_conf_t *)ngx_pcalloc(cf->pool, sizeof(mytest_conf_t));if(mycf == NULL){return NULL;}mycf->upstream.connect_timeout = 60000;mycf->upstream.send_timeout = 60000;mycf->upstream.read_timeout = 60000;mycf->upstream.store_access = 0600;mycf->upstream.buffering = 0;mycf->upstream.bufs.num = 8;mycf->upstream.bufs.size = ngx_pagesize;mycf->upstream.buffer_size = ngx_pagesize;mycf->upstream.busy_buffers_size = 2 * ngx_pagesize;mycf->upstream.temp_file_write_size = 2 * ngx_pagesize;mycf->upstream.max_temp_file_size = 1024 * 1024 *1024;mycf->upstream.hide_headers = NGX_CONF_UNSET_PTR;mycf->upstream.pass_headers = NGX_CONF_UNSET_PTR;return mycf;}static char *mytest_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child){mytest_conf_t *prev = (mytest_conf_t *)parent;mytest_conf_t *conf = (mytest_conf_t *)child;ngx_hash_init_t hash;hash.max_size = 100;hash.bucket_size = 1024; = "proxy_headers_hash";if(ngx_http_upstream_hide_headers_hash(cf,&conf->upstream, &prev->upstream,mytest_upstream_hide_headers,&hash)!=NGX_OK){ return NGX_CONF_ERROR;}return NGX_CONF_OK;}static ngx_int_t mytest_upstream_create_request(ngx_http_request_t *r){static ngx_str_t backendQueryLine = ngx_string("GET /search?q=%V HTTP/1.1\r\nHost: \r\nConnection: close\r\n\r\n");ngx_int_t queryLineLen = backendQueryLine.len + r->args.len - 2;ngx_buf_t *b = ngx_create_temp_buf(r->pool, queryLineLen);if(b == NULL) return NGX_ERROR;b->last = b->pos + queryLineLen;ngx_snprintf(b->pos, queryLineLen, (char *)backendQueryLine.data, &r->args);r->upstream->request_bufs = ngx_alloc_chain_link(r->pool);if(r->upstream->request_bufs == NULL) return NGX_ERROR;r->upstream->request_bufs->buf = b;r->upstream->request_bufs->next = NULL;r->upstream->request_sent = 0;r->upstream->header_sent = 0;r->header_hash = 1;return NGX_OK;}static ngx_int_t mytest_upstream_process_status_line(ngx_http_request_t *r){size_t len;ngx_int_t rc;ngx_http_upstream_t *u;mytest_ctx_t *ctx = ngx_http_get_module_ctx(r, ngx_http_mytest_module);if(ctx == NULL) return NGX_ERROR;u = r->upstream;rc = ngx_http_parse_status_line(r, &u->buffer, &ctx->status);if(rc == NGX_AGAIN) return rc;if(rc == NGX_ERROR){ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "upstream sent to valid HTTP/1.0 header");r->http_version = NGX_HTTP_VERSION_9;u->state->status = NGX_HTTP_OK;return NGX_OK;}if(u->state){u->state->status = ctx->status.code;}u->headers_in.status_n = ctx->status.code;len = ctx->status.end - ctx->status.start;u->headers_in.status_line.len = len;u->headers_in.status_line.data = ngx_pcalloc(r->pool, len);if(u->headers_in.status_line.data == NULL) return NGX_ERROR;ngx_memcpy(u->headers_in.status_line.data, ctx->status.start, len);u->process_header = mytest_upstream_process_header;return mytest_upstream_process_header(r);}static ngx_int_t mytest_upstream_process_header(ngx_http_request_t *r){ngx_int_t rc;ngx_table_elt_t *h;ngx_http_upstream_header_t *hh;ngx_http_upstream_main_conf_t *umcf;umcf = ngx_http_get_module_main_conf(r, ngx_http_upstream_module);for(;;){rc = ngx_http_parse_header_line(r, &r->upstream->buffer, 1);if(rc == NGX_OK){h = ngx_list_push(&r->upstream->headers_in.headers);if(h == NULL) return NGX_ERROR;h->hash = r->header_hash;h->key.len = r->header_name_end - r->header_name_start;h->value.len = r->header_end - r->header_start;h->key.data = ngx_pcalloc(r->pool, h->key.len + 1 + h->value.len + 1 + h->key.len);if(h->key.data == NULL) return NGX_ERROR;h->value.data = h->key.data + h->key.len + 1;h->lowcase_key = h->key.data + h->key.len + 1 + h->value.len + 1;ngx_memcpy(h->key.data, r->header_name_start, h->key.len);h->key.data[h->key.len]='\0';ngx_memcpy(h->value.data, r->header_start, h->value.len);h->value.data[h->value.len] = '\0';if(h->key.len == r->lowcase_index){ngx_memcpy(h->lowcase_key, r->lowcase_header, h->key.len);}else{ngx_strlow(h->lowcase_key, h->key.data, h->key.len);}hh = ngx_hash_find(&umcf->headers_in_hash, h->hash, h->lowcase_key, h->key.len);if(hh && hh->handler(r, h, hh->offset)!=NGX_OK) return NGX_ERROR;continue;}if(rc == NGX_HTTP_PARSE_HEADER_DONE){if(r->upstream->headers_in.server == NULL){h = ngx_list_push(&r->upstream->headers_in.headers);if(h == NULL) return NGX_ERROR;h->hash = ngx_hash(ngx_hash(ngx_hash(ngx_hash(ngx_hash('s', 'e'), 'r'), 'v'), 'e'), 'r');ngx_str_set(&h->key, "Server");ngx_str_null(&h->value);h->lowcase_key = (u_char *)"server";}if(r->upstream->headers_in.date == NULL){h = ngx_list_push(&r->upstream->headers_in.headers);if(h == NULL) return NGX_ERROR;h->hash = ngx_hash(ngx_hash(ngx_hash('d', 'a'), 't'), 'e');ngx_str_set(&h->key, "Date");ngx_str_null(&h->value);h->lowcase_key = (u_char *)"date";}return NGX_OK;}if(rc == NGX_AGAIN) return NGX_AGAIN;ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "upstream sent invalid header");return NGX_HTTP_UPSTREAM_FT_INVALID_HEADER;}}static void mytest_upstream_finalize_request(ngx_http_request_t *r, ngx_int_t rc){ngx_log_error(NGX_LOG_DEBUG, r->connection->log, 0, "mytest_upstream_finalize_request");}static char *mytest(ngx_conf_t *cf, ngx_command_t *cmd, void *conf){ngx_http_core_loc_conf_t *clcf;clcf = ngx_http_conf_get_module_loc_conf(cf,ngx_http_core_module);clcf->handler = mytest_handler;return NGX_CONF_OK;}static ngx_int_t mytest_handler(ngx_http_request_t *r){mytest_ctx_t *myctx = ngx_http_get_module_ctx(r, ngx_http_mytest_module);if(myctx == NULL){myctx = ngx_pcalloc(r->pool, sizeof(mytest_ctx_t));if(myctx == NULL) return NGX_ERROR;ngx_http_set_ctx(r, myctx, ngx_http_mytest_module);}if(ngx_http_upstream_create(r)!=NGX_OK){ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "ngx_http_upstream_create() failed");return NGX_ERROR;}mytest_conf_t *mycf = (mytest_conf_t *)ngx_http_get_module_loc_conf(r, ngx_http_mytest_module);ngx_http_upstream_t *u = r->upstream;u->conf = &mycf->upstream;u->buffering = mycf->upstream.buffering;u->resolved = (ngx_http_upstream_resolved_t *) ngx_pcalloc(r->pool, sizeof(ngx_http_upstream_resolved_t));if(u->resolved == NULL){ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "ngx_pcalloc resolved error. %s", strerror(errno));return NGX_ERROR;}static struct sockaddr_in backendSockAddr;struct hostent *pHost = gethostbyname((char *)"");if(pHost == NULL){ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "gethostbyname fail. %s", strerror(errno));return NGX_ERROR;}backendSockAddr.sin_family = AF_INET;backendSockAddr.sin_port = htons((in_port_t)80);char *pDmsIP = inet_ntoa(*(struct in_addr *)(pHost->h_addr_list[0]));backendSockAddr.sin_addr.s_addr = inet_addr(pDmsIP);myctx->backendServer.data = (u_char *)pDmsIP;myctx->backendServer.len = strlen(pDmsIP);u->resolved->sockaddr = (struct sockaddr *)&backendSockAddr;u->resolved->port = htons((in_port_t)80);u->resolved->socklen = sizeof(struct sockaddr_in);u->resolved->naddrs = 1;u->create_request = mytest_upstream_create_request;u->process_header = mytest_upstream_process_status_line;u->finalize_request = mytest_upstream_finalize_request;r->main->count++;ngx_http_upstream_init(r);return NGX_DONE;}注意：《Nginx深入解析》的demo少了这句：“u->resolved->port = htons((in_port_t)80);”，否则报错“2016/09/09 11:24:18 [error] 28352#0: *1 no port in upstream "", client: 127.0.0.1, server: localhost, request: "GET /mytest?q=test HTTP/1.1", host: "localhost"”编译脚本./configure --prefix=/usr/local/nginx --add-module=/root/Workspace/nginx-modules/ngx_http_mytest_module --with-debugsudo makesudo make install安装后即可到/usr/local/nginx下配置nginx.conf进行测试。