Nginx(六)：配置解析之location解析
nginx成为非常流行的代理服务软件，最根本的原因也许是在于其强悍性能。但还有一些必要的条件，比如功能的完整，配置的易用，能够解决各种各样的实际需求问题，这些是一个好的软件的必备特性。
那么，今天我们就来看看nginx配置的部分原则和解析原理吧。我们只做location部分的细节解析，但其他配置道理基本相通，推一及二即可。
1：nginx配置的基本原则
nginx是支持高度配置化的，那么也许就会涉及许多部分的配置，要如何协调好这些配置，是个问题。比如是否将配置定义一个个独立的文件，或者其他。
然而，nginx使用一个统一的配置文件，管理起了所有的配置工作。即 nginx.conf, 其默认位置是 $NGINX_HOME/nginx.conf, 在这个主配置文件中，又可以包含其他任意多的配置文件，从而达到统一管理的作用。
其默认配置nginx.conf如下：
#user nobody;worker_processes 1;#error_log logs/error.log;#error_log logs/error.log notice;#error_log logs/error.log info;#pid logs/nginx.pid;events {worker_connections 1024;}http {include mime.types;default_type application/octet-stream;#log_format main '$remote_addr - $remote_user [$time_local] "$request" '# '$status $body_bytes_sent "$http_referer" '# '"$http_user_agent" "$http_x_forwarded_for"';#access_log logs/access.log main;sendfile on;#tcp_nopush on;#keepalive_timeout 0;keepalive_timeout 65;#gzip on;server {listen 80;server_name localhost;#charset koi8-r;#access_log logs/host.access.log main;location / {root html;index index.html index.htm;}#error_page 404 /404.html;# redirect server error pages to the static page /50x.html#error_page 500 502 503 504 /50x.html;location = /50x.html {root html;}# proxy the PHP scripts to Apache listening on 127.0.0.1:80##location ~ \.php$ {# proxy_pass http://127.0.0.1;#}# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000##location ~ \.php$ {# root html;# fastcgi_pass 127.0.0.1:9000;# fastcgi_index index.php;# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;# include fastcgi_params;#}# deny access to .htaccess files, if Apache's document root# concurs with nginx's one##location ~ /\.ht {# deny all;#}}# another virtual host using mix of IP-, name-, and port-based configuration##server {# listen 8000;# listen somename:8080;# server_name somename alias another.alias;# location / {# root html;# index index.html index.htm;# }#}# HTTPS server##server {# listen 443 ssl;# server_name localhost;# ssl_certificate cert.pem;# ssl_certificate_key cert.key;# ssl_session_cache shared:SSL:1m;# ssl_session_timeout 5m;# ssl_ciphers HIGH:!aNULL:!MD5;# ssl_prefer_server_ciphers on;# location / {# root html;# index index.html index.htm;# }#}}
这很明显不是什么标准语言语法，但其同样遵从一定的准则，从而让用户更易于理解配置。如：
1. 每一个细配置项，都使用一个';'作为结束标识;
2. '#' 代表该行被注释（这几乎是linux默认标准）;
3. 使用'{}'表示一个配置块，'{}'中代表其子项配置;
4. 使用include可以包含其他文件的配置，相当于将其中的配置项copy到当前位置，该包含路径可以是相对路径也可以是绝对路径;
因此，基本上，你只要按照这个标准来做配置，至少语法 是不会有误了。但是，具体应该如何配置呢？实际上这要依赖于某类操作的具体实现，比如 location 的 配置， user 的配置，都是有各自的含义的。如果想要具体了解各细节配置，则必须要查询官网的配置定义了。请参考： https://docs.nginx.com/nginx/admin-guide/basic-functionality/managing-configuration-files/
总体上来说，nginx有几个顶级配置:
events – 连接类的配置，比如最大连接数配置
http – 重头戏，http模块配置，所有的代理服务http服务都在其子配置下
mail – 邮件配置
stream – TCP、UDP 底层通信协议配置，功能与http模块相仿
一般地我们接接触最多的应该就是http配置了，至于其他功能，没有实践就没有发言权，略去不说。
2. location的配置用例
location的本义是用于定位一个http请求匹配情况，用于确定某个路径的请求应该如何做转换处理。它是属于 http 模块下的 server 模块下的一个选项配置。即 nginx -> http -> server -> location {..} 是其配置体现。它拥有相当多的配置项，因为做反向代理或其他服务器时，往往都可以通过这个配置，将功能完成。
如下几个配置项，可供参考：
http {upstream backend {ip_hash;server backend1.example.com weight=5;server backend2.example.com;server 192.0.0.1 backup;}server {root /www/data;# 路径相等处理，优先级最高location = / {#...}# 根路径配置，优先级最低location / {root /data/www;}# 带前缀的配置，优先级其次location /images/ {root /data;}# 正则匹配的配置，优先级较高location ~ \.(gif|jpg|png)$ {root /data/images;}# 正则取反配置location ^~ \.(php)$ {root /data/other;}# 反向代理的配置，将请求转换给后端服务# 如果backend是一个 upstream 配置，则做为一个负载均衡器使用location /api1 {proxy_set_header Host $host;proxy_set_header X-Real-IP $remote_addr;proxy_pass http://backend;}location /api2 {proxy_pass http://www.abc.com;}# 路径重写location /users/ {rewrite ^/users/(.*)$ /show?user=$1 break;}# 带状态码的返回配置location /wrong/url {return 404;open_file_cache_errors off;}location /permanently/moved/url {return 301 http://www.example.com/moved/here;}# 响应内容替换location / {sub_filter 'href="http://127.0.0.1:8080/' 'href="https://$host/';sub_filter 'img src="http://127.0.0.1:8080/' 'img src="https://$host/';sub_filter_once on;}}}
更多内容可查阅官网: https://docs.nginx.com/nginx/admin-guide/web-server/web-server/
总体上来说，location提供了可以配置如何查找本地文件，以及可以配置如何转发请求到其他服务器的方式。其中，还有很多附加的设置各种需求变量的实现，以辅助我们实现一些正常请求提供的内容。配置比较多，到真正使用时，按需配置即可。一般也是一次配置，永久使用，不会太费事。
3. location配置的解析
nginx有自己的一套配置方法，那么这些配置好了的语句，如何应用到具体的服务上呢？自然是需要先进行解析，然后放置到对应的内存空间变量中，然后在需要的时候进行读取判定，以及转换了。大体思路如此，但如何解析配置却并非易事。因为我们的配置是无数现有配置的任意组合，如何有效的放置到可理解的位置，应该需要单独的数据结构设计，以及解析步骤。实际上，这也相当于是一个简单的编译器或解析器，它需要将文本解析为认识的东西。
下面我们就一起来看看nginx都是如何解析这些配置的吧！（这自然是在启动时完成的工作）
// 首先，nginx会解析启动行命令，这里面可以指定配置文件// core/nginx.cstatic ngx_int_tngx_get_options(int argc, char *const *argv){u_char *p;ngx_int_t i;for (i = 1; i < argc; i++) {p = (u_char *) argv[i];if (*p++ != '-') {ngx_log_stderr(0, "invalid option: \"%s\"", argv[i]);return NGX_ERROR;}while (*p) {switch (*p++) {case '?':case 'h':ngx_show_version = 1;ngx_show_help = 1;break;case 'v':ngx_show_version = 1;break;case 'V':ngx_show_version = 1;ngx_show_configure = 1;break;// -t 测试配置文件有效性case 't':ngx_test_config = 1;break;case 'T':ngx_test_config = 1;ngx_dump_config = 1;break;case 'q':ngx_quiet_mode = 1;break;case 'p':if (*p) {ngx_prefix = p;goto next;}if (argv[++i]) {ngx_prefix = (u_char *) argv[i];goto next;}ngx_log_stderr(0, "option \"-p\" requires directory name");return NGX_ERROR;// -c nginx.conf 指定nginx配置文件路径case 'c':if (*p) {ngx_conf_file = p;goto next;}if (argv[++i]) {ngx_conf_file = (u_char *) argv[i];goto next;}ngx_log_stderr(0, "option \"-c\" requires file name");return NGX_ERROR;case 'g':if (*p) {ngx_conf_params = p;goto next;}if (argv[++i]) {ngx_conf_params = (u_char *) argv[i];goto next;}ngx_log_stderr(0, "option \"-g\" requires parameter");return NGX_ERROR;// -s (stop|quit|reopen|reload) 向现有运行的nginx进程发起控制命令case 's':// 紧贴式给出命令: -sstop, -sreloadif (*p) {ngx_signal = (char *) p;} else if (argv[++i]) {ngx_signal = argv[i];} else {ngx_log_stderr(0, "option \"-s\" requires parameter");return NGX_ERROR;}if (ngx_strcmp(ngx_signal, "stop") == 0|| ngx_strcmp(ngx_signal, "quit") == 0|| ngx_strcmp(ngx_signal, "reopen") == 0|| ngx_strcmp(ngx_signal, "reload") == 0){ngx_process = NGX_PROCESS_SIGNALLER;goto next;}ngx_log_stderr(0, "invalid option: \"-s %s\"", ngx_signal);return NGX_ERROR;default:ngx_log_stderr(0, "invalid option: \"%c\"", *(p - 1));return NGX_ERROR;}}next:continue;}return NGX_OK;}
以上，是对命令行参数的简单解析，解析出来的变量放入到各全局变量中：ngx_show_version|ngx_show_help|ngx_show_configure|ngx_test_config|ngx_dump_config|ngx_quiet_mode|ngx_prefix|ngx_conf_file|ngx_conf_params|ngx_signal.
以上，最重要的是两个参数：-c -s, 用于指定配置文件和操作现有nginx进程。当然，对于配置解析，自然最重要的是 -c 命令了。但对于一些没有指定的配置值，则使用系统的默认值。其处理如下：
// core/nginx.cstatic ngx_int_tngx_process_options(ngx_cycle_t *cycle){u_char *p;size_t len;if (ngx_prefix) {len = ngx_strlen(ngx_prefix);p = ngx_prefix;if (len && !ngx_path_separator(p[len - 1])) {p = ngx_pnalloc(cycle->pool, len + 1);if (p == NULL) {return NGX_ERROR;}ngx_memcpy(p, ngx_prefix, len);p[len++] = '/';}cycle->conf_prefix.len = len;cycle->conf_prefix.data = p;cycle->prefix.len = len;cycle->prefix.data = p;} else {#ifndef NGX_PREFIXp = ngx_pnalloc(cycle->pool, NGX_MAX_PATH);if (p == NULL) {return NGX_ERROR;}if (ngx_getcwd(p, NGX_MAX_PATH) == 0) {ngx_log_stderr(ngx_errno, "[emerg]: " ngx_getcwd_n " failed");return NGX_ERROR;}len = ngx_strlen(p);p[len++] = '/';cycle->conf_prefix.len = len;cycle->conf_prefix.data = p;cycle->prefix.len = len;cycle->prefix.data = p;#else#ifdef NGX_CONF_PREFIX// 默认路径前缀: conf/ngx_str_set(&cycle->conf_prefix, NGX_CONF_PREFIX);#elsengx_str_set(&cycle->conf_prefix, NGX_PREFIX);#endifngx_str_set(&cycle->prefix, NGX_PREFIX);#endif}if (ngx_conf_file) {cycle->conf_file.len = ngx_strlen(ngx_conf_file);cycle->conf_file.data = ngx_conf_file;} else {// 默认配置文件: conf/nginx.confngx_str_set(&cycle->conf_file, NGX_CONF_PATH);}if (ngx_conf_full_name(cycle, &cycle->conf_file, 0) != NGX_OK) {return NGX_ERROR;}for (p = cycle->conf_file.data + cycle->conf_file.len - 1;p > cycle->conf_file.data;p--){if (ngx_path_separator(*p)) {cycle->conf_prefix.len = p - cycle->conf_file.data + 1;cycle->conf_prefix.data = cycle->conf_file.data;break;}}if (ngx_conf_params) {cycle->conf_param.len = ngx_strlen(ngx_conf_params);cycle->conf_param.data = ngx_conf_params;}if (ngx_test_config) {cycle->log->log_level = NGX_LOG_INFO;}return NGX_OK;}
真正的配置文件解析是在初始化cycle的时候处理实现的：
// core/ngx_cycle.cngx_cycle_t *ngx_init_cycle(ngx_cycle_t *old_cycle){void *rv;char **senv;ngx_uint_t i, n;ngx_log_t *log;ngx_time_t *tp;ngx_conf_t conf;ngx_pool_t *pool;ngx_cycle_t *cycle, **old;ngx_shm_zone_t *shm_zone, *oshm_zone;ngx_list_part_t *part, *opart;ngx_open_file_t *file;ngx_listening_t *ls, *nls;ngx_core_conf_t *ccf, *old_ccf;ngx_core_module_t *module;char hostname[NGX_MAXHOSTNAMELEN];ngx_timezone_update();/* force localtime update with a new timezone */tp = ngx_timeofday();tp->sec = 0;ngx_time_update();log = old_cycle->log;pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);if (pool == NULL) {return NULL;}pool->log = log;cycle = ngx_pcalloc(pool, sizeof(ngx_cycle_t));if (cycle == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->pool = pool;cycle->log = log;cycle->old_cycle = old_cycle;cycle->conf_prefix.len = old_cycle->conf_prefix.len;cycle->conf_prefix.data = ngx_pstrdup(pool, &old_cycle->conf_prefix);if (cycle->conf_prefix.data == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->prefix.len = old_cycle->prefix.len;cycle->prefix.data = ngx_pstrdup(pool, &old_cycle->prefix);if (cycle->prefix.data == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->conf_file.len = old_cycle->conf_file.len;cycle->conf_file.data = ngx_pnalloc(pool, old_cycle->conf_file.len + 1);if (cycle->conf_file.data == NULL) {ngx_destroy_pool(pool);return NULL;}ngx_cpystrn(cycle->conf_file.data, old_cycle->conf_file.data,old_cycle->conf_file.len + 1);cycle->conf_param.len = old_cycle->conf_param.len;cycle->conf_param.data = ngx_pstrdup(pool, &old_cycle->conf_param);if (cycle->conf_param.data == NULL) {ngx_destroy_pool(pool);return NULL;}n = old_cycle->paths.nelts ? old_cycle->paths.nelts : 10;if (ngx_array_init(&cycle->paths, pool, n, sizeof(ngx_path_t *))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}ngx_memzero(cycle->paths.elts, n * sizeof(ngx_path_t *));if (ngx_array_init(&cycle->config_dump, pool, 1, sizeof(ngx_conf_dump_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}// 使用红黑树存放配置信息ngx_rbtree_init(&cycle->config_dump_rbtree, &cycle->config_dump_sentinel,ngx_str_rbtree_insert_value);// 默认使用 20 个端口服务if (old_cycle->open_files.part.nelts) {n = old_cycle->open_files.part.nelts;for (part = old_cycle->open_files.part.next; part; part = part->next) {n += part->nelts;}} else {n = 20;}// 每个监听端口使用一个 open_files 表示if (ngx_list_init(&cycle->open_files, pool, n, sizeof(ngx_open_file_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}if (old_cycle->shared_memory.part.nelts) {n = old_cycle->shared_memory.part.nelts;for (part = old_cycle->shared_memory.part.next; part; part = part->next){n += part->nelts;}} else {n = 1;}if (ngx_list_init(&cycle->shared_memory, pool, n, sizeof(ngx_shm_zone_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}n = old_cycle->listening.nelts ? old_cycle->listening.nelts : 10;if (ngx_array_init(&cycle->listening, pool, n, sizeof(ngx_listening_t))!= NGX_OK){ngx_destroy_pool(pool);return NULL;}ngx_memzero(cycle->listening.elts, n * sizeof(ngx_listening_t));ngx_queue_init(&cycle->reusable_connections_queue);cycle->conf_ctx = ngx_pcalloc(pool, ngx_max_module * sizeof(void *));if (cycle->conf_ctx == NULL) {ngx_destroy_pool(pool);return NULL;}// 获取当前机器的hostnameif (gethostname(hostname, NGX_MAXHOSTNAMELEN) == -1) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno, "gethostname() failed");ngx_destroy_pool(pool);return NULL;}/* on Linux gethostname() silently truncates name that does not fit */hostname[NGX_MAXHOSTNAMELEN - 1] = '\0';cycle->hostname.len = ngx_strlen(hostname);cycle->hostname.data = ngx_pnalloc(pool, cycle->hostname.len);if (cycle->hostname.data == NULL) {ngx_destroy_pool(pool);return NULL;}ngx_strlow(cycle->hostname.data, (u_char *) hostname, cycle->hostname.len);// 创建module内存空间if (ngx_cycle_modules(cycle) != NGX_OK) {ngx_destroy_pool(pool);return NULL;}// 让各模块依次进行配置for (i = 0; cycle->modules[i]; i++) {// NGINX_CORE_MODULE 可以进行配置文件处理// 即几套顶级模块, http,events,mail,...if (cycle->modules[i]->type != NGX_CORE_MODULE) {continue;}module = cycle->modules[i]->ctx;// 调用各模块的 create_conf 实现配置加载// 其中，以为的http模块会进行解析，其实却没有if (module->create_conf) {rv = module->create_conf(cycle);if (rv == NULL) {ngx_destroy_pool(pool);return NULL;}cycle->conf_ctx[cycle->modules[i]->index] = rv;}}senv = environ;ngx_memzero(&conf, sizeof(ngx_conf_t));/* STUB: init array ? */conf.args = ngx_array_create(pool, 10, sizeof(ngx_str_t));if (conf.args == NULL) {ngx_destroy_pool(pool);return NULL;}conf.temp_pool = ngx_create_pool(NGX_CYCLE_POOL_SIZE, log);if (conf.temp_pool == NULL) {ngx_destroy_pool(pool);return NULL;}conf.ctx = cycle->conf_ctx;conf.cycle = cycle;conf.pool = pool;conf.log = log;conf.module_type = NGX_CORE_MODULE;conf.cmd_type = NGX_MAIN_CONF;#if 0log->log_level = NGX_LOG_DEBUG_ALL;#endifif (ngx_conf_param(&conf) != NGX_CONF_OK) {environ = senv;ngx_destroy_cycle_pools(&conf);return NULL;}if (ngx_conf_parse(&conf, &cycle->conf_file) != NGX_CONF_OK) {environ = senv;ngx_destroy_cycle_pools(&conf);return NULL;}if (ngx_test_config && !ngx_quiet_mode) {ngx_log_stderr(0, "the configuration file %s syntax is ok",cycle->conf_file.data);}for (i = 0; cycle->modules[i]; i++) {if (cycle->modules[i]->type != NGX_CORE_MODULE) {continue;}module = cycle->modules[i]->ctx;if (module->init_conf) {if (module->init_conf(cycle,cycle->conf_ctx[cycle->modules[i]->index])== NGX_CONF_ERROR){environ = senv;ngx_destroy_cycle_pools(&conf);return NULL;}}}if (ngx_process == NGX_PROCESS_SIGNALLER) {return cycle;}ccf = (ngx_core_conf_t *) ngx_get_conf(cycle->conf_ctx, ngx_core_module);if (ngx_test_config) {if (ngx_create_pidfile(&ccf->pid, log) != NGX_OK) {goto failed;}} else if (!ngx_is_init_cycle(old_cycle)) {/** we do not create the pid file in the first ngx_init_cycle() call* because we need to write the demonized process pid*/old_ccf = (ngx_core_conf_t *) ngx_get_conf(old_cycle->conf_ctx,ngx_core_module);if (ccf->pid.len != old_ccf->pid.len|| ngx_strcmp(ccf->pid.data, old_ccf->pid.data) != 0){/* new pid file name */if (ngx_create_pidfile(&ccf->pid, log) != NGX_OK) {goto failed;}ngx_delete_pidfile(old_cycle);}}if (ngx_test_lockfile(cycle->lock_file.data, log) != NGX_OK) {goto failed;}if (ngx_create_paths(cycle, ccf->user) != NGX_OK) {goto failed;}if (ngx_log_open_default(cycle) != NGX_OK) {goto failed;}/* open the new files */part = &cycle->open_files.part;file = part->elts;for (i = 0; /* void */ ; i++) {if (i >= part->nelts) {if (part->next == NULL) {break;}part = part->next;file = part->elts;i = 0;}if (file[i].name.len == 0) {continue;}file[i].fd = ngx_open_file(file[i].name.data,NGX_FILE_APPEND,NGX_FILE_CREATE_OR_OPEN,NGX_FILE_DEFAULT_ACCESS);ngx_log_debug3(NGX_LOG_DEBUG_CORE, log, 0,"log: %p %d \"%s\"",&file[i], file[i].fd, file[i].name.data);if (file[i].fd == NGX_INVALID_FILE) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,ngx_open_file_n " \"%s\" failed",file[i].name.data);goto failed;}#if !(NGX_WIN32)if (fcntl(file[i].fd, F_SETFD, FD_CLOEXEC) == -1) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,"fcntl(FD_CLOEXEC) \"%s\" failed",file[i].name.data);goto failed;}#endif}cycle->log = &cycle->new_log;pool->log = &cycle->new_log;/* create shared memory */part = &cycle->shared_memory.part;shm_zone = part->elts;for (i = 0; /* void */ ; i++) {if (i >= part->nelts) {if (part->next == NULL) {break;}part = part->next;shm_zone = part->elts;i = 0;}if (shm_zone[i].shm.size == 0) {ngx_log_error(NGX_LOG_EMERG, log, 0,"zero size shared memory zone \"%V\"",&shm_zone[i].shm.name);goto failed;}shm_zone[i].shm.log = cycle->log;opart = &old_cycle->shared_memory.part;oshm_zone = opart->elts;for (n = 0; /* void */ ; n++) {if (n >= opart->nelts) {if (opart->next == NULL) {break;}opart = opart->next;oshm_zone = opart->elts;n = 0;}if (shm_zone[i].shm.name.len != oshm_zone[n].shm.name.len) {continue;}if (ngx_strncmp(shm_zone[i].shm.name.data,oshm_zone[n].shm.name.data,shm_zone[i].shm.name.len)!= 0){continue;}if (shm_zone[i].tag == oshm_zone[n].tag&& shm_zone[i].shm.size == oshm_zone[n].shm.size&& !shm_zone[i].noreuse){shm_zone[i].shm.addr = oshm_zone[n].shm.addr;#if (NGX_WIN32)shm_zone[i].shm.handle = oshm_zone[n].shm.handle;#endifif (shm_zone[i].init(&shm_zone[i], oshm_zone[n].data)!= NGX_OK){goto failed;}goto shm_zone_found;}break;}if (ngx_shm_alloc(&shm_zone[i].shm) != NGX_OK) {goto failed;}if (ngx_init_zone_pool(cycle, &shm_zone[i]) != NGX_OK) {goto failed;}if (shm_zone[i].init(&shm_zone[i], NULL) != NGX_OK) {goto failed;}shm_zone_found:continue;}/* handle the listening sockets */if (old_cycle->listening.nelts) {ls = old_cycle->listening.elts;for (i = 0; i < old_cycle->listening.nelts; i++) {ls[i].remain = 0;}nls = cycle->listening.elts;for (n = 0; n < cycle->listening.nelts; n++) {for (i = 0; i < old_cycle->listening.nelts; i++) {if (ls[i].ignore) {continue;}if (ls[i].remain) {continue;}if (ls[i].type != nls[n].type) {continue;}if (ngx_cmp_sockaddr(nls[n].sockaddr, nls[n].socklen,ls[i].sockaddr, ls[i].socklen, 1)== NGX_OK){nls[n].fd = ls[i].fd;nls[n].inherited = ls[i].inherited;nls[n].previous = &ls[i];ls[i].remain = 1;if (ls[i].backlog != nls[n].backlog) {nls[n].listen = 1;}#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)/** FreeBSD, except the most recent versions,* could not remove accept filter*/nls[n].deferred_accept = ls[i].deferred_accept;if (ls[i].accept_filter && nls[n].accept_filter) {if (ngx_strcmp(ls[i].accept_filter,nls[n].accept_filter)!= 0){nls[n].delete_deferred = 1;nls[n].add_deferred = 1;}} else if (ls[i].accept_filter) {nls[n].delete_deferred = 1;} else if (nls[n].accept_filter) {nls[n].add_deferred = 1;}#endif#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)if (ls[i].deferred_accept && !nls[n].deferred_accept) {nls[n].delete_deferred = 1;} else if (ls[i].deferred_accept != nls[n].deferred_accept){nls[n].add_deferred = 1;}#endif#if (NGX_HAVE_REUSEPORT)if (nls[n].reuseport && !ls[i].reuseport) {nls[n].add_reuseport = 1;}#endifbreak;}}if (nls[n].fd == (ngx_socket_t) -1) {nls[n].open = 1;#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)if (nls[n].accept_filter) {nls[n].add_deferred = 1;}#endif#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)if (nls[n].deferred_accept) {nls[n].add_deferred = 1;}#endif}}} else {ls = cycle->listening.elts;for (i = 0; i < cycle->listening.nelts; i++) {ls[i].open = 1;#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)if (ls[i].accept_filter) {ls[i].add_deferred = 1;}#endif#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)if (ls[i].deferred_accept) {ls[i].add_deferred = 1;}#endif}}if (ngx_open_listening_sockets(cycle) != NGX_OK) {goto failed;}if (!ngx_test_config) {ngx_configure_listening_sockets(cycle);}/* commit the new cycle configuration */if (!ngx_use_stderr) {(void) ngx_log_redirect_stderr(cycle);}pool->log = cycle->log;if (ngx_init_modules(cycle) != NGX_OK) {/* fatal */exit(1);}/* close and delete stuff that lefts from an old cycle *//* free the unnecessary shared memory */opart = &old_cycle->shared_memory.part;oshm_zone = opart->elts;for (i = 0; /* void */ ; i++) {if (i >= opart->nelts) {if (opart->next == NULL) {goto old_shm_zone_done;}opart = opart->next;oshm_zone = opart->elts;i = 0;}part = &cycle->shared_memory.part;shm_zone = part->elts;for (n = 0; /* void */ ; n++) {if (n >= part->nelts) {if (part->next == NULL) {break;}part = part->next;shm_zone = part->elts;n = 0;}if (oshm_zone[i].shm.name.len != shm_zone[n].shm.name.len) {continue;}if (ngx_strncmp(oshm_zone[i].shm.name.data,shm_zone[n].shm.name.data,oshm_zone[i].shm.name.len)!= 0){continue;}if (oshm_zone[i].tag == shm_zone[n].tag&& oshm_zone[i].shm.size == shm_zone[n].shm.size&& !oshm_zone[i].noreuse){goto live_shm_zone;}break;}ngx_shm_free(&oshm_zone[i].shm);live_shm_zone:continue;}old_shm_zone_done:/* close the unnecessary listening sockets */ls = old_cycle->listening.elts;for (i = 0; i < old_cycle->listening.nelts; i++) {if (ls[i].remain || ls[i].fd == (ngx_socket_t) -1) {continue;}if (ngx_close_socket(ls[i].fd) == -1) {ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,ngx_close_socket_n " listening socket on %V failed",&ls[i].addr_text);}#if (NGX_HAVE_UNIX_DOMAIN)if (ls[i].sockaddr->sa_family == AF_UNIX) {u_char *name;name = ls[i].addr_text.data + sizeof("unix:") - 1;ngx_log_error(NGX_LOG_WARN, cycle->log, 0,"deleting socket %s", name);if (ngx_delete_file(name) == NGX_FILE_ERROR) {ngx_log_error(NGX_LOG_EMERG, cycle->log, ngx_socket_errno,ngx_delete_file_n " %s failed", name);}}#endif}/* close the unnecessary open files */part = &old_cycle->open_files.part;file = part->elts;for (i = 0; /* void */ ; i++) {if (i >= part->nelts) {if (part->next == NULL) {break;}part = part->next;file = part->elts;i = 0;}if (file[i].fd == NGX_INVALID_FILE || file[i].fd == ngx_stderr) {continue;}if (ngx_close_file(file[i].fd) == NGX_FILE_ERROR) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,ngx_close_file_n " \"%s\" failed",file[i].name.data);}}ngx_destroy_pool(conf.temp_pool);if (ngx_process == NGX_PROCESS_MASTER || ngx_is_init_cycle(old_cycle)) {ngx_destroy_pool(old_cycle->pool);cycle->old_cycle = NULL;return cycle;}if (ngx_temp_pool == NULL) {ngx_temp_pool = ngx_create_pool(128, cycle->log);if (ngx_temp_pool == NULL) {ngx_log_error(NGX_LOG_EMERG, cycle->log, 0,"could not create ngx_temp_pool");exit(1);}n = 10;if (ngx_array_init(&ngx_old_cycles, ngx_temp_pool, n,sizeof(ngx_cycle_t *))!= NGX_OK){exit(1);}ngx_memzero(ngx_old_cycles.elts, n * sizeof(ngx_cycle_t *));ngx_cleaner_event.handler = ngx_clean_old_cycles;ngx_cleaner_event.log = cycle->log;ngx_cleaner_event.data = &dumb;dumb.fd = (ngx_socket_t) -1;}ngx_temp_pool->log = cycle->log;old = ngx_array_push(&ngx_old_cycles);if (old == NULL) {exit(1);}*old = old_cycle;if (!ngx_cleaner_event.timer_set) {ngx_add_timer(&ngx_cleaner_event, 30000);ngx_cleaner_event.timer_set = 1;}return cycle;failed:if (!ngx_is_init_cycle(old_cycle)) {old_ccf = (ngx_core_conf_t *) ngx_get_conf(old_cycle->conf_ctx,ngx_core_module);if (old_ccf->environment) {environ = old_ccf->environment;}}/* rollback the new cycle configuration */part = &cycle->open_files.part;file = part->elts;for (i = 0; /* void */ ; i++) {if (i >= part->nelts) {if (part->next == NULL) {break;}part = part->next;file = part->elts;i = 0;}if (file[i].fd == NGX_INVALID_FILE || file[i].fd == ngx_stderr) {continue;}if (ngx_close_file(file[i].fd) == NGX_FILE_ERROR) {ngx_log_error(NGX_LOG_EMERG, log, ngx_errno,ngx_close_file_n " \"%s\" failed",file[i].name.data);}}/* free the newly created shared memory */part = &cycle->shared_memory.part;shm_zone = part->elts;for (i = 0; /* void */ ; i++) {if (i >= part->nelts) {if (part->next == NULL) {break;}part = part->next;shm_zone = part->elts;i = 0;}if (shm_zone[i].shm.addr == NULL) {continue;}opart = &old_cycle->shared_memory.part;oshm_zone = opart->elts;for (n = 0; /* void */ ; n++) {if (n >= opart->nelts) {if (opart->next == NULL) {break;}opart = opart->next;oshm_zone = opart->elts;n = 0;}if (shm_zone[i].shm.name.len != oshm_zone[n].shm.name.len) {continue;}if (ngx_strncmp(shm_zone[i].shm.name.data,oshm_zone[n].shm.name.data,shm_zone[i].shm.name.len)!= 0){continue;}if (shm_zone[i].tag == oshm_zone[n].tag&& shm_zone[i].shm.size == oshm_zone[n].shm.size&& !shm_zone[i].noreuse){goto old_shm_zone_found;}break;}ngx_shm_free(&shm_zone[i].shm);old_shm_zone_found:continue;}if (ngx_test_config) {ngx_destroy_cycle_pools(&conf);return NULL;}ls = cycle->listening.elts;for (i = 0; i < cycle->listening.nelts; i++) {if (ls[i].fd == (ngx_socket_t) -1 || !ls[i].open) {continue;}if (ngx_close_socket(ls[i].fd) == -1) {ngx_log_error(NGX_LOG_EMERG, log, ngx_socket_errno,ngx_close_socket_n " %V failed",&ls[i].addr_text);}}ngx_destroy_cycle_pools(&conf);return NULL;}
nginx中设置了几个初始化的点，create_conf, init_conf, 供各模块实现各自的解析逻辑，以及使用一个全局的解析 ngx_conf_parse() 实现文件解析。
那么 http 作为独立的模块，其是否参与配置解析呢？我们看下其模块的配置即可：
// http 模块的配置简略// http/ngx_http.cstatic ngx_core_module_t ngx_http_module_ctx = {ngx_string("http"),// 不做 create_conf 处理NULL,NULL};ngx_module_t ngx_http_module = {NGX_MODULE_V1,&ngx_http_module_ctx, /* module context */ngx_http_commands, /* module directives */NGX_CORE_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};
真正的解析工作在 ngx_conf_file.c 文件中进行， 有ngx_conf_param(), ngx_conf_parse() 完成具体的解析。
// core/ngx_conf_file.cchar *ngx_conf_param(ngx_conf_t *cf){char *rv;ngx_str_t *param;ngx_buf_t b;ngx_conf_file_t conf_file;param = &cf->cycle->conf_param;if (param->len == 0) {return NGX_CONF_OK;}ngx_memzero(&conf_file, sizeof(ngx_conf_file_t));ngx_memzero(&b, sizeof(ngx_buf_t));b.start = param->data;b.pos = param->data;b.last = param->data + param->len;b.end = b.last;b.temporary = 1;conf_file.file.fd = NGX_INVALID_FILE;conf_file.file.name.data = NULL;conf_file.line = 0;cf->conf_file = &conf_file;cf->conf_file->buffer = &b;// 解析param信息，不解析配置文件rv = ngx_conf_parse(cf, NULL);cf->conf_file = NULL;return rv;}char *ngx_conf_parse(ngx_conf_t *cf, ngx_str_t *filename){char *rv;ngx_fd_t fd;ngx_int_t rc;ngx_buf_t buf;ngx_conf_file_t *prev, conf_file;enum {parse_file = 0,parse_block,parse_param} type;#if (NGX_SUPPRESS_WARN)fd = NGX_INVALID_FILE;prev = NULL;#endif// 如果给定配置文件，则解析if (filename) {/* open configuration file */// 打开配置文件fd = ngx_open_file(filename->data, NGX_FILE_RDONLY, NGX_FILE_OPEN, 0);if (fd == NGX_INVALID_FILE) {ngx_conf_log_error(NGX_LOG_EMERG, cf, ngx_errno,ngx_open_file_n " \"%s\" failed",filename->data);return NGX_CONF_ERROR;}prev = cf->conf_file;cf->conf_file = &conf_file;if (ngx_fd_info(fd, &cf->conf_file->file.info) == NGX_FILE_ERROR) {ngx_log_error(NGX_LOG_EMERG, cf->log, ngx_errno,ngx_fd_info_n " \"%s\" failed", filename->data);}cf->conf_file->buffer = &buf;// NGX_CONF_BUFFER=1024buf.start = ngx_alloc(NGX_CONF_BUFFER, cf->log);if (buf.start == NULL) {goto failed;}buf.pos = buf.start;buf.last = buf.start;buf.end = buf.last + NGX_CONF_BUFFER;buf.temporary = 1; // 初始化配置文件信息cf->conf_file->file.fd = fd;cf->conf_file->file.name.len = filename->len;cf->conf_file->file.name.data = filename->data;cf->conf_file->file.offset = 0;cf->conf_file->file.log = cf->log;cf->conf_file->line = 1;type = parse_file;if (ngx_dump_config#if (NGX_DEBUG)|| 1#endif){if (ngx_conf_add_dump(cf, filename) != NGX_OK) {goto failed;}} else {cf->conf_file->dump = NULL;}} else if (cf->conf_file->file.fd != NGX_INVALID_FILE) {type = parse_block;} else {type = parse_param;}// 此处实现真正的解析操作for ( ;; ) {// 重要1: 读取出一个个地token信息, 以pos, start等变量做标识起始rc = ngx_conf_read_token(cf);/** ngx_conf_read_token() may return** NGX_ERROR there is error* NGX_OK the token terminated by ";" was found* NGX_CONF_BLOCK_START the token terminated by "{" was found* NGX_CONF_BLOCK_DONE the "}" was found* NGX_CONF_FILE_DONE the configuration file is done*/if (rc == NGX_ERROR) {goto done;}if (rc == NGX_CONF_BLOCK_DONE) {if (type != parse_block) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "unexpected \"}\"");goto failed;}goto done;}if (rc == NGX_CONF_FILE_DONE) {if (type == parse_block) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unexpected end of file, expecting \"}\"");goto failed;}goto done;}if (rc == NGX_CONF_BLOCK_START) {if (type == parse_param) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"block directives are not supported ""in -g option");goto failed;}}/* rc == NGX_OK || rc == NGX_CONF_BLOCK_START */if (cf->handler) {/** the custom handler, i.e., that is used in the http's* "types { ... }" directive*/if (rc == NGX_CONF_BLOCK_START) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "unexpected \"{\"");goto failed;}rv = (*cf->handler)(cf, NULL, cf->handler_conf);if (rv == NGX_CONF_OK) {continue;}if (rv == NGX_CONF_ERROR) {goto failed;}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "%s", rv);goto failed;}// 重要2: 将解析出的变量进行细致处理rc = ngx_conf_handler(cf, rc);if (rc == NGX_ERROR) {goto failed;}}failed:rc = NGX_ERROR;done:if (filename) {if (cf->conf_file->buffer->start) {ngx_free(cf->conf_file->buffer->start);}if (ngx_close_file(fd) == NGX_FILE_ERROR) {ngx_log_error(NGX_LOG_ALERT, cf->log, ngx_errno,ngx_close_file_n " %s failed",filename->data);rc = NGX_ERROR;}cf->conf_file = prev;}if (rc == NGX_ERROR) {return NGX_CONF_ERROR;}return NGX_CONF_OK;}// 读取一个个地 token 信息static ngx_int_tngx_conf_read_token(ngx_conf_t *cf){u_char *start, ch, *src, *dst;off_t file_size;size_t len;ssize_t n, size;ngx_uint_t found, need_space, last_space, sharp_comment, variable;ngx_uint_t quoted, s_quoted, d_quoted, start_line;ngx_str_t *word;ngx_buf_t *b, *dump;found = 0;need_space = 0;last_space = 1;sharp_comment = 0;variable = 0;quoted = 0;s_quoted = 0;d_quoted = 0;cf->args->nelts = 0;b = cf->conf_file->buffer;dump = cf->conf_file->dump;start = b->pos;start_line = cf->conf_file->line;file_size = ngx_file_size(&cf->conf_file->file.info);for ( ;; ) {// last默认是最大buffer，pos默认为0，所以以下逻辑不一定走if (b->pos >= b->last) {if (cf->conf_file->file.offset >= file_size) {if (cf->args->nelts > 0 || !last_space) {if (cf->conf_file->file.fd == NGX_INVALID_FILE) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unexpected end of parameter, ""expecting \";\"");return NGX_ERROR;}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unexpected end of file, ""expecting \";\" or \"}\"");return NGX_ERROR;}return NGX_CONF_FILE_DONE;}// 默认两值相等，len为0len = b->pos - start;if (len == NGX_CONF_BUFFER) {cf->conf_file->line = start_line;if (d_quoted) {ch = '"';} else if (s_quoted) {ch = '\'';} else {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"too long parameter \"%*s...\" started",10, start);return NGX_ERROR;}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"too long parameter, probably ""missing terminating \"%c\" character", ch);return NGX_ERROR;}if (len) {ngx_memmove(b->start, start, len);}// 计算剩余大小size = (ssize_t) (file_size - cf->conf_file->file.offset);// 如果剩余大小超出当前缓冲的大小，则只能取当前缓冲剩余大小if (size > b->end - (b->start + len)) {size = b->end - (b->start + len);}// 从配置文件中读取size大小的数据出来，放到buf中备用，相当于尽量一次全部读取n = ngx_read_file(&cf->conf_file->file, b->start + len, size,cf->conf_file->file.offset);if (n == NGX_ERROR) {return NGX_ERROR;}if (n != size) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,ngx_read_file_n " returned ""only %z bytes instead of %z",n, size);return NGX_ERROR;}// 交换各偏移信息b->pos = b->start + len;b->last = b->pos + n;start = b->start;if (dump) {dump->last = ngx_cpymem(dump->last, b->pos, size);}}// 从文件中读出一个字符用以判定，即如果假设文件已读取完，则相当于一个个字符取出判定ch = *b->pos++;// 遇到换行，line++，注释标识重置if (ch == LF) {cf->conf_file->line++;if (sharp_comment) {sharp_comment = 0;}}// 如果注释标识有效，则忽略当前段的字符，直到标识被清除if (sharp_comment) {continue;}// 引号闭合处理if (quoted) {quoted = 0;continue;}// 判断是否有新的语句开始，类似空格都可以if (need_space) {if (ch == ' ' || ch == '\t' || ch == CR || ch == LF) {last_space = 1;need_space = 0;continue;}// 遇到分号，当前解析结束，即得到一个独立语句，如 root /www;if (ch == ';') {return NGX_OK;}// 遇到块也结束当前解析，交由子处理器处理if (ch == '{') {return NGX_CONF_BLOCK_START;}if (ch == ')') {last_space = 1;need_space = 0;} else {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unexpected \"%c\"", ch);return NGX_ERROR;}}if (last_space) {// 新语句开始，行号暂存start = b->pos - 1;start_line = cf->conf_file->line;// 忽略空格类字符if (ch == ' ' || ch == '\t' || ch == CR || ch == LF) {continue;}switch (ch) {case ';':case '{':if (cf->args->nelts == 0) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unexpected \"%c\"", ch);return NGX_ERROR;}// 语句结束，nelts 到底是啥？if (ch == '{') {return NGX_CONF_BLOCK_START;}return NGX_OK;case '}':if (cf->args->nelts != 0) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unexpected \"}\"");return NGX_ERROR;}return NGX_CONF_BLOCK_DONE;case '#':sharp_comment = 1;continue;case '\\': // 转义符quoted = 1;last_space = 0;continue;case '"':start++;d_quoted = 1;last_space = 0;continue;case '\'':start++;s_quoted = 1;last_space = 0;continue;case '$': // 变量解析variable = 1;last_space = 0;continue;default:last_space = 0;}} else {// ${xxx} 变量if (ch == '{' && variable) {continue;}variable = 0;if (ch == '\\') {quoted = 1;continue;}if (ch == '$') {variable = 1;continue;}// 引号处理if (d_quoted) {if (ch == '"') {d_quoted = 0;need_space = 1;found = 1;}} else if (s_quoted) {if (ch == '\'') {s_quoted = 0;need_space = 1;found = 1;}} else if (ch == ' ' || ch == '\t' || ch == CR || ch == LF|| ch == ';' || ch == '{'){last_space = 1;found = 1; // 完整解析一个语句}if (found) {word = ngx_array_push(cf->args);if (word == NULL) {return NGX_ERROR;}word->data = ngx_pnalloc(cf->pool, b->pos - 1 - start + 1);if (word->data == NULL) {return NGX_ERROR;}// 将解析出的语句赋值到 args 中for (dst = word->data, src = start, len = 0;src < b->pos - 1;len++){if (*src == '\\') {switch (src[1]) {case '"':case '\'':case '\\':// 去除转义标识src++;break;case 't':// 翻译转义*dst++ = '\t';src += 2;continue;case 'r':*dst++ = '\r';src += 2;continue;case 'n':*dst++ = '\n';src += 2;continue;}}*dst++ = *src++;}*dst = '\0';word->len = len;if (ch == ';') {return NGX_OK;}if (ch == '{') {return NGX_CONF_BLOCK_START;}found = 0;}}}}
大体原理是：读取一个个token，然后进行依次翻译，分小语句，大block,... 类型依次处理。将解析的结果放入cf->args中。其解析结果如 location ~ /api/.*go { ,如 listen 80 81;
还差一个细节，就是读取到token之后，又是如何传递给各模块的呢？实际就是上面的重点2：ngx_conf_handler() 处理。
static ngx_int_tngx_conf_handler(ngx_conf_t *cf, ngx_int_t last){char *rv;void *conf, **confp;ngx_uint_t i, found;ngx_str_t *name;ngx_command_t *cmd;// 获取最后存入的配置变量名name = cf->args->elts;found = 0;// 遍历模块的 commands 列表，依次调用进行处理, 比如 root /www 处理// location /api {..} 处理for (i = 0; cf->cycle->modules[i]; i++) {cmd = cf->cycle->modules[i]->commands;if (cmd == NULL) {continue;}for ( /* void */ ; cmd->name.len; cmd++) {// 名字不同必然不负责解析if (name->len != cmd->name.len) {continue;}if (ngx_strcmp(name->data, cmd->name.data) != 0) {continue;}found = 1;// 配置模块处理if (cf->cycle->modules[i]->type != NGX_CONF_MODULE&& cf->cycle->modules[i]->type != cf->module_type){continue;}/* is the directive's location right ? */// 变量类型判定if (!(cmd->type & cf->cmd_type)) {continue;}if (!(cmd->type & NGX_CONF_BLOCK) && last != NGX_OK) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"directive \"%s\" is not terminated by \";\"",name->data);return NGX_ERROR;}if ((cmd->type & NGX_CONF_BLOCK) && last != NGX_CONF_BLOCK_START) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"directive \"%s\" has no opening \"{\"",name->data);return NGX_ERROR;}/* is the directive's argument count right ? */// 参数个数匹配if (!(cmd->type & NGX_CONF_ANY)) {if (cmd->type & NGX_CONF_FLAG) {if (cf->args->nelts != 2) {goto invalid;}} else if (cmd->type & NGX_CONF_1MORE) {if (cf->args->nelts < 2) {goto invalid;}} else if (cmd->type & NGX_CONF_2MORE) {if (cf->args->nelts < 3) {goto invalid;}} else if (cf->args->nelts > NGX_CONF_MAX_ARGS) {goto invalid;} else if (!(cmd->type & argument_number[cf->args->nelts - 1])){goto invalid;}}/* set up the directive's configuration context */conf = NULL;// 找不同的配置级别位置存储（这指针用得6啊）if (cmd->type & NGX_DIRECT_CONF) {conf = ((void **) cf->ctx)[cf->cycle->modules[i]->index];} else if (cmd->type & NGX_MAIN_CONF) {conf = &(((void **) cf->ctx)[cf->cycle->modules[i]->index]);} else if (cf->ctx) {confp = *(void **) ((char *) cf->ctx + cmd->conf);if (confp) {conf = confp[cf->cycle->modules[i]->ctx_index];}}// 调用各命令的set方法，处理配置语义// 实际上就涉及到内嵌套解析问题了// 同样不会很简单哦rv = cmd->set(cf, cmd, conf);if (rv == NGX_CONF_OK) {return NGX_OK;}if (rv == NGX_CONF_ERROR) {return NGX_ERROR;}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"\"%s\" directive %s", name->data, rv);return NGX_ERROR;}}// 配置使用错误if (found) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"\"%s\" directive is not allowed here", name->data);return NGX_ERROR;}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"unknown directive \"%s\"", name->data);return NGX_ERROR;invalid:ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid number of arguments in \"%s\" directive",name->data);return NGX_ERROR;}
将解析出的配置信息接入到各子模块之后，才算是真正意义上的解析成功，也才能被各子模块使用。
下面我们再来看个样例，子模块如何解析配置，http location ....
listen 80; 的解析比较简单些，有兴趣可查看：
static char *ngx_http_core_listen(ngx_conf_t *cf, ngx_command_t *cmd, void *conf){ngx_http_core_srv_conf_t *cscf = conf;ngx_str_t *value, size;ngx_url_t u;ngx_uint_t n;ngx_http_listen_opt_t lsopt;cscf->listen = 1;value = cf->args->elts;ngx_memzero(&u, sizeof(ngx_url_t));u.url = value[1];u.listen = 1;u.default_port = 80;if (ngx_parse_url(cf->pool, &u) != NGX_OK) {if (u.err) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"%s in \"%V\" of the \"listen\" directive",u.err, &u.url);}return NGX_CONF_ERROR;}ngx_memzero(&lsopt, sizeof(ngx_http_listen_opt_t));lsopt.backlog = NGX_LISTEN_BACKLOG;lsopt.rcvbuf = -1;lsopt.sndbuf = -1;#if (NGX_HAVE_SETFIB)lsopt.setfib = -1;#endif#if (NGX_HAVE_TCP_FASTOPEN)lsopt.fastopen = -1;#endif#if (NGX_HAVE_INET6)lsopt.ipv6only = 1;#endif// 更多参数解析，见官方文档说明for (n = 2; n < cf->args->nelts; n++) {if (ngx_strcmp(value[n].data, "default_server") == 0|| ngx_strcmp(value[n].data, "default") == 0){lsopt.default_server = 1;continue;}if (ngx_strcmp(value[n].data, "bind") == 0) {lsopt.set = 1;lsopt.bind = 1;continue;}#if (NGX_HAVE_SETFIB)if (ngx_strncmp(value[n].data, "setfib=", 7) == 0) {lsopt.setfib = ngx_atoi(value[n].data + 7, value[n].len - 7);lsopt.set = 1;lsopt.bind = 1;if (lsopt.setfib == NGX_ERROR) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid setfib \"%V\"", &value[n]);return NGX_CONF_ERROR;}continue;}#endif#if (NGX_HAVE_TCP_FASTOPEN)if (ngx_strncmp(value[n].data, "fastopen=", 9) == 0) {lsopt.fastopen = ngx_atoi(value[n].data + 9, value[n].len - 9);lsopt.set = 1;lsopt.bind = 1;if (lsopt.fastopen == NGX_ERROR) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid fastopen \"%V\"", &value[n]);return NGX_CONF_ERROR;}continue;}#endifif (ngx_strncmp(value[n].data, "backlog=", 8) == 0) {lsopt.backlog = ngx_atoi(value[n].data + 8, value[n].len - 8);lsopt.set = 1;lsopt.bind = 1;if (lsopt.backlog == NGX_ERROR || lsopt.backlog == 0) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid backlog \"%V\"", &value[n]);return NGX_CONF_ERROR;}continue;}if (ngx_strncmp(value[n].data, "rcvbuf=", 7) == 0) {size.len = value[n].len - 7;size.data = value[n].data + 7;lsopt.rcvbuf = ngx_parse_size(&size);lsopt.set = 1;lsopt.bind = 1;if (lsopt.rcvbuf == NGX_ERROR) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid rcvbuf \"%V\"", &value[n]);return NGX_CONF_ERROR;}continue;}if (ngx_strncmp(value[n].data, "sndbuf=", 7) == 0) {size.len = value[n].len - 7;size.data = value[n].data + 7;lsopt.sndbuf = ngx_parse_size(&size);lsopt.set = 1;lsopt.bind = 1;if (lsopt.sndbuf == NGX_ERROR) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid sndbuf \"%V\"", &value[n]);return NGX_CONF_ERROR;}continue;}if (ngx_strncmp(value[n].data, "accept_filter=", 14) == 0) {#if (NGX_HAVE_DEFERRED_ACCEPT && defined SO_ACCEPTFILTER)lsopt.accept_filter = (char *) &value[n].data[14];lsopt.set = 1;lsopt.bind = 1;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"accept filters \"%V\" are not supported ""on this platform, ignored",&value[n]);#endifcontinue;}if (ngx_strcmp(value[n].data, "deferred") == 0) {#if (NGX_HAVE_DEFERRED_ACCEPT && defined TCP_DEFER_ACCEPT)lsopt.deferred_accept = 1;lsopt.set = 1;lsopt.bind = 1;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"the deferred accept is not supported ""on this platform, ignored");#endifcontinue;}if (ngx_strncmp(value[n].data, "ipv6only=o", 10) == 0) {#if (NGX_HAVE_INET6 && defined IPV6_V6ONLY)if (ngx_strcmp(&value[n].data[10], "n") == 0) {lsopt.ipv6only = 1;} else if (ngx_strcmp(&value[n].data[10], "ff") == 0) {lsopt.ipv6only = 0;} else {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid ipv6only flags \"%s\"",&value[n].data[9]);return NGX_CONF_ERROR;}lsopt.set = 1;lsopt.bind = 1;continue;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"ipv6only is not supported ""on this platform");return NGX_CONF_ERROR;#endif}if (ngx_strcmp(value[n].data, "reuseport") == 0) {#if (NGX_HAVE_REUSEPORT)lsopt.reuseport = 1;lsopt.set = 1;lsopt.bind = 1;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"reuseport is not supported ""on this platform, ignored");#endifcontinue;}if (ngx_strcmp(value[n].data, "ssl") == 0) {#if (NGX_HTTP_SSL)lsopt.ssl = 1;continue;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"the \"ssl\" parameter requires ""ngx_http_ssl_module");return NGX_CONF_ERROR;#endif}if (ngx_strcmp(value[n].data, "http2") == 0) {#if (NGX_HTTP_V2)lsopt.http2 = 1;continue;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"the \"http2\" parameter requires ""ngx_http_v2_module");return NGX_CONF_ERROR;#endif}if (ngx_strcmp(value[n].data, "spdy") == 0) {ngx_conf_log_error(NGX_LOG_WARN, cf, 0,"invalid parameter \"spdy\": ""ngx_http_spdy_module was superseded ""by ngx_http_v2_module");continue;}if (ngx_strncmp(value[n].data, "so_keepalive=", 13) == 0) {if (ngx_strcmp(&value[n].data[13], "on") == 0) {lsopt.so_keepalive = 1;} else if (ngx_strcmp(&value[n].data[13], "off") == 0) {lsopt.so_keepalive = 2;} else {#if (NGX_HAVE_KEEPALIVE_TUNABLE)u_char *p, *end;ngx_str_t s;end = value[n].data + value[n].len;s.data = value[n].data + 13;p = ngx_strlchr(s.data, end, ':');if (p == NULL) {p = end;}if (p > s.data) {s.len = p - s.data;lsopt.tcp_keepidle = ngx_parse_time(&s, 1);if (lsopt.tcp_keepidle == (time_t) NGX_ERROR) {goto invalid_so_keepalive;}}s.data = (p < end) ? (p + 1) : end;p = ngx_strlchr(s.data, end, ':');if (p == NULL) {p = end;}if (p > s.data) {s.len = p - s.data;lsopt.tcp_keepintvl = ngx_parse_time(&s, 1);if (lsopt.tcp_keepintvl == (time_t) NGX_ERROR) {goto invalid_so_keepalive;}}s.data = (p < end) ? (p + 1) : end;if (s.data < end) {s.len = end - s.data;lsopt.tcp_keepcnt = ngx_atoi(s.data, s.len);if (lsopt.tcp_keepcnt == NGX_ERROR) {goto invalid_so_keepalive;}}if (lsopt.tcp_keepidle == 0 && lsopt.tcp_keepintvl == 0&& lsopt.tcp_keepcnt == 0){goto invalid_so_keepalive;}lsopt.so_keepalive = 1;#elsengx_conf_log_error(NGX_LOG_EMERG, cf, 0,"the \"so_keepalive\" parameter accepts ""only \"on\" or \"off\" on this platform");return NGX_CONF_ERROR;#endif}lsopt.set = 1;lsopt.bind = 1;continue;#if (NGX_HAVE_KEEPALIVE_TUNABLE)invalid_so_keepalive:ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid so_keepalive value: \"%s\"",&value[n].data[13]);return NGX_CONF_ERROR;#endif}if (ngx_strcmp(value[n].data, "proxy_protocol") == 0) {lsopt.proxy_protocol = 1;continue;}ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid parameter \"%V\"", &value[n]);return NGX_CONF_ERROR;}// 将监听端口加入列表for (n = 0; n < u.naddrs; n++) {lsopt.sockaddr = u.addrs[n].sockaddr;lsopt.socklen = u.addrs[n].socklen;lsopt.addr_text = u.addrs[n].name;lsopt.wildcard = ngx_inet_wildcard(lsopt.sockaddr);if (ngx_http_add_listen(cf, cscf, &lsopt) != NGX_OK) {return NGX_CONF_ERROR;}}return NGX_CONF_OK;}
location 的解析则肯定会复杂很多，因为它是一个块级的配置，内部将会有很多复杂的配置，想想这必然又涉及到递归解析了。
// location /xx {..} 的解析static char *ngx_http_core_location(ngx_conf_t *cf, ngx_command_t *cmd, void *dummy){char *rv;u_char *mod;size_t len;ngx_str_t *value, *name;ngx_uint_t i;ngx_conf_t save;ngx_http_module_t *module;ngx_http_conf_ctx_t *ctx, *pctx;ngx_http_core_loc_conf_t *clcf, *pclcf;ctx = ngx_pcalloc(cf->pool, sizeof(ngx_http_conf_ctx_t));if (ctx == NULL) {return NGX_CONF_ERROR;}pctx = cf->ctx;ctx->main_conf = pctx->main_conf;ctx->srv_conf = pctx->srv_conf;ctx->loc_conf = ngx_pcalloc(cf->pool, sizeof(void *) * ngx_http_max_module);if (ctx->loc_conf == NULL) {return NGX_CONF_ERROR;}// 嵌套解析for (i = 0; cf->cycle->modules[i]; i++) {if (cf->cycle->modules[i]->type != NGX_HTTP_MODULE) {continue;}module = cf->cycle->modules[i]->ctx;if (module->create_loc_conf) {// 将解析的值放入 ctx 中，备用ctx->loc_conf[cf->cycle->modules[i]->ctx_index] =module->create_loc_conf(cf);if (ctx->loc_conf[cf->cycle->modules[i]->ctx_index] == NULL) {return NGX_CONF_ERROR;}}}clcf = ctx->loc_conf[ngx_http_core_module.ctx_index];clcf->loc_conf = ctx->loc_conf;value = cf->args->elts;if (cf->args->nelts == 3) {len = value[1].len;mod = value[1].data;name = &value[2];// 疏松写法// uri 模式匹配if (len == 1 && mod[0] == '=') {clcf->name = *name;clcf->exact_match = 1;} else if (len == 2 && mod[0] == '^' && mod[1] == '~') {clcf->name = *name;clcf->noregex = 1;} else if (len == 1 && mod[0] == '~') {if (ngx_http_core_regex_location(cf, clcf, name, 0) != NGX_OK) {return NGX_CONF_ERROR;}} else if (len == 2 && mod[0] == '~' && mod[1] == '*') {if (ngx_http_core_regex_location(cf, clcf, name, 1) != NGX_OK) {return NGX_CONF_ERROR;}} else {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"invalid location modifier \"%V\"", &value[1]);return NGX_CONF_ERROR;}} else {name = &value[1];// 紧密写法if (name->data[0] == '=') {clcf->name.len = name->len - 1;clcf->name.data = name->data + 1;clcf->exact_match = 1;} else if (name->data[0] == '^' && name->data[1] == '~') {clcf->name.len = name->len - 2;clcf->name.data = name->data + 2;clcf->noregex = 1;} else if (name->data[0] == '~') {name->len--;name->data++;if (name->data[0] == '*') {name->len--;name->data++;if (ngx_http_core_regex_location(cf, clcf, name, 1) != NGX_OK) {return NGX_CONF_ERROR;}} else {if (ngx_http_core_regex_location(cf, clcf, name, 0) != NGX_OK) {return NGX_CONF_ERROR;}}} else {clcf->name = *name;if (name->data[0] == '@') {clcf->named = 1;}}}pclcf = pctx->loc_conf[ngx_http_core_module.ctx_index];if (cf->cmd_type == NGX_HTTP_LOC_CONF) {/* nested location */#if 0clcf->prev_location = pclcf;#endifif (pclcf->exact_match) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"location \"%V\" cannot be inside ""the exact location \"%V\"",&clcf->name, &pclcf->name);return NGX_CONF_ERROR;}if (pclcf->named) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"location \"%V\" cannot be inside ""the named location \"%V\"",&clcf->name, &pclcf->name);return NGX_CONF_ERROR;}if (clcf->named) {ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"named location \"%V\" can be ""on the server level only",&clcf->name);return NGX_CONF_ERROR;}len = pclcf->name.len;#if (NGX_PCRE)if (clcf->regex == NULL&& ngx_filename_cmp(clcf->name.data, pclcf->name.data, len) != 0)#elseif (ngx_filename_cmp(clcf->name.data, pclcf->name.data, len) != 0)#endif{ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,"location \"%V\" is outside location \"%V\"",&clcf->name, &pclcf->name);return NGX_CONF_ERROR;}}// 添加到location列表中，备用if (ngx_http_add_location(cf, &pclcf->locations, clcf) != NGX_OK) {return NGX_CONF_ERROR;}save = *cf;cf->ctx = ctx;cf->cmd_type = NGX_HTTP_LOC_CONF;// 递归解析rv = ngx_conf_parse(cf, NULL);*cf = save;return rv;}
同样，它会遍历其http模块下有哪些可以解析的命令，然后交其处理，然后再处理自身的逻辑。从而完成整个块的配置解析。
4. location配置的应用
上一节已经解析出location的各项配置了，那么它是如何运用到实际中呢？实际上，就是在需要的时候，从相应配置变量中取出来使用判定即可。
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出处：https://www.cnblogs.com/yougewe/p/14289846.html
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