Nginx(六)：配置解析之location解析
nginx成為非常流行的代理服務(wù)軟件，最根本的原因也許是在于其強(qiáng)悍性能。但還有一些必要的條件，比如功能的完整，配置的易用，能夠解決各種各樣的實(shí)際需求問(wèn)題，這些是一個(gè)好的軟件的必備特性。
那么，今天我們就來(lái)看看nginx配置的部分原則和解析原理吧。我們只做location部分的細(xì)節(jié)解析，但其他配置道理基本相通，推一及二即可。
1：nginx配置的基本原則
nginx是支持高度配置化的，那么也許就會(huì)涉及許多部分的配置，要如何協(xié)調(diào)好這些配置，是個(gè)問(wèn)題。比如是否將配置定義一個(gè)個(gè)獨(dú)立的文件，或者其他。
然而，nginx使用一個(gè)統(tǒng)一的配置文件，管理起了所有的配置工作。即 nginx.conf, 其默認(rèn)位置是 $NGINX_HOME/nginx.conf, 在這個(gè)主配置文件中，又可以包含其他任意多的配置文件，從而達(dá)到統(tǒng)一管理的作用。
其默認(rèn)配置nginx.conf如下：
#user nobody;worker_processes 1;#error_log logs/error.log;#error_log logs/error.log notice;#error_log logs/error.log info;#pid logs/nginx.pid;events {worker_connections 1024;}http {include mime.types;default_type application/octet-stream;#log_format main '$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;# }#}}
這很明顯不是什么標(biāo)準(zhǔn)語(yǔ)言語(yǔ)法，但其同樣遵從一定的準(zhǔn)則，從而讓用戶(hù)更易于理解配置。如：
1. 每一個(gè)細(xì)配置項(xiàng)，都使用一個(gè)';'作為結(jié)束標(biāo)識(shí);
2. '#' 代表該行被注釋?zhuān)ㄟ@幾乎是linux默認(rèn)標(biāo)準(zhǔn)）;
3. 使用'{}'表示一個(gè)配置塊，'{}'中代表其子項(xiàng)配置;
4. 使用include可以包含其他文件的配置，相當(dāng)于將其中的配置項(xiàng)copy到當(dāng)前位置，該包含路徑可以是相對(duì)路徑也可以是絕對(duì)路徑;
因此，基本上，你只要按照這個(gè)標(biāo)準(zhǔn)來(lái)做配置，至少語(yǔ)法 是不會(huì)有誤了。但是，具體應(yīng)該如何配置呢？實(shí)際上這要依賴(lài)于某類(lèi)操作的具體實(shí)現(xiàn)，比如 location 的 配置， user 的配置，都是有各自的含義的。如果想要具體了解各細(xì)節(jié)配置，則必須要查詢(xún)官網(wǎng)的配置定義了。請(qǐng)參考：?https://docs.nginx.com/nginx/admin-guide/basic-functionality/managing-configuration-files/
總體上來(lái)說(shuō)，nginx有幾個(gè)頂級(jí)配置:?
events – 連接類(lèi)的配置，比如最大連接數(shù)配置
http – 重頭戲，http模塊配置，所有的代理服務(wù)http服務(wù)都在其子配置下
mail – 郵件配置
stream – TCP、UDP 底層通信協(xié)議配置，功能與http模塊相仿
一般地我們接接觸最多的應(yīng)該就是http配置了，至于其他功能，沒(méi)有實(shí)踐就沒(méi)有發(fā)言權(quán)，略去不說(shuō)。
2. location的配置用例
location的本義是用于定位一個(gè)http請(qǐng)求匹配情況，用于確定某個(gè)路徑的請(qǐng)求應(yīng)該如何做轉(zhuǎn)換處理。它是屬于 http 模塊下的 server 模塊下的一個(gè)選項(xiàng)配置。即 nginx -> http -> server -> location {..} 是其配置體現(xiàn)。它擁有相當(dāng)多的配置項(xiàng)，因?yàn)樽龇聪虼砘蚱渌?wù)器時(shí)，往往都可以通過(guò)這個(gè)配置，將功能完成。
如下幾個(gè)配置項(xiàng)，可供參考：
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;# 路徑相等處理，優(yōu)先級(jí)最高location = / {#...}# 根路徑配置，優(yōu)先級(jí)最低location / {root /data/www;}# 帶前綴的配置，優(yōu)先級(jí)其次location /images/ {root /data;}# 正則匹配的配置，優(yōu)先級(jí)較高location ~ \.(gif|jpg|png)$ {root /data/images;}# 正則取反配置location ^~ \.(php)$ {root /data/other;}# 反向代理的配置，將請(qǐng)求轉(zhuǎn)換給后端服務(wù)# 如果backend是一個(gè) upstream 配置，則做為一個(gè)負(fù)載均衡器使用location /api1 {proxy_set_header Host $host;proxy_set_header X-Real-IP $remote_addr;proxy_pass http://backend;}location /api2 {proxy_pass http://www.abc.com;}# 路徑重寫(xiě)location /users/ {rewrite ^/users/(.*)$ /show?user=$1 break;}# 帶狀態(tài)碼的返回配置location /wrong/url {return 404;open_file_cache_errors off;}location /permanently/moved/url {return 301 http://www.example.com/moved/here;}# 響應(yīng)內(nèi)容替換location / {sub_filter 'href="https://$host/';sub_filter 'img src="http://127.0.0.1:8080/' 'img src="https://$host/';sub_filter_once on;}}}
更多內(nèi)容可查閱官網(wǎng): https://docs.nginx.com/nginx/admin-guide/web-server/web-server/
總體上來(lái)說(shuō)，location提供了可以配置如何查找本地文件，以及可以配置如何轉(zhuǎn)發(fā)請(qǐng)求到其他服務(wù)器的方式。其中，還有很多附加的設(shè)置各種需求變量的實(shí)現(xiàn)，以輔助我們實(shí)現(xiàn)一些正常請(qǐng)求提供的內(nèi)容。配置比較多，到真正使用時(shí)，按需配置即可。一般也是一次配置，永久使用，不會(huì)太費(fèi)事。
3. location配置的解析
nginx有自己的一套配置方法，那么這些配置好了的語(yǔ)句，如何應(yīng)用到具體的服務(wù)上呢？自然是需要先進(jìn)行解析，然后放置到對(duì)應(yīng)的內(nèi)存空間變量中，然后在需要的時(shí)候進(jìn)行讀取判定，以及轉(zhuǎn)換了。大體思路如此，但如何解析配置卻并非易事。因?yàn)槲覀兊呐渲檬菬o(wú)數(shù)現(xiàn)有配置的任意組合，如何有效的放置到可理解的位置，應(yīng)該需要單獨(dú)的數(shù)據(jù)結(jié)構(gòu)設(shè)計(jì)，以及解析步驟。實(shí)際上，這也相當(dāng)于是一個(gè)簡(jiǎn)單的編譯器或解析器，它需要將文本解析為認(rèn)識(shí)的東西。
下面我們就一起來(lái)看看nginx都是如何解析這些配置的吧！（這自然是在啟動(dòng)時(shí)完成的工作）
// 首先，nginx會(huì)解析啟動(dòng)行命令，這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 測(cè)試配置文件有效性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配置文件路徑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) 向現(xiàn)有運(yùn)行的nginx進(jìn)程發(fā)起控制命令case 's':// 緊貼式給出命令: -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，是對(duì)命令行參數(shù)的簡(jiǎn)單解析，解析出來(lái)的變量放入到各全局變量中：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，最重要的是兩個(gè)參數(shù)：-c -s, 用于指定配置文件和操作現(xiàn)有nginx進(jìn)程。當(dāng)然，對(duì)于配置解析，自然最重要的是 -c 命令了。但對(duì)于一些沒(méi)有指定的配置值，則使用系統(tǒng)的默認(rèn)值。其處理如下：
// 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// 默認(rèn)路徑前綴: 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 {// 默認(rèn)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的時(shí)候處理實(shí)現(xiàn)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;}// 使用紅黑樹(shù)存放配置信息ngx_rbtree_init(&cycle->config_dump_rbtree, &cycle->config_dump_sentinel,ngx_str_rbtree_insert_value);// 默認(rèn)使用 20 個(gè)端口服務(wù)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;}// 每個(gè)監(jiān)聽(tīng)端口使用一個(gè) 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;}// 獲取當(dāng)前機(jī)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);// 創(chuàng)建module內(nèi)存空間if (ngx_cycle_modules(cycle) != NGX_OK) {ngx_destroy_pool(pool);return NULL;}// 讓各模塊依次進(jìn)行配置for (i = 0; cycle->modules[i]; i++) {// NGINX_CORE_MODULE 可以進(jìn)行配置文件處理// 即幾套頂級(jí)模塊, http,events,mail,...if (cycle->modules[i]->type != NGX_CORE_MODULE) {continue;}module = cycle->modules[i]->ctx;// 調(diào)用各模塊的 create_conf 實(shí)現(xiàn)配置加載// 其中，以為的http模塊會(huì)進(jìn)行解析，其實(shí)卻沒(méi)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中設(shè)置了幾個(gè)初始化的點(diǎn)，create_conf, init_conf, 供各模塊實(shí)現(xiàn)各自的解析邏輯，以及使用一個(gè)全局的解析? ngx_conf_parse()?實(shí)現(xiàn)文件解析。
那么 http 作為獨(dú)立的模塊，其是否參與配置解析呢？我們看下其模塊的配置即可：
// http 模塊的配置簡(jiǎn)略// http/ngx_http.cstatic ngx_core_module_t ngx_http_module_ctx = {ngx_string("http"),// 不做 create_conf 處理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 文件中進(jìn)行，?有ngx_conf_param(), ngx_conf_parse()?完成具體的解析。
// 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// 如果給定配置文件，則解析if (filename) {/* open configuration file */// 打開(kāi)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;}// 此處實(shí)現(xiàn)真正的解析操作for ( ;; ) {// 重要1: 讀取出一個(gè)個(gè)地token信息, 以pos, start等變量做標(biāo)識(shí)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: 將解析出的變量進(jìn)行細(xì)致處理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;}// 讀取一個(gè)個(gè)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默認(rèn)是最大buffer，pos默認(rèn)為0，所以以下邏輯不一定走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;}// 默認(rèn)兩值相等，len為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);}// 計(jì)算剩余大小size = (ssize_t) (file_size - cf->conf_file->file.offset);// 如果剩余大小超出當(dāng)前緩沖的大小，則只能取當(dāng)前緩沖剩余大小if (size > b->end - (b->start + len)) {size = b->end - (b->start + len);}// 從配置文件中讀取size大小的數(shù)據(jù)出來(lái)，放到buf中備用，相當(dāng)于盡量一次全部讀取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;}// 交換各偏移信息b->pos = b->start + len;b->last = b->pos + n;start = b->start;if (dump) {dump->last = ngx_cpymem(dump->last, b->pos, size);}}// 從文件中讀出一個(gè)字符用以判定，即如果假設(shè)文件已讀取完，則相當(dāng)于一個(gè)個(gè)字符取出判定ch = *b->pos++;// 遇到換行，line++，注釋標(biāo)識(shí)重置if (ch == LF) {cf->conf_file->line++;if (sharp_comment) {sharp_comment = 0;}}// 如果注釋標(biāo)識(shí)有效，則忽略當(dāng)前段的字符，直到標(biāo)識(shí)被清除if (sharp_comment) {continue;}// 引號(hào)閉合處理if (quoted) {quoted = 0;continue;}// 判斷是否有新的語(yǔ)句開(kāi)始，類(lèi)似空格都可以if (need_space) {if (ch == ' ' || ch == '\t' || ch == CR || ch == LF) {last_space = 1;need_space = 0;continue;}// 遇到分號(hào)，當(dāng)前解析結(jié)束，即得到一個(gè)獨(dú)立語(yǔ)句，如 root /www;if (ch == ';') {return NGX_OK;}// 遇到塊也結(jié)束當(dāng)前解析，交由子處理器處理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) {// 新語(yǔ)句開(kāi)始，行號(hào)暫存start = b->pos - 1;start_line = cf->conf_file->line;// 忽略空格類(lèi)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;}// 語(yǔ)句結(jié)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 '\\': // 轉(zhuǎn)義符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 '$': // 變量解析variable = 1;last_space = 0;continue;default:last_space = 0;}} else {// ${xxx} 變量if (ch == '{' && variable) {continue;}variable = 0;if (ch == '\\') {quoted = 1;continue;}if (ch == '$') {variable = 1;continue;}// 引號(hào)處理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; // 完整解析一個(gè)語(yǔ)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;}// 將解析出的語(yǔ)句賦值到 args 中for (dst = word->data, src = start, len = 0;src < b->pos - 1;len++){if (*src == '\\') {switch (src[1]) {case '"':case '\'':case '\\':// 去除轉(zhuǎn)義標(biāo)識(shí)src++;break;case 't':// 翻譯轉(zhuǎn)義*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;}}}}
大體原理是：讀取一個(gè)個(gè)token，然后進(jìn)行依次翻譯，分小語(yǔ)句，大block,... 類(lèi)型依次處理。將解析的結(jié)果放入cf->args中。其解析結(jié)果如 location ~ /api/.*go { ,如 listen 80 81;
還差一個(gè)細(xì)節(jié)，就是讀取到token之后，又是如何傳遞給各模塊的呢？實(shí)際就是上面的重點(diǎn)2：ngx_conf_handler()?處理。
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;// 獲取最后存入的配置變量名name = cf->args->elts;found = 0;// 遍歷模塊的 commands 列表，依次調(diào)用進(jìn)行處理, 比如 root /www 處理// location /api {..} 處理for (i = 0; cf->cycle->modules[i]; i++) {cmd = cf->cycle->modules[i]->commands;if (cmd == NULL) {continue;}for ( /* void */ ; cmd->name.len; cmd++) {// 名字不同必然不負(fù)責(zé)解析if (name->len != cmd->name.len) {continue;}if (ngx_strcmp(name->data, cmd->name.data) != 0) {continue;}found = 1;// 配置模塊處理if (cf->cycle->modules[i]->type != NGX_CONF_MODULE&& cf->cycle->modules[i]->type != cf->module_type){continue;}/* is the directive's location right ? */// 變量類(lèi)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 ? */// 參數(shù)個(gè)數(shù)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;// 找不同的配置級(jí)別位置存儲(chǔ)（這指針用得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];}}// 調(diào)用各命令的set方法，處理配置語(yǔ)義// 實(shí)際上就涉及到內(nèi)嵌套解析問(wèn)題了// 同樣不會(huì)很簡(jiǎn)單哦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;}}// 配置使用錯(cuò)誤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;}
將解析出的配置信息接入到各子模塊之后，才算是真正意義上的解析成功，也才能被各子模塊使用。
下面我們?cè)賮?lái)看個(gè)樣例，子模塊如何解析配置，http location ....
listen 80;?的解析比較簡(jiǎn)單些，有興趣可查看：
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// 更多參數(shù)解析，見(jiàn)官方文檔說(shuō)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;}// 將監(jiān)聽(tīng)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 的解析則肯定會(huì)復(fù)雜很多，因?yàn)樗且粋€(gè)塊級(jí)的配置，內(nèi)部將會(huì)有很多復(fù)雜的配置，想想這必然又涉及到遞歸解析了。
// 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) {// 將解析的值放入 ctx 中，備用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];// 疏松寫(xiě)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];// 緊密寫(xiě)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，備用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;// 遞歸解析rv = ngx_conf_parse(cf, NULL);*cf = save;return rv;}
同樣，它會(huì)遍歷其http模塊下有哪些可以解析的命令，然后交其處理，然后再處理自身的邏輯。從而完成整個(gè)塊的配置解析。
4. location配置的應(yīng)用
上一節(jié)已經(jīng)解析出location的各項(xiàng)配置了，那么它是如何運(yùn)用到實(shí)際中呢？實(shí)際上，就是在需要的時(shí)候，從相應(yīng)配置變量中取出來(lái)使用判定即可。
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出處：https://www.cnblogs.com/yougewe/p/14289846.html
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