nginx怎么處理http請(qǐng)求

//接收到http請(qǐng)求行與請(qǐng)求頭后，http的處理流程,是第一個(gè)http處理請(qǐng)求的讀事件回調(diào)? //這個(gè)函數(shù)執(zhí)行后，將把讀寫(xiě)事件的回調(diào)設(shè)置為ngx_http_request_handler。這樣下次再有事件時(shí)? //將調(diào)用ngx_http_request_handler函數(shù)來(lái)處理，而不會(huì)再調(diào)用ngx_http_process_request了? static?void?ngx_http_process_request(ngx_http_request_t?*r)? {? ??ngx_connection_t?*c;? ??c?=?r->connection;? ??//因?yàn)橐呀?jīng)接收完http請(qǐng)求行、請(qǐng)求頭部了，準(zhǔn)備調(diào)用各個(gè)http模塊處理請(qǐng)求了。? ??//因此需要接收任何來(lái)自客戶端的讀事件，也就不存在接收http請(qǐng)求頭部超時(shí)問(wèn)題? ??if?(c->read->timer_set)?? ??{? ????ngx_del_timer(c->read);? ??}? ??//重新設(shè)置當(dāng)前連接的讀寫(xiě)事件回調(diào)? ??c->read->handler?=?ngx_http_request_handler;? ??c->write->handler?=?ngx_http_request_handler;? ??//設(shè)置http請(qǐng)求對(duì)象的讀事件回調(diào)，這個(gè)回調(diào)不做任何的事情。? ??//那http請(qǐng)求對(duì)象的讀事件回調(diào)，與上面的連接對(duì)應(yīng)的讀事件回調(diào)有什么關(guān)系呢?? ??//當(dāng)讀事件發(fā)生后，連接對(duì)應(yīng)的讀事件回調(diào)ngx_http_request_handler會(huì)被調(diào)用，? ??//在這個(gè)回調(diào)內(nèi)會(huì)調(diào)用http請(qǐng)求對(duì)象的讀事件回調(diào)ngx_http_block_reading，而這個(gè)回調(diào)是? ??//不會(huì)做任何事件的，因此相當(dāng)于忽略了讀事件。因?yàn)橐呀?jīng)接收完了請(qǐng)求行請(qǐng)求頭，現(xiàn)在要做的是調(diào)用各個(gè)http模塊，? ??//對(duì)接收到的請(qǐng)求行請(qǐng)求頭進(jìn)行處理? ??r->read_event_handler?=?ngx_http_block_reading;? ? ??//調(diào)用各個(gè)http模塊協(xié)同處理這個(gè)請(qǐng)求? ??ngx_http_handler(r);? ??//處理子請(qǐng)求? ??ngx_http_run_posted_requests(c);? }

//http請(qǐng)求處理讀與寫(xiě)事件的回調(diào)，在ngx_http_process_request函數(shù)中設(shè)置。? //這個(gè)函數(shù)中將會(huì)調(diào)用http請(qǐng)求對(duì)象的讀寫(xiě)事件回調(diào)。將event事件模塊與http框架關(guān)聯(lián)起來(lái)? static?void?ngx_http_request_handler(ngx_event_t?*ev)? {? ??//如果同時(shí)發(fā)生讀寫(xiě)事件，則只有寫(xiě)事件才會(huì)觸發(fā)。寫(xiě)事件優(yōu)先級(jí)更高? ??if?(ev->write)?? ??{? ????r->write_event_handler(r);??//在函數(shù)ngx_http_handler設(shè)置為:ngx_http_core_run_phases? ? ??}? ??else? ??{? ????r->read_event_handler(r);??//在函數(shù)ngx_http_process_request設(shè)置為:ngx_http_block_reading? ??}? ? ??//處理子請(qǐng)求? ??ngx_http_run_posted_requests(c);? }

//調(diào)用各個(gè)http模塊協(xié)同處理這個(gè)請(qǐng)求? void?ngx_http_handler(ngx_http_request_t?*r)? {? ??//不需要進(jìn)行內(nèi)部跳轉(zhuǎn)。什么是內(nèi)部跳轉(zhuǎn)??例如有個(gè)location結(jié)構(gòu)，里面的? ??//? ??if?(!r->internal)??? ??{? ????//將數(shù)組序號(hào)設(shè)為0,表示從數(shù)組第一個(gè)元素開(kāi)始處理http請(qǐng)求? ????//這個(gè)下標(biāo)很重要，決定了當(dāng)前要處理的是11個(gè)階段中的哪一個(gè)階段，? ????//以及由這個(gè)階段的哪個(gè)http模塊處理請(qǐng)求? ????r->phase_handler?=?0;? ??}?? ??else?? ??{? ????//需要做內(nèi)部跳轉(zhuǎn)? ????cmcf?=?ngx_http_get_module_main_conf(r,?ngx_http_core_module);? ????//將序號(hào)設(shè)置為server_rewrite_index? ????r->phase_handler?=?cmcf->phase_engine.server_rewrite_index;? ??}? ??//設(shè)置請(qǐng)求對(duì)象的寫(xiě)事件回調(diào)，這個(gè)回調(diào)將會(huì)調(diào)度介入11個(gè)http階段的各個(gè)http模塊? ??//共同完成對(duì)請(qǐng)求的處理? ??r->write_event_handler?=?ngx_http_core_run_phases;? ??//開(kāi)始調(diào)度介入11個(gè)http階段的各個(gè)http模塊? ??ngx_http_core_run_phases(r);? }

//調(diào)用各個(gè)http模塊協(xié)同處理這個(gè)請(qǐng)求,?checker函數(shù)內(nèi)部會(huì)修改phase_handler? void?ngx_http_core_run_phases(ngx_http_request_t?*r)? {? ??cmcf?=?ngx_http_get_module_main_conf(r,?ngx_http_core_module);? ??ph?=?cmcf->phase_engine.handlers;? ??//調(diào)用各個(gè)http模塊的checker方法，使得各個(gè)http模塊可以介入http請(qǐng)求? ??while?(ph[r->phase_handler].checker)? ??{? ????rc?=?ph[r->phase_handler].checker(r,?&ph[r->phase_handler]);? ????//從http模塊返回ngx_ok，http框架則會(huì)把控制全交還給事件模塊? ????if?(rc?==?ngx_ok)????? ????{? ??????return;? ????}? ??}

//開(kāi)始解析http塊? static?char?*?ngx_http_block(ngx_conf_t?*cf,?ngx_command_t?*cmd,?void?*conf)? {? ??//http配置解析完成后的后續(xù)處理,使得各個(gè)http模塊可以介入到11個(gè)http階段? ??for?(m?=?0;?ngx_modules[m];?m++)?? ??{? ????if?(ngx_modules[m]->type?!=?ngx_http_module)?? ????{? ??????continue;? ????}? ? ????module?=?ngx_modules[m]->ctx;? ????if?(module->postconfiguration)?? ????{? ??????//每一個(gè)http模塊的在這個(gè)postconfiguration函數(shù)中，都可以把自己注冊(cè)到11個(gè)http階段? ??????if?(module->postconfiguration(cf)?!=?ngx_ok)?? ??????{? ????????return?ngx_conf_error;? ??????}? ????}? ??}? }

//靜態(tài)模塊將自己注冊(cè)到11個(gè)http請(qǐng)求階段中的ngx_http_content_phase階段? static?ngx_int_t?ngx_http_static_init(ngx_conf_t?*cf)? {? ??cmcf?=?ngx_http_conf_get_module_main_conf(cf,?ngx_http_core_module);? ??h?=?ngx_array_push(&cmcf->phases[ngx_http_content_phase].handlers);? ? ??//靜態(tài)模塊在ngx_http_content_phase階段的處理方法? ??*h?=?ngx_http_static_handler;? ? ??return?ngx_ok;? }

//訪問(wèn)權(quán)限模塊將自己注冊(cè)到11個(gè)http請(qǐng)求階段中的ngx_http_access_phase階段? static?ngx_int_t?ngx_http_access_init(ngx_conf_t?*cf)? {? ??cmcf?=?ngx_http_conf_get_module_main_conf(cf,?ngx_http_core_module);? ??h?=?ngx_array_push(&cmcf->phases[ngx_http_access_phase].handlers);? ??? ??//訪問(wèn)權(quán)限模塊在ngx_http_access_phase階段的處理方法? ??*h?=?ngx_http_access_handler;? ??? ??return?ngx_ok;? }

//開(kāi)始解析http塊? static?char?*?ngx_http_block(ngx_conf_t?*cf,?ngx_command_t?*cmd,?void?*conf)? {? ????//初始化請(qǐng)求的各個(gè)階段? ??if?(ngx_http_init_phase_handlers(cf,?cmcf)?!=?ngx_ok)?? ??{? ????return?ngx_conf_error;? ??}? }

//初始化請(qǐng)求的各個(gè)階段? static?ngx_int_t?ngx_http_init_phase_handlers(ngx_conf_t?*cf,?ngx_http_core_main_conf_t?*cmcf)? {? ??//11個(gè)http請(qǐng)求階段，每一個(gè)階段都可以有多個(gè)http模塊介入。? ??//這里統(tǒng)計(jì)11個(gè)節(jié)點(diǎn)一共有多個(gè)少http模塊。以便下面開(kāi)辟空間? ??for?(i?=?0;?i?phases[i].handlers.nelts;? ??}? ??//開(kāi)辟空間，存放介入11個(gè)處理階段的所有http模塊的回調(diào)? ??ph?=?ngx_pcalloc(cf->pool,n?*?sizeof(ngx_http_phase_handler_t)?+?sizeof(void?*));? ??cmcf->phase_engine.handlers?=?ph;? ??n?=?0;? ? ??//對(duì)于每一個(gè)http處理階段，給該階段中所有介入的http模塊賦值? ??for?(i?=?0;?i?phases[i].handlers.elts;? ? ????switch?(i)?? ????{? ??????case?ngx_http_server_rewrite_phase://根據(jù)請(qǐng)求的uri查找location之前，修改請(qǐng)求的uri階段? ????????if?(cmcf->phase_engine.server_rewrite_index?==?(ngx_uint_t)?-1)?? ????????{? ??????????cmcf->phase_engine.server_rewrite_index?=?n;?//重定向模塊在數(shù)組中的位置? ????????}? ????????checker?=?ngx_http_core_rewrite_phase;???//每一個(gè)階段的checker回調(diào)? ????????break;? ??????case?ngx_http_find_config_phase://根據(jù)請(qǐng)求的uri查找location階段(只能由http框架實(shí)現(xiàn))? ????????find_config_index?=?n;? ????????ph->checker?=?ngx_http_core_find_config_phase;? ????????n++;? ????????ph++;? ????????continue;? ??????case?ngx_http_rewrite_phase:??//根據(jù)請(qǐng)求的rui查找location之后，修改請(qǐng)求的uri階段? ????????if?(cmcf->phase_engine.location_rewrite_index?==?(ngx_uint_t)?-1)? ????????{? ??????????cmcf->phase_engine.location_rewrite_index?=?n;? ????????}? ????????checker?=?ngx_http_core_rewrite_phase;? ????????break;? ??????case?ngx_http_post_rewrite_phase:?//ngx_http_rewrite_phase階段修改rul后，防止遞歸修改uri導(dǎo)致死循環(huán)階段? ????????if?(use_rewrite)?? ????????{? ??????????ph->checker?=?ngx_http_core_post_rewrite_phase;? ??????????ph->next?=?find_config_index;//目的是為了地址重寫(xiě)后，跳轉(zhuǎn)到ngx_http_find_config_phase階段，根據(jù)? ????????????????????????//url重寫(xiě)查找location? ??????????n++;? ??????????ph++;? ????????}? ????????continue;? ??????case?ngx_http_access_phase:?????//是否允許訪問(wèn)服務(wù)器階段? ????????checker?=?ngx_http_core_access_phase;? ????????n++;? ????????break;? ??????case?ngx_http_post_access_phase:??//根據(jù)ngx_http_access_phase階段的錯(cuò)誤碼，給客戶端構(gòu)造響應(yīng)階段? ????????if?(use_access)?? ????????{? ??????????ph->checker?=?ngx_http_core_post_access_phase;? ??????????ph->next?=?n;? ??????????ph++;? ????????}? ????????continue;? ??????case?ngx_http_try_files_phase:???//try_file階段? ????????if?(cmcf->try_files)?? ????????{? ??????????ph->checker?=?ngx_http_core_try_files_phase;? ??????????n++;? ??????????ph++;? ????????}? ????????continue;? ??????case?ngx_http_content_phase:????//處理http請(qǐng)求內(nèi)容階段，大部分http模塊最愿意介入的階段? ????????checker?=?ngx_http_core_content_phase;? ????????break;? ??????default:? ????????//ngx_http_post_read_phase,?? ????????//ngx_http_preaccess_phase,?? ????????//ngx_http_log_phase三個(gè)階段的checker方法? ????????checker?=?ngx_http_core_generic_phase;? ????}? ????n?+=?cmcf->phases[i].handlers.nelts;? ????//每一個(gè)階段中所介入的所有http模塊，同一個(gè)階段中的所有http模塊有唯一的checker回調(diào)，? ????//但handler回調(diào)每一個(gè)模塊自己實(shí)現(xiàn)? ????for?(j?=?cmcf->phases[i].handlers.nelts?-?1;?j?>=0;?j--)?? ????{? ??????ph->checker?=?checker;????? ??????ph->handler?=?h[j];? ??????ph->next?=?n;? ??????ph++;? ????}? ??}? ??return?ngx_ok;? }

//ngx_http_post_read_phase,?? //ngx_http_preaccess_phase,?? //ngx_http_log_phase三個(gè)階段的checker方法? //返回值:?ngx_ok，http框架會(huì)將控制權(quán)交還給epoll模塊? ngx_int_t?ngx_http_core_generic_phase(ngx_http_request_t?*r,ngx_http_phase_handler_t?*ph)? {? ??ngx_int_t?rc;? ??//調(diào)用http模塊的處理方法，這樣這個(gè)http模塊就介入到了這個(gè)請(qǐng)求階段? ??rc?=?ph->handler(r);? ??//跳轉(zhuǎn)到下一個(gè)http階段執(zhí)行? ??if?(rc?==?ngx_ok)????????? ??{? ????r->phase_handler?=?ph->next;? ????return?ngx_again;? ??}? ??? ??//執(zhí)行本階段的下一個(gè)http模塊? ??if?(rc?==?ngx_declined)?????? ??{? ????r->phase_handler++;? ????return?ngx_again;? ??}? ? ??//表示剛執(zhí)行的handler無(wú)法在這一次調(diào)度中處理完這一個(gè)階段，? ??//需要多次調(diào)度才能完成? ??if?(rc?==?ngx_again?||?rc?==?ngx_done)?? ??????????????????????? ??{? ????return?ngx_ok;? ??}? ??//返回出錯(cuò)? ??/*?rc?==?ngx_error?||?rc?==?ngx_http_...?*/? ??ngx_http_finalize_request(r,?rc);? ? ??return?ngx_ok;? }