Nginx源码阅读（ngx

Nginx源码阅读（ngx

ngx_http_process_request()执行流程

ngx_http_process_request() {...ngx_http_handler() {...ngx_http_core_run_phases()}ngx_http_run_posted_requests() // 处理post请求
}

ngx_http_process_request()

void
ngx_http_process_request(ngx_http_request_t *r)
{ngx_connection_t  *c;c = r->connection;#if (NGX_HTTP_SSL)if (r->http_connection->ssl) {long                      rc;X509                     *cert;ngx_http_ssl_srv_conf_t  *sscf;if (c->ssl == NULL) {ngx_log_error(NGX_LOG_INFO, c->log, 0,"client sent plain HTTP request to HTTPS port");ngx_http_finalize_request(r, NGX_HTTP_TO_HTTPS);return;}sscf = ngx_http_get_module_srv_conf(r, ngx_http_ssl_module);if (sscf->verify) {rc = SSL_get_verify_result(c->ssl->connection);if (rc != X509_V_OK&& (sscf->verify != 3 || !ngx_ssl_verify_error_optional(rc))){ngx_log_error(NGX_LOG_INFO, c->log, 0,"client SSL certificate verify error: (%l:%s)",rc, X509_verify_cert_error_string(rc));ngx_ssl_remove_cached_session(sscf-&,(SSL_get0_session(c->ssl->connection)));ngx_http_finalize_request(r, NGX_HTTPS_CERT_ERROR);return;}if (sscf->verify == 1) {cert = SSL_get_peer_certificate(c->ssl->connection);if (cert == NULL) {ngx_log_error(NGX_LOG_INFO, c->log, 0,"client sent no required SSL certificate");ngx_ssl_remove_cached_session(sscf-&,(SSL_get0_session(c->ssl->connection)));ngx_http_finalize_request(r, NGX_HTTPS_NO_CERT);return;}X509_free(cert);}}}#endif// 若读事件在定时器中if (c->read->timer_set) {// 将读事件从定时器中删除ngx_del_timer(c->read);}#if (NGX_STAT_STUB)(void) ngx_atomic_fetch_add(ngx_stat_reading, -1);r->stat_reading = 0;(void) ngx_atomic_fetch_add(ngx_stat_writing, 1);r->stat_writing = 1;
#endif// 修改读写事件的回调函数为ngx_http_request_handler()c->read->handler = ngx_http_request_handler;c->write->handler = ngx_http_request_handler;// 设置r->read_event_handler为ngx_http_block_reading()r->read_event_handler = ngx_http_block_reading;ngx_http_handler(r);ngx_http_run_posted_requests(c);
}// 调用r->read_event_handler或r->write_event_handler
static void
ngx_http_request_handler(ngx_event_t *ev)
{ngx_connection_t    *c;ngx_http_request_t  *r;c = ev->data;r = c->data;ngx_http_set_log_request(c->log, r);ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,"http run request: "%V?%V"", &r->uri, &r->args);if (ev->write) {r->write_event_handler(r);} else {r->read_event_handler(r);}ngx_http_run_posted_requests(c);
}void
ngx_http_block_reading(ngx_http_request_t *r)
{ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,"http reading blocked");/* aio does not call this handler */if ((ngx_event_flags & NGX_USE_LEVEL_EVENT)&& r->connection->read->active){if (ngx_del_event(r->connection->read, NGX_READ_EVENT, 0) != NGX_OK) {ngx_http_close_request(r, 0);}}
}

ngx_http_handler()

/* ngx_http_phase_engine_t结构体的handlers数组保存了请求需要经历的所有回调方法，ngx_http_request_t结构体的phase_handler指定着请求将要执行的handlers数组中的方法位置 */
typedef struct {...ngx_http_phase_engine_t    phase_engine;...
} ngx_http_core_main_conf_t;typedef struct {ngx_http_phase_handler_t  *handlers;...
} ngx_http_phase_engine_t;struct ngx_http_phase_handler_s {ngx_http_phase_handler_pt  checker; // 同一阶段的所有handler的checker相同ngx_http_handler_pt        handler;ngx_uint_t                 next;
};

void
ngx_http_handler(ngx_http_request_t *r)
{ngx_http_core_main_conf_t  *cmcf;r->connection->log->action = NULL;r->connection->unexpected_eof = 0;// 若不需要重定向if (!r->internal) {switch (r->tion_type) {case 0:r->keepalive = (r->http_version > NGX_HTTP_VERSION_10);break;case NGX_HTTP_CONNECTION_CLOSE:r->keepalive = 0;break;case NGX_HTTP_CONNECTION_KEEP_ALIVE:r->keepalive = 1;break;}r->lingering_close = (r->t_length_n > 0|| r->headers_in.chunked);// phase_handler为0表示从ngx_http_phase_engine_t结构体的handlers数组的第一个回调方法开始执行r->phase_handler = 0;} else {cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);// phase_handler为server_rewrite_index表示从NGX_HTTP_SERVER_REWRITE_PHASE阶段的第一个回调方法开始执行r->phase_handler = cmcf->phase_engine.server_rewrite_index;}r->valid_location = 1;
#if (NGX_HTTP_GZIP)r->gzip_tested = 0;r->gzip_ok = 0;r->gzip_vary = 0;
#endif// 设置r->write_event_handler为ngx_http_core_run_phases()并执行该函数r->write_event_handler = ngx_http_core_run_phases;ngx_http_core_run_phases(r);
}

ngx_http_core_run_phase()

void
ngx_http_core_run_phases(ngx_http_request_t *r)
{ngx_int_t                   rc;ngx_http_phase_handler_t   *ph;ngx_http_core_main_conf_t  *cmcf;cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module);ph = cmcf->phase_engine.handlers;while (ph[r->phase_handler].checker) {// checker方法会修改r->phase_handlerrc = ph[r->phase_handler].checker(r, &ph[r->phase_handler]);// 若checker方法返回NGX_OK，意味着把控制权交还给事件模块；否则意味着向下执行handlers数组中的回调方法if (rc == NGX_OK) {return;}}
}

ngx_http_request_handler()

static void
ngx_http_request_handler(ngx_event_t *ev)
{ngx_connection_t    *c;ngx_http_request_t  *r;c = ev->data;r = c->data;ngx_http_set_log_request(c->log, r);ngx_log_debug2(NGX_LOG_DEBUG_HTTP, c->log, 0,"http run request: "%V?%V"", &r->uri, &r->args);if (ev->write) {r->write_event_handler(r); // 调用ngx_http_core_run_phases()} else {r->read_event_handler(r); // 调用ngx_http_block_reading()}ngx_http_run_posted_requests(c); // 处理post请求
}