上一篇中，我们了解了如何nginx的配置原则及解析框架，以及解析location配置的具体实现，相信大家对该部分已经有了比较深刻的认识。
本篇，我们进一步来了解下，解析之后的配置，如何应用到实际中的吧。当然，我们只讲解 location 的查找过程。
1. location的接入流程
在nginx的前几篇中，我们已经了解了，nginx对于网络的请求接入过程，是一个基于事件的io模型，这是其高性能的根本。io接入之后，再通过 accept -> read -> init_http -> wait_request -> process_request_line -> process_request_header -> process_request ... 的过程，然后就是具体的处理实现。
而对于location的处理，则是在 ngx_http_handler() 接入之后的分发工作。
// http/ngx_http_core_module.c void ngx_http_handler(ngx_http_request_t *r) { ngx_http_core_main_conf_t *cmcf; r->connection->log->action = NULL; if (!r->internal) { switch (r->headers_in.connection_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->headers_in.content_length_n > 0 || r->headers_in.chunked); r->phase_handler = 0; } else { cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module); 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 r->write_event_handler = ngx_http_core_run_phases; ngx_http_core_run_phases(r); } // http/ngx_http_core_module.c 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; // 依次遍历各checker, 直到有一个可以处理 while (ph[r->phase_handler].checker) { rc = ph[r->phase_handler].checker(r, &ph[r->phase_handler]); if (rc == NGX_OK) { return; } } } ngx_int_t ngx_http_core_find_config_phase(ngx_http_request_t *r, ngx_http_phase_handler_t *ph) { u_char *p; size_t len; ngx_int_t rc; ngx_http_core_loc_conf_t *clcf; r->content_handler = NULL; r->uri_changed = 0; // 查找location的实现，接入查找流程 rc = ngx_http_core_find_location(r); if (rc == NGX_ERROR) { ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR); return NGX_OK; } clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module); if (!r->internal && clcf->internal) { ngx_http_finalize_request(r, NGX_HTTP_NOT_FOUND); return NGX_OK; } ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "using configuration \"%s%V\"", (clcf->noname ? "*" : (clcf->exact_match ? "=" : "")), &clcf->name); // 将查找到的信息，更新到当前会话中 ngx_http_update_location_config(r); ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "http cl:%O max:%O", r->headers_in.content_length_n, clcf->client_max_body_size); if (r->headers_in.content_length_n != -1 && !r->discard_body && clcf->client_max_body_size && clcf->client_max_body_size < r->headers_in.content_length_n) { ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "client intended to send too large body: %O bytes", r->headers_in.content_length_n); r->expect_tested = 1; (void) ngx_http_discard_request_body(r); ngx_http_finalize_request(r, NGX_HTTP_REQUEST_ENTITY_TOO_LARGE); return NGX_OK; } if (rc == NGX_DONE) { ngx_http_clear_location(r); r->headers_out.location = ngx_list_push(&r->headers_out.headers); if (r->headers_out.location == NULL) { ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR); return NGX_OK; } r->headers_out.location->hash = 1; ngx_str_set(&r->headers_out.location->key, "Location"); if (r->args.len == 0) { r->headers_out.location->value = clcf->name; } else { len = clcf->name.len + 1 + r->args.len; p = ngx_pnalloc(r->pool, len); if (p == NULL) { ngx_http_clear_location(r); ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR); return NGX_OK; } r->headers_out.location->value.len = len; r->headers_out.location->value.data = p; p = ngx_cpymem(p, clcf->name.data, clcf->name.len); *p++ = '?'; ngx_memcpy(p, r->args.data, r->args.len); } ngx_http_finalize_request(r, NGX_HTTP_MOVED_PERMANENTLY); return NGX_OK; } r->phase_handler++; return NGX_AGAIN; }