0、需求变化 我们想传递参数给 /api.php，比如 /api.php?x=y，其中y是变化的。 1、解决 诊断1：不支持变量 查看源码auth_request指令是不支
0、需求变化
我们想传递参数给 /api.php，比如 /api.php?x=y，其中y是变化的。
1、解决
诊断1：不支持变量
查看源码auth_request指令是不支持变量的。注意，nginx的变量是以$标识的，比如$uri就是个变量，但是如果源码不支持，它就是个字符串值了。
ngx_http_auth_request(ngx_conf_t *cf, ngx_command_t *cmd, void *conf){ ngx_http_auth_request_conf_t *arcf = conf; ngx_str_t *value; if (arcf->uri.data != NULL) { return "is duplicate"; } value = cf->args->elts; if (ngx_strcmp(value[1].data, "off") == 0) { arcf->uri.len = 0; arcf->uri.data = (u_char *) ""; return NGX_CONF_OK; } arcf->uri = value[1]; // 不支持变量，可比较下面的改动 return NGX_CONF_OK;}诊断2：不支持参数
简单讲，auth_request /api.php?p1=a&p2=b...，后面的 ?... 是无效的，后端接收不到，只认uri（/api.php)，一个折衷解决方法就是改变url格式，/api.php/a/b/...
static ngx_int_tngx_http_auth_request_handler(ngx_http_request_t *r){ ... if (ctx != NULL) { ... ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "auth request unexpected status: %d", ctx->status); return NGX_HTTP_INTERNAL_SERVER_ERROR; } . /* 第三个参数NULL,是args参数，所以不支持参数 */ if (ngx_http_subrequest(r, &arcf->uri, NULL, &sr, ps, NGX_HTTP_SUBREQUEST_WAITED) != NGX_OK) { return NGX_ERROR; }
3、改进版源码
/* * Copyright (C) FattyHong * Copyright (C) Maxim Dounin * Copyright (C) Nginx, Inc. *//* proxy_pass directive now support variables */#include <ngx_config.h>#include <ngx_core.h>#include <ngx_http.h>typedef struct { ngx_str_t uri; ngx_array_t *auth_lengths; ngx_array_t *auth_values; ngx_array_t *vars;} ngx_http_auth_request_conf_t;typedef struct { ngx_uint_t done; ngx_uint_t status; ngx_http_request_t *subrequest;} ngx_http_auth_request_ctx_t;typedef struct { ngx_int_t index; ngx_http_complex_value_t value; ngx_http_set_variable_pt set_handler;} ngx_http_auth_request_variable_t;static ngx_int_t ngx_http_auth_request_handler(ngx_http_request_t *r);static ngx_int_t ngx_http_auth_request_done(ngx_http_request_t *r, void *data, ngx_int_t rc);static ngx_int_t ngx_http_auth_request_set_variables(ngx_http_request_t *r, ngx_http_auth_request_conf_t *arcf, ngx_http_auth_request_ctx_t *ctx);static ngx_int_t ngx_http_auth_request_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data);static void *ngx_http_auth_request_create_conf(ngx_conf_t *cf);static char *ngx_http_auth_request_merge_conf(ngx_conf_t *cf, void *parent, void *child);static ngx_int_t ngx_http_auth_request_init(ngx_conf_t *cf);static char *ngx_http_auth_request(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);static char *ngx_http_auth_request_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf);static ngx_command_t ngx_http_auth_request_commands[] = { { ngx_string("auth_request"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE1, ngx_http_auth_request, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, { ngx_string("auth_request_set"), NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_CONF_TAKE2, ngx_http_auth_request_set, NGX_HTTP_LOC_CONF_OFFSET, 0, NULL }, ngx_null_command};static ngx_http_module_t ngx_http_auth_request_module_ctx = { NULL, /* preconfiguration */ ngx_http_auth_request_init, /* postconfiguration */ NULL, /* create main configuration */ NULL, /* init main configuration */ NULL, /* create server configuration */ NULL, /* merge server configuration */ ngx_http_auth_request_create_conf, /* create location configuration */ ngx_http_auth_request_merge_conf /* merge location configuration */};ngx_module_t ngx_http_auth_request_module = { NGX_MODULE_V1, &ngx_http_auth_request_module_ctx, /* module context */ ngx_http_auth_request_commands, /* module directives */ NGX_HTTP_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};static ngx_int_tngx_http_auth_request_handler(ngx_http_request_t *r){ ngx_str_t uri; ngx_table_elt_t *h, *ho; ngx_http_request_t *sr; ngx_http_post_subrequest_t *ps; ngx_http_auth_request_ctx_t *ctx; ngx_http_auth_request_conf_t *arcf; arcf = ngx_http_get_module_loc_conf(r, ngx_http_auth_request_module); if (arcf->uri.len == 0) { return NGX_DECLINED; } ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "auth request handler"); ctx = ngx_http_get_module_ctx(r, ngx_http_auth_request_module); if (ctx != NULL) { if (!ctx->done) { return NGX_AGAIN; } /* * as soon as we are done - explicitly set variables to make * sure they will be available after internal redirects */ if (ngx_http_auth_request_set_variables(r, arcf, ctx) != NGX_OK) { return NGX_ERROR; } /* return appropriate status */ if (ctx->status == NGX_HTTP_FORBIDDEN) { return ctx->status; } if (ctx->status == NGX_HTTP_UNAUTHORIZED) { sr = ctx->subrequest; h = sr->headers_out.www_authenticate; if (!h && sr->upstream) { h = sr->upstream->headers_in.www_authenticate; } if (h) { ho = ngx_list_push(&r->headers_out.headers); if (ho == NULL) { return NGX_ERROR; } *ho = *h; r->headers_out.www_authenticate = ho; } return ctx->status; } if (ctx->status >= NGX_HTTP_OK && ctx->status < NGX_HTTP_SPECIAL_RESPONSE) { return NGX_OK; } ngx_log_error(NGX_LOG_ERR, r->connection->log, 0, "auth request unexpected status: %d", ctx->status); return NGX_HTTP_INTERNAL_SERVER_ERROR; } ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_auth_request_ctx_t)); if (ctx == NULL) { return NGX_ERROR; } ps = ngx_palloc(r->pool, sizeof(ngx_http_post_subrequest_t)); if (ps == NULL) { return NGX_ERROR; } ps->handler = ngx_http_auth_request_done; ps->data = ctx; if (arcf->auth_lengths == NULL) { uri = arcf->uri; } else { if (ngx_http_script_run(r, &uri, arcf->auth_lengths->elts, 0, arcf->auth_values->elts) == NULL) { return NGX_HTTP_INTERNAL_SERVER_ERROR; } } if (ngx_http_subrequest(r, &uri, NULL, &sr, ps, NGX_HTTP_SUBREQUEST_WAITED) != NGX_OK) { return NGX_ERROR; } /* * allocate fake request body to avoid attempts to read it and to make * sure real body file (if already read) won't be closed by upstream */ sr->request_body = ngx_pcalloc(r->pool, sizeof(ngx_http_request_body_t)); if (sr->request_body == NULL) { return NGX_ERROR; } sr->header_only = 1; ctx->subrequest = sr; ngx_http_set_ctx(r, ctx, ngx_http_auth_request_module); return NGX_AGAIN;}static ngx_int_tngx_http_auth_request_done(ngx_http_request_t *r, void *data, ngx_int_t rc){ ngx_http_auth_request_ctx_t *ctx = data; ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "auth request done s:%d", r->headers_out.status); ctx->done = 1; ctx->status = r->headers_out.status; return rc;}static ngx_int_tngx_http_auth_request_set_variables(ngx_http_request_t *r, ngx_http_auth_request_conf_t *arcf, ngx_http_auth_request_ctx_t *ctx){ ngx_str_t val; ngx_http_variable_t *v; ngx_http_variable_value_t *vv; ngx_http_auth_request_variable_t *av, *last; ngx_http_core_main_conf_t *cmcf; ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "auth request set variables"); if (arcf->vars == NULL) { return NGX_OK; } cmcf = ngx_http_get_module_main_conf(r, ngx_http_core_module); v = cmcf->variables.elts; av = arcf->vars->elts; last = av + arcf->vars->nelts; while (av < last) { /* * explicitly set new value to make sure it will be available after * internal redirects */ vv = &r->variables[av->index]; if (ngx_http_complex_value(ctx->subrequest, &av->value, &val) != NGX_OK) { return NGX_ERROR; } vv->valid = 1; vv->not_found = 0; vv->data = val.data; vv->len = val.len; if (av->set_handler) { /* * set_handler only available in cmcf->variables_keys, so we store * it explicitly */ av->set_handler(r, vv, v[av->index].data); } av++; } return NGX_OK;}static ngx_int_tngx_http_auth_request_variable(ngx_http_request_t *r, ngx_http_variable_value_t *v, uintptr_t data){ ngx_log_debug0(NGX_LOG_DEBUG_HTTP, r->connection->log, 0, "auth request variable"); v->not_found = 1; return NGX_OK;}static void *ngx_http_auth_request_create_conf(ngx_conf_t *cf){ ngx_http_auth_request_conf_t *conf; conf = ngx_pcalloc(cf->pool, sizeof(ngx_http_auth_request_conf_t)); if (conf == NULL) { return NULL; } /* * set by ngx_pcalloc(): * * conf->uri = { 0, NULL }; */ conf->vars = NGX_CONF_UNSET_PTR; return conf;}static char *ngx_http_auth_request_merge_conf(ngx_conf_t *cf, void *parent, void *child){ ngx_http_auth_request_conf_t *prev = parent; ngx_http_auth_request_conf_t *conf = child; ngx_conf_merge_str_value(conf->uri, prev->uri, ""); ngx_conf_merge_ptr_value(conf->vars, prev->vars, NULL); return NGX_CONF_OK;}static ngx_int_tngx_http_auth_request_init(ngx_conf_t *cf){ ngx_http_handler_pt *h; ngx_http_core_main_conf_t *cmcf; cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module); h = ngx_array_push(&cmcf->phases[NGX_HTTP_ACCESS_PHASE].handlers); if (h == NULL) { return NGX_ERROR; } *h = ngx_http_auth_request_handler; return NGX_OK;}static char *ngx_http_auth_request(ngx_conf_t *cf, ngx_command_t *cmd, void *conf){ ngx_http_auth_request_conf_t *arcf = conf; ngx_str_t *value, *url; ngx_uint_t n; ngx_http_script_compile_t sc; if (arcf->uri.data != NULL) { return "is duplicate"; } value = cf->args->elts; if (ngx_strcmp(value[1].data, "off") == 0) { arcf->uri.len = 0; arcf->uri.data = (u_char *) ""; return NGX_CONF_OK; } arcf->uri = value[1]; url = &value[1]; n = ngx_http_script_variables_count(url); if (n) { ngx_memzero(&sc, sizeof(ngx_http_script_compile_t)); sc.cf = cf; sc.source = url; sc.lengths = &arcf->auth_lengths; sc.values = &arcf->auth_values; sc.variables = n; sc.complete_lengths = 1; sc.complete_values = 1; if (ngx_http_script_compile(&sc) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK; } return NGX_CONF_OK;}static char *ngx_http_auth_request_set(ngx_conf_t *cf, ngx_command_t *cmd, void *conf){ ngx_http_auth_request_conf_t *arcf = conf; ngx_str_t *value; ngx_http_variable_t *v; ngx_http_auth_request_variable_t *av; ngx_http_compile_complex_value_t ccv; value = cf->args->elts; if (value[1].data[0] != '$') { ngx_conf_log_error(NGX_LOG_EMERG, cf, 0, "invalid variable name /"%V/"", &value[1]); return NGX_CONF_ERROR; } value[1].len--; value[1].data++; if (arcf->vars == NGX_CONF_UNSET_PTR) { arcf->vars = ngx_array_create(cf->pool, 1, sizeof(ngx_http_auth_request_variable_t)); if (arcf->vars == NULL) { return NGX_CONF_ERROR; } } av = ngx_array_push(arcf->vars); if (av == NULL) { return NGX_CONF_ERROR; } v = ngx_http_add_variable(cf, &value[1], NGX_HTTP_VAR_CHANGEABLE); if (v == NULL) { return NGX_CONF_ERROR; } av->index = ngx_http_get_variable_index(cf, &value[1]); if (av->index == NGX_ERROR) { return NGX_CONF_ERROR; } if (v->get_handler == NULL) { v->get_handler = ngx_http_auth_request_variable; v->data = (uintptr_t) av; } av->set_handler = v->set_handler; ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t)); ccv.cf = cf; ccv.value = &value[2]; ccv.complex_value = &av->value; if (ngx_http_compile_complex_value(&ccv) != NGX_OK) { return NGX_CONF_ERROR; } return NGX_CONF_OK;}
4、小结
需求变化是推动技术改进的最直接方式，回避或过度处理都会付出更多技术代价。如上面需求可以不改源码，但会让技术方案实施更复杂。也可以更深度改动，比如把args加进去，这样就必须处理读参数，处理参数等细节，处理有点过头，还不如等需求再变化去推动。所以保持简单和拥抱变化。
