feat: server rewrite code

add 2 directive
1. server_rewrite_by_lua_block
2. server_rewrite_by_lua_file

Author: xiaobiaozhao

config

@@ -261,6 +261,7 @@ HTTP_LUA_SRCS=" \
             $ngx_addon_dir/src/ngx_http_lua_util.c \
             $ngx_addon_dir/src/ngx_http_lua_cache.c \
             $ngx_addon_dir/src/ngx_http_lua_contentby.c \
+            $ngx_addon_dir/src/ngx_http_lua_server_rewriteby.c \
             $ngx_addon_dir/src/ngx_http_lua_rewriteby.c \
             $ngx_addon_dir/src/ngx_http_lua_accessby.c \
             $ngx_addon_dir/src/ngx_http_lua_setby.c \
@@ -325,6 +326,7 @@ HTTP_LUA_DEPS=" \
             $ngx_addon_dir/src/ngx_http_lua_util.h \
             $ngx_addon_dir/src/ngx_http_lua_cache.h \
             $ngx_addon_dir/src/ngx_http_lua_contentby.h \
+            $ngx_addon_dir/src/ngx_http_lua_server_rewriteby.c \
             $ngx_addon_dir/src/ngx_http_lua_rewriteby.h \
             $ngx_addon_dir/src/ngx_http_lua_accessby.h \
             $ngx_addon_dir/src/ngx_http_lua_setby.h \

doc/HttpLuaModule.wiki

@@ -1568,6 +1568,88 @@ Nginx variables are supported in the file path for dynamic dispatch, for example
 
 But be very careful about malicious user inputs and always carefully validate or filter out the user-supplied path components.
 
+== server_rewrite_by_lua_block ==
+
+'''syntax:''' ''server_rewrite_by_lua_block { lua-script }''
+
+'''context:''' ''http, server''
+
+'''phase:''' ''server rewrite''
+
+Acts as a server rewrite phase handler and executes Lua code string specified in <code>{ lua-script }</code> for every request.
+The Lua code may make [[#Nginx API for Lua|API calls]] and is executed as a new spawned coroutine in an independent global environment (i.e. a sandbox).
+
+<geshi lang="nginx">
+server {
+    ...
+
+    server_rewrite_by_lua_block {
+        ngx.ctx.a = "server_rewrite_by_lua_block in http"
+    }
+
+    location /lua {
+        content_by_lua_block {
+            ngx.say(ngx.ctx.a)
+            ngx.log(ngx.INFO, ngx.ctx.a)
+       	}
+    }
+}
+</geshi>
+
+Just as any other rewrite phase handlers, [[#server_rewrite_by_lua_block|server_rewrite_by_lua_block]] also runs in subrequests.
+
+<geshi lang="nginx">
+server {
+    server_rewrite_by_lua_block {
+        ngx.log(ngx.INFO, "is_subrequest:", ngx.is_subrequest)
+    }
+
+    location /lua {
+        content_by_lua_block {
+            local res = ngx.location.capture("/sub")
+            ngx.print(res.body)
+        }
+    }
+
+    location /sub {
+        content_by_lua_block {
+            ngx.say("OK")
+        }
+    }
+}
+</geshi>
+
+Note that when calling <code>ngx.exit(ngx.OK)</code> within a [[#server_rewrite_by_lua_block|server_rewrite_by_lua_block]] handler, the Nginx request processing control flow will still continue to the content handler. To terminate the current request from within a [[#server_rewrite_by_lua_block|server_rewrite_by_lua_block]] handler, call [[#ngx.exit|ngx.exit]] with status >= 200 (<code>ngx.HTTP_OK</code>) and status < 300 (<code>ngx.HTTP_SPECIAL_RESPONSE</code>) for successful quits and <code>ngx.exit(ngx.HTTP_INTERNAL_SERVER_ERROR)</code> (or its friends) for failures.
+
+
+<geshi lang="nginx">
+    server_rewrite_by_lua_block {
+        ngx.exit(503)
+    }
+
+    location /bar {
+        ...
+        # never exec
+    }
+</geshi>
+
+
+== server_rewrite_by_lua_file ==
+
+'''syntax:''' ''server_rewrite_by_lua_file <path-to-lua-script-file>''
+
+'''context:''' ''http, server''
+
+'''phase:''' ''server rewrite''
+
+Equivalent to [[#server_rewrite_by_lua_block|server_rewrite_by_lua_block]], except that the file specified by <code><path-to-lua-script-file></code> contains the Lua code, or, as from the <code>v0.10.22</code> release, the [[#LuaJIT bytecode support|LuaJIT bytecode]] to be executed.
+
+Nginx variables can be used in the <code><path-to-lua-script-file></code> string to provide flexibility. This however carries some risks and is not ordinarily recommended.
+
+When a relative path like <code>foo/bar.lua</code> is given, they will be turned into the absolute path relative to the <code>server prefix</code> path determined by the <code>-p PATH</code> command-line option while starting the Nginx server.
+
+When the Lua code cache is turned on (by default), the user code is loaded once at the first request and cached and the Nginx config must be reloaded each time the Lua source file is modified. The Lua code cache can be temporarily disabled during development by switching [[#lua_code_cache|lua_code_cache]] <code>off</code> in <code>nginx.conf</code> to avoid reloading Nginx.
+
 == rewrite_by_lua ==
 
 '''syntax:''' ''rewrite_by_lua <lua-script-str>''

src/ngx_http_lua_common.h

@@ -305,6 +305,7 @@ struct ngx_http_lua_main_conf_s {
     unsigned             requires_log:1;
     unsigned             requires_shm:1;
     unsigned             requires_capture_log:1;
+    unsigned             requires_server_rewrite:1;
 };
 
 
@@ -368,6 +369,7 @@ typedef struct {
 
     ngx_flag_t              http10_buffering;
 
+    ngx_http_handler_pt     server_rewrite_handler;
     ngx_http_handler_pt     rewrite_handler;
     ngx_http_handler_pt     access_handler;
     ngx_http_handler_pt     content_handler;
@@ -376,6 +378,14 @@ typedef struct {
 
     ngx_http_output_body_filter_pt         body_filter_handler;
 
+    u_char *server_rewrite_chunkname;
+    ngx_http_complex_value_t server_rewrite_src; /*  server_rewrite_by_lua
+                                             inline script/script
+                                             file path */
+
+    u_char *server_rewrite_src_key; /* cached key for server_rewrite_src */
+    int server_rewrite_src_ref;
+
     u_char                  *rewrite_chunkname;
     ngx_http_complex_value_t rewrite_src;    /*  rewrite_by_lua
                                                 inline script/script
@@ -629,7 +639,7 @@ typedef struct ngx_http_lua_ctx_s {
                                        response headers */
     unsigned         mime_set:1;    /* whether the user has set Content-Type
                                        response header */
-
+    unsigned         entered_server_rewrite_phase:1;
     unsigned         entered_rewrite_phase:1;
     unsigned         entered_access_phase:1;
     unsigned         entered_content_phase:1;

src/ngx_http_lua_directive.c

@@ -17,6 +17,7 @@
 #include "ngx_http_lua_cache.h"
 #include "ngx_http_lua_contentby.h"
 #include "ngx_http_lua_accessby.h"
+#include "ngx_http_lua_server_rewriteby.h"
 #include "ngx_http_lua_rewriteby.h"
 #include "ngx_http_lua_logby.h"
 #include "ngx_http_lua_headerfilterby.h"
@@ -590,6 +591,88 @@ ngx_http_lua_rewrite_by_lua(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
 }
 
 
+char *
+ngx_http_lua_server_rewrite_by_lua_block(ngx_conf_t *cf,
+    ngx_command_t *cmd, void *conf)
+{
+    char        *rv;
+    ngx_conf_t   save;
+    save = *cf;
+    cf->handler = ngx_http_lua_server_rewrite_by_lua;
+    cf->handler_conf = conf;
+
+    rv = ngx_http_lua_conf_lua_block_parse(cf, cmd);
+
+    *cf = save;
+
+    return rv;
+}
+
+
+char *
+ngx_http_lua_server_rewrite_by_lua(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf)
+{
+    u_char                      *cache_key = NULL;
+    ngx_str_t                   *value;
+    ngx_http_lua_main_conf_t    *lmcf;
+    ngx_http_lua_loc_conf_t     *llcf = conf;
+
+    ngx_http_compile_complex_value_t         ccv;
+
+    dd("enter");
+
+    /*  must specify a content handler */
+    if (cmd->post == NULL) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (llcf->server_rewrite_handler) {
+        return "is duplicate";
+    }
+
+    value = cf->args->elts;
+
+    if (value[1].len == 0) {
+        /*  Oops...Invalid location conf */
+        ngx_conf_log_error(NGX_LOG_ERR, cf, 0,
+                           "invalid location config: no runnable Lua code");
+
+        return NGX_CONF_ERROR;
+    }
+
+    /* only for by_file */
+    ngx_memzero(&ccv, sizeof(ngx_http_compile_complex_value_t));
+    ccv.cf = cf;
+    ccv.value = &value[1];
+    ccv.complex_value = &llcf->server_rewrite_src;
+
+    if (ngx_http_compile_complex_value(&ccv) != NGX_OK) {
+        return NGX_CONF_ERROR;
+    }
+
+    if (llcf->server_rewrite_src.lengths == NULL) {
+        /* no variable found */
+        cache_key = ngx_http_lua_gen_file_cache_key(cf, value[1].data,
+                                                    value[1].len);
+        if (cache_key == NULL) {
+            return NGX_CONF_ERROR;
+        }
+    }
+
+
+    llcf->server_rewrite_src_key = cache_key;
+    llcf->server_rewrite_handler = (ngx_http_handler_pt) cmd->post;
+
+    lmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_lua_module);
+
+    lmcf->requires_server_rewrite = 1;
+    lmcf->requires_capture_filter = 1;
+
+    return NGX_CONF_OK;
+}
+
+
 char *
 ngx_http_lua_access_by_lua_block(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf)

src/ngx_http_lua_directive.h

@@ -25,6 +25,10 @@ char *ngx_http_lua_content_by_lua_block(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
 char *ngx_http_lua_content_by_lua(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
+char *ngx_http_lua_server_rewrite_by_lua(ngx_conf_t *cf, ngx_command_t *cmd,
+    void *conf);
+char *ngx_http_lua_server_rewrite_by_lua_block(ngx_conf_t *cf,
+    ngx_command_t *cmd, void *conf);
 char *ngx_http_lua_rewrite_by_lua_block(ngx_conf_t *cf, ngx_command_t *cmd,
     void *conf);
 char *ngx_http_lua_rewrite_by_lua(ngx_conf_t *cf, ngx_command_t *cmd,

src/ngx_http_lua_module.c

@@ -14,6 +14,7 @@
 #include "ngx_http_lua_directive.h"
 #include "ngx_http_lua_capturefilter.h"
 #include "ngx_http_lua_contentby.h"
+#include "ngx_http_lua_server_rewriteby.h"
 #include "ngx_http_lua_rewriteby.h"
 #include "ngx_http_lua_accessby.h"
 #include "ngx_http_lua_logby.h"
@@ -290,6 +291,22 @@ static ngx_command_t ngx_http_lua_cmds[] = {
       (void *) ngx_http_lua_filter_set_by_lua_file },
 #endif
 
+    /* server_rewrite_by_lua_block { <inline script> } */
+    { ngx_string("server_rewrite_by_lua_block"),
+        NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_BLOCK|NGX_CONF_NOARGS,
+        ngx_http_lua_server_rewrite_by_lua_block,
+        NGX_HTTP_LOC_CONF_OFFSET,
+        0,
+        (void *) ngx_http_lua_server_rewrite_handler_inline },
+
+    /* server_rewrite_by_lua_file filename; */
+    { ngx_string("server_rewrite_by_lua_file"),
+        NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_CONF_TAKE1,
+        ngx_http_lua_server_rewrite_by_lua,
+        NGX_HTTP_LOC_CONF_OFFSET,
+        0,
+        (void *) ngx_http_lua_server_rewrite_handler_file },
+
     /* rewrite_by_lua "<inline script>" */
     { ngx_string("rewrite_by_lua"),
       NGX_HTTP_MAIN_CONF|NGX_HTTP_SRV_CONF|NGX_HTTP_LOC_CONF|NGX_HTTP_LIF_CONF
@@ -752,6 +769,16 @@ ngx_http_lua_init(ngx_conf_t *cf)
 
     cmcf = ngx_http_conf_get_module_main_conf(cf, ngx_http_core_module);
 
+    if (lmcf->requires_server_rewrite) {
+        h = ngx_array_push(
+          &cmcf->phases[NGX_HTTP_SERVER_REWRITE_PHASE].handlers);
+        if (h == NULL) {
+            return NGX_ERROR;
+        }
+
+        *h = ngx_http_lua_server_rewrite_handler;
+    }
+
     if (lmcf->requires_rewrite) {
         h = ngx_array_push(&cmcf->phases[NGX_HTTP_REWRITE_PHASE].handlers);
         if (h == NULL) {
@@ -1366,6 +1393,14 @@ ngx_http_lua_merge_loc_conf(ngx_conf_t *cf, void *parent, void *child)
     ngx_http_lua_loc_conf_t *prev = parent;
     ngx_http_lua_loc_conf_t *conf = child;
 
+    if (conf->server_rewrite_src.value.len == 0) {
+        conf->server_rewrite_src = prev->server_rewrite_src;
+        conf->server_rewrite_handler = prev->server_rewrite_handler;
+        conf->server_rewrite_src_ref = prev->server_rewrite_src_ref;
+        conf->server_rewrite_src_key = prev->server_rewrite_src_key;
+        conf->server_rewrite_chunkname = prev->server_rewrite_chunkname;
+    }
+
     if (conf->rewrite_src.value.len == 0) {
         conf->rewrite_src = prev->rewrite_src;
         conf->rewrite_handler = prev->rewrite_handler;