nginx lua模块常用的指令

 init_by_lua 'cjson = require "cjson"'; server{location= /api {content_by_lua '
                ngx.say(cjson.encode({dog = 5, cat = 6}))
            ';}}

location /foo {set$diff'';# we have to predefine the $diff variable here 
        set_by_lua $sum'
            local a = 32
            local b = 56
 
            ngx.var.diff = a - b;  -- write to $diff directly
            return a + b;          -- return the $sum value normally
        ';echo "sum = $sum, diff = $diff";}

location /nginx_var {# MIME type determined by default_type:default_type'text/plain'; 
# try access /nginx_var?a=hello,worldcontent_by_lua "ngx.print(ngx.var['arg_a'], '\n')";}

location /foo {
          set$a12;# create and initialize $a
          set$b'';# create and initialize $b
          rewrite_by_lua 'ngx.var.b = tonumber(ngx.var.a) + 1';
          if($b='13'){
             rewrite ^ /bar redirect;
             break;
          }
    
         echo "res = $b";
    }

location /foo {set$a12;# create and initialize $aset$b'';# create and initialize $brewrite_by_lua '
            ngx.var.b = tonumber(ngx.var.a) + 1
            if tonumber(ngx.var.b) == 13 then
                return ngx.redirect("/bar");
            end
        '; 
        echo "res = $b";}

location / {deny    192.168.1.1;allow   192.168.1.0/24;allow   10.1.1.0/16;deny    all; 
        access_by_lua '
            local res = ngx.location.capture("/mysql", { ... })
            ...
        '; # proxy_pass/fastcgi_pass/...}

location / {proxy_passhttp://mybackend;header_filter_by_lua 'ngx.header.Foo = "blah"';}

location /t {echo hello world;echo hiya globe; 
        body_filter_by_lua '
            local chunk = ngx.arg[1]
            if string.match(chunk, "hello") then
                ngx.arg[2] = true  -- new eof
                return
            end
 
            -- just throw away any remaining chunk data
            ngx.arg[1] = nil
        ';}