diff --git a/.travis.yml b/.travis.yml
index 3f5cf76bf..22e7496c5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -56,7 +56,7 @@ install:
   - git clone https://github.com/openresty/openresty.git ../openresty
   - git clone https://github.com/openresty/openresty-devel-utils.git
   - git clone https://github.com/simpl/ngx_devel_kit.git ../ndk-nginx-module
-  - git clone https://github.com/openresty/lua-nginx-module.git ../lua-nginx-module
+  - git clone -b decode_args https://github.com/hongliang5316/lua-nginx-module.git ../lua-nginx-module
   - git clone https://github.com/openresty/no-pool-nginx.git ../no-pool-nginx
   - git clone https://github.com/openresty/echo-nginx-module.git ../echo-nginx-module
   - git clone https://github.com/openresty/lua-resty-lrucache.git
diff --git a/lib/resty/core.lua b/lib/resty/core.lua
index 71bb94642..53953e3cb 100644
--- a/lib/resty/core.lua
+++ b/lib/resty/core.lua
@@ -14,6 +14,7 @@ require "resty.core.request"
 require "resty.core.response"
 require "resty.core.time"
 require "resty.core.worker"
+require "resty.core.string"
 
 
 local base = require "resty.core.base"
diff --git a/lib/resty/core/string.lua b/lib/resty/core/string.lua
new file mode 100644
index 000000000..0735a2327
--- /dev/null
+++ b/lib/resty/core/string.lua
@@ -0,0 +1,89 @@
+-- Copyright (C) Yichun Zhang (agentzh)
+
+
+local ffi = require 'ffi'
+local base = require "resty.core.base"
+
+
+local new_tab = base.new_tab
+local C = ffi.C
+local ffi_cast = ffi.cast
+local ffi_str = ffi.string
+local get_string_buf = base.get_string_buf
+local ngx = ngx
+local type = type
+local tonumber = tonumber
+
+
+ffi.cdef[[
+    typedef struct {
+        ngx_http_lua_ffi_str_t   key;
+        ngx_http_lua_ffi_str_t   value;
+    } ngx_http_lua_ffi_table_elt_t;
+
+    int ngx_http_lua_ffi_get_args_count(const char *args,
+        size_t buf_len, int max);
+
+    int ngx_http_lua_ffi_decode_args(char *buf, const char *args,
+        size_t len, ngx_http_lua_ffi_table_elt_t *out, int count);
+]]
+
+
+local table_elt_type = ffi.typeof("ngx_http_lua_ffi_table_elt_t*")
+local table_elt_size = ffi.sizeof("ngx_http_lua_ffi_table_elt_t")
+
+
+function ngx.decode_args(str, max_args)
+    max_args = tonumber(max_args)
+    if not max_args or max_args < 0 then
+        max_args = -1
+    end
+
+    local args_len = #str
+
+    local n = C.ngx_http_lua_ffi_get_args_count(str, args_len, max_args)
+    if n == 0 then
+        return {}
+    end
+
+    local strbuf = get_string_buf(args_len + n * table_elt_size)
+    local kvbuf = ffi_cast(table_elt_type, strbuf + args_len)
+
+    local nargs = C.ngx_http_lua_ffi_decode_args(strbuf, str,
+                                                 args_len, kvbuf, n)
+
+    local args = new_tab(0, nargs)
+    for i = 0, nargs - 1 do
+        local arg = kvbuf[i]
+
+        local key = arg.key
+        key = ffi_str(key.data, key.len)
+
+        local value = arg.value
+        local len = value.len
+        if len == -1 then
+            value = true
+        else
+            value = ffi_str(value.data, len)
+        end
+
+        local existing = args[key]
+        if existing then
+            if type(existing) == "table" then
+                existing[#existing + 1] = value
+            else
+                args[key] = {existing, value}
+            end
+
+        else
+            args[key] = value
+        end
+    end
+
+    return args
+end
+
+
+return {
+    version = base.version
+}
diff --git a/t/string.t b/t/string.t
new file mode 100644
index 000000000..428341693
--- /dev/null
+++ b/t/string.t
@@ -0,0 +1,256 @@
+# vim:set ft=nginx ts=4 sw=4 et fdm=marker:
+use lib 'lib';
+use Test::Nginx::Socket::Lua 'no_plan';
+use Cwd qw(cwd);
+
+#worker_connections(1014);
+#master_process_enabled(1);
+#log_level('warn');
+
+repeat_each(2);
+
+my $pwd = cwd();
+
+our $HttpConfig = <<_EOC_;
+    lua_shared_dict dogs 1m;
+    lua_package_path "$pwd/lib/?.lua;../lua-resty-lrucache/lib/?.lua;;";
+    init_by_lua_block {
+        local verbose = false
+        if verbose then
+            local dump = require "jit.dump"
+            dump.on("b", "$Test::Nginx::Util::ErrLogFile")
+        else
+            local v = require "jit.v"
+            v.on("$Test::Nginx::Util::ErrLogFile")
+        end
+
+        require "resty.core"
+        -- jit.off()
+    }
+_EOC_
+
+#no_diff();
+#no_long_string();
+check_accum_error_log();
+run_tests();
+
+__DATA__
+
+=== TEST 1 ngx.decode_args (sanity)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = "a=bar&b=foo"
+            args = ngx.decode_args(args)
+            ngx.say("a = ", args.a)
+            ngx.say("b = ", args.b)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+a = bar
+b = foo
+
+
+
+=== TEST 2: ngx.decode_args (multi-value)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = "a=bar&b=foo&a=baz"
+            args = ngx.decode_args(args)
+            ngx.say("a = ", table.concat(args.a, ", "))
+            ngx.say("b = ", args.b)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+a = bar, baz
+b = foo
+
+
+
+=== TEST 3: ngx.decode_args (empty string)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = ""
+            args = ngx.decode_args(args)
+            ngx.say("n = ", #args)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+n = 0
+
+
+
+=== TEST 4: ngx.decode_args (boolean args)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = "a&b"
+            args = ngx.decode_args(args)
+            ngx.say("a = ", args.a)
+            ngx.say("b = ", args.b)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+a = true
+b = true
+
+
+
+=== TEST 5: ngx.decode_args (empty value args)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = "a=&b="
+            args = ngx.decode_args(args)
+            ngx.say("a = ", args.a)
+            ngx.say("b = ", args.b)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+a = 
+b = 
+
+
+
+=== TEST 6: ngx.decode_args (max_args = 1)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = "a=bar&b=foo"
+            args = ngx.decode_args(args, 1)
+            ngx.say("a = ", args.a)
+            ngx.say("b = ", args.b)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+a = bar
+b = nil
+
+
+
+=== TEST 7: ngx.decode_args (max_args = -1)
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local args = "a=bar&b=foo"
+            args = ngx.decode_args(args, -1)
+            ngx.say("a = ", args.a)
+            ngx.say("b = ", args.b)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+a = bar
+b = foo
+
+
+
+=== TEST 8: ngx.decode_args should not modify lua strings in place
+--- http_config eval: $::HttpConfig
+--- config
+    location /lua {
+        content_by_lua '
+            local s = "f+f=bar&B=foo"
+            args = ngx.decode_args(s)
+            local arr = {}
+            for k, v in pairs(args) do
+                table.insert(arr, k)
+            end
+            table.sort(arr)
+            for i, k in ipairs(arr) do
+                ngx.say("key: ", k)
+            end
+            ngx.say("s = ", s)
+        ';
+    }
+--- request
+GET /lua
+--- response_body
+key: B
+key: f f
+s = f+f=bar&B=foo
+--- no_error_log
+[error]
+
+
+
+=== TEST 9: ngx.decode_args should not modify lua strings in place (sample from Xu Jian)
+--- http_config eval: $::HttpConfig
+--- config
+    lua_need_request_body on;
+    location /t {
+        content_by_lua '
+            function split(s, delimiter)
+                local result = {}
+                local from = 1
+                local delim_from, delim_to = string.find(s, delimiter, from)
+                while delim_from do
+                    table.insert(result, string.sub(s, from, delim_from - 1))
+                    from = delim_to + 1
+                    delim_from, delim_to = string.find(s, delimiter, from)
+                end
+                table.insert(result, string.sub(s, from))
+                return result
+            end
+
+            local post_data = ngx.req.get_body_data()
+
+            local commands = split(post_data, "||")
+            for _, command in pairs(commands) do
+                --command = ngx.unescape_uri(command)
+                local request_args = ngx.decode_args(command, 0)
+                local arr = {}
+                for k, v in pairs(request_args) do
+                    table.insert(arr, k)
+                end
+                table.sort(arr)
+                for i, k in ipairs(arr) do
+                    ngx.say(k, ": ", request_args[k])
+                end
+                ngx.say(" ===============")
+            end
+        ';
+    }
+--- request
+POST /t
+method=zadd&key=User%3A1227713%3Alikes%3Atwitters&arg1=1356514698&arg2=780984852||method=zadd&key=User%3A1227713%3Alikes%3Atwitters&arg1=1356514698&arg2=780984852||method=zadd&key=User%3A1227713%3Alikes%3Atwitters&arg1=1356514698&arg2=780984852
+--- response_body
+arg1: 1356514698
+arg2: 780984852
+key: User:1227713:likes:twitters
+method: zadd
+ ===============
+arg1: 1356514698
+arg2: 780984852
+key: User:1227713:likes:twitters
+method: zadd
+ ===============
+arg1: 1356514698
+arg2: 780984852
+key: User:1227713:likes:twitters
+method: zadd
+ ===============
+--- no_error_log
+[error]