增加sql的waf功能

resty/core/utils.lua

@@ -0,0 +1,46 @@
+-- Copyright (C) Yichun Zhang (agentzh)
+
+
+local ffi = require "ffi"
+local base = require "resty.core.base"
+
+
+local C = ffi.C
+local ffi_str = ffi.string
+local ffi_copy = ffi.copy
+local byte = string.byte
+local str_find = string.find
+local get_string_buf = base.get_string_buf
+local subsystem = ngx.config.subsystem
+
+
+local _M = {
+    version = base.version
+}
+
+
+if subsystem == "http" then
+    ffi.cdef[[
+    void ngx_http_lua_ffi_str_replace_char(unsigned char *buf, size_t len,
+        const unsigned char find, const unsigned char replace);
+    ]]
+
+
+    function _M.str_replace_char(str, find, replace)
+        if not str_find(str, find, nil, true) then
+            return str
+        end
+
+        local len = #str
+        local buf = get_string_buf(len)
+        ffi_copy(buf, str, len)
+
+        C.ngx_http_lua_ffi_str_replace_char(buf, len, byte(find),
+                                            byte(replace))
+
+        return ffi_str(buf, len)
+    end
+end
+
+
+return _M