openresty使用lua处理gzip压缩解压

1.安装依赖

yum install -y gcc gcc-c++ make cmake automake zlib-devel zlib -y

2.下载lua-zlib包，并解压

wget https://github.com/brimworks/lua-zlib/archive/master.zip
unzip lua-zlib-master.zip
cd /usr/local/software/lua-zlib-master

cmake -DLUA_INCLUDE_DIR=/usr/local/openresty/luajit/include/luajit-2.1

若报错：CMake Error at CMakeLists.txt:27 (find_package):
By not providing "FindLua.cmake" in CMAKE_MODULE_PATH this project has
asked CMake to find a package configuration file provided by "Lua", but
CMake did not find one.

在 /usr/local/share/cmake-2.8/Modules目录下（该目录可能不存在 FindLua.cmake，查询其他.cmke文件获取目录），有 FindLua51.cmake，改名为 FindLua.cmake，重新执行上个命令。

make

cp zlib.so /usr/local/openresty/lualib/zlib.so

3.lua脚本调用

--案例1
local zip = require 'zlib'
local uncompress = zip.inflate()
local compress = zip.deflate()

local deflated, eof, bytes_in,bytes_out =compress("asdasdasdasdasdasdasdasdasd", 'finish')
print(deflated, eof, bytes_in,bytes_out)
local uss,ret,getin,getout=uncompress(deflated)print(uss,ret,getin,getout)

print(uss,ret,getin,getout)

--案例2
--Table to Str
local function ToStringEx(value)
    if type(value)=='table' then
       return TableToStr(value)
    elseif type(value)=='string' then
        return "\'"..value.."\'"
    else
       return tostring(value)
    end
end

local function TableToStr(t)
    if t == nil then return "" end
    local retstr= "{"

    local i = 1
    for key,value in pairs(t) do
        local signal = ","
        if i==1 then
          signal = ""
        end

        if key == i then
            retstr = retstr..signal..ToStringEx(value)
        else
            if type(key)=='number' or type(key) == 'string' then
                retstr = retstr..signal..'['..ToStringEx(key).."]="..ToStringEx(value)
            else
                if type(key)=='userdata' then
                    retstr = retstr..signal.."*s"..TableToStr(getmetatable(key)).."*e".."="..ToStringEx(value)
                else
                    retstr = retstr..signal..key.."="..ToStringEx(value)
                end
            end
        end

        i = i+1
    end

     retstr = retstr.."}"
     return retstr
end

--获取请求头table
local headers_tab = ngx.req.get_headers()
print("headers_tab:"..TableToStr(headers_tab))
 
 -- 获取未解析的请求头字符串
local headers_str = ngx.req.raw_header()
print(headers_str)

--根据header的值来判断是否需要解压body数据
--post请求参数  
local zlib = require "zlib"
local binfilegzip = ngx.req.get_headers()["binfile-gzip"]
print("binfilegzip header:"..binfilegzip)
ngx.req.read_body()  
if binfilegzip == "true" then
  local body = ngx.req.get_body_data()
    if body then
        local stream = zlib.inflate()
        bodydata = stream(body)
        print("post_body_data:"..bodydata)
    end
else
  local post_params_tab = ngx.req.get_post_args()
  print("body_params_tab:"..TableToStr(post_params_tab))
  local post_body_data = ngx.req.get_body_data()
  print("post_body_data:"..post_body_data)
end

4.zlib库不能直接压缩gzip格式，使用lua-ffi-zlib

源码路径：https://github.com/hamishforbes/lua-ffi-zlib

调用：

local ffi_zlib = require "lib.ffi-zlib"

local chunk = 16384
    local count = 0 
    
    local input = function(bufsize)  
        local start = count > 0 and bufsize*count or 1  
        local data = str:sub(start, (bufsize*(count+1)-1))  
        if data == "" then  
            data = nil  
        end
        print(data)
        count = count + 1  
        return data  
    end 
    local output_table = {}  
    local output = function(data)
        insert(output_table, data)
    end 
    local ok, err = ffi_zlib.deflateGzip(input, output, chunk)  
    if not ok then  
        print(err)
    end  
    local compress = concat(output_table,'')  
    ngx.header["Content-Encoding"] = "gzip"

ngx.print(compress)