lua-resty-ffi-br

BR compress&decompress library, dependencies google's brotli project.

Table of Contents

[TOC]

Status

This library is product ready.

Description

This Lua library use brotli do compress and decompress. User need download brotli and complie as dynamic library.

User need put libbrotlicommon.so.1、libbrotlidec.so、libbrotlienc.so in the lua_package_cpath directory.

Synopsis

local br = require("resty.ffi-br")

local ok, err
local enc, dec
enc, err = br.new_encoder(1024)
if not enc then
    ngx.say("new encoder fail " .. err)
    ngx.exit(200)
end

dec, err = br.new_decoder(1024)
if not dec then
    ngx.say("new decoder fail " .. err)
    ngx.exit(200)
end

local function gen_text(size)
    local l = {}

    for _ = 0, size do
        local s = string.char(math.random(32, 126))
        l[#l+1] = s
    end

    return table.concat(l)
end

local text_len = 4096
local text = gen_text(text_len)

local input, output, output_table
local function new_input(t)
    local text = t
    local text_len = #text
    local count = 0
    return function(size)
        local start = count > 0 and size*count or 1
        local finish = (size*(count+1) - 1)
        count = count + 1
        if start > text_len then
            return nil, true
        end

        local data = text:sub(start, finish)

        return data
    end
end

input = new_input(text)

output_table = {}
output = function(data) output_table[#output_table+1] = data end

ok, err = enc:compressStream(input, output)
if not ok then
    ngx.say("compress fail " .. err)
    ngx.exit(200)
end

local compressed = table.concat(output_table, "")
input = new_input(compressed)
output_table = {}
ok, err = dec:decompressStream(input, output)
if not ok then
    ngx.say("decompress fail " .. err)
    ngx.exit(200)
end

local final = table.concat(output_table, "")

if final == text then
    ngx.say("compress & decompress success")
else
    ngx.say("compress & decompress fail")
end

ngx.say(string.format("ver enc: %s dec: %s", enc:version(), dec:version()))

Methods

new_encoder

syntax:

local br = require "resty.ffi-br"
local enc, err = br.new_encoder(size, opts)

create new br encode for compress.

• size: buffer size
• opts: options table, support
  • quality: Brotli compression quality (compression) level. Acceptable values are in the range from 0 to 11.
  • lgwin: Brotli window size. Acceptable values from 10 to 24, when lgwin 10 window size is 1k, when 24 window size is 16m.

enc:compressStream

syntax:

local ok, err = enc:compressStream(input, output)

compress data from input function and call output function save compressed data.

new_decoder

syntax:

local br = require "resty.ffi-br"
local enc, err = br.new_decoder(size, opts)

create new br decoder for decompress.

• size: buffer size
• opts: options table, support
  • large_window: Flag that determines if "Large Window Brotli" is used.
  • disable_ring_buffer_reallocation: Disable "canny" ring buffer allocation strategy. Ring buffer is allocated according to window size, despite the real size of the content.

dec:decompressStream

syntax:

local ok, err = enc:decompressStream(input, output)

decompress data from input function and call output function save decompressed data.