用luasocket读取双色球中奖号码

其实是蛮简单的一个功能，就是读取这个页面：http://61.129.89.226/fcopen/cp_kjgg_dfw.jsp?lottery_type=ssq&lottery_issue=2012138，把某一个期的中奖号码抽取出来。

【luarocks安装library】

首先，如果是想用某个库，真没必要自己wget再make， install啥的，太烦。lua社区提供了一个非常好用的工具，用法和apt(advanced package tools)很类似：

apt-cache search xxx
sudo apt-get install xxxluarocks search xxx
luarocks install xxx

这里需要luasocket，很简单：

$ luarocks search socket

Search results:
===============

Rockspecs and source rocks:
---------------------------

luasocket
2.0.2-5 (rockspec) - http://luarocks.org/repositories/rocks
2.0.2-5 (src) - http://luarocks.org/repositories/rocks
2.0.2-4 (rockspec) - http://luarocks.org/repositories/rocks
。。。。。。

$ luarocks install luasocket
Installing http://luarocks.org/repositories/rocks/luasocket-2.0.2-5.src.rock...
Archive: /tmp/luarocks_luarocks-rock-luasocket-2.0.2-5-2574/luasocket-2.0.2-5.src.rock
。。。。。。
cd src; cp mime.so.1.0.2 /home/baiyanh/.luarocks/lib/luarocks/rocks/luasocket/2.0.2-5/lib/mime/core.so
Updating manifest for /home/baiyanh/.luarocks/lib/luarocks/rocks

【读取页面】

然后用luasocket发送http get request，来获取web页面：

issuenum = arg[1]
if not issuenum thenerror "please provide the lottery issue num!"
endsocket = require "socket"host = '61.129.89.226'
port = 80
fileformat = '/fcopen/cp_kjgg_dfw.jsp?lottery_type=ssq&lottery_issue=%s'
starting = '开奖结果'
numpattern = '>%d%d<'function getlotterywinner(issuenum)local client = assert(socket.connect(host, port))client:send('GET ' .. string.format(fileformat, issuenum)  .. " HTTP/1.0\r\n\r\n")local line = client:receive('*l')local start = falselocal winner = {}while line doif line:find(starting) thenstart = trueendif start thenlocal num = line:match(numpattern)if num thentable.insert(winner, num:sub(2, -2))endendif #winner == 7 then break endline = client:receive('*l')endclient:close()return winner
end--http://61.129.89.226/fcopen/cp_kjgg_dfw.jsp?lottery_type=ssq&lottery_issue=2012138
winner = getlotterywinner(issuenum)
for _, v in ipairs(winner) doio.write(v .. "  ")
end
io.write("\n")

但遗憾的是，上述代码无法正确输出结果，事实上，上面“开奖结果”根本无法匹配 - 为什么？

【解决编码问题】

查看双色球网页的source，可以看到这么一行：

<meta http-equiv="Content-Type" content="text/html; charset=gb2312">

该网页的编码是gb2312，而我写在lua代码中的“开奖结果”，是和这个lua脚本采用同样的编码：utf8，所以无法匹配（他们在内存中的表示方式不同，匹配自然失败） - 知道了原因就好办了，只要把他们转成同样的编码即可：

转码的方向 - 自然是把“开奖结果”转成gb2312最省钱
用什么库 - lua提供了对iconv库的wrapper，叫lua-iconv

好，下载：

$ luarocks install lua-iconv
Installing http://luarocks.org/repositories/rocks/lua-iconv-7-1.src.rock...
Archive: /tmp/luarocks_luarocks-rock-lua-iconv-7-1-2223/lua-iconv-7-1.src.rock
inflating: lua-iconv-7-1.rockspec
extracting: lua-iconv-7.tar.gz
gcc -O2 -I/usr/include/lua5.1 -c luaiconv.c -o luaiconv.o -I/usr/include
gcc -shared -o iconv.so -L/usr/local/lib luaiconv.o -L/usr/lib
Updating manifest for /home/baiyanh/.luarocks/lib/luarocks/rocks

要熟悉iconv很简单，因为linux下自带了一个iconv的命令行工具，查看支持的编码：

$ iconv --list | grep "^GB"
GB//
GB2312//
GB13000//
GB18030//
GBK//
GB_1988-80//
GB_198880//

修改代码：

iconv = require "iconv"
cd = iconv.new('gb2312', 'utf8')
starting = cd:iconv('开奖结果')

运行：

$ lua getlotterywinner.lua 2012138
01 07 16 17 19 21 14

【玩点酷的】

下面用这个小程序做点有意思的事：查看03年以来蓝色球各个数字的概率，或许对指导我买彩票有一定的帮助（篮球中了，最少也有5块奖金了：））

历年每年的期数都不相同，但所有的期数都列在这个网页中了：http://61.129.89.226/fcopen/cp_kjgg_dfw.jsp?lottery_type=ssq&lottery_issue=2012138，所有只要拿到所有的期数，然后调用上面的函数得到中奖号码，统计一下就ok了：

function allissues()local client = assert(socket.connect(host, port))client:send('GET ' .. string.format(fileformat, 2012138)  .. " HTTP/1.0\r\n\r\n")local line = client:receive('*l')local issuepattern = '>%d%d%d%d%d%d%d<'return function ()while line dolocal issuenum = line:match(issuepattern)line = client:receive('*l')if issuenum thenreturn issuenum:sub(2, -2)endendreturn nilendendlocal data = {}
local count = 0
for issuenum in allissues() docount = count + 1print ("getting " .. issuenum .. "...")local winner = getlotterywinner(issuenum)local blue = tonumber(winner[7])if not data[blue] thendata[blue] = 0enddata[blue] = data[blue] + 1
endfor k, v in pairs(data) doprint(string.format("%2d: %3d/%d = %0.4f", k,  v, count, v/count))
end

最终结果：

1: 90/1423 = 0.0632
2: 88/1423 = 0.0618
3: 90/1423 = 0.0632
4: 78/1423 = 0.0548
5: 96/1423 = 0.0675
6: 85/1423 = 0.0597
7: 77/1423 = 0.0541
8: 76/1423 = 0.0534
9: 100/1423 = 0.0703
10: 86/1423 = 0.0604
11: 101/1423 = 0.0710
12: 90/1423 = 0.0632
13: 91/1423 = 0.0639
14: 91/1423 = 0.0639
15: 91/1423 = 0.0639
16: 93/1423 = 0.0654