Ruby笔记

1.数组遍历方法总结

    array = (1..10).to_a

    length = array.length
    length.times do t
    print "#{array[t]} "
    end
    puts "n"

    length = array.length-1
    for i in 0..length do
    print "#{array[i]} "
    end
    puts "n"

    for i in array do
        print "#{i} "
    end
    puts "n"

    array.each{x print x," "}
    puts "n"

    length = array.length
    i = 0
    while i< length do
    print "#{array[i]} "
    i = i+1
    end
    puts "n"

    length = array.length
    i = 0
    until i==length do
    print "#{array[i]} "
    i += 1
    end
    puts "n"

    array.each_index do i
    print "#{array[i]} "

2.Ruby连接数据库

• mysql

    require 'mysql'
    begin
    	db = Mysql.init
    	db.options(Mysql::SET_CHARSET_NAME, 'utf8')
    	db = Mysql.real_connect("127.0.0.1", "root", "123456", "test", 3306)
    	db.query("SET NAMES utf8")
    	db.query("drop table if exists tb_test")
    	db.query("create table tb_test (id int,
    	text LONGTEXT) ENGINE=MyISAM DEFAULT CHARSET=utf8")
    	db.query("insert into tb_test (id, text) values (
    	1,'first line'),(2,'second line')")
    	printf "%d rows were inserted\n",db.affected_rows
    	rslt = db.query("select text from tb_test")
    	while row = rslt.fetch_row do
    		puts row[0]
    	end
    rescue Mysql::Error => e
    		puts "Error code: #{e.errno}"
    		puts "Error message: #{e.error}"
    		puts "Error SQLSTATE: #{e.sqlstate}" if e.respond_to?("sqlstate")
    ensure
    		db.close if db
    end

• redis

    #!/bin/ruby

    require 'redis'

    def writeToFile(file,content)
        fp = File.new(file,"a+")
        if fp
            fp.syswrite(content)
        else
            puts "..."
        end
    end

    def connect(host)
        redis = Redis.new(:host => host,:port => 6379)
        redis.info.keys.each do |key|
            puts "#{key}:\t"+redis.info["#{key}"]
        end
    end

    connect("1.1.1.1")

• sqlite3

    require 'sqlite3'

    db = SQLite3::Database.new('test.db')

    db.execute("create table test(
    				ID integet not null,
    				Username varchar(20) null,
    				Password varchar(64) null)")
    db.execute("insert into test(ID.Username,Password)
    	values('0','admin','admin')")
    db.execute("select * from test")
    db.execute("update test set password='12345' where id=0")

3.Ruby socket

• 服务端：

    require 'socket'

    server = TCPServer.open('0.0.0.0', 8080)
    loop do
        Thread.start(server.accept) do |client|
            begin
    			while true
    				puts "#{client.to_i} online"
    				data = client.read()
    				throw "empty" if data.empty?
    				#puts data.length
    				puts data
    			end
            rescue Exception => e
                puts "#{client.to_i} offline"
            end
        end
    end

• 客户端：

    require 'socket'

    hostname = '127.0.0.1'
    port = 8080
    buf = 'test'
    s = TCPSocket.open(hostname, port)
    s.write buf
    sleep(1)
    s.close

4.ruby gem 文档服务

rubygems.org上的gem文档访问起来太慢了，其实gem本身就自带doc的功能

安装gem的时候会默认安装相应gem的doc，如果不想占用空间安装doc，则gem install XXX --no-doc 即可。

使用下列命令可以启动gem自带的文档：

    gem server --port 1234

然后访问http://localhost:1234就可以查看相关的gem文档。

5.ruby改变控制台输出内容的颜色

     puts "\033[1m前景色\033[0m\n"
    puts "   \033[30mBlack (30)\033[0m\n"
    puts "   \033[31mRed (31)\033[0m\n"
    puts "   \033[32mGreen (32)\033[0m\n"
    puts "   \033[33mYellow (33)\033[0m\n"
    puts "   \033[34mBlue (34)\033[0m\n"
    puts "   \033[35mMagenta (35)\033[0m\n"
    puts "   \033[36mCyan (36)\033[0m\n"
    puts "   \033[37mWhite (37)\033[0m\n"
    puts ''
    puts "\033[1m背景色\033[0m\n"
    puts "   \033[40m\033[37mBlack (40), White Text\033[0m\n"
    puts "   \033[41mRed (41)\033[0m\n"
    puts "   \033[42mGreen (42)\033[0m\n"
    puts "   \033[43mYellow (43)\033[0m\n"
    puts "   \033[44mBlue (44)\033[0m\n"
    puts "   \033[45mMagenta (45)\033[0m\n"
    puts "   \033[46mCyan (46)\033[0m\n"
    puts "   \033[47mWhite (47)\033[0m\n"
    puts ''
    puts "\033[1m其他\033[0m\n"
    puts "   Reset (0)"
    puts "   \033[1mBold (1)\033[0m\n"
    puts "   \033[4mUnderlined (4)\033[0m\n"

6.一些比较特别的包

Ruby json gem

https://rubygems.global.ssl.fastly.net/gems/json-1.8.3.gem

树莓派wiringpi gpio包

http://pi.gadgetoid.com/article/wiringpi-as-a-ruby-gem

7.安装rvm的正确姿势

参考自:http://rvm.io/rvm/install

首先添加gpg公钥:

    gpg --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3

安装稳定版本的rvm

    curl -sSL https://get.rvm.io | bash -s stable --ruby

8.解决kali2.0中RVM不能编译ruby-2.3.3

• 错误详情：

ruby-2.3.3 - #compiling.......................................................................-
Error running '__rvm_make -j4',
showing last 15 lines of /usr/local/rvm/log/1488041042_ruby-2.3.3/make.log
exts.mk:210: recipe for target 'ext/openssl/all' failed
make[1]: *** [ext/openssl/all] Error 2
make[1]: *** Waiting for unfinished jobs....
installing default nkf libraries
compiling objspace_dump.c
linking shared-object json/ext/generator.so
make[2]: Leaving directory '/usr/local/rvm/src/ruby-2.3.3/ext/json/generator'
linking shared-object objspace.so
make[2]: Leaving directory '/usr/local/rvm/src/ruby-2.3.3/ext/objspace'
linking shared-object nkf.so
make[2]: Leaving directory '/usr/local/rvm/src/ruby-2.3.3/ext/nkf'
make[1]: Leaving directory '/usr/local/rvm/src/ruby-2.3.3'
uncommon.mk:203: recipe for target 'build-ext' failed
make: *** [build-ext] Error 2
++ return 2
There has been an error while running make. Halting the installation.

查看/usr/local/rvm/log/1488041042_ruby-2.3.3/make.log发现是openssl版本过老导致的。

• 解决：
  
  第一步：先安装用于rvm的openssl：

rvm pkg install openssl

第二步：编译安装ruby，指定openssl目录（我的是/usr/local/rvm/usr/）

rvm install ruby-2.3.3 --with-openssl-dir=/usr/local/rvm/usr/

9.设置Gems默认源为ruby-china

现在没有淘宝源了，只有ruby-china源

gem sources --add https://gems.ruby-china.org/ --remove https://rubygems.org/

设置Bundler默认源为ruby-china：

bundle config mirror.https://rubygems.org https://gems.ruby-china.org

这样修改以后，即使Gemfile中指定了Source，也会用国内的源。