在Ubuntu 15.04中安装Ruby on Rails

本篇我们会学习如何用rbenv在Ubuntu 15.04中安装Ruby on Rails。我们选择Ubuntu作为操作系统是因为Ubuntu是Linux发行版中自带很多包和完整文档的操作系统，因此我认为这是正确的选择。如果你还没有安装最新的Ubuntu，你可以从下载iso文件开始。

安装 Ruby

我们要做的第一件事是更新Ubuntu包并且为Ruby安装一些依赖。

1. <span class="pln">sudo apt</span><span class="pun">-</span><span class="kwd">get</span><span class="pln"> update</span>
2. <span class="pln">sudo apt</span><span class="pun">-</span><span class="kwd">get</span><span class="pln"> install git</span><span class="pun">-</span><span class="pln">core curl zlib1g</span><span class="pun">-</span><span class="pln">dev build</span><span class="pun">-</span><span class="pln">essential libssl</span><span class="pun">-</span><span class="pln">dev libreadline</span><span class="pun">-</span><span class="pln">dev libyaml</span><span class="pun">-</span><span class="pln">dev libsqlite3</span><span class="pun">-</span><span class="pln">dev sqlite3 libxml2</span><span class="pun">-</span><span class="pln">dev libxslt1</span><span class="pun">-</span><span class="pln">dev libcurl4</span><span class="pun">-</span><span class="pln">openssl</span><span class="pun">-</span><span class="pln">dev Python</span><span class="pun">-</span><span class="pln">software</span><span class="pun">-</span><span class="pln">properties libffi</span><span class="pun">-</span><span class="pln">dev</span>

有三种方法来安装Ruby：rbenv、rvm和从源码安装。每种都有各自的好处，但是近来开发者们更倾向使用rbenv而不是rvm和源码来安装。我们将安装最新的Ruby版本，2.2.2。

用rbenv来安装只有简单的两步。第一步安装rbenv，接着是ruby-build：

1. <span class="pln">cd</span>
2. <span class="pln">git clone git</span><span class="pun">:</span><span class="com">//github.com/sstephenson/rbenv.git .rbenv</span>
3. <span class="pln">echo </span><span class="str">'eval "$(rbenv init -)"'</span><span class="pun">>></span><span class="pun">~/.</span><span class="pln">bashrc</span>
4. <span class="kwd">exec</span><span class="pln"> $SHELL</span>
5. <span class="pln">git clone git</span><span class="pun">:</span><span class="com">//github.com/sstephenson/ruby-build.git ~/.rbenv/plugins/ruby-build</span>
6. <span class="pln">echo </span><span class="str">'export PATH="$HOME/.rbenv/plugins/ruby-build/bin:$PATH"'</span><span class="pun">>></span><span class="pun">~/.</span><span class="pln">bashrc</span>
7. <span class="kwd">exec</span><span class="pln"> $SHELL</span>
8. <span class="pln">git clone https</span><span class="pun">:</span><span class="com">//github.com/sstephenson/rbenv-gem-rehash.git ~/.rbenv/plugins/rbenv-gem-rehash</span>
9. <span class="pln">rbenv install </span><span class="lit">2.2</span><span class="pun">.</span><span class="lit">2</span>
10. <span class="pln">rbenv </span><span class="kwd">global</span><span class="lit">2.2</span><span class="pun">.</span><span class="lit">2</span>
11. <span class="pln">ruby </span><span class="pun">-</span><span class="pln">v</span>

我们需要安装Bundler，但是我们要在安装之前告诉rubygems不要为每个包安装本地文档。

1. <span class="pln">echo </span><span class="str">"gem: --no-ri --no-rdoc"</span><span class="pun">></span><span class="pun">~/.</span><span class="pln">gemrc</span>
2. <span class="pln">gem install bundler</span>

配置 GIT

配置git之前，你要创建一个github账号，你可以注册一个github 账号。我们需要git作为版本控制系统，因此我们要设置它来匹配github账号。

用户的github账号来替换下面的Name 和 Email address 。

1. <span class="pln">git config </span><span class="pun">--</span><span class="kwd">global</span><span class="pln"> color</span><span class="pun">.</span><span class="pln">ui </span><span class="kwd">true</span>
2. <span class="pln">git config </span><span class="pun">--</span><span class="kwd">global</span><span class="pln"> user</span><span class="pun">.</span><span class="pln">name </span><span class="str">"YOUR NAME"</span>
3. <span class="pln">git config </span><span class="pun">--</span><span class="kwd">global</span><span class="pln"> user</span><span class="pun">.</span><span class="pln">email </span><span class="str">"YOUR@EMAIL.com"</span>
4. <span class="pln">ssh</span><span class="pun">-</span><span class="pln">keygen </span><span class="pun">-</span><span class="pln">t rsa </span><span class="pun">-</span><span class="pln">C </span><span class="str">"YOUR@EMAIL.com"</span>

接下来用新生成的ssh key添加到github账号中。这样你需要复制下面命令的输出并粘贴在Github的设置页面里面。

1. <span class="pln">cat </span><span class="pun">~</span><span class="str">/.ssh/</span><span class="pln">id_rsa</span><span class="pun">.</span><span class="pln">pub</span>

如果你做完了，检查是否已经成功。

1. <span class="pln">ssh </span><span class="pun">-</span><span class="pln">T git@github</span><span class="pun">.</span><span class="pln">com</span>

你应该得到下面这样的信息。

1. <span class="typ">Hi</span><span class="pln"> excid3</span><span class="pun">!</span><span class="typ">You</span><span class="str">'ve successfully authenticated, but GitHub does not provide shell access.</span>

安装 Rails

我们需要安装像NodeJS这样的javascript运行时环境，因为近来Rails的依赖越来越多了。这样我们可以合并和压缩你的javascript，从而提供一个更快的生产环境。

我们需要添加PPA来安装nodeJS。

1. <span class="pln">sudo add</span><span class="pun">-</span><span class="pln">apt</span><span class="pun">-</span><span class="pln">repository ppa</span><span class="pun">:</span><span class="pln">chris</span><span class="pun">-</span><span class="pln">lea</span><span class="pun">/</span><span class="pln">node</span><span class="pun">.</span><span class="pln">js</span>
2. <span class="pln">sudo apt</span><span class="pun">-</span><span class="kwd">get</span><span class="pln"> update</span>
3. <span class="pln">sudo apt</span><span class="pun">-</span><span class="kwd">get</span><span class="pln"> install nodejs</span>

如果在更新时遇到了问题，你可以试试这个命令：

1. <span class="com"># Note the new setup script name for Node.js v0.12</span>
2. <span class="pln">curl </span><span class="pun">-</span><span class="pln">sL https</span><span class="pun">:</span><span class="com">//deb.nodesource.com/setup_0.12 | sudo bash -</span>
3. <span class="com"># Then install with:</span>
4. <span class="pln">sudo apt</span><span class="pun">-</span><span class="kwd">get</span><span class="pln"> install </span><span class="pun">-</span><span class="pln">y nodejs</span>

下一步，用这个命令安装 rails：

1. <span class="pln">gem install rails </span><span class="pun">-</span><span class="pln">v </span><span class="lit">4.2</span><span class="pun">.</span><span class="lit">1</span>

因为我们正在使用rbenv，用下面的命令来让rails的执行程序可以使用。

1. <span class="pln">rbenv rehash</span>

要确保rails已经正确安装，你可以运行rails -v，显示如下：

1. <span class="pln">rails </span><span class="pun">-</span><span class="pln">v</span>
2. <span class="com"># Rails 4.2.1</span>

如果你得到的是不同的结果可能是环境没有设置正确。

设置 MySQL

或许你已经熟悉MySQL了，你可以从Ubuntu的仓库中安装MySQL的客户端与服务端。你可以在安装时设置root用户密码。这个信息将来会进入你rails程序的database.yml文件中。用下面的命令来安装mysql。

1. <span class="pln">sudo apt</span><span class="pun">-</span><span class="kwd">get</span><span class="pln"> install mysql</span><span class="pun">-</span><span class="pln">server mysql</span><span class="pun">-</span><span class="pln">client libmysqlclient</span><span class="pun">-</span><span class="pln">dev</span>

安装libmysqlclient-dev用于mysql2 gem的编译；在设置rails程序时，rails通过它来连接mysql。

最后一步

让我们尝试创建你的第一个rails程序：

1. <span class="com"># 使用 MySQL 数据库</span>
2. <span class="pln">rails </span><span class="kwd">new</span><span class="pln"> myapp </span><span class="pun">-</span><span class="pln">d mysql</span>
3. <span class="com"># 进入到应用目录</span>
4. <span class="pln">cd myapp</span>
5. <span class="com"># 创建数据库</span>
6. <span class="pln">rake db</span><span class="pun">:</span><span class="pln">create</span>
7. <span class="pln">rails server</span>

访问http://localhost:3000来访问你的新网站。现在你的电脑上已经可以构建rails程序了。

如果你在创建数据库时遇到了“Access denied for user 'root'@'localhost' (Using password: NO)”这个错误信息，你需要更新你的config/database.yml文件来匹配数据库的用户名和密码。

1. <span class="com"># 编辑配置文件夹中的 database.yml</span>
2. <span class="pln">nano config</span><span class="pun">/</span><span class="pln">database</span><span class="pun">.</span><span class="pln">yml</span>

接着填入MySql root用户的密码。

退出 (Ctrl+X)并保存。

总结

Rails是用Ruby写的， 也是随着rails一起使用的编程语言。在Ubuntu 15.04中Ruby on Rails可以用rbenv、 rvm和源码的方式来安装。本篇我们使用的是rbenv方式并用了MySQL作为数据库。有任何的问题或建议，请在评论栏指出。

Ruby on rails初体验系列文章：

via: http://linoxide.com/ubuntu-how-to/installing-ruby-rails-using-rbenv-ubuntu-15-04/

作者：Obet 译者：geekpi 校对：wxy

本文由 LCTT 原创翻译，Linux中国 荣誉推出