国科大ruby选课原型系统的环境搭建(Ubuntu 16.04)
步骤：
1.查看系统版本
wsy@ubuntu:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 16.04.3 LTS
Release: 16.04
Codename: xenial
2.更新软件（可以避免以后遇到的一些问题）
wsy@ubuntu:~$ sudo apt-get update
3.安装curl(如果没安装curl的话才安装)
wsy@ubuntu:~$ sudo apt-get install curl
Reading package lists... Done
Building dependency tree
Reading state information... Done
4.安装rvm(curl是一种命令行工具，作用是发出网络请求，然后得到和提取数据，显示在"标准输出"（stdout）上面。使用-L参数，curl就会跳转到新的网址。)
wsy@ubuntu:~$ curl -L get.rvm.io | bash -s stable
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 194 100 194 0 0 77 0 0:00:02 0:00:02 --:--:-- 77
100 24361 100 24361 0 0 5050 0 0:00:04 0:00:04 --:--:-- 15321
Downloading https://github.com/rvm/rvm/archive/1.29.4.tar.gz
4.1如果公钥报错的话执行以下操作
wsy@ubuntu:~$ gpg2 --keyserver hkp://keys.gnupg.net --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3
wsy@ubuntu:~$
wsy@ubuntu:~$ curl -sSL https://get.rvm.io | bash -s stable
wsy@ubuntu:~$
wsy@ubuntu:~$ source ~/.bashrc #这两个加入之后就能检测到ruby和rails
wsy@ubuntu:~$ source ~/.bash_profile #这两个加入之后就能检测到ruby和rails
5.使用RVM安装RUBY
wsy@ubuntu:~$ echo "ruby_url=https://cache.ruby-china.org/pub/ruby" > ~/.rvm/user/db #输出重定向到文件，这个语句似乎并没有用
wsy@ubuntu:~$ rvm list known
wsy@ubuntu:~$ rvm install "ruby-2.3.0"
6.安装rails
wsy@ubuntu:~$ gem install rails -v 4.2.6
wsy@ubuntu:~$ rails -v
7.安装git并下载原型系统
wsy@ubuntu:~/Desktop$ sudo apt install git
wsy@ubuntu:~/Desktop$ git clone https://github.com/PENGZhaoqing/CourseSelect
wsy@ubuntu:~/Desktop$ cd CourseSelect/
8.执行bundle install
wsy@ubuntu:~/Desktop/CourseSelect$ bundle install#可能的报错信息参考本文件上面部分
9.安装postgresql和pgadmin3，并创建新用户dbuser
wsy@ubuntu:~/Desktop/CourseSelect$ sudo apt-get install postgresql
wsy@ubuntu:~/Desktop/CourseSelect$ sudo adduser dbuser #新建一个Linux新用户，可以取你想要的名字，这里为dbuser。
wsy@ubuntu:~/Desktop/CourseSelect$ sudo apt-get install pgadmin3
10.切换用户并启动postgres
wsy@ubuntu:~$ sudo su - postgres
postgres@ubuntu:~$ psql
11.创建用户并设置密码
postgres=# \password postgres
postgres=# CREATE USER dbuser WITH PASSWORD 'dbuser';
CREATE ROLE
12.新建数据库并授权
postgres=# CREATE DATABASE dbuser OWNER dbuser;
CREATE DATABASE
postgres=# CREATE DATABASE courseselect_development OWNER dbuser;
CREATE DATABASE
13.给数据库授权（貌似没用）
postgres=# GRANT ALL PRIVILEGES ON DATABASE dbuser to dbuser;
GRANT
postgres=# \q
14.切换用户，并解决ruby -v失效问题
postgres@ubuntu:~$ su wsy
Password:
wsy@ubuntu:~$ cd ~/Desktop/CourseSelect/
wsy@ubuntu:~/Desktop$ source ~/.bashrc & source ~/.bash_profile
15.执行rake db:migrate和rake db:seed
wsy@ubuntu:/var/lib/postgresql$ cd ~/Desktop/CourseSelect/
wsy@ubuntu:~/Desktop/CourseSelect$ rake db:migrate
wsy@ubuntu:~/Desktop/CourseSelect$ rake db:seed
16.启动rails server
wsy@ubuntu:~/Desktop/CourseSelect$ rails s
问题汇总
su: Authentication failure解决：在ubuntu中，root账户默认不可用。使用这个获得root:sudo -i- rake db:migrate报错：
Ruby on Rails , No Rakefile found
解决： https://stackoverflow.com/questions/18452701/ruby-on-rails-no-rakefile-found-error - postgresql相关知识：
- PostgreSQL新手入门：http://www.ruanyifeng.com/blog/2013/12/getting_started_with_postgresql.html
- Ubuntu 安装和配置postgresql:
https://blog.csdn.net/zpf336/article/details/ 50843674 - 修改PostgreSQL数据库默认用户postgres的密码 http://www.cnblogs.com/kaituorensheng/p/4735191.html
- PostgreSQL忘记密码 https://www.jianshu.com/p/1464f3b966e9
- 修改系统用户postgres的密码（区别于修改postgres里的postgres用户）：
1.使用sudo -i命令切换到root状态
2.删除postgres的密码：passwd -d postgres
3.设置用户postgres的新密码：sudo -u postgres passwd然后输入 两次新密码
4.现在可以试试su postgres了
- 切换用户并启动postgres(3种方法)
法1：
wsy@ubuntu:~/Desktop/CourseSelect$ sudo su - postgres #然后，切换到postgres用户。
postgres@ubuntu:/home/wsy/Desktop/CourseSelect$ psql #下一步，使用psql命令登录PostgreSQL控制台。
法2：
wsy@ubuntu:~/Desktop/CourseSelect$ sudo -u postgres psql
psql (9.5.14)
Type "help" for help.
法3：
wsy@ubuntu:/etc/postgresql/9.5/main$ psql -h 127.0.0.1 -U postgres
- 修改PostgreSQL数据库默认用户postgres的密码(两种方法)
法1：
postgres=# ALTER USER postgres WITH PASSWORD 'postgres'; #第一件事是使用\password命令，为postgres用户设置一个密码。（不要落下分号）
法2：
postgres=# \password postgres
Enter new password:
Enter it again:
ALTER ROLE
- 执行bundle install报错：
报错1: Could not fetch specs from https://gems.ruby-china.org/
详细信息：
wsy@ubuntu:~/Desktop/CourseSelect$ bundle install
Fetching source index from https://gems.ruby-china.org/
Retrying fetcher due to error (2/4): Bundler::HTTPError Could not fetch specs from https://gems.ruby-china.org/
Retrying fetcher due to error (3/4): Bundler::HTTPError Could not fetch specs from https://gems.ruby-china.org/
Retrying fetcher due to error (4/4): Bundler::HTTPError Could not fetch specs from https://gems.ruby-china.org/
Could not fetch specs from https://gems.ruby-china.org/
解决思路： 将原来的https://gems.ruby-china.org/修改为https://gems.ruby-china.com/
wsy@ubuntu:~/Desktop/CourseSelect$ gem sources --add https://gems.ruby-china.com/ --remove https://rubygems.org/
wsy@ubuntu:~/Desktop/CourseSelect$ gem sources -l #查看修改后的配置
wsy@ubuntu:~/Desktop/CourseSelect$ cd CourseSelect
wsy@ubuntu:~/Desktop/CourseSelect$ vi Gemfile 然后将第一行改为：source 'https://gems.ruby-china.com'
报错2： An error occurred while installing pg (0.18.4)
详细信息：
Gem::Ext::BuildError: ERROR: Failed to build gem native extension.
current directory: /home/wsy/.rvm/gems/ruby-2.3.0/gems/pg-0.18.4/ext
/home/wsy/.rvm/rubies/ruby-2.3.0/bin/ruby -r ./siteconf20181118-99965-1ksvqt7.rb extconf.rb
checking for pg_config... no No pg_config... trying anyway. If building fails, please try again with
--with-pg-config=/path/to/pg_config
checking for libpq-fe.h... no
Can't find the 'libpq-fe.h header
*** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
...
An error occurred while installing pg (0.18.4), and Bundler cannot continue.
Make sure that `gem install pg -v '0.18.4' --source 'https://gems.ruby-china.com/'` succeeds before bundling.
解决：
wsy@ubuntu:~/Desktop/CourseSelect$ sudo apt-get install libpq-dev
wsy@ubuntu:~/Desktop/CourseSelect$ gem install pg
wsy@ubuntu:~/Desktop/CourseSelect$ bundle install