我无法启动我的 Rails 服务器。错误显示：
$ rails server
/usr/local/lib/ruby/gems/1.9.1/gems/mysql2-0.3.13/lib/mysql2a.rb:8:in `require': libmysqlclient.so.18: cannot open shared object file: No such file or directory - /usr/local/lib/ruby/gems/1.9.1/gems/mysql2-0.3.13/lib/mysql2/mysql2.so (LoadError)
from /usr/local/lib/ruby/gems/1.9.1/gems/mysql2-0.3.13/lib/mysql2.rb:8:in `<top (required)>'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `require'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:72:in `block (2 levels) in require'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `each'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:70:in `block in require'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `each'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler/runtime.rb:59:in `require'
from /usr/local/lib/ruby/gems/1.9.1/gems/bundler-1.3.5/lib/bundler.rb:132:in `require'
from /home/marslo/Study/Codes/Ruby/RailsBegin/config/application.rb:7:in `<top (required)>'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-4.0.0/lib/rails/commands.rb:76:in `require'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-4.0.0/lib/rails/commands.rb:76:in `block in <top (required)>'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-4.0.0/lib/rails/commands.rb:73:in `tap'
from /usr/local/lib/ruby/gems/1.9.1/gems/railties-4.0.0/lib/rails/commands.rb:73:in `<top (required)>'
from bin/rails:4:in `require'
from bin/rails:4:in `<main>'
但！mysql2.so 可以支持 !!! ：
$ ls -al /usr/local/lib/ruby/gems/1.9.1/gems/mysql2-0.3.13/lib/mysql2/mysql2.so
-rwxr-xr-x 1 root root 131K Oct 7 00:31 /usr/local/lib/ruby/gems/1.9.1/gems/mysql2-0.3.13/lib/mysql2/mysql2.so
我已经从源代码安装了 mysql 。它安装在：
$ whereis mysql
mysql: /usr/local/mysql
我尝试通过 gem安装mysql2--with-mysql-config，一切正常：
$ sudo gem install mysql2 -- --with-mysql-config=/usr/local/mysql/bin/mysql_config
Building native extensions. This could take a while...
Successfully installed mysql2-0.3.13
1 gem installed
Installing ri documentation for mysql2-0.3.13...
Installing RDoc documentation for mysql2-0.3.13...
这是我的database.yml：
development:
adapter: mysql2
encoding: utf8
database: RailsBegin_development
pool: 5
username: root
password: passwd
host: localhost
socket: /tmp/mysql.sock
这是我的数据库：
mysql> SHOW DATABASES;
+------------------------+
| Database |
+------------------------+
| information_schema |
| RailsBegin_development |
| mysql |
| performance_schema |
| test |
+------------------------+
5 rows in set (0.00 sec)
这是我的捆绑安装：
$ bundle install
Using rake (10.1.0)
Using i18n (0.6.5)
Using minitest (4.7.5)
Using multi_json (1.8.1)
Using atomic (1.1.14)
Using thread_safe (0.1.3)
Using tzinfo (0.3.37)
Using activesupport (4.0.0)
Using builder (3.1.4)
Using erubis (2.7.0)
Using rack (1.5.2)
Using rack-test (0.6.2)
Using actionpack (4.0.0)
Using mime-types (1.25)
Using polyglot (0.3.3)
Using treetop (1.4.15)
Using mail (2.5.4)
Using actionmailer (4.0.0)
Using activemodel (4.0.0)
Using activerecord-deprecated_finders (1.0.3)
Using arel (4.0.0)
Using activerecord (4.0.0)
Using coffee-script-source (1.6.3)
Using execjs (2.0.2)
Using coffee-script (2.2.0)
Using thor (0.18.1)
Using railties (4.0.0)
Using coffee-rails (4.0.0)
Using hike (1.2.3)
Using jbuilder (1.5.1)
Using jquery-rails (3.0.4)
Using json (1.8.0)
Using mysql2 (0.3.13)
Using bundler (1.3.5)
Using tilt (1.4.1)
Using sprockets (2.10.0)
Using sprockets-rails (2.0.0)
Using rails (4.0.0)
Using rdoc (3.12.2)
Using sass (3.2.12)
Using sass-rails (4.0.0)
Using sdoc (0.3.20)
Using turbolinks (1.3.0)
Using uglifier (2.2.1)
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.
我不知道它有什么问题。每个人都可以帮助我吗？提前致谢！！
=============
更新 1
我已经卸载了 mysql2 并重新安装为0.3.11：
$ sudo gem install mysql2 -v 0.3.11 -- --with-mysql-config=/usr/local/mysql/bin/mysql_config --with-mysql-lib=/usr/local/mysql/lib --with-mysql-bin=/usr/local/mysql/bin
Fetching: mysql2-0.3.11.gem (100%)
Building native extensions. This could take a while...
Successfully installed mysql2-0.3.11
1 gem installed
Installing ri documentation for mysql2-0.3.11...
Installing RDoc documentation for mysql2-0.3.11...
并更新Gemfile：
gem 'mysql2', '~> 0.3.11'
并再次捆绑安装，但仍然安装了 0.3.13！：
$ bundle install
Fetching gem metadata from https://rubygems.org/...........
Fetching gem metadata from https://rubygems.org/..
Resolving dependencies...
Using rake (10.1.0)
Using i18n (0.6.5)
Using minitest (4.7.5)
Using multi_json (1.8.1)
Using atomic (1.1.14)
Using thread_safe (0.1.3)
Using tzinfo (0.3.37)
Using activesupport (4.0.0)
Using builder (3.1.4)
Using erubis (2.7.0)
Using rack (1.5.2)
Using rack-test (0.6.2)
Using actionpack (4.0.0)
Using mime-types (1.25)
Using polyglot (0.3.3)
Using treetop (1.4.15)
Using mail (2.5.4)
Using actionmailer (4.0.0)
Using activemodel (4.0.0)
Using activerecord-deprecated_finders (1.0.3)
Using arel (4.0.0)
Using activerecord (4.0.0)
Using bundler (1.3.5)
Using coffee-script-source (1.6.3)
Using execjs (2.0.2)
Using coffee-script (2.2.0)
Using thor (0.18.1)
Using railties (4.0.0)
Using coffee-rails (4.0.0)
Using hike (1.2.3)
Using jbuilder (1.5.1)
Using jquery-rails (3.0.4)
Using json (1.8.0)
Installing mysql2 (0.3.13)
Using tilt (1.4.1)
Using sprockets (2.10.0)
Using sprockets-rails (2.0.0)
Using rails (4.0.0)
Using rdoc (3.12.2)
Using sass (3.2.12)
Using sass-rails (4.0.0)
Using sdoc (0.3.20)
Using turbolinks (1.3.0)
Using uglifier (2.2.1)
Your bundle is complete!
Use `bundle show [gemname]` to see where a bundled gem is installed.
这里的宝石清单：
$ gem list | grep mysql2
mysql2 (0.3.13, 0.3.11)
顺便说一句，mysql（源代码安装）的所有者是mysql：
$ ls -al
total 160K
-rw-r--r-- 1 mysql mysql 18K Sep 10 15:38 COPYING
-rw-r--r-- 1 mysql mysql 2.5K Sep 10 15:38 README
-rw-r--r-- 1 mysql mysql 87K Sep 10 15:38 INSTALL-BINARY
drwxr-xr-x 2 mysql mysql 4.0K Oct 1 23:51 docs/
drwxr-xr-x 3 mysql mysql 4.0K Oct 1 23:51 include/
drwxr-xr-x 3 mysql mysql 4.0K Oct 1 23:51 lib/
drwxr-xr-x 10 mysql mysql 4.0K Oct 1 23:52 mysql-test/
drwxr-xr-x 28 mysql mysql 4.0K Oct 1 23:52 share/
drwxr-xr-x 2 mysql mysql 4.0K Oct 1 23:52 scripts/
drwxr-xr-x 4 mysql mysql 4.0K Oct 1 23:52 sql-bench/
drwxr-xr-x 4 mysql mysql 4.0K Oct 1 23:52 man/
drwxr-xr-x 3 mysql mysql 4.0K Oct 1 23:52 support-files/
-rw-r--r-- 1 mysql mysql 943 Oct 1 23:55 my.cnf
drwxr-xr-x 2 mysql mysql 4.0K Oct 1 23:57 bin/
drwxr-xr-x 6 mysql mysql 4.0K Oct 7 01:04 data/
但是， ruby 的所有者是root。
是因为权限问题吗？
=====================
更新 2
安装 mysql2 版本：0.3.11，使用--platform=ruby：
$ sudo gem uninstall mysql2
$ sudo gem install mysql2 -v 0.3.11 --platform=ruby -- --with-mysql-config=/usr/local/mysql/bin/mysql_config --with-mysql-lib=/usr/local/mysql/lib --with-mysql-bin=/usr/local/mysql/bin
$ rm -rf Gemfile.lock
$ bundle install
mysql变量可以通过以下方式找到：
$ mysqladmin variables
并且，安装NodeJS：
$ sudo apt-get install nodejs
而且，它会起作用的！
$ rails server
=> Booting WEBrick
=> Rails 4.0.0 application starting in development on http://0.0.0.0:3000
=> Run `rails server -h` for more startup options
=> Ctrl-C to shutdown server
[2013-10-07 21:08:06] INFO WEBrick 1.3.1
[2013-10-07 21:08:06] INFO ruby 1.9.3 (2013-06-27) [i686-linux]
[2013-10-07 21:08:06] INFO WEBrick::HTTPServer#start: pid=3676 port=3000
不要忘记启动mysql服务器：
$ sudo service mysql start
=====================
更新 3
CentOS 的 NodeJS 安装：
$ sudo yum groupinstall 'Development Tools'
$ mkdir nodjs && cd $_
$ wget http://nodejs.org/dist/node-latest.tar.gz
--2013-10-12 16:01:53-- http://nodejs.org/dist/node-latest.tar.gz
Resolving nodejs.org... 165.225.133.150
Connecting to nodejs.org|165.225.133.150|:80... connected.
HTTP request sent, awaiting response... 200 OK
Length: 13633041 (13M) [application/octet-stream]
Saving to: “node-latest.tar.gz”
100%[============================================================================>] 13,633,041 513K/s in 36s
2013-10-12 16:02:31 (375 KB/s) - “node-latest.tar.gz” saved [13633041/13633041]
$ tar xzf node-latest.tar.gz
$ cd node-v0.10.20/
$ ./configure
$ make
$ sudo make install
====================
笔记
- 这与权限问题无关
- 如果Gemfile中有任何更新，请在运行bundle install之前先删除Gemfile.lock