Ruby on Rails errors:

(新手期)

Q1: rvm 无法使用

$ rvm use 1.9.3 --default

RVM is not a function, selecting rubies with 'rvm use ...' will not work.

You need to change your terminal emulator preferences to allow login shell.
Sometimes it is required to use `/bin/bash --login` as the command.
Please visit https://rvm.io/integration/gnome-terminal/ for an example.

使用：

 source ~/.rvm/scripts/rvm

或者：

echo '[[ -s "$HOME/.rvm/scripts/rvm" ]] && . "$HOME/.rvm/scripts/rvm"' >>~/.bashrc
source ~/.bashrc

Q2: bundle install httpError

run  bundle install
The dependency tzinfo-data (>= 0) will be unused by any of the platforms Bundler is installing for. Bundler is installing for ruby but the dependency is only for x86-mingw32, x86-mswin32, x64-mingw32, java. To add those platforms to the bundle, run `bundle lock --add-platform x86-mingw32 x86-mswin32 x64-mingw32 java`.
Fetching source index from https://rubygems.org/

Retrying fetcher due to error (2/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org/
Retrying fetcher due to error (3/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org/
Retrying fetcher due to error (4/4): Bundler::HTTPError Could not fetch specs from https://rubygems.org

[^网络原因，需要翻墙]:

gem sources --add https://gems.ruby-china.org/ --remove https://rubygems.org/
gem sources -l
gem install rails #如果装rails时失败，就需要重装

#rails 项目需要使用Gemfile 和 Bundle 我们可以用 Bundler 的 Gem 源代码镜像命令。
bundle config mirror.https://rubygems.org https://gems.ruby-china.org 
#这样你不用改你的 Gemfile 的 source

参考链接：ruby-china镜像站快如闪电！

Q3: 生产秘钥 rails4 rails5 不同

ArgumentError: Missing `secret_key_base` for 'production' environment, set this string with `rails credentials:edit`

需要添加生产密钥

在rails4 中这个密钥是通过 rake secret RAILS_ENV=production 创建后放到服务器端的/home/xxx/your_web_app/shared/config/secrets.yml中的，而在rails5中改成了master.key ,使用时需要在本地的/home/xxx/your_web_app/config/deploy.rb 的:link_file手动添加 ‘config/master.key’

如：

# Default value for :linked_files is []                                          
append :linked_files, "config/database.yml", "config/master.key"

Q4: rake aborted!

$ sudo rake secret --trace
rake aborted!
LoadError: cannot load such file -- bundler/setup

这一个可以尝试提权，用root权限运行

Beginning in Rails 4, Rails ships with a rails binstub at ./bin/rails that should be used instead of the Bundler-generated rails binstub.

Q5: The page you were looking for doesn't exist.

The page you were looking for doesn't exist.

You may have mistyped the address or the page may have moved.

本地测试可以，远程服务器不行.检查了一下，路由有问题，处理好远程仓库的代码（因为服务器上应该是从远程仓库上拉取代码的）

Q6: 下拉菜单无法下拉 (使用bootstrap)

下拉菜单无法下拉 (使用bootstrap)

这个功能需要js支持，所以需要包含必要的js库，在/app/assert/javascript/application.js里面添加

//= require jquery

Q7:.... ? ..... : .....

syntax error, unexpected ';' : expecting keyword_end ...cost?BCrypt::Engine::MIN_COST : BCrypt::Engine.cost

这是一个.... ? ..... : ..... 的表达式，居然没有发现，因此中间的问号与前面的判断条件需要有一个空格隔开。

Q8: 开放stmp服务的25端口

F, [2018-09-06T20:33:15.955037 #21413] FATAL -- : [bdf765fc-3c26-4d8f-87be-c5357887f443] ActionView::Template::Error (Missing host to link to! Please provide the :host parameter, set default_url_options[:host], or set :only_path to true):
F, [2018-09-06T20:33:15.955131 #21413] FATAL -- : [bdf765fc-3c26-4d8f-87be-c5357887f443]     3: <p>
[bdf765fc-3c26-4d8f-87be-c5357887f443]     4: Welcome to the Sample App! Click on the link below to activate your account:
[bdf765fc-3c26-4d8f-87be-c5357887f443]     5: </p>
[bdf765fc-3c26-4d8f-87be-c5357887f443]     6: <%= link_to "Activate", edit_account_activation_url(@user.activation_token,
[bdf765fc-3c26-4d8f-87be-c5357887f443]     7:                                                     email: @user.email) %>
F, [2018-09-06T20:33:15.955158 #21413] FATAL -- : [bdf765fc-3c26-4d8f-87be-c5357887f443]
F, [2018-09-06T20:33:15.955180 #21413] FATAL -- : [bdf765fc-3c26-4d8f-87be-c5357887f443] app/views/user_mailer/account_activation.html.erb:6:in `_app_views_user_mailer_account_activation_html_erb__374929091__625207508'
[bdf765fc-3c26-4d8f-87be-c5357887f443] app/mailers/user_mailer.rb:11:in `account_activation'
[bdf765fc-3c26-4d8f-87be-c5357887f443] app/models/user.rb:48:in `send_activation_email'
[bdf765fc-3c26-4d8f-87be-c5357887f443] app/controllers/users_controller.rb:18:in `create'

首先是我看的教程没有配置邮件服务器的主机host

然而配置完成后又出现内网连接超时的问题，

I, [2018-10-07T23:58:53.103195 #26716]  INFO -- : [084c0592-31a4-492c-8686-9cac1b6d2ead] Completed 500 Internal Server Error in 30173ms (ActiveRecord: 7.9ms)
F, [2018-10-07T23:58:53.104096 #26716] FATAL -- : [084c0592-31a4-492c-8686-9cac1b6d2ead]
F, [2018-10-07T23:58:53.104154 #26716] FATAL -- : [084c0592-31a4-492c-8686-9cac1b6d2ead] Net::OpenTimeout (execution expired):
F, [2018-10-07T23:58:53.104187 #26716] FATAL -- : [084c0592-31a4-492c-8686-9cac1b6d2ead]
F, [2018-10-07T23:58:53.104220 #26716] FATAL -- : [084c0592-31a4-492c-8686-9cac1b6d2ead] app/models/user.rb:48:in `send_activation_email'
[084c0592-31a4-492c-8686-9cac1b6d2ead] app/controllers/users_controller.rb:18:in `create'

结果发现是：腾讯云封禁了stmp服务的25端口，so。。工单申请解禁之后就可以正确发送激活的邮箱了。

Q7: 服务器端运维

如何在服务器端增删model对象的属性

在current文件夹下运行 rails console prodution才能正常访问生产环境下的数据信息

因为模型的文件model/在当前项目文件夹是没有文件的，即便rails可以运行，他也找不到model对象就会出现：

irb(main):001:0> User.first
Traceback (most recent call last):
        1: from (irb):1
NameError (uninitialized constant User)

另外需要注意的是，如果本地用的mysql和远程使用的mysql密码不一样的话，，database.yml的配置也要不一样

服务器端的用户模型已经有reset_at 属性，使用的迁移肯定有问题

要注意旧的时间戳的迁移，在已经执行过迁移之后重新使用db:migrate是没有效果的，除非db:rollback之后才有效果，想要对数据库做新的增删，需要建立新的迁移文档d

本地测试非常非常重要啊小老弟

所以别在瞎提交本地分支到服务器进行部署，弄错了，麻烦得一匹

Q9: 科学计算环境

对了不要别的什么科学计算环境下运行rails虚拟环境

其实就是anaconda，会触发LoadError

Q10: 测试固件

测试失败之　固件错误　　显示nil

解决方法：　在test/fixtures/xxx.yml 中添加所需要的测试固件

'nil' is not an ActiveModel-compatible object. It must implement :to_partial_path.
view的变量是nil ,所以无法渲染界面

解决：检查对应的controller 中是否定义了这个变量

Q11: Gemfile与本地的包版本不同

/.rbenv/versions/2.5.1/lib/ruby/gems/2.5.0/gems/bundler-1.16.2/lib/bundler/runtime.rb:313:in `check_for_activated_spec!': You have already activated i18n 1.1.1, but your Gemfile requires i18n 1.1.0. Prepending `bundle exec` to your command may solve this. (Gem::LoadError)