Ruby-on-rails 验证：仅字母、数字和 -
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Validate: Only letters, numbers and -
提问by atmorell
I would like to validate my users, so they can only use a-z and - in their username.
我想验证我的用户，所以他们只能在他们的用户名中使用 az 和 - 。
validates_format_of :username, :with => /[a-z]/
However this rule also allows spaces ._@
但是这个规则也允许空格 ._@
Username should use only letters, numbers, spaces, and .-_@ please.
Any ideas?
有任何想法吗？
Best regards. Asbj?rn Morell
此致。Asbj?rn 莫雷尔
回答by Matthew Schinckel
You may need to say the whole string must match:
您可能需要说整个字符串必须匹配：
validates_format_of :username, :with => /^[-a-z]+$/
You may also need to replace ^ with \A and $ with \Z, if you don't want to match a newline at the start/end. (thanks to BaroqueBobcat)
如果您不想在开始/结束处匹配换行符，您可能还需要将 ^ 替换为 \A 并将 $ 替换为 \Z。（感谢BaroqueBobcat）
Appending an i will cause it to match in a case-insensitive manner. (thanks to Omar Qureshi).
附加 i 将使其以不区分大小写的方式匹配。（感谢奥马尔·库雷希）。
(I also originally left off the +: thanks to Chuck)
（我最初也离开了+：感谢Chuck）
回答by laffuste
More complex solution but reusable and with more fine grained error messaging.
更复杂的解决方案，但可重用且具有更细粒度的错误消息。
Custom validator:
自定义验证器：
app/validators/username_convention_validator.rb
应用程序/验证器/用户名_convention_validator.rb
class UsernameConventionValidator < ActiveModel::EachValidator
def validate_each(record, field, value)
unless value.blank?
record.errors[field] << "is not alphanumeric (letters, numbers, underscores or periods)" unless value =~ /^[[:alnum:]._-]+$/
record.errors[field] << "should start with a letter" unless value[0] =~ /[A-Za-z]/
record.errors[field] << "contains illegal characters" unless value.ascii_only?
end
end
end
(Notice it does allow ' . - _ ' and doesnt allow non ascii, for completeness sake)
（注意它确实允许 ' . - _ ' 并且不允许非 ascii，为了完整起见）
Usage:
用法：
app/models/user.rb
应用程序/模型/user.rb
validates :name,
:presence => true,
:uniqueness => true,
:username_convention => true
回答by djna
The [] may contain several "rules" so [a-z0-9] gives lowercase letters and numbers
[] 可能包含多个“规则”，因此 [a-z0-9] 给出小写字母和数字
the special character - must go at the start of the rule
特殊字符 - 必须放在规则的开头
Does
做
[-a-z0-9@_.]
give the effect you want?
给你想要的效果？
回答by Codebeef
validates_format_of :username, :with => /^[\w\-@]*$/
Note the *, which means '0 or more'
注意 *，表示“0 或更多”
回答by Damir Zeki?
Simply change the regular expression to match all characters your specification states (\wcovers all alphanumeric characters -- letters and numbers -- and an underscore).
只需更改正则表达式以匹配您的规范说明的所有字符（\w涵盖所有字母数字字符——字母和数字——以及下划线）。
validates_format_of :username, :with => /[\w \.\-@]+/
