3 ms·

I'm sure this will break a ridiculous number of regular expressions for email address validation.

by rbranson 17y ago

jedberg 17y ago
Yes, but that is their own fault for trying to use a regex to validate email addresses. :)
- atlbeer 17y ago
  (?:(?:\r\n)?[ \t])(?:(?:(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?: \r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:( ?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?:\r\n)?[ \t])))@(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\0 31]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\ ](?:(?:\r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+ (?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?: (?:\r\n)?[ \t])))|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z |(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?:\r\n) ?[ \t]))\<(?:(?:\r\n)?[ \t])(?:@(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\ r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n) ?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t] )))(?:,@(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t])* )(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t])))) :(?:(?:\r\n)?[ \t]))?(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+ |\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?:\r \n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?: \r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t ]))"(?:(?:\r\n)?[ \t])))@(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031 ]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\]( ?:(?:\r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(? :(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(? :\r\n)?[ \t])))\>(?:(?:\r\n)?[ \t]))|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(? :(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)? 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  - _dan 17y ago
    I wish people would stop posting that. Yes, that covers most (though not all) of the RFC definitions of what constitutes an email address, but in practice you only want to accept a tiny subset of those.
    - statictype 17y ago
      Curious: Why would you want to accept only a tiny subset of those? What do you gain by that?
      - _dan 17y ago
        Well, the really simple example is the string "postmaster". It is a perfectly legitimate email address, and almost always deliverable. But rarely something you want to actually accept.

I'm sure this will break a ridiculous number of regular expressions for email address validation.

jedberg 17y ago

Yes, but that is their own fault for trying to use a regex to validate email addresses. :)

atlbeer 17y ago
(?:(?:\r\n)?[ \t])(?:(?:(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?: \r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:( ?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?:\r\n)?[ \t])))@(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\0 31]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\ ](?:(?:\r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+ (?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?: (?:\r\n)?[ \t])))|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z |(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?:\r\n) ?[ \t]))\<(?:(?:\r\n)?[ \t])(?:@(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\ r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n) ?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t] )))(?:,@(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t])* )(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t] )+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(?:\r\n)?[ \t])))) :(?:(?:\r\n)?[ \t]))?(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?:\r\n)?[ \t])+ |\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t]))"(?:(?:\r \n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(?:(?: \r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)?[ \t ]))"(?:(?:\r\n)?[ \t])))@(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031 ]+(?:(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\]( ?:(?:\r\n)?[ \t]))(?:\.(?:(?:\r\n)?[ \t])(?:[^()<>@,;:\\".\[\] \000-\031]+(? :(?:(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|\[([^\[\]\r\\]|\\.)\](?:(? :\r\n)?[ \t])))\>(?:(?:\r\n)?[ \t]))|(?:[^()<>@,;:\\".\[\] \000-\031]+(?:(? :(?:\r\n)?[ \t])+|\Z|(?=[\["()<>@,;:\\".\[\]]))|"(?:[^\"\r\\]|\\.|(?:(?:\r\n)? 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- _dan 17y ago
  I wish people would stop posting that. Yes, that covers most (though not all) of the RFC definitions of what constitutes an email address, but in practice you only want to accept a tiny subset of those.
  - statictype 17y ago
    Curious: Why would you want to accept only a tiny subset of those? What do you gain by that?
    - _dan 17y ago
      Well, the really simple example is the string "postmaster". It is a perfectly legitimate email address, and almost always deliverable. But rarely something you want to actually accept.