{"id":36592,"date":"2022-07-26T15:17:06","date_gmt":"2022-07-26T19:17:06","guid":{"rendered":"https:\/\/mjtsai.com\/blog\/?p=36592"},"modified":"2022-08-04T16:05:10","modified_gmt":"2022-08-04T20:05:10","slug":"mail-links-and-percentages","status":"publish","type":"post","link":"https:\/\/mjtsai.com\/blog\/2022\/07\/26\/mail-links-and-percentages\/","title":{"rendered":"Mail Links and Percentages"},"content":{"rendered":"

Dr. Drang<\/a>:<\/p>\n

\n

Yesterday, John Voorhees wrote a nice article at MacStories<\/a> about creating links to specific email messages. His system is in the form of a Shortcut, but the real work is done by an AppleScript. The AppleScript is an extension of one John Gruber wrote<\/a> 15 years ago.<\/p>\n

[…]<\/p>\n

The questions I needed to answer were:<\/p>\n

    \n
  1. Are reserved characters used in message IDs?<\/li>\n
  2. If so, do they need to be percent-encoded in a message<\/code> URL?<\/li>\n<\/ol>\n

    […]<\/p>\n

    None of the reserved characters caused a problem except the percent sign itself.<\/p>\n<\/blockquote>\n

    However, that does not mean that the strings are valid URLs, and in fact even putting the message ID in unencoded angle brackets will prevent it from working with NSURL<\/code>. I think what’s happening here is that Mail is receiving the URL as a string and removing the percent escapes directly, without actually parsing it as a URL.<\/p>\n

    So, if you store unencoded links you are setting yourself up for trouble if Mail changes how it works, if you ever want to redirect the message:<\/tt> scheme to a different app, or if you want to detect message:<\/tt> URLs that are embedded in a document. Lots of e-mails unfortunately don’t follow the specification<\/a>, and I’ve seen Message-ID headers that include the \"<\/tt> and )<\/tt> characters, as well as spaces, which could mess up the way Markdown<\/a> interprets the links.<\/p>\n

    If you want to handle more than the percent symbol, here’s an AppleScript that will escape the other characters, too:<\/p>\n

    \nuse AppleScript version \"2.4\"\nuse framework \"Foundation\"\n\non URLFromMessageID(_messageID)\n    set _components to my NSURLComponents's alloc's init\n    _components's setScheme:\"message\"\n    _components's setHost:(\"<\" & _messageID & \">\")\n    return _components's |URL|'s absoluteString() as Unicode text\nend URLFromMessageID\n<\/pre>\n\n
    Another issue to be aware of is that the Message-ID header sometimes includes text outside of the angle brackets. This should not be included in the URL. However, if you are using Mail’s message id<\/code> AppleScript property, as Gruber’s script does, it will remove the extraneous text for you (just as it removes the angle brackets themselves).<\/p>\n\n
    Previously:<\/p>\n