I have a single page app, which has URLs like http://example.com/#!something/something/. The problem is that when I send email containing link to such url, hotmail users get them wrong (I have noticed it only in hotmail, everyone else is good).
The ! is encoded to %21 which makes the url wrong: http://example.com/#%21something/something/
Any ideas what can be done except rewriting my app :-). I am using swiftmailer to send email, but I highly doubt that this is relevant.
According to RFC3986, the "!" character is valid in the fragment (#...) component of URIs, so it should not get encoded using percent-encoding. In this sense, this seems to be an outlook.com bug.
One workaround is to use plain-text emails: based on my tests, outlook.com encodes !'s HTML email links only and plain-text emails are safe.
The real solution, however, is to do your own normalization in the client-side code. URL cracking and normalization is a really tricky business, so I'd expect issues with other email clients, too. Running JavaScript decodeUriComponent() against window.location.hash should give you the unencoded "#!/something/something" version regardless whether the exclamation mark was encoded or not. I understand this calls for modifying the web application that you wanted to avoid, but to my best knowledge this is the way to go.
