fix: support utf-7 and legacy encodings in email parsing#2109
Open
alpapad wants to merge 1 commit into
Open
Conversation
Register CodePagesEncodingProvider to enable legacy code page encodings
(ISO-8859-8, Windows-1252, etc.) which are commonly used in older email
clients and are not available by default in .NET 5+.
Add Utf7EncodingProvider and Utf7WrapperEncoding to re-enable UTF-7
decoding for legacy email messages. .NET 9+ blocks Encoding.GetEncoding(65000)
and Encoding.GetEncoding("utf-7") before consulting registered providers.
The workaround registers a custom encoding that reports CodePage=65002 (a
private-use value not blocked by .NET). MimeKit caches utf-7→65002 and
subsequent codepage lookups are intercepted by the provider, delegating
actual encoding/decoding to the still-functional Encoding.UTF7 instance.
Contributor
|
Thank you for your contribution to smtp4dev! 🎉 Before we can merge your pull request, we need you to sign our Contributor License Agreement (CLA). 📝 Please read the CLA: Contributor License Agreement ✍️ To sign the CLA, please comment on this PR with exactly: This is a one-time requirement for new contributors. Thank you for your understanding! 🙏 I have read the CLA Document and I hereby sign the CLA You can retrigger this bot by commenting recheck in this Pull Request. Posted by the CLA Assistant Lite bot. |
Author
|
I have read the CLA Document and I hereby sign the CLA |
|
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
Register CodePagesEncodingProvider to enable legacy code page encodings (ISO-8859-8, Windows-1252, etc.) which are commonly used in older email clients and are not available by default in .NET 5+.
Add Utf7EncodingProvider and Utf7WrapperEncoding to re-enable UTF-7 decoding for legacy email messages. .NET 9+ blocks Encoding.GetEncoding(65000) and Encoding.GetEncoding("utf-7") before consulting registered providers. The workaround registers a custom encoding that reports CodePage=65002 (a private-use value not blocked by .NET). MimeKit caches utf-7→65002 and subsequent codepage lookups are intercepted by the provider, delegating actual encoding/decoding to the still-functional Encoding.UTF7 instance.