discourse/lib/email
Martin Brennan dede942007
FEATURE: Allow email image embed with secure media (#10563)
This PR introduces a few important changes to secure media redaction in emails. First of all, two new site settings have been introduced:

* `secure_media_allow_embed_images_in_emails`: If enabled we will embed secure images in emails instead of redacting them.
* `secure_media_max_email_embed_image_size_kb`: The cap to the size of the secure image we will embed, defaulting to 1mb, so the email does not become too big. Max is 10mb. Works in tandem with `email_total_attachment_size_limit_kb`.

`Email::Sender` will now attach images to the email based on these settings. The sender will also call `inline_secure_images` in `Email::Styles` after secure media is redacted and attachments are added to replace redaction messages with attached images. I went with attachment and `cid` URLs because base64 image support is _still_ flaky in email clients.

All redaction of secure media is now handled in `Email::Styles` and calls out to `PrettyText.strip_secure_media` to do the actual stripping and replacing with placeholders. `app/mailers/group_smtp_mailer.rb` and `app/mailers/user_notifications.rb` no longer do any stripping because they are earlier in the pipeline than `Email::Styles`.

Finally the redaction notice has been restyled and includes a link to the media that the user can click, which will show it to them if they have the necessary permissions.

![image](https://user-images.githubusercontent.com/920448/92341012-b9a2c380-f0ff-11ea-860e-b376b4528357.png)
2020-09-10 09:50:16 +10:00
..
authentication_results.rb enqueue spam/dmarc failing emails instead of hiding (#8674) 2020-01-21 11:12:00 -05:00
build_email_helper.rb DEV: Upgrading Discourse to Zeitwerk (#8098) 2019-10-02 14:01:53 +10:00
cleaner.rb FEATURE: Remove attachments and truncate raw field for incoming emails (#8253) 2019-10-30 16:54:35 +11:00
message_builder.rb FEATURE: Implement support for IMAP and SMTP email protocols. (#8301) 2020-07-10 12:05:55 +03:00
processor.rb FEATURE: Implement support for IMAP and SMTP email protocols. (#8301) 2020-07-10 12:05:55 +03:00
receiver.rb FEATURE: IMAP delete email sync for group inboxes (#10392) 2020-08-12 10:16:26 +10:00
renderer.rb FIX: during concurrent emails generation renderer should not be reused 2019-10-10 08:50:48 +11:00
sender.rb FEATURE: Allow email image embed with secure media (#10563) 2020-09-10 09:50:16 +10:00
styles.rb FEATURE: Allow email image embed with secure media (#10563) 2020-09-10 09:50:16 +10:00