TLDR; this commit vastly improves how whitespaces are handled when converting from HTML to Markdown.
It also adds support for converting HTML <tables> to markdown tables.
The previous 'remove_whitespaces!' method was traversing the whole HTML tree and used a heuristic to remove
leading and trailing whitespaces whenever it was appropriate (ie. mostly before and after HTML block elements)
It was a good idea, but it was very limited and leaded to bad conversion when the html had leading whitespaces on several lines for example.
One such example can be found [here](https://meta.discourse.org/t/86782).
For various reasons, most of the whitespaces in a HTML file is ignored when the page is being displayed in a browser.
The rules that the browsers follow are the [CSS' White Space Processing Rules](https://www.w3.org/TR/css-text-3/#white-space-rules).
They can be quite complicated when you take into account RTL languages and other various tidbits but they boils down to the following:
- Collapse whitespaces down to one space (0x20) inside an inline context (ie. nodes/tags that are being displaying on the same line)
- Remove any leading/trailing whitespaces inside an inline context
One quick & dirty way of getting this 90% solved would be to do 'HTML.gsub!(/[[:space:]]+/, " ")'.
We would also need to hoist <pre> elements in order to not mess with their whitespaces.
Unfortunately, this solution let some whitespaces creep around HTML tags which leads to more '.strip!' calls than I can bear.
I decided to "emulate" the browser's handling of whitespaces and came up with a solution in 4 parts
1. remove_not_allowed!
The HtmlToMarkdown library is recursively "visiting" all the nodes in the HTML in order to convert them to Markdown.
All the nodes that aren't handled by the library (eg. <script>, <style> or any non-textual HTML tags) are "swallowed".
In order to reduce the number of nodes visited, the method 'remove_not_allowed!' will automatically delete all the nodes
that have no "visitor" (eg. a 'visit_<tag>' method) defined.
2. remove_hidden!
Similar purpose as the previous method (eg. reducing number of nodes visited), there's no point trying to convert something that is hidden.
The 'remove_hidden!' method removes any nodes that was hidden using the "hidden" HTML attribute, some CSS or with a width or height equal to 0.
3. hoist_line_breaks!
The 'hoist_line_breaks!' method is there to handle <br> tags. I know those tiny <br> don't do much but they can be quite annoying.
The <br> tags are inline elements but they visually work like a block element (ie. they create a new line).
If you have the following HTML "<i>Foo<br>Bar</i>", it ends up visually similar to "<i>Foo</i><br><i>Bar</i>".
The latter being much more easy to process than the former, so that's what this method is doing.
The "hoist_line_breaks" will hoist <br> tags out of inline tags until their parent is a block element.
4. remove_whitespaces!
The "remove_whitespaces!" is where all the whitespace removal is happening. It's broken down into 4 methods as well
- remove_whitespaces!
- is_inline?
- collapse_spaces!
- remove_trailing_space!
The 'remove_whitespace!' method is recursively walking the HTML tree (skipping <pre> tags).
If a node has any children, they will be chunked into groups of inline elements vs block elements.
For each chunks of inline elements, it will call the "collapse_space!" and "remove_trailing_space!" methods.
For each chunks of block elements, it will call "remote_whitespace!" to keep walking the HTML tree recursively.
The "is_inline?" method determines whether a node is part of a inline context.
A node is inline iif it's a text node or it's an inline tag, but not <br>, and all its children are also inline.
The "collapse_spaces!" method will collapse any kind of (white) space into a single space (" ") character, even accros tags.
For example, if we have " Foo \n<i> Bar </i>\t42", it will return "Foo <i>Bar </i>42".
Finally, the "remove_trailing_space!" method is there to remove any trailing space that might creep in at the end of the inline chunk.
This solution is not 100% bullet-proof.
It does not support RTL languages at all and has some caveats that I felt were not worth the work to get properly fixed.
FIX: better detection of hidden elements when converting HTML to Markdown
FIX: take into account the 'allowed_href_schemes' site setting when converting HTML <a> to Markdown
FIX: added support for 'mailto:' scheme when converting <a> from HTML to Markdown
FIX: added support for <img> dimensions when converting from HTML to Markdown
FIX: added support for <dl>, <dd> and <dt> when converting from HTML to Markdown
FIX: added support for multilines emphases, strongs and strikes when converting from HTML to Markdown
FIX: added support for <acronym> when converting from HTML to Markdown
DEV: remove unused 'sanitize' gem
Wow, did you just read all that?! Congratz, here's a cookie: 🍪.
We have the `# frozen_string_literal: true` comment on all our
files. This means all string literals are frozen. There is no need
to call #freeze on any literals.
For files with `# frozen_string_literal: true`
```
puts %w{a b}[0].frozen?
=> true
puts "hi".frozen?
=> true
puts "a #{1} b".frozen?
=> true
puts ("a " + "b").frozen?
=> false
puts (-("a " + "b")).frozen?
=> true
```
For more details see: https://samsaffron.com/archive/2018/02/16/reducing-string-duplication-in-ruby
We need to recreate the badge_posts view each time we change
column on the posts table.
The p.* is auto expanded on view create, cascade should not have
been used
avg_time on posts and topics have not been used in a year.
This uses a re-runnable ddl transaction diasabled migration to
drop the column, cause it touchs very high traffic table and may
deadlock
* Rename all instances of bookmarkWithReminder and bookmark_with_reminder to just bookmark
* Delete old bookmark code at the same time
* Add migration to remove the bookmarkWithReminder post menu item if people have it set in site settings
pry-nav is not yet supported on latest pry, this holds off on
upgrading pry, which in turn holds off on upgrading deps
Stripping pry-nav for now till it works with latest pry
On some installations, there may be a leftover symlink which uses the
old plugin name:
public/plugins/discourse-internet-explorer ->
-> plugins/discourse-internet-explorer/public
This is to help with the migration to Ember CLI. In the current running
version of Discourse everything should be the same as before, just with
a few extra files that are not used. However, using Ember CLI this can
be installed as an Ember addon.
Co-Authored-By: Jarek Radosz <jradosz@gmail.com>
Repro steps for current failure:
- use mobile view
- click on a different user avatar to show user card
- click message
- close composer
- cloak is still showing and prevents any click
Before this commit, the presence state of users were stored on the
server side and any updates to the state meant we had to publish the
entire state to the clients. Also, the way the state of users were
stored on the server side meant we didn't have a way to differentiate
between replying users and whispering users.
In this redesign, we decided to move the tracking of users state to the client
side and have the server publish client events instead. As a result of
this change, we're able to remove the number of opened connections
needed to track presence and also reduce the payload that is sent for
each event.
At the same time, we've also improved on the restrictions when publishing message_bus messages. Users that
do not have permission to see certain events will not receive messages
for those events.
* Bookmarks with reminders is a core feature now, no need to have a separate URL
* Keep around the old /u/:username/activity/bookmarks-with-reminders route for backwards compat in Ember but just redirect to user activity bookmarks.
