Under rare conditions due to bad HTTP timing and so on a draft could be
set at the exact same time from 2 unicorn workers.
When this happened and all the stars aligned, one of the sets would win
and the other would raise an error.
This transparently handles the situation without adding any cost to the
draft system.
The alternative is to add a distributed mutex, tricky DB transaction or handle
the error in the controller. However this seems like a reasonable way to
work around a pretty big edge case.
Previously our index was non unique, causing situations where a user could
have multiple drafts stored in the table for the same exact entity.
This does not properly reflect reality and needed to change as in certain
cases duplicate drafts could be created causing internal data inconsistency
This ensures we can very quickly figure out which topics are banners if
a banner is set.
Previously you would have to scan an entire table to find banners
This is a major change to draft internals. Previously there were quite a
few cases where the draft system would say "draft saved", when in fact
we just skipped saving.
This commit ensures the draft system deals with draft ownership handover in
a predictable way.
For example:
- Window 1 editing draft
- Window 2 editing same draft at the same time
Previously we would allow window 1 and 2 to just fight on the same draft
each window overwriting the same draft over an over.
This commit introduces an ownership concept where either window 1 or 2 win
and user is prompted on the loser window to reload screen to correct the issue
This also corrects edge cases where a user could have multiple browser windows
open and posts in 1 window, later to post in the second window. Previously
drafts would break in the second window, this corrects it.
Doing .pluck(:column).first is a very common pattern in Discourse and in
most cases, a limit cause isn't being added. Instead of adding a limit
clause to all these callsites, this commit adds two new methods to
ActiveRecord::Relation:
pluck_first, equivalent to limit(1).pluck(*columns).first
and pluck_first! which, like other finder methods, raises an exception
when no record is found
Under exceptional situations the automatic draft feature can fail.
This new **hidden, default off** site setting
`backup_drafts_to_pm_length` will automatically backup any draft that is
saved by the system to a dedicated PM (originating from self)
The body of that PM will contain the text of the reply.
We can enable this feature strategically on sites exhibiting issues to
diagnose issues with the draft system and offer a recourse to users who
appear to lose drafts. We automatically checkpoint these drafts every 5
minutes forcing a new revision each 5 minutes so you can revert to old
content.
Longer term we are considering automatically enabling this kind of feature
for extremely long drafts where the risk is really high one could lose
days of writing.
* drafts in user profile: only show to user herself (not to admins), use avatar replying to (instead of topic OP), add keyboard shortcut for drafts, simplify display labels
* use JSON when testing Draft.stream
* add drafts.json endpoint, user profile tab with drafts stream
* improve drafts stream display in user profile
* truncate excerpts in drafts list, better handling for resume draft action
* improve draft stream SQL query, add rspec tests
* if composer is open, quietly close it when user opens another draft from drafts stream; load PM draft only when user is in /u/username/messages (instead of /u/username)
* cleanup
* linting fixes
* apply prettier styling to modified files
* add client tests for drafts, includes a fixture for drafts.json
* improvements to code following review
* refresh drafts route when user deletes a draft open in the composer while being in the drafts route; minor prettier scss fix
* added more spec tests, deleted an acceptance test for removing drafts that was too finicky, formatting and code style fixes, added appEvent for draft:destroyed
* prettier, eslint fixes
* use "username_lower" from users table, added error handling for rejected promises
* adds guardian spec for can_see_drafts, adds improvements following code review
* move DraftsController spec to its own file
* fix failing drafts qunit test, use getOwner instead of deprecated this.container
* limit test fixture for draft.json testing to new_topic request only
Introduce new patterns for direct sql that are safe and fast.
MiniSql is not prone to memory bloat that can happen with direct PG usage.
It also has an extremely fast materializer and very a convenient API
- DB.exec(sql, *params) => runs sql returns row count
- DB.query(sql, *params) => runs sql returns usable objects (not a hash)
- DB.query_hash(sql, *params) => runs sql returns an array of hashes
- DB.query_single(sql, *params) => runs sql and returns a flat one dimensional array
- DB.build(sql) => returns a sql builder
See more at: https://github.com/discourse/mini_sql
- how long were people typing?
- how long was composer open?
- how many drafts were created?
- correct, draft saved to go away after you continue typing
store in Post.find(xyz).post_stat
