def vote_post(user_id, post_id, amount=1):
"""Handles voting on posts
"""
# Get the comment so we can check who the author is
author_uid = get_post(post_id).get('user_id')
if not has_voted(user_id, post_id):
if author_uid != user_id:
r.zadd(k.POST_VOTES.format(post_id), amount, user_id)
# Increment the score by amount (can be negative)
# Post score can go lower than 0
m.db.posts.update({'_id': post_id},
{'$inc': {'score': amount}})
if amount < 0:
# Don't decrement the users score if it is already at 0
# we use a query to ONLY find user if the score if greater than
# 0. This might seem stange but it is in the only way to keep
# this atomic
m.db.users.update({'_id': author_uid, 'score': {'$gt': 0}},
{'$inc': {'score': amount}})
else:
# If its an increment it doesn't really matter
m.db.users.update({'_id': author_uid},
{'$inc': {'score': amount}})
else:
raise CantVoteOnOwn
else:
raise AlreadyVoted
def back_feed(who_id, whom_id):
"""Takes 5 lastest posts from user with ``who_id`` places them in user
with ``whom_id`` feed.
The reason behind this is that new users may follow someone but still have
and empty feed, which makes them sad :( so we'll give them some. If the
posts are to old for a non user they will be removed when the feed is
trimmed, but they may make it in to the feed but not at the top.
:param who_id: user who just followed ``who_id``
:type who_id: str
:param whom_id: user who was just followed by ``whom_id``
:type whom_id: str
:returns: None
"""
# Get followee's last 5 un-approved posts (doesn't matter if isn't any)
# We only need the IDs and the created time
posts = m.db.posts.find(
{'user_id': whom_id, 'reply_to': None,
'permission': {'$lte': k.PERM_PJUU}},
{'_id': True, 'created': True},
).sort('created', -1).limit(5)
# Iterate the cursor and append the posts to the users feed
for post in posts:
timestamp = post.get('created')
post_id = post.get('_id')
# Place on the feed
r.zadd(k.USER_FEED.format(who_id), timestamp, post_id)
# Trim the feed to the 1000 max
r.zremrangebyrank(k.USER_FEED.format(who_id), 0, -1000)
def alert(self, alert, user_ids):
"""Will attempt to alert the user with uid to the alert being managed.
This will call the alerts before_alert() method, which allows you to
change the alert per user. It's not needed though.
"""
# Check that the manager actually has an alert
if not isinstance(alert, BaseAlert):
raise ValueError('alert must be a BaseAlert object')
# Ensure uids is iterable
# Stopped strings being passed in
if not isinstance(user_ids, Iterable) or isinstance(user_ids, str) or \
isinstance(user_ids, unicode):
raise TypeError('user_ids must be iterable')
# Create the alert object
r.set(k.ALERT.format(alert.alert_id), jsonpickle.encode(alert))
# Set the 4WK timeout on it
r.expire(k.ALERT.format(alert.alert_id), k.EXPIRE_4WKS)
for user_id in user_ids:
r.zadd(k.USER_ALERTS.format(user_id), alert.timestamp,
alert.alert_id)
def vote_comment(uid, cid, amount=1):
"""Handles voting on posts
"""
# Ensure user has not voted before and ensure its a comment check
if not has_voted(uid, cid, comment=True):
author_uid = get_comment_author(cid)
if author_uid != uid:
r.zadd(K.COMMENT_VOTES.format(cid), amount, uid)
# Post scores can be negative.
# INCRBY with a minus value is the same a DECRBY
r.hincrby(K.COMMENT.format(cid), 'score', amount=amount)
# Get the score of the author
cur_user_score = r.hget(K.USER.format(author_uid), 'score')
# Stop users scores going lower than 0
cur_user_score = int(cur_user_score)
if cur_user_score <= 0 and amount < 0:
amount = 0
# Increment the users score
r.hincrby(K.USER.format(author_uid), 'score', amount=amount)
else:
raise CantVoteOnOwn
else:
raise AlreadyVoted
def alert(self, alert, user_ids):
"""Will attempt to alert the user with uid to the alert being managed.
This will call the alerts before_alert() method, which allows you to
change the alert per user. It's not needed though.
"""
# Check that the manager actually has an alert
if not isinstance(alert, BaseAlert):
raise ValueError('alert must be a BaseAlert object')
# Ensure uids is iterable
# Stopped strings being passed in
if not isinstance(user_ids, Iterable) or isinstance(user_ids, str) or \
isinstance(user_ids, unicode):
raise TypeError('user_ids must be iterable')
# Create the alert object
r.set(k.ALERT.format(alert.alert_id), jsonpickle.encode(alert))
# Set the 4WK timeout on it
r.expire(k.ALERT.format(alert.alert_id), k.EXPIRE_4WKS)
for user_id in user_ids:
r.zadd(k.USER_ALERTS.format(user_id), alert.timestamp,
alert.alert_id)
def populate_approved_followers_feeds(user_id, post_id, timestamp):
"""Fan out a post_id to all the users approved followers."""
# Get a list of ALL users who are following a user
followers = r.zrange(k.USER_APPROVED.format(user_id), 0, -1)
# This is not transactional as to not hold Redis up.
for follower_id in followers:
# Add the pid to the list
r.zadd(k.USER_FEED.format(follower_id), timestamp, post_id)
# Stop followers feeds from growing to large, doesn't matter if it
# doesn't exist
r.zremrangebyrank(k.USER_FEED.format(follower_id), 0, -1000)
def approve_user(who_uid, whom_uid):
"""Allow a user to approve a follower"""
# Check that the user is actually following.
# Fail if not
if r.zrank(k.USER_FOLLOWERS.format(who_uid), whom_uid) is None:
return False
# Add the user to the approved list
# No alert is generated
r.zadd(k.USER_APPROVED.format(who_uid), timestamp(), whom_uid)
return True
def approve_user(who_uid, whom_uid):
"""Allow a user to approve a follower"""
# Check that the user is actually following.
# Fail if not
if r.zrank(k.USER_FOLLOWERS.format(who_uid), whom_uid) is None:
return False
# Add the user to the approved list
# No alert is generated
r.zadd(k.USER_APPROVED.format(who_uid), timestamp(), whom_uid)
return True
def flag_post(user_id, post_id):
"""Flags a post for moderator review.
:returns: True if flagged, false if removed.
`CantFlagOwn` in case of error.
"""
# Get the comment so we can check who the author is
post = get_post(post_id)
if post.get('user_id') != user_id:
if not has_flagged(user_id, post_id):
# Increment the flag count by one and store the user name
r.zadd(k.POST_FLAGS.format(post_id), timestamp(), user_id)
m.db.posts.update({'_id': post_id},
{'$inc': {'flags': 1}})
else:
raise AlreadyFlagged
else:
raise CantFlagOwn
def follow_user(who_uid, whom_uid):
"""Add whom to who's following zset and who to whom's followers zset.
Generate an alert for this action.
"""
# Check that we are not already following the user
if r.zrank(k.USER_FOLLOWING.format(who_uid), whom_uid) is not None:
return False
# Follow user
# Score is based on UTC epoch time
r.zadd(k.USER_FOLLOWING.format(who_uid), timestamp(), whom_uid)
r.zadd(k.USER_FOLLOWERS.format(whom_uid), timestamp(), who_uid)
# Create an alert and inform whom that who is now following them
alert = FollowAlert(who_uid)
AlertManager().alert(alert, [whom_uid])
# Back fill the who's feed with some posts from whom
back_feed(who_uid, whom_uid)
return True
def follow_user(who_uid, whom_uid):
"""Add whom to who's following zset and who to whom's followers zset.
Generate an alert for this action.
"""
# Check that we are not already following the user
if r.zrank(k.USER_FOLLOWING.format(who_uid), whom_uid) is not None:
return False
# Follow user
# Score is based on UTC epoch time
r.zadd(k.USER_FOLLOWING.format(who_uid), timestamp(), whom_uid)
r.zadd(k.USER_FOLLOWERS.format(whom_uid), timestamp(), who_uid)
# Create an alert and inform whom that who is now following them
alert = FollowAlert(who_uid)
AlertManager().alert(alert, [whom_uid])
# Back fill the who's feed with some posts from whom
back_feed(who_uid, whom_uid)
return True
def vote_post(user_id, post_id, amount=1, ts=None):
"""Handles voting on posts
:param user_id: User who is voting
:type user_id: str
:param post_id: ID of the post the user is voting on
:type post_id: int
:param amount: The way to vote (-1 or 1)
:type amount: int
:param ts: Timestamp to use for vote (ONLY FOR TESTING)
:type ts: int
:returns: -1 if downvote, 0 if reverse vote and +1 if upvote
"""
if ts is None:
ts = timestamp()
# Get the comment so we can check who the author is
author_uid = get_post(post_id).get('user_id')
# Votes can ONLY ever be -1 or 1 and nothing else
# we use the sign to store the time and score in one zset score
amount = 1 if amount >= 0 else -1
voted = has_voted(user_id, post_id)
if not voted:
if author_uid != user_id:
# Store the timestamp of the vote with the sign of the vote
r.zadd(k.POST_VOTES.format(post_id), amount * timestamp(), user_id)
# Update post score
m.db.posts.update({'_id': post_id},
{'$inc': {'score': amount}})
# Update user score
m.db.users.update({'_id': author_uid},
{'$inc': {'score': amount}})
return amount
else:
raise CantVoteOnOwn
elif voted and abs(voted) + k.VOTE_TIMEOUT > ts:
# No need to check if user is current user because it can't
# happen in the first place
# Remove the vote from Redis
r.zrem(k.POST_VOTES.format(post_id), user_id)
previous_vote = -1 if voted < 0 else 1
# Calculate how much to increment/decrement the scores by
# Saves multiple trips to Mongo
if amount == previous_vote:
if previous_vote < 0:
amount = 1
result = 0
else:
amount = -1
result = 0
else:
# We will only register the new vote if it is NOT a vote reversal.
r.zadd(k.POST_VOTES.format(post_id), amount * timestamp(), user_id)
if previous_vote < 0:
amount = 2
result = 1
else:
amount = -2
result = -1
# Update post score
m.db.posts.update({'_id': post_id},
{'$inc': {'score': amount}})
# Update user score
m.db.users.update({'_id': author_uid},
{'$inc': {'score': amount}})
return result
else:
raise AlreadyVoted
def create_post(user_id, username, body, reply_to=None, upload=None,
permission=k.PERM_PUBLIC):
"""Creates a new post
This handled both posts and what used to be called comments. If the
reply_to field is not None then the post will be treat as a comment.
You will need to make sure the reply_to post exists.
:param user_id: The user id of the user posting the post
:type user_id: str
:param username: The user name of the user posting (saves a lookup)
:type username: str
:param body: The content of the post
:type body: str
:param reply_to: The post id of the post this is a reply to if any
:type reply_to: str
:param upload:
:returns: The post id of the new post
:param permission: Who can see/interact with the post you are posting
:type permission: int
:rtype: str or None
"""
# Get a new UUID for the post_id ("_id" in MongoDB)
post_id = get_uuid()
# Get the timestamp, we will use this to populate users feeds
post_time = timestamp()
post = {
'_id': post_id, # Newly created post id
'user_id': user_id, # User id of the poster
'username': username, # Username of the poster
'body': body, # Body of the post
'created': post_time, # Unix timestamp for this moment in time
'score': 0, # Atomic score counter
}
if reply_to is not None:
# If the is a reply it must have this property
post['reply_to'] = reply_to
else:
# Replies don't need a comment count
post['comment_count'] = 0
# Set the permission a user needs to view
post['permission'] = permission
# TODO: Make the upload process better at dealing with issues
if upload:
# If there is an upload along with this post it needs to go for
# processing.
# process_upload() can throw an Exception of UploadError. We will let
# it fall through as a 500 is okay I think.
# TODO: Turn this in to a Queue task at some point
filename = process_upload(upload)
if filename is not None:
# If the upload process was okay attach the filename to the doc
post['upload'] = filename
else:
# Stop the image upload process here if something went wrong.
return None
# Process everything thats needed in a post
links, mentions, hashtags = parse_post(body)
# Only add the fields if we need too.
if links:
post['links'] = links
if mentions:
post['mentions'] = mentions
if hashtags:
post['hashtags'] = hashtags
# Add the post to the database
# If the post isn't stored, result will be None
result = m.db.posts.insert(post)
# Only carry out the rest of the actions if the insert was successful
if result:
if reply_to is None:
# Add post to authors feed
r.zadd(k.USER_FEED.format(user_id), post_time, post_id)
# Ensure the feed does not grow to large
r.zremrangebyrank(k.USER_FEED.format(user_id), 0, -1000)
# Subscribe the poster to there post
subscribe(user_id, post_id, SubscriptionReasons.POSTER)
# Alert everyone tagged in the post
alert_tagees(mentions, user_id, post_id)
# Append to all followers feeds or approved followers based
# on the posts permission
if permission < k.PERM_APPROVED:
populate_followers_feeds(user_id, post_id, post_time)
else:
populate_approved_followers_feeds(user_id, post_id, post_time)
else:
# To reduce database look ups on the read path we will increment
# the reply_to's comment count.
m.db.posts.update({'_id': reply_to},
{'$inc': {'comment_count': 1}})
# Alert all subscribers to the post that a new comment has been
# added. We do this before subscribing anyone new
alert = CommentingAlert(user_id, reply_to)
subscribers = []
# Iterate through subscribers and let them know about the comment
for subscriber_id in get_subscribers(reply_to):
# Ensure we don't get alerted for our own comments
if subscriber_id != user_id:
subscribers.append(subscriber_id)
# Push the comment alert out to all subscribers
AlertManager().alert(alert, subscribers)
# Subscribe the user to the post, will not change anything if they
# are already subscribed
subscribe(user_id, reply_to, SubscriptionReasons.COMMENTER)
# Alert everyone tagged in the post
alert_tagees(mentions, user_id, reply_to)
return post_id
# If there was a problem putting the post in to Mongo we will return None
return None # pragma: no cover
