def set_user_role(self, role, uid=None, user_name=None):
# Make sure the role is valid
if not Perms.is_valid_role(role):
raise ValidationError("%server_error_invalid_role")
with Transaction(self.db):
# Read the user data
user = self.db.get_user(uid=uid, user_name=user_name)
if user is None:
raise NotFoundError()
# Update the role
if role != user.role:
# Delete any active session, if the user has fewer permissions
perms_old = Perms.lookup_role_permissions(user.role)
perms_new = Perms.lookup_role_permissions(role)
if perms_old & (perms_new ^ perms_old):
# Note: (perms_new ^ perms_old) contains the changed
# permission bits, perms_old & (perms_new ^ perms_old)
# is not equal to zero if a bit that changed was active in
# perms_old.
self.db.purge_sessions_for_user(user.uid)
# Write the user back with the updated role
user.role = role
self.db.update_user(user)
def update_user_settings(self, uid, settings):
"""
Merges the currently stored settings with the given settings object.
Returns the updated settings object.
"""
# TODO: Provide method to not update the settings, as currently an
# ill-behaving client has no chance to remove setting keys.
# Make sure the "settings" object is a dictionary
if not isinstance(settings, dict):
raise ValidationError()
# Perform the update
with Transaction(self.db):
# Merge the new settings with the old values
if (uid in self.db.settings):
for key, value in json.loads(self.db.settings[uid]).items():
if not key in settings:
settings[key] = value
# Serialise the settings to a string
settings_str = json.dumps(settings, sort_keys=True)
if len(settings_str) > API.MAX_SETTINGS_LEN:
raise ValidationError()
# Store the merged values in the database
self.db.settings[uid] = settings_str
return settings
def create_post(self, post):
"""
Creates a new post.
"""
# Coerce the post into a new Post object, make sure the pid is set to
# "None"; otherwise the post would not get its own pid
p = API.coerce_post(post)
if not p.pid is None:
raise ValidationError()
# The revision must be set to zero
if p.revision != 0:
raise ValidationError()
# Insert the post into the database
with Transaction(self.db):
# Create the post in the database
p.pid = self.db.create_post(p)
# Update the fulltext search
self.db.update_fulltext(p.pid, p)
# Insert keywords
keywords = self.db.keywords
for keyword in API._split(p.keywords):
keywords[keyword] = p.pid
# Convert the post back to a dictionary
return API._post_to_dict(p)
def import_from_object(self, obj):
"""
Restors a database backup formerly created by the export_to_json
function. This will delete the current content of the database.
@param obj is a Python object that has been deserialised from JSON
"""
# Make sure that this operation is atomic
with Transaction(self.db):
# Delete everything in the database
self.db.purge()
# Go through all restorable tables (i.e., it doesn't make much sense
# to backup the challenges, sessions, cache, keywords tables).
if "configuration" in obj:
for key, value in obj["configuration"].items():
self.db.configuration[key] = value
if "posts" in obj:
for post in obj["posts"]:
p = API.coerce_post(post)
self.db.create_post(p)
self.db.update_fulltext(p.pid, p)
if "posts_history" in obj:
for post in obj["posts_history"]:
self.db.create_post(API.coerce_post(post), history=True)
if "users" in obj:
for user in obj["users"]:
self.db.create_user(API.coerce_user(user))
if "settings" in obj:
for key, value in obj["settings"].items():
self.db.settings[key] = value
# Rebuild the keywords table
self._rebuild_keywords()
def get_user_settings(self, uid):
"""
Reads the user settings from the database and serialises them into a
JSON object. Returns an empty object if the user has not stored any
settings yet.
"""
with Transaction(self.db):
if (uid in self.db.settings):
return json.loads(self.db.settings[uid])
return {}
def update_post(self, post):
"""
Updates an already existing post.
"""
# Coerce the given post into a Post object, make sure the pid is set
p = API.coerce_post(post)
if p.pid is None:
raise ValidationError()
with Transaction(self.db):
# Fetch the post that is supposed to be updated
pid = p.pid
old_post = self.db.get_post(pid)
if old_post is None:
raise NotFoundError()
# Do nothing if there is no difference between the old and new post
if ((old_post.author == p.author) and (old_post.date == p.date)
and (old_post.keywords == p.keywords)
and (old_post.content == p.content)):
return API._post_to_dict(p)
# Make sure that the revision of the given post is equal to the
# revision of the old post; increment the revision of the post that
# is to be stored.
if old_post.revision != p.revision:
raise ConflictError()
p.revision += 1
# Copy the original creation uid and time
p.cuid = old_post.cuid
p.ctime = old_post.ctime
# Insert the old post into the history table
self.db.create_post(old_post, history=True)
# Remove keywords associated with the old post
keywords = self.db.keywords
for keyword in API._split(old_post.keywords):
keywords[keyword] = keywords[keyword] - set((pid, ))
# Update the post in the normal posts table
if self.db.update_post(p) == 0:
raise NotFoundError()
# Update the fulltext search
self.db.update_fulltext(pid, p)
# Insert the new keywords
keywords = self.db.keywords
for keyword in API._split(p.keywords):
keywords[keyword] = pid
return API._post_to_dict(p)
def get_configuration_object(self):
"""
Returns a JSON serialisable object containing the global configuration
options.
"""
with Transaction(self.db):
c = self.db.configuration
return {
"login_methods": {
"username_password":
c["login_method_username_password"] == "1",
"cas": c["login_method_cas"] == "1",
},
"salt": c["salt"],
}
def _login_method_username_password(self, user_name, challenge, response):
"""
Internal implementation of the _login_method_username_password function.
"""
# Make sure the user name, challenge, and response are of the
# correct format
user_name = str(user_name).strip().lower()
challenge, response = str(challenge), str(response)
if not (API.USER_RE.match(user_name) and API.HEX64_RE.match(challenge)
and API.HEX64_RE.match(response)):
raise ValidationError()
# Make sure the valid is valid (do this outside of the transaction
# below to avoid purged sessions being rolled back.
if not self._check_password_login_challenge(challenge):
raise AuthentificationError()
# Lookup the user, check the user role and compute the expected response
with Transaction(self.db):
# Make sure the user exists. If the user name does not exist, raise
# an authentification error, i.e. do not expose the users'
# non-existance to the client
user = self.db.get_user_by_name(user_name)
if user is None:
raise AuthentificationError()
# Make sure the user can actually login using a password
if user.auth_method != "password":
raise AuthentificationError()
# Make sure the user has the right permissions
if Perms.lookup_role_permissions(user.role) <= 0:
raise AuthentificationError()
# Compute the expected password hash
expected_response = self._hash_password(
bytes.fromhex(user.password), challenge)
if expected_response != response:
raise AuthentificationError()
# Okay, all this worked. Let's create a session for the user and
# return the sid
sid = os.urandom(32).hex()
self.db.create_session(sid, user.uid)
return self.get_session_data(sid)
def export_to_object(self, export_passwords=False):
"""
Exports the entire database into a JSON serialisable object. Some tables
with volatile data (such as the "cache", "challenges", and "sessions"
tables) will not be exported.
"""
with Transaction(self.db):
# Export the configuration options
config_obj = {}
for key, value in self.db.configuration.items():
config_obj[key] = value
# Export the posts
posts_arr = []
for post in self.db.list_posts():
posts_arr.append(asdict(post))
# Export the post history
posts_history_arr = []
for post in self.db.list_posts(history=True):
posts_history_arr.append(asdict(post))
# Export the users
users_arr = []
for user in self.db.list_users():
user_obj = asdict(user)
if not export_passwords:
user_obj["reset_password"] = True
del user_obj["password"]
users_arr.append(user_obj)
# Export the user settings
settings_obj = {}
for key, value in self.db.settings.items():
settings_obj[key] = value
# Return the completely assembled object
return {
"configuration": config_obj,
"posts": posts_arr,
"posts_history": posts_history_arr,
"users": users_arr,
"settings": settings_obj
}
def get_session_data(self, sid):
"""
Returns the session data. Returns None if the given session is not
available or invalid. Updates the session mtime in order to re-validate
the session. The session data is an object containing the following elements:
{
"sid": <the session id>,
"uid": <the numerical user id>,
"name": <the canonical user name>,
"display_name": <the user-defined display name>,
"role": <the user role string>,
"reset_password": <true if the user must reset the password>,
}
"""
# Validate the session identifier
if not API.HEX64_RE.match(sid):
raise ValidationError()
# Remove any stale sessions, then try to fetch the user data associated
# with the session
self.db.purge_stale_sessions(API.SESSION_TIMEOUT)
with Transaction(self.db):
# Fetch the UID corresponding to the session
uid = self.db.get_session_uid(sid)
if not uid:
return None
# Advance the session mtime
self.db.update_session_mtime(sid)
# Get the user data associated with the UID
user = self.db.get_user_by_id(uid)
return {
"sid": sid,
"uid": uid,
"name": user.name,
"display_name": user.display_name,
"role": user.role,
"reset_password": user.reset_password,
}
def _check_password_login_challenge(self, challenge):
"""
Used internally. Returns True and deletes the given challenge if it
existed, returns
False if the challenge is invalid (i.e. too old).
"""
with Transaction(self.db):
# Delete stale challenges
self.db.purge_stale_challenges(API.CHALLENGE_TIMEOUT)
# Check whether the callenge exists
if not challenge in self.db.challenges:
return False
# Delete the challenge
del self.db.challenges[challenge]
return True
def reset_user_password(self, uid=None, user_name=None):
with Transaction(self.db):
user = self.db.get_user(uid=uid, user_name=user_name)
if user is None:
raise NotFoundError()
# Create a random password
password = self.create_random_password()
password_hash = self._hash_password(password)
# Set the password and the reset_password flag
user.password = password_hash
user.reset_password = True
# Write the user back to the database
self.db.update_user(user)
# Return the generated password for display
return password
def get_password_login_challenge(self):
"""
Creates a login challenge and returns an object containing both the
challenge and the salt.
"""
with Transaction(self.db):
# Fetch the current UNIX time and create a random challenge
challenge = os.urandom(32).hex()
# Delete old challenges
self.db.purge_stale_challenges(API.CHALLENGE_TIMEOUT)
# Store the challenge and its creation time in the database
self.db.challenges[challenge] = self.db.now()
# Return a challenge object ready to be sent to the client
return {
"salt": self.db.configuration["salt"],
"challenge": challenge
}
def delete_post(self, pid):
# Make sure the given post id is and integer and non-negative
if not isinstance(pid, int) or pid < 0:
raise ValidationError()
with Transaction(self.db):
# Fetch the post that is supposed to be deleted
post = self.db.get_post(pid)
if post is None:
raise NotFoundError()
# Delete all keywords associated with the post
keywords = self.db.keywords
for keyword in API._split(post.keywords):
keywords[keyword] = keywords[keyword] - set((pid, ))
# Delete the post from the history, the main post table, and the
# fulltext search index
self.db.delete_post(pid)
self.db.delete_post(pid, history=True)
self.db.delete_fulltext(pid)
def update_user(self, properties, uid=None, user_name=None):
"""
Updates attributes of a user by merging the given properties into an
existing user structure.
"""
with Transaction(self.db):
# Try to fetch the user, either by user name or uid
user = self.db.get_user(uid=uid, user_name=user_name)
if user is None:
raise NotFoundError()
# Make sure the settings we're trying to update actually exist, and,
# in case they do, update the corresponding value
for key, value in properties.items():
# If we're updating the password to a new password and the new
# password is actually different from the current password,
# then reset the "reset_password" flag
if ((key == "password")
and (value.lower() != user.password.lower())):
user.reset_password = False
# Update all other properties
if hasattr(user, key):
setattr(user, key, value)
else:
raise ValidationError()
# Coerce the updated user to make sure all new settings adhere to
# the rules
user_new = API.coerce_user(asdict(user))
try:
self.db.update_user(user_new)
except UniqueKeyViolationError:
raise ConflictError()
return asdict(user_new)
def _rebuild_keywords(self):
"""
Given the current list of posts, rebuilds the index that maps keywords
onto a set of posts. This function is used after importing a backup.
"""
with Transaction(self.db):
# Delete all keywords
self.db.keywords.clear()
# List all posts and construct a mapping between posts and keywords
keywords = {}
for post in self.db.list_posts():
for keyword in API._split(post.keywords):
if keyword in keywords:
keywords[keyword].add(post.pid)
else:
keywords[keyword] = {
post.pid,
}
# Insert the keywords into the database; the keywords dictionary
# is a MultiDict, i.e., it stores a set per keyword
for keyword, pids in keywords.items():
self.db.keywords[keyword] = pids
def delete_user(self, uid=None, user_name=None, force=False):
"""
Deletes the user with the given uid or user name. Per default, does not
delete users who already have posts; to this end, "force" has to be set
to True. Important: this function will move all content generated by
this user to the dummy "[deleted]" user account.
@param uid is the numerical id of the user that should be deleted.
Supply either uid or user_name.
@param user_name is the name of the user that should be deleted. Supply
either uid or user_name.
@param force if true, force the deletion of users who contributed
content.
"""
with Transaction(self.db):
# Read the user data
user = self.db.get_user(uid=uid, user_name=user_name)
if user is None:
raise NotFoundError()
# Check whether the user has any posts. If yes, either rewrite these
# posts to the "[deleted]" user (if force=True) or do nothing and
# abort (if force=False).
def _rewrite(history):
# List all the posts for the user
filter = FilterUID(user.uid) | FilterAuthor(user.uid)
user_posts = self.db.list_posts(history=history, filter=filter)
# Abort if we found any posts, and "force" is not set
if len(user_posts) > 0 and not force:
return False
# Otherwise, update the post CUID or MUID to "0" and update the
# post
for post in user_posts:
if post.cuid == user.uid:
post.cuid = 0
if post.muid == user.uid:
post.muid = 0
if post.author == user.uid:
post.author = 0
self.db.update_post(post, history=history)
return True
# Rewrite both the current post table and the history table
if not (_rewrite(history=False) and _rewrite(history=True)):
return False
# Delete all sessions for this user
self.db.purge_sessions_for_user(user.uid)
# Delete all settings for this user
if user.uid in self.db.settings:
del self.db.settings[user.uid]
# Delete the user account itself
self.db.delete_user(user.uid)
# Success!
return True
def _init(self):
if self.db.open and self.perform_initialisation:
with Transaction(self.db):
self._init_configuration()
self._init_users()
self.perform_initialisation = False