def follow_user(self, other_username: str) -> None:
"""Match the requested user and create a FOLLOWING relationship between us and them."""
graph.run(
"""MATCH (me:User {username: $me})
MATCH (u2:User {username: $username})
MERGE (me)-[r:FOLLOWING {since: datetime($since)}]->(u2)""",
me=self.username,
username=other_username,
since=datetime.now().strftime("%Y-%m-%d"),
)
def add_post(self, text: str) -> None:
"""Create a Post node and a POSTED relationship."""
graph.run(
"""
MATCH (u:User {username: $username})
CREATE (p:Post {content: $content})
CREATE (u)-[:POSTED {posted_on: datetime($on)}]->(p)
""",
username=self.username,
content=text,
on=datetime.now().strftime("%Y-%m-%dT%H:%M:%S"),
)
def get_number_of_followed(self) -> int:
res = graph.run(
"""MATCH (:User {username: $username})-[:FOLLOWING]->(f:User) return count(f)""",
username=self.username,
)
res = res.data()
return int(res[0]["count(f)"]) if res else 0
def find(self) -> List[dict]:
"""Helper to check if user with username exists."""
res = graph.run(
"MATCH (u:User {username: $username}) RETURN u LIMIT 1",
username=self.username,
)
return res.data()
def get_most_followed() -> List[dict]:
"""Return a list of the 10 most followed users and the number of people that follow them."""
res = graph.run(
"""
MATCH (u:User)<-[r:FOLLOWING]-(:User)
RETURN u.username as suggestion, count(r) as followedBy
ORDER BY followedBy DESC
LIMIT 10"""
)
return [
{"username": row["suggestion"], "followed_by": row["followedBy"]} for row in res
]
def register(self, password: str) -> bool:
"""Check if user exists and if not create it with the given password."""
if not self.find():
res = graph.run(
"CREATE (_:User {username: $username, password: $password, id:$id})",
username=self.username,
password=bcrypt.encrypt(password),
id=uuid4().hex,
)
return True
else:
return False
def recommended_people(username):
"""Return a list of users followed by users the user with username is following.
AKA friends of friends.
"""
res = graph.run(
"""
MATCH (u:User)-[:FOLLOWING]->(:User)-[:FOLLOWING]->(ff:User)
WHERE NOT
(u)-[:FOLLOWING]->(ff)
AND u.username = $username
RETURN ff.username as suggestion,count(ff) as friendsInCommon
ORDER BY friendsInCommon DESC
""",
username=username,
)
return [
{"username": row["suggestion"], "followed_by": row["friendsInCommon"]}
for row in res
]
def get_recent_posts(username):
"""Get all posts by users we follow and our own posts."""
res = graph.run(
"""
MATCH (u:User {username: $username})-[*1..2]->(p:Post)
WITH p
MATCH (p)<-[po:POSTED]-(poster:User)
RETURN poster.username as poster, p.content as content, po.posted_on as posted_on
ORDER BY posted_on DESC
""",
username=username,
)
return [
{
"poster": row["poster"],
"content": row["content"],
"posted_on": row["posted_on"],
}
for row in res
]