notes.txt

MongoDB
  - get MongoDB Client URL

Path to connect
  - cluster -> collection -> database -> post
  - code
    MONGO_CLIENT = os.getenv('MONGO_CLIENT_URL_FROM_ENV')
    cluster = MongoClient(MONGO_CLIENT)
    db = cluster["database-name"]
    collection = db["collection-name"]

post
  - a key-value pair collection
  - python dictionary
  - actual data which is supposed to be inserted

How to insert
  - collection.insert_one(post)
  - collection.insert_many(list-of-posts))

How to search
  - collection.find({"search-parameter": key})
  - returns a pymongo.cursor.Cursor object
  - its a list of all the possible results
  - loop through it for accessing each post
  - How to search one
    - collection.find_one({"search-parameter": key})
    - returns one post


- select * from table equivalent
  - collection.find({})
  - returns a pymongo.cursor.Cursor object
  - its a list of all the possible results
  - loop through it for accessing each post


- How to update
  - collection.update_one({"update-parameter": old-value}, {update-operator: {"update-parameter": new-value}})



- Update operators
  - $currentDate - Sets the value of a field to current date, either as a Date or a Timestamp.
  - $inc - Increments the value of the field by the specified amount.
  - $min - Only updates the field if the specified value is less than the existing field value.
  - $max - Only updates the field if the specified value is greater than the existing field value.
  - $mul - Multiplies the value of the field by the specified amount.
  - $rename - Renames a field.
  - $set - Sets the value of a field in a document.
  - $setOnInsert - Sets the value of a field if an update results in an insert of a document. Has no effect on update operations that modify existing documents.
  - $unset - Removes the specified field from a document.
  

- HTTP
  - client-server
  - request-response
  - stateless
  - for tracking state, use sessions/cookies
  - application layer protocol
  - http uses TCP


- Authentication
  - authentication - verifying identity
    - failed - (401 Unauthorized)
  - authorization - verifying permissions
    - failed - (403 Forbidden)


- Stateful
  - session + cookie
- Stateless
  - token + JWT/OAuth


Session Based Authentication
  - user sends credentials (Email/Username + Password)
  - server verifies credentials from DB
  - server creates a temporary user session
  - server issues a cookie with session ID
  - user sends the cookie with each request
  - server validates it against session store & grants access
  - when user logs out, sever destroys the session & clears the cookie