I am looking how to create an efficient model which will satisfy the requirements I put below. I have tried using gcloud-node but have noticed it has limitations with read consistencies, references, etc. I would prefer to write this is nodejs, but would be open to writing in java or python as long as it would improve my model. I am building around the new pricing model which will come July 1st.
My application consists of a closed email system. In essence what happens is users register to the site. These user's can make friends. Then they can send emails to each other.
Components of the app:
Users - Unlimited amount of users can join.
Friends - A User can have 200 confirmed friends and 100 pending friend requests. When a friendlist is retrieved it should show the name of the friend. (I will also need to receive the id of the friends so I can use it on my client side to create emails).
Emails - Users can send emails to their friends and they can receive emails from their friends. The user can then view all their sent emails independently(sentbox) and all their received emails independently(inbox). They can also view the the emails sent between themselves and a friend order by newest. The emails should show the senders and receivers names. Once an email is read it needs to be marked as read.
My model looks something like this, but as you can see their are inefficiencies.
Datastore Kinds:
USER
-email (id) //The email doesn't need to be the id, but I need to be able to retrieve users by their email
-hash_password
-name
-account_status
-created_date
FRIEND
-id (auto-generated)
-friend1
-friend2
-status
EMAIL
-id (auto-generated)
-from
-to
-mutual_id
-message
-created_date
-has_seen
Procedures of the application:
Register - Get operation to see if a user with this email exists. If does not insert key.
Login - Get operation to get user based on email. If exists retrieve the hash_password from the entity and compare to user's input.
Send friend request - Friend data will be written twice for every relationship. Then using the index on friend1 and index on status I will query all the friends for a user and filter only those which are 'pending'. I will then count these friends and see if they are over X. Again I will do this for the other user. If they are both not over the pending limit, I will insert the friend request. This needs to run in a transaction.
Accept a friend request - Friend data will be written twice for every relationship. Then using the index on friend1 and index on status I will query all the friends for a user and filter only those which are pending. I will then count these friends and see if they are over X. Again I will do this for the other user. If they are both not over the pending limit, I will change both entities's status to accepted as a transaction.
Show confirmed friends - Friend data will be written twice for every relationship. Then using the index on friend1 and index on status I will query all the friends for a user and filter only those which are accepted. Not sure how I will show the friend's names (e.g what happens if a user changed their name this needs to be reflected in all friend relationships and emails!).
Show pending friends - Friend data will be written twice for every relationship. Then using the index on friend1 and index on status I will query all the friends for a user and filter only those which are pending. Not sure how I will show the friend's names (e.g what happens if a user changed their name this needs to be reflected in all friend relationships and emails!).
View sent emails - Using the index on the from property I would query to get all the sent emails from a user 5 at a time ordered by created_date (newest first). (e.g what happens if a user changed their name this needs to be reflected in all friend relationships and emails!).
View received emails - Using the index on the to property I would query to get all the received emails to a user 5 at a time ordered by created_date (newest first). When a emails is seen it will update that entities has_seen property to true. (e.g what happens if a user changed their name this needs to be reflected in all friend relationships and emails!).
View emails between 2 users - Using the index on mutual_id which is based on [lower_lexicographic_email]:[higher_lexicographic_email] to query the mutual emails. Ordered by newest, 5 at a time. (e.g what happens if a user changed their name this needs to be reflected in all friend relationships and emails!).
Create email - Using the friend1 and status index I will confirm the user's are friends. If they are friends, I will insert an email.
