The following setup is under MacOS. If you are using another operating system, please search on the internet or contact us.

Python is assumed to be installed before this procedure.

Open your terminal, input command:

python -m venv venv

And run command:

source venv/bin/activate

Run pip install related packages:

pip install -r requirements.txt

A secret key is necessary in this project. Input command:

export JWT_SECRET_KEY="6cfb8684b95028909c82dcea7244cb04f009f0a07dde210f71e00b97f663a144"

Or use your own secret key.

MongoDB is assumed to be installed, and MongoDB replica set should be properly set up. In the following instructions, we set up a MongoDB replica set locally.

sudo lsof -i:27017
sudo kill PID

sudo mkdir -p /your/path/to/rs1
sudo mkdir -p /your/path/to/rs2
sudo mkdir -p /your/path/to/rs3
sudo chmod 755 /your/path/to/rs*

The terminal tool screen is assumed to be installed before this procedure.

screen -S mongodb1
sudo mongod --port 27017 --dbpath /your/path/to/rs1 --replSet myReplicaSet --bind_ip localhost
ctrl-a d (leave the screen session)
screen -S mongodb2
sudo mongod --port 27018 --dbpath /your/path/to/rs2 --replSet myReplicaSet --bind_ip localhost
ctrl-a d (leave the screen session)
screen -S mongodb3
sudo mongod --port 27019 --dbpath /your/path/to/rs3 --replSet myReplicaSet --bind_ip localhost
ctrl-a d (leave the screen session)

mongosh --port 27017

Inside the mongosh:

rs.initiate({ _id: "myReplicaSet", members: [ { _id: 0, host: "localhost:27017" }] })
rs.add("localhost:27018")
rs.add("localhost:27019")

You can check the health status for each port with rs.status().

Go to the project directory, and activate the virtual environment.

source venv/bin/activate

Start the flask app:

python main.py

Now the flask app should be running on http://127.0.0.1:5000

To enable users to manage their data separately and securely, we have user registration and user login api.

curl -X POST 'localhost:5000/.register' -d '{"username":"dsci551","password":"123"}' 

It will return {"result":"User created"}

curl -X POST 'localhost:5000/.login' -d '{"username":"dsci551","password":"123"}' 

It will return {"access_token":"eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmcmVzaCI6ZmFsc2UsImlhdCI6MTY4MjczMDI3NSwianRpIjoiNzNhN2E2NmYtMDk2ZC00NzhlLTllOTQtOGIxMDk1NDNmNGIyIiwidHlwZSI6ImFjY2VzcyIsInN1YiI6ImRzY2k1NTEiLCJuYmYiOjE2ODI3MzAyNzV9.PoatX68cG3WAF5DoT2JMnmwxTGykXOyepUUPiBLqxHo"} You should always inlcude a header -H "Authorization: Bearer {token}" for any operations other than register and login. Take creating a collection as an example:

curl -X POST -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJmcmVzaCI6ZmFsc2UsImlhdCI6MTY4MjczMDI3NSwianRpIjoiNzNhN2E2NmYtMDk2ZC00NzhlLTllOTQtOGIxMDk1NDNmNGIyIiwidHlwZSI6ImFjY2VzcyIsInN1YiI6ImRzY2k1NTEiLCJuYmYiOjE2ODI3MzAyNzV9.PoatX68cG3WAF5DoT2JMnmwxTGykXOyepUUPiBLqxHo" http://localhost:5000/.create_collection/dsci551

For following curl command I will use -H "Authorization: Bearer {token}" to save space. For creating index (index is used to support filtering):

curl -X POST -h "Authorization: Bearer {token}" http://localhost:5000/.create_index/dsci551?byValue=1

For creating listener (listener is used for real-time synchronization):

curl -X POST -h "Authorization: Bearer {token}" http://localhost:5000/.create_listener/dsci551

there are PUT, POST, GET, PATCH, DELETE methods implemented to support same functionalities covered by https://firebase.google.com/docs/reference/rest/database?hl=en We provide some examples below

curl -H "Authorization: Bearer {token} " -X PUT 'localhost:5000/dsci551.json' -d '{"yxj":{"info":{"address":"620 S Virgil ave"}}}'

curl -H "Authorization: Bearer {token} " -X POST 'localhost:5000/dsci551.json' -d '{"info":{"address":"620 S Virgil ave"}}'

You will get the unique id from the return message.

curl -H "Authorization: Bearer {token} " -X GET 'localhost:5000/dsci551/yxj.json'

For GET command with orderBy, you need to create related index first except for orderBy="$key". The following command create index for orderBy="$value" when the path is /dsci551

curl -X POST -h "Authorization: Bearer {token}" http://localhost:5000/.create_index/dsci551?byValue=1

curl -H "Authorization: Bearer {token} " -X PATCH 'localhost:5000/dsci551/yxj/info.json' -d '{"address":"621 S Virgil ave"}'

curl -H "Authorization: Bearer {token} " -X DELETE 'localhost:5000/dsci551/yxj.json'

To delete the collection:

curl -H "Authorization: Bearer {token} " -X DELETE 'localhost:5000/dsci551.json'

The routing for .create_collection is like this '/.create_collection/<collection_name>', the name after .create_collection will be created.

For .create_index, it is designed to support the orderBy functionality in GET method, however, due to the limit of backend MongoDB, an index will not be guaranteed used to speed up the filtering process. By looking at how does orderBy works in GET, we can get an idea about what index should be created before filtering.

curl -H "Authorization: Bearer {token} " -X GET 'localhost:5000/dsci551/william/subjects/DSCI551/HW.json?orderBy="$value"'

The corresponding .create_index command is:

curl -H "Authorization: Bearer {token} " -X POST 'localhost:5000/.create_index/dsci551/subjects/DSCI551/HW?byValue=1'

You can also have GET command like:

curl -H "Authorization: Bearer {token} " -X GET 'localhost:5000/dsci551/william/subjects/DSCI551.json?orderBy="HW'

The corresponding index command is:

curl -H "Authorization: Bearer {token} " -X POST 'localhost:5000/.create_index/dsci551/subjects/DSCI551/HW'

The above two examples are for illustrations, it is unlikely that both make sense in the same collection.

If you use GET command with orderBy="$value", the path must be /path.json?orderBy="$value", and for .create_index, the path must be /path?byValue=1. There is no ambiguity. However, for orderBy="subpath", there might be ambiguity in the index creating. The following two GET command share the same .create_index command.

 curl -H "Authorization: Bearer {token} " -X GET 'localhost:5000/dsci551/william/subjects/DSCI551.json?orderBy="HW'

  curl -H "Authorization: Bearer {token} " -X GET 'localhost:5000/dsci551/william/subjects.json?orderBy="DSCI551/HW'

The .create_index command:

curl -H "Authorization: Bearer {token} " -X POST 'localhost:5000/.create_index/dsci551/subjects/DSCI551/HW'

However, there is no ambiguity for a specific collection. Thus, this should not be a problem in practice.

Listener is a must for real-time synchronization based on socket, the path format is '/.create_listener/<collection_name>'. Thus, the listener can be created only on the collection level, there is no way to create a listener specfic to a field.

The client uses this emulated Firebase should use socket client, like the one provided by socketio package in python. Make the socket client connects to 'http://localhost:5000'.

Like Firebase, no dot '.' is allowed in any key. Besides, please exclude unnecessary space in your input json object.