dalanmiller / rethinkdb-workshop

A simple exercise app meant for learning how to use RethinkDB

RethinkDB Workshop

Learn the basics of RethinkDB and ReQL(RethinkDB query language) through building a simple chat app.

This repo teaches you the basics of ReQL by having the user write ReQL queries to get this chat app to work.

Setup: Install RethinkDB and Node.js

If using Mac:

brew install rethinkdb
brew install node

You then want to actually run RethinkDB.

You can have RethinkDB start up with your system boot by using the launch ctl... command you see when running brew info rethinkdb. Or you can run it just for this instance by opening a new terminal window and just running rethinkdb. In that directory RethinkDB will create a new folder rethinkdb_data where it will store data.

After installing RethinkDB and Node.js, go to the root directory of the repo and install all app dependencies.

npm install

You can now run the node server using the following command:

# Mac and Linux
npm run dev
# Windows
node server

Instructions

To get started, take a look at the instructions in the server/index.js file

You will be working solely by writing code in the server/index.js file.

After starting node and creating the necessary tables, you can now start writing ReQL queries to complete the excercise.

Complete all three steps to get the chat app working. Each step will involve writing a ReQL query to get a part of the app working.

1. Inserting messages: /server/index.js:L122
2. Getting messages: /server/index.js:L74
3. Listening for messages: /server/index.js:L101

After completing these three steps, your chat app will run correctly.

If you get stuck:

Don't spend more than 10 minutes on any single step. If you get stuck, there are branches with the solutions for each step. Consult these branches and move on to the next one.

Extra credit:

If you finish with all steps, consider implementing some of the following features:

1. Adding rooms to chat app
2. Displaying users in room/chat
3. Add multiple nodes to the RethinkDB cluter
4. Add message search
5. Add message liking
6. Add the ability to delete messages

Step 1 : Inserting messages

Query instructions:

Insert a document into the messages table with the following attributes: text, email, created

Fields:

`text`: A string with the message text from the user
`email`: An email address that exists in the `users` table
`created`: A Unix Timestamp `(new Date()).getTime()`

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/getTime

Callback instructions:

There is no need for a callback.

Result:

Once you write this query, you'll be able to insert new messages in the front-end and see them in the database

Step 2: Getting messages

Query instructions:

Write a query that gets all messages, ordered by created (a secondary index)

Callback instructions:

Return the messages array as a JSON document through res:

  res.json(messages);

Result:

Once you have written this query, you'll be able to see all previously inserted messages when loading the page

Step 3 : listening for messages

Query instructions:

Write a query that listens to changes in the messages table.

HINT: the query will return a cursor, not an array

HINT: the objects returned by the cursor have a new_val and an old_val property

http://rethinkdb.com/docs/changefeeds/javascript/

Callback instructions:

Every time a change is pushed by the database, push that change to the client by emitting a socket event:

  socket.emit('message', row.new_val);

Result:

Once you write this query, you'll be able to see new messages be displayed as they are being added