Learn Neo4j, Pm2 and Redwoodjs

In this course we will learn some of the basics of getting data into and out of Neo4J, as well as touch on some of the libraries and tooling available in the Neo4J community ecosystem, which we will leverage to quickly create and use a full-featured GraphQL API.

We will start by learning how to run and interact with Neo4J locally. Then we will develop a graph model in which to store the data that we pull from SWAPI via REST. We will then create an Apollo GraphQL API driven by a few simple schemas which fit into this model. We will then write some simple code to crawl SWAPI and insert the data into Neo4J through our GraphQL API. Once there is data in the store, we will learn about some of the features in `neo4j-graphql-js` that make connecting and accessing our graph Nodes easier.

Neo4j delivers the lightning-fast read and write performance you need. Neo4j combines native graph storage, scalable architecture optimized for speed, and ACID compliance to ensure predictability of relationship-based queries.

neo4j

Build a Neo4J & GraphQL API

RedwoodJS takes the JAMstack philosophy to the next level. It brings together all the tools modern web development has to offer:

- React
- GraphQL
- Prisma

RedwoodJS abstracts database management away from you so that you can just build your schema and it will do all the plumbing. This collection will go over how to create a RedwoodJS project and the scripts that will help make your developer experience a joy.


Bringing full-stack to the JAMstack

Do you love the JAMstack philosophy but need a database-backed web app? Want great developer experience and easy scaling? Redwood is here! Built on React, GraphQL, and Prisma, Redwood works with the components and development workflow you love, but with simple conventions and helpers to make your experience even better.

redwoodjs

Introduction to RedwoodJS: full-stack framework for JAMstack

React is one of the web’s most popular frameworks for building JavaScript applications. 

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We use `yarn redwood generate page` (`yarn rw` for short) in this lesson to generate an `IndexPage` component. 

The first argument to `yarn rw generate page` is the name of the page you are generating. The second argument is the path you want the page to show up on. So `yarn rw generate page index /` will generate an `IndexPage` component and insert a route entry in our `web/src/Routes.js` file.

We learn that redwood import `React` for you so you don't have to import it manually when you are creating a component.

Generate a Page Using the Redwood CLI

In this lesson, we are going over how to generate a `RedwoodJS` project.

We can create a `RedwoodJS` project with `yarn create redwood-app ./my-redwood-project`.

`yarn` will generate the `RedwoodJS` app in the file folder you specified without installing any globals.

To run the `RedwoodJS` app, we use `yarn redwood dev`. This runs the Redwood client as well as the `GraphQL` backend.

Generate a Redwood Project

RedwoodJS provides a `Link` component that we can use to navigate around our app. We can provide a `to` prop with the path that we want to navigate to.

RedwoodJS takes this a step further and provides a `routes` object from `@redwoodjs/router`. This object is aware of all the routes defined in `web/Routes.js`. This allows us to use the methods on this object rather than referencing the our routes with a string literal. We can then change the route path without having to change all of the references to that route all over our app.

Use RedwoodJS Link and routes Object to Navigate

RedwoodJS gives us a cli command to generate layouts.

`yarn redwood generate layout main`

This will generate a `MainLayout` component in `src/layouts/MainLayout/`. We can use this layout component to define any headers or footers we want to share across multiple pages. 

Extract a RedwoodJS Layout Component

PM2 is a production process manager for Node.js applications with a built-in load balancer. It allows you to keep applications alive forever, to reload them without downtime and to facilitate common system admin tasks.

This video shows how to enable features in your pm2 config file that allow you to prevent runaway apps from bringing your server down. Setting max memory used, number of running processes allowed and maximum restart attempts are all covered.

Controlling runaway apps using pm2

In this video, you will learn how to pass environment variables to your node.js app using the pm2 config file. This is useful for setting options inside your app such as production or development.

Passing environment variables to node.js using pm2

In this video, learn how to automatically restart your node.js app using pm2 when the code for your app changes. You will also learn how to exclude files and directories from restarting your app (such as static assets, css, images, etc.).

Restarting your node.js app on code change using pm2

There are different types of data in Neo4J: Nodes and Relationships. We will cover the ways to create each type of data: creating nodes with properties, creating nodes with relationships, and creating constraints on nodes and relationships.

Create Nodes and Relationships in Neo4J with Cypher

Once there is data in Neo4J, we need to be able to access it. We will cover the structure of a cypher query to return parts of our graph.

Read Nodes and Relationships in Neo4J with Cypher

The data in our graph is unlikely to stay the same forever. We will cover the syntax used to find and modify existing data in different ways through the use of parameters.

Update Nodes and Relationships in Neo4J with Cypher

Nothing lives forever, so we need to know how to use DELETE and DETACH to get rid of nodes and relationships we no longer want in our graph.

Delete Nodes and Relationships in Neo4J with Cypher

We will learn about `neo4j-graphql-js` and how to leverage it to quickly create a full-featured API backed by Neo4J. We will create a few simple schemas to represent our model.

Use neo4j-graphql-js to Create a Simple API

We will learn to use the `@relation` directive provided by `neo4j-graphql-js` to make the relationships in our model explicit in our schemas.

Explicitly Model Schema Relationships with the @relation Directive in neo4j-graphql-js

We will use automatically generated mutations in a Apollo GraphQL API augmented with `neo4j-graphql-js` to insert data that we get from SWAPI into Neo4J.

Create Data in Neo4J Through a GraphQL API

We will use the `@cypher` directive provided by `neo4j-graphql-js` to return data about how nodes are related to each other in our schemas without writing custom resolvers.


Build Complex Schema Relationships with the @cypher Directive in neo4j-graphql-js

We will use our own custom mutations in an Apollo GraphQL API to update or create data that we scrape from SWAPI into Neo4J with. We will use the `@cypher` directive to use custom merge statements in these mutations.


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