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Create the Backend | Angular Todos

Table of Contents​

Step 1 - Create a New App​

  1. Hopefully, you've had the chance to create an Amplication account, but if not, don't fret! Visit https://app.amplication.com/ and you'll be directed to the login screen. Here you can log in to an existing Amplication account, or create one, by signing in with a GitHub account.

    You should end up at the New App page, but if not you can get to it here.

  2. Click the New App button in the top right corner.

    create an Amplication app

  3. Name your application whatever you'd like, and then click "Create Project."

  4. Click "New service +," in the top right corner, and then "Create Service" in the bottom right of the new page.

    Click "New service +"

    then "Create Service"

Step 2 - Create an Entity​

An entity is equivalent to a collection in a NoSQL database or a table in a relational database. By default, a User entity is created for you. This entity will eventually help us handle authentication. But first, let's deal with the backend. The main entity will be used to store tasks created by users.

  1. Click the "Entities" button in the left hand bar to go to the entities page.

    Click the "Entities" button

  2. Click Add entity.

    add entity

  3. When a New Entity modal appears, input Task into the input field and click Create Entity.

    With the entity created we'll want to define a few fields for task elements.

  4. On the left-hand panel, you'll see the Fields this entity has, and at the very bottom, there will be an option to add a field.

    Add field option

  5. The first field will be Text. Type that into the Add field input and hit enter.

    The new field will be created and a few options will appear.

    text field

  6. Notice a dropdown for the Data Type of this field is set to Single Line Text. That's perfect as it'll be a string input of a task. There are many different data types Amplication can enforce for fields.

  7. The only change that needs to be made here is this will be a required field. Toggle the Required Field switch.

    Changes will be automatically saved.

  8. Like before, create a new field called Completed. This field should also be a required field, but we will change the data type. Click the Data Type dropdown and change this field to be a Boolean.

  9. The final field we will need to create should be called UID. This field will be used to relate a task to a user. Mark this as a required field. In the Data Type dropdown select Relation to Entity.

  10. The Related Entity dropdown should appear, select User. A modal asking to create a relation between a Task and a User will appear. Click Create to create the relation. To learn more about entity relations, there's an article on the docs website here.

Step 3 - Create a Role​

Amplication allows for granular permission to create, read, update, and delete entries in the different entities of the backend.

User's who will be creating tasks in the Todo app will need to be granted certain permissions to create, read, and update their tasks and prevent them from doing other things.

  1. Click the Roles icon on the left-hand panel.

    roles button

  2. Then, much like the properties, we added to the Task entity, create a role called Todo User.

    create a new role

Step 4 - Assign Permissions​

With a role for users of the Todo app created, we'll want to assign certain permissions to the Todo User role.

  1. Return to the entities page by clicking the Entities icon on the left-hand panel, again.

    By default, every role has CRUD (create, read, update, and delete) access to every entity. It is important to limit the scope of our Todo users.

  2. Select the User entity from the list of entities, and on the left-hand, panel select Permissions.

    Every type of command is granted to All Roles. Users with the User or Todo User role have full access to the User entity. This can be dangerous.

    The default admin account created by the backend has the role User, so we don't want to mess with that. What we will eventually do is have it so all new users are assigned the Todo User role, and we will limit their access to certain commands.

  3. Toggle the permissions for each of the entity's commands to Granular and toggle on the User role. Now the only user who can access User accounts will have the User role, which will belong only to the admin account.

    users permissions

  4. Return to the Entities page and now select the Task entity. Click Permissions. Toggle the Delete command, to Granular and enable access to the User role. Both Users (the admin) and Todo Users (regular users of the app) will be able to create, read, and update tasks; but only Users will be able to delete tasks.

    tasks permissions

Step 5 - Connect to GitHub​

Amplication provides code sync with GitHub. We'll want to set this up with the repository we created in the previous step.

note

Enterprise plan users can also sync with other git providers like Bitbucket.

  1. Click the Connect to Github icon on the left-hand panel. Then click Go to project settings.

    Connect to GitHub Go to project settings

  2. Click Connect to Github. This will allow you to connect with either your GitHub account, or with a GitHub organization.

    Connect to GitHub

  3. Finally click Select repository. From here select the GitHub repository we created previously.

    Select repository

Step 6 - Build the Backend​

With the new Task entity created, and a relation with User's created, and connecting our project with GitHub. We're now ready to commit our changes and build the application.

On the right-side panel is the Pending changes where the changes to Task and User, as well as other changes, will appear.

pending changes

  1. Click Commit changes & build to finalize the changes and to create a Pull Request on GitHub with the backend we created.

    Amplication by default creates a secure environment where all requests need to be authenticated. For this use case, we will want to ease some of those protections. Thanks to Amplication's extensibility, we can build on top of everything that was generated for us.

  2. Visit GitHub and navigate to the repository that's linked to this project. You'll see that a new pull request has been opened!

    Go to view code

  3. Review the pull request and the code that was generated for yourself, then merge the pull request.

  4. Finally, return to your code editor and pull down the changes made on GitHub.

Step 7 - Run the Backend​

  1. The admin-ui and server folders generated by Amplication are two new node projects that need to be set up. One thing both will need is their dependencies. In the package.json update the postinstall script:

    "postinstall": "npm i --prefix web && npm i --prefix apps/first-service-admin && npm i --prefix apps/first-service"
caution

Make sure that you replace first-service with the name of the service that you created in Step 1 in the above postinstall script.

  1. Open a new terminal and run this command

    npm run postinstall

    This command will install the dependencies of all the subfolders. Another useful aspect of this command is that if you were to push this project to GitHub and cloned the repo when you run npm install this script will occur after the install to install the dependencies of the subfolders automatically.

  2. Install npm-run-all as a dev dependency as follows:

    npm install -D npm-run-all

  3. Update the start script in package.json and add the following script as well:

    "start": "npm-run-all -p start:frontend start:backend",
    "start:frontend": "npm --prefix web start",
    "start:admin": "npm --prefix admin-ui start",
    "start:backend": "npm --prefix server start",

    We've also set the start to script to run our frontend and backend code at the same time.

  4. Before starting the server there are a few additional steps required. Read server/README.md for directions to:

    • Create a Prisma client
    • Start a database in Docker
    • Initiate the database

  5. When those steps have been completed run the following command:

    npm run start

Step 8 - Wrap Up​

The frontend of the Todo app will be running at http://localhost:4200/, and the backend will be running at http://localhost:3000/.

Visiting http://localhost:3000/ will greet you with a 404 error. Instead, visit http://localhost:3000/api/ to see all the endpoints of the backend and to see what our REST endpoints will look like.

With our backend created and running locally, we're almost ready to link it to the frontend. First, we'll need to make some additions to the code.

To view the changes for this step, visit here.