API Router/Handler

police-data-trust

To get started:

Fork a copy of the main repo to your GitHub account.
Clone your fork: git clone [email protected]:YOUR_GITHUB_NAME/police-data-trust.git
Add the main repo to your remotes

cd police-data-trust
git remote add upstream https://github.com/codeforboston/police-data-trust.git
git fetch upstream

Now, whenever new code is merged you can pull in changes to your local repository:

git checkout main
git pull upstream main

Installation (Full Application)

This method uses Docker to run the complete application stack.

Make sure that Docker is installed on your machine.
Create a .env file by running cp .env.template .env in the root of your local project folder, and add your preferred PostgreSQL username and password:

Note When running locally, you may need to update one of the ports in the .env file if it conflicts with another application on your machine.

Build and run the project with docker-compose build && docker-compose up -d && docker-compose logs -f

Installation (Frontend Only)

This method runs the frontend natively on your computer and does not require a running backend, which can be convenient.

Make sure that you have node 16+ and either npm 7+ or yarn installed.
Follow the install instructions in the frontend directory.

Testing with Docker

All code must pass the unit tests and style checks before it can be merged into the main branch. You can run the tests locally by opening up a comand line interface to a docker container while it's running the application:

docker exec -it "police-data-trust-api-1" /bin/bash

You'll need to replace police-data-trust-api-1 with the name of the container you'd like tro connect to. You can see the names of all currently running containers by running docker container ls

docker container ls
CONTAINER ID   IMAGE                   COMMAND                  CREATED              STATUS              PORTS                    NAMES
c0cf********   police-data-trust-api   "/bin/sh -c '/wait &…"   About a minute ago   Up About a minute   0.0.0.0:5001->5001/tcp   police-data-trust-api-1
5e6f********   postgres:16.1           "docker-entrypoint.s…"   3 days ago           Up About a minute   0.0.0.0:5432->5432/tcp   police-data-trust-db-1
dacd********   police-data-trust-web   "docker-entrypoint.s…"   3 days ago           Up About a minute   0.0.0.0:3000->3000/tcp   police-data-trust-web-1

Backend Tests

The current backend tests can be found in the GitHub Actions workflow file python-tests.yml

To run the tests locally, first start the application with docker-compose. Then open up a command line interface to the running container:

docker exec -it "police-data-trust-api-1" /bin/bash

Then run the tests:

flake8 backend/
python -m pytest

Front End Tests

The current frontend tests can be found in the GitHub Actions workflow file frontend-checks.yml

To run the tests locally, first start the application with docker-compose. Then open up a command line interface to the running container:

docker exec -it "police-data-trust-web-1" /bin/bash

Then run the tests:

npm run lint
npm run check-formatting
npm run test
npm run check-types

Documentation

Docs

Code Standards

Typescript Style Guide

This style guide is intended to act as a quick reference for the most common scenarios

Custom Types

For this codebase, we are using interfaces instead of type aliases.

Utilizing Types

We are aiming for a loose standard of explicitly typing as little as possible (relying on type inference or third-party library typing files to do the work whenever convenient), but as much as necessary (function params/args are a good example of what the compiler is bad at inferring). Erring on the side of 'stricter than absolutely necessary' definitely works for us!
The any type should never be utilized here. Prefer union types in the case of values that are initially null (such as values that come from API calls), or unknown in case of a type being truly impossible to discern ahead of time.
When typing primitive values declared with const, explicitly typing them will be necessary to prevent their type from being implied as the literal value of said primitive, rather than it's corresponding data type.

Functions

Always use explicit typing in the case of function params and return types.
If function parameters don't get modified by the function, strongly consider making them readonly to prevent mutation and have clearer code.

React

Prefer the .tsx file extension when JSX is involved, and .ts when it isn't.

Props

Refer to the React/TypeScript Cheatsheet for examples of common propTypes.
In the case of components that accept other React components as props, prefer typing those as React.ReactNode.

Hooks

Prefer type inference for useState for simple cases. If the hook initializes with a nullish value, strongly consider a union type.
Since useEffect and useLayoutEffect don't return values, typing them is not necessary.
When typing useRef, refer to the React/TypeScript cheatsheet for guidance on your specific situation.

Forms & Events

Type inference should be sufficient in the case of inline event handlers.
IDE tooling (such as VSCode autocomplete) will offer helpful suggestions for specific event handler types.
The React/TypeScript cheatsheet has a list of specific event types.