A package that helps with the management and expansion of a maintainable firebase backend
MIT License
A package that helps with the management and expansion of a maintainable firebase backend
Let's to start out by going through a high level overview of how the backend will be setup. This overview will go over the types of functions we use as well as the actual code structure.
The backend is built around the strengths that firebase poses in their serverless cloud functions setup. Focussing on those strengths we can break the system into two types of functions (could also be called a micro-service if you choose to). Reactive and RESTul
We have an enforced code structure that will help with the organization of the backend as well as the overall maintenance as it grows. There's 3 major things to go over.
Organize your firebase functions
folder into api domain folders (groups
) and function type (reactive
, restful
).
src
{group_name_folder}
reactive
- onSomeTrigger.function.ts
- onSomeOtherTrigger.function.ts
restful
- someEndpointName.endpoint.ts
- someOtherEndpointName.endpoint.ts
- index.ts
package.json
We'll start off by installing the package dedicated to using this system
firebase-backend
. Install the package through npm
npm install firebase-backend
Then you can open the index.ts file in your source folder and update it to
import { FunctionParser } from 'firebase-backend';
exports = new FunctionParser({ rootPath: __dirname, exports, verbose: true })
.exports;
These are the two magical lines of code that allows us to dynamically add and export functions as the backend grows without ever changing the index file 🥳. And that's also all we need to set it up. Now we can start creating functions 😎
If you want to prefix all the generated cloud functions, for versioning, or for any use case, see the example below. This will add the version v2_ infront of all deployed functions keeping your previously deployed functions in tact.
import { FunctionParser } from 'firebase-backend';
exports = new FunctionParser(__dirname, exports).exports;
const backendVersion = 'v2';
const seperator = '_';
for (const key in exports) {
if (Object.prototype.hasOwnProperty.call(exports, key)) {
exports[`${backendVersion}${seperator}${key}`] = exports[key];
delete exports[key];
}
}
Create
Let's say we wanted to make an endpoint where a client application could add a payment method for a user.
users
addPaymentMethod
src/users/restful/addPaymentMethod.endpoint.ts
endpoint.ts
file extension identifies the function as an HTTP endpoint// src/users/restful/addPaymentMethod.endpoint.ts
import { Request, Response } from 'express';
import { Post } from 'firebase-backend'; // Get, Post, Put, Update, Delete available
// Use the `Post` class which is extended from the `Endpoint` class.
export default new Post((request: Request, response: Response) => {
// Read the values out of the body
const cardNumber = request.body['card_number'];
const cardHolder = request.body['card_holder'];
// Do your thing with the values
var paymentToken = `${cardNumber}_${cardHolder}`;
// Send your response. 201 to indicate the creation of a new resource
return response.status(201).send({
token: paymentToken,
});
});
Middleware You can now pass an array of middleware you'd want to add to an endpoint:
// src/users/restful/auth.middleware.ts
import { Request, Response, NextFunction } from 'express'
export const authMiddleware = (req: Request, res: Response, next: NextFunction) => { ... }
// src/users/restful/addPaymentMethod.endpoint.ts
import { Request, Response } from 'express'
import { EndpointMiddleware, Post } from 'firebase-backend'
import { authMiddleware } from './auth.middleware'
export default new Post((req: Request, res: Response) => {}, {
middlewares: [authMiddleware]
})
Testing
To test this out we'll run the following command in the functions folder.
npm run serve
This will build the TypeScript code and then serve the functions locally through the emulator. If this is successful you should see the following in the console. You should see the functions API has deployed (locally) a function at the following url
http://localhost:5001/boxtout-fireship/us-central1/users-api
All the endpoints in the users resource group will be deployed under the
/user-api
function. This means that we can make a post request to the endpoint
with the expected data and check if we get back a result. I'm going to use
PostMan to test this out. So we'll put in the above
url and add /addpaymentmethod
at the end of it. Select post as the HTTP
request type and then pass in a body.
{
"card_number": "5418754514815181",
"card_holder": "FilledStacks"
}
When we execute this we get back the token in the format we supplied
{
"token": "5418754514815181_FilledStacks"
}
There we have it, your first endpoint created. Next up is reactive functions.
Create
Let's say we wanted to make a function that would run when the firestore db had a user record updated.
users
onUserCreated
src/users/reactive/onUserCreated.function.ts
function.ts
file extension identifies the function as reactive// src/users/reactive/onUserCreated.function.ts
import * as functions from 'firebase-functions';
export default functions.firestore
.document('users/{userId}')
.onCreate((userSnapshot, context) => {
const data = userSnapshot.data();
console.log(`User Created | send an email to ${data.email}`);
});
Run npm run build
in the functions folder. Then run firebase emulators:start
.
You should now have a function deployed at users-onUserCreated
as well as at
users-api
. All the api endpoints go under the one api function, but the
reactive functions are added as their own functions. Lets test this out.
Testing
At the bottom of your logs you'll see a link to firestore
http://localhost:4000/firestore . Open that in your browser. You'll see an
empty page. Click on start collection, make the collection id users
. Add a
field called email and put the value [email protected] and save the
document. When this is saved you should see the logs printing out the following
message
i functions: Beginning execution of "users-onUserCreated"
> User id created TybqxAwnC4X5DWLgtXOp
> {"severity":"WARNING","message":"Function returned undefined, expected Promise or value"}
i functions: Finished "users-onUserCreated" in ~1s
> User Created | send an email to [email protected]
And that's it! You've created a reactive function as well as a http endpoint. Going further when you want to expand you backend you simply create a new file in the dedicated folder depending on the function type and it'll be added automatically.
The way that the default TypeScript project is setup is not sufficient for
consistent deployments and debugging. Because of that we'll add some additional
things into our project. We'll start by making sure that old function code don't
lurk around when we're testing any new changes. To fix that we'll add a new
package into the functions folder called rimraf
npm install -D rimraf
Then we'll add 2 new scripts into the package.json
. Above the build
script
we'll add clean
and prebuild
.
"scripts": {
"lint": "eslint --ext .js,.ts .",
"clean": "rimraf lib/",
"prebuild": "npm run clean",
"build": "tsc",
"serve": "npm run build && firebase emulators:start --only functions",
"shell": "npm run build && firebase functions:shell",
"start": "npm run shell",
"deploy": "firebase deploy --only functions",
"logs": "firebase functions:log"
}
This will now clean out your generated code before building the new code.
And finally we can deploy our backend. We first run npm run build
when that's
complete we run npm run deploy
and that will push all the latest function code
to your firebase project.
FilledStacks [email protected]
Contributions, issues and feature requests are welcome!
Feel free to check issues page.
Copyright © 2021 FilledStacks [email protected].
This project is MIT licensed.