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passkit-generator/examples/cloudflare-worker/webpack5.x/README.md
2022-02-05 23:24:08 +01:00

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# Cloudflare Workers example (wrangler + Webpack 5)
This is a sample project for showing passkit-generator working on a Cloudflare Worker.
Cloudflare Workers are serverless function based on Browser's V8 (instead of Node). For this reason several APIs require to be polyfilled.
Cloudflare Workers have a tool, wrangler, which comes out with Webpack 4 to bundle things and polyfill those missing Node.JS APIs (e.g. Buffer).
**In this example aims, instead, to show how to build with Webpack 5 instead of Webpack 4.**
This example offers just the generation of a single static `boardingPass`.
> Please note that creating and publishing a Cloudflare Workers with passkit-generator, might require you to buy a plan.
> Cloudflare limits are pretty low.
## Setting up
Install all the dependencies through `npm install`.
Configure wrangler and your account [according to the guide](https://developers.cloudflare.com/workers/get-started/guide).
### Secrets and certificates
This example uses some environmental variables (secrets), which can be set through Wrangler CLI or through Dashboard, as per [this official guide](https://developers.cloudflare.com/workers/platform/environment-variables#adding-secrets-via-wrangler):
- `SIGNER_CERT`
- `SIGNER_KEY`
- `SIGNER_PASSPHRASE`
- `WWDR`
So, assuming you have `certificates` folder in the root of passkit-generator, you'll be able to do such:
```sh
$ cat ../../../certificates/signerKey.pem | npx wrangler secret put SIGNER_KEY
```
These variables are exposed on `globalThis`.
### Running locally
To run the worker locally, run `npm run example`. This command will run the webserver on `0.0.0.0`, so it can also be accessed from other devices on the network.
### Publishing
To publish the worker, you'll need to run `npx wrangler whoami` to get the Account ID. Set it to `account_id` in `wrangler.toml`.
## Example details
Since our project is made in Typescript, we needed a way to compile it. The way shown, uses `ts-loader`.
As per `ts-loader` dependencies, it required webpack to be `*`, so v5 would automatically get download. We added webpack explicitly, so we don't leave anything undetailed.
Along with this, we needed to setup a different `webpack.config.js` and tell wrangler where to find it, through `wrangler.toml`.
`webpack.config.js` will detail several things for us:
- how to handle module assets, through [Asset Modules](https://webpack.js.org/guides/asset-modules/), in a way we can still import them with ES Modules syntax;
- Node.JS modules that will get polyfilled;
- Modules that [will be provided everywhere without the need to import them explicitly](https://webpack.js.org/plugins/provide-plugin/). This is the case of Node.js APIs and modules, like Buffer, which is available on both `global` and through `Buffer` module. Since Buffer must be polyfilled "manually", this allows us to tell modules Buffer should be imported in for compatibility (e.g. do-not-zip);
Another detail you should pay attention to, is that `package.json`'s `main` field **should be your worker entry-point**, as per [cloudflare documentation (paragraph)](https://developers.cloudflare.com/workers/cli-wrangler/configuration#:~:text=ensure%20the%20main%20field%20in%20your%20package.json%20references%20the%20worker%20script%20you%20want%20to%20publish)
Lastly, we needed to set `type = "javascript"` on the top of `wrangler.toml`, as per [the documentation](https://developers.cloudflare.com/workers/cli-wrangler/webpack) and set a custom build command as per the documentation as well (same link as above).