This repo is an example of how to compose a middleware component with a business logic component.

The github-oauth/ directory contains an API for using GitHub oauth in an application. It consists of

1. The authorize handler which kicks off the github oauth flow allowing a user to give permissions to a GitHub app
2. The callback handler which GitHub uses as the redirect url in the oauth flow. The callback handler is responsible for taking a code from the URL param and exchanging it for authentication token from GitHub for the user.
3. The authenticate handler which validates a given access token in an incoming request with the GitHub user API.
4. The login handler which returns a login button.

The example/ directory contains a Spin application which consists of one http handler which returns an HTTP response contains Hello, Fermyon! in the body. In the spin.toml file, the component build instructions point to a build.sh script which builds the example component and composes it with the github-oauth component.

• Install cargo component:

cargo install --git https://github.com/bytecodealliance/cargo-component cargo-component

• Install a fork of wasm-tools:

cargo install --git https://github.com/dicej/wasm-tools --branch wasm-compose-resource-imports wasm-tools --locked

• Install latest Spin

• Create a GitHub App. The callback URL should be http://127.0.0.1:3000/login/callback. Accept defaults and input dummy values for the rest of the fields.

  • Save the Client ID
  • Generate a new Client Secret and save that as well

• In example/spin.toml: replace <YOUR GITHUB CLIENT ID> with the Client ID from your GitHub APP and <YOUR GITHUB CLIENT SECRET> with the Client Secret from your GitHub App

# Build the middleware
cargo component build --manifest-path github-oauth/Cargo.toml --release

# Build and run the example
spin up --build -f example

# Open http://127.0.0.1:3000/login in a browser