FedCM Prototyping IDP

This is an standalone demonstrator IDP implementation in typescript that provides basic functionality for creating accounts with an IDP, logging in and logging out of an IDP as a prerequisite to test Browser and RP implementations of the FedCM API.

This is absolutely not meant for production use and does not implement any security mechanism for the base IDP functionality, use this for demonstration/prototyping/testing purposes only.

Getting Started

To get started:

1. Clone this repository

2. Install node.js and npm

3. Install dependencies

   npm install

4. Build the project

   npm run build

5. Run on localhost (Port 8080)

   npm run start-local

Note: It is not supported to run multiple IDPs on different localhost ports or different ports on the same hostname (i.e. localhost:8080 and localhost:8081).

Deployment options

This setup currently supports three deployment options. It can be run on locally, deployed using dedicated domains (default) and via Heroku (deployed on localhost, Heroku takes care of the rest)

Default deployment

The default deployment assumes that the setup is using dedicated etlD+1s to run IDPs. This setup currently supports running any number of IDP - supported IDP hostnames will be fetched from the idp_metadata.json configuration file and started automatically accordingly.

Start the server once the domains are set using

npm start

The IDPs will be available on the given hostnames via https.

Local deployment

Single IDP

Start server using.

npm start-local

The IDP will be available on localhost:8080 via http, w.r.t to configuring the FedCM Browser API call on the RP side use configURL: http://localhost:8080/fedcm.json

Multiple IDPs

This setup currently supports running any number of IDP locally - supported IDP hostnames will be fetched from the idp_metadata.json configuration file and started automatically accordingly.

In order to run multiple IDPs locally use multiple .localhost hostnames, e.g. idp-1.localhost, idp-2.localhost, etc. and add them to the idp_metadata.json configuration file.

Note: This of course requires you to add the respective hostnames to your /etc/hosts file to point to 127.0.0.1

Start the server once the domains are set using

npm start-local

The IDPs will be available on the given hostnames via http on port 8080, w.r.t to configuring the FedCM Browser API call on the RP side use configURL: http://idp-1.localhost:8080/fedcm.json and so on.

Heroku

This setup can be deployed via Heroku PaaS - Follow the respective instructions here - Other than Heroku specifics no further configuration is necessary, the setup will automatically fetch the Heroku app domain and adjust accordingly.

Certificate configuration

In case not run locally or via Heroku this setup expects a certs subdirectory in the root of the project containing a subdirectory for the configured domains. Basic setup:

Create the certs directory

mkdir certs

Create directory for your IDP domain(s)

mkdir certs/your-first-idp-domain.com

Put the respective certificates into this directory, i.e. privkey.pem and fullchain.pem

Make sure access rights to both the folders and the files are setup correctly.

General configuration

Clients

Supported Clients must be configured in config/client_metadata.json. Note that eligible clients and origins are validated as defined in the FedCM specification.

IDPs

IDP configuration is contained in config/idp_metadata.json. In order to host an IDP on a etlD+1 / other than localhost (configured by default for local deployment), add a respective entry to the JSON configuration object (may contain multiple). The branding configuration can be adjusted to your needs per IDP.

    "your-domain-goes-here": {
        "branding": {
            "background_color": "rgb(255, 255, 204)",
            "color": "0xffffff",
            "icons": [
                {
                    "url": "{baseUrl}/images/yourlogo.webp",
                    "size": 32
                }
            ]
        }
    }

{baseUrl} is automatically replaced at runtime, additional IDP logos must be place in src/public/images

Supported features

IDP User management:

• Create account
• Delete account
• Sign-in / Sign-out
• Account persistence in PouchDB
• Profile Page (show user info)
• passkey support (single authenticator per user, passwordless login)
• Approved Clients Management (display, revoke)

IDP:

• Client registration (static, build time)
• IDP registration (static, build time)
• Baseline FedCM related security
  • Clients checks (origin, referer, etc.)
  • Accounts mismatch checks

FedCM API:

• Baseline APIs
  • .well-known/web-identity
  • IDP manifest (fedcm.json)
  • accounts_endpoint
  • id-assertion-endpoint
• Extended APIs
  • UserInfo API (personalized login button)
  • IDP Sign-In API
  • Support for User Interaction UX (Scope management)
    • For more information, see issue #477.

Known working browsers

• Chrome 115, 116 (Android, MacOS)
• Chrome Canary 117 (Android, MacOS)
• Edge 115, 116 (Android, MacOS)