Be able to fetch attestations from the EAS graph in the backend

[oscarwroche]

Quoth ChatGPT:

Use a thin Backend-For-Frontend that calls The Graph when you need:

• Keys/secrets (Graph Studio, private subgraphs, or provider fallbacks) you don’t want to expose in the browser,
• Caching and stability (set Cache-Control, retries, backoff; shield the UI from Graph hiccups),
• Normalization / versioning (subgraph schema changes → keep your API stable),
• Joins with your DB (e.g., merge attestations with your profiles table or permissions),
• Aggregation (leaderboards, counts, “top skills”, pagination windows),
• Rate limiting and abuse protection,
• GDPR/logging control (avoid leaking user traces to third parties directly),
• Consistent formatting across clients (web, mobile).

Pattern:

• /api/attestations?address=…&skill=… → your backend:

  1. Queries The Graph,
  2. Merges/filters with Postgres (optional),
  3. Responds with a stable DTO,
  4. Sends cache headers (s-maxage, stale-while-revalidate) for CDNs.

[oscarwroche]

Find testnet where there is an EAS graph

[joelamouche]

Here is the list of GraphQL urls... https://docs.attest.org/docs/developer-tools/api

Seems like they don't have amoy so maybe I will deploy on Base Sepolia

[oscarwroche]

As discussed with @joelamouche it might be overkill to use TheGraph and using a RPC endpoint should be enough.
Using the alloy library like in this example should do the trick.

[oscarwroche]

Initials Specs

• Create new indexer Rust service / folder in root folder

Domain

• Create EthereumEvent entity with EthereumEventType enum
• Create EthereumEventRepository repository
• Create EthereumEventPollingService service

Application

• Create poll use case that takes no arguments and polls all events for all types from EthereumEventType enum and stores them using the EthereumEventRepository repository

Infrastructrure

• Create PostgresEthereumEventRepository repository implementation
• Add migration for new ethereum_events table
• Add Dockerfile
• Update docker-compose
• Add /poll POST endpoint (no arguments)