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feat: Implement event polling loop for indexer #45

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7 changes: 7 additions & 0 deletions indexer/common/src/handlers/index.ts
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import { Event } from '../rpc';

export interface EventHandler {
name: string;
supports(event: Event): boolean;
handle(event: Event): Promise<void>;
}
6 changes: 6 additions & 0 deletions indexer/common/src/poller/README.md
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# Event Poller

The Event Poller is responsible for continuously fetching Soroban events from the Stellar network and dispatching them to registered handlers.

## Architecture

1 change: 1 addition & 0 deletions indexer/common/src/poller/index.ts
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export * from './EventPoller';
4 changes: 4 additions & 0 deletions indexer/common/src/repositories/index.ts
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export interface CursorRepository {
getCursor(): Promise<number>;
saveCursor(ledger: number): Promise<void>;
}
Comment on lines +1 to +4

@coderabbitai coderabbitai Bot Jun 26, 2026

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🗄️ Data Integrity & Integration | 🟠 Major | 🏗️ Heavy lift

Ledger-only cursoring can skip or replay events.

Persisting only a ledger number is not enough once polling is batched with limit: if a single ledger contains more events than one poll returns, the next resume point cannot distinguish “mid-ledger” from “fully processed.” That makes replay or event loss dependent on how startLedger is interpreted downstream. Please promote the cursor contract to a stable event-level position (for example event.id/paging token plus ledger) or define resume semantics that make partial-ledger progress unambiguous.

🤖 Prompt for AI Agents 
Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@indexer/common/src/repositories/index.ts` around lines 1 - 4, The
CursorRepository contract only stores a ledger number, which is ambiguous when
polling in batches and can cause skipped or replayed events. Update the cursor
model used by getCursor and saveCursor to persist a stable event-level position,
such as event.id or a paging token together with the ledger, and adjust any
callers/implementations to resume from that unambiguous position instead of
relying on ledger-only start semantics.

20 changes: 20 additions & 0 deletions indexer/common/src/rpc/index.ts
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export interface Event {
id: string;
ledger: number;
contractId: string;
topics: string[];
data: any;
timestamp: Date;
}

export interface GetEventsParams {
startLedger: number;
limit?: number;
contractId?: string;
topics?: string[];
}

export interface SorobanRpc {
getEvents(params: GetEventsParams): Promise<Event[]>;
getLatestLedger(): Promise<number>;
}