POLLING-BRIDGE

Polling bridge is the polling-bridge integration pattern — a component periodically polls an external source (SFTP, database, REST API) to detect new EDI messages and push them into the internal gateway.

Definition

Polling bridge is one of the Hohpe & Woolf Enterprise Integration Patterns. The poller applies a cursor (timestamp, file mtime, offset) and only scans the delta zone. A concurrency lock (Redis or DB) prevents double processing.

Origin

Pattern codified in Enterprise Integration Patterns (Hohpe & Woolf, 2003). Still current for legacy sources that don't emit native events (SFTP, OFTP2 partners).

Use

An EDI gateway polls a partner SFTP every 60 seconds: ls /inbound, downloads each unseen file (cursor 'processed files' in Redis), publishes each payload on Kafka, archives to S3. Added latency: 30s average.

Related terms

• Webhook bridge — push counterpart.
• SFTP — typical source.
• Backpressure (EDI) — throttling.
• Catch-up cursor — tool.