RabbitMQ کے پاس کئی exchange types ہیں جو یہ طے کرتے ہیں کہ پیغامات queues تک کیسے روٹ ہوں — direct، topic، fanout، اور headers۔ انہیں سمجھنا RabbitMQ کے لچکدار routing کے لیے اہم ہے، جو مختلف messaging patterns کو فعال کرتا ہے۔
exchange کی اقسام
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DIRECT → routes by an EXACT routing key match:
→ message routing key = queue binding key → delivered to that queue
→ for: routing to specific queues by a key (e.g. route by severity, type)
FANOUT → broadcasts to ALL bound queues (ignores routing key):
→ every queue bound to the exchange gets the message → PUB/SUB (one-to-many)
→ for: broadcasting events to all interested consumers
TOPIC → routes by PATTERN matching on the routing key (wildcards):
→ routing keys like "order.created", "order.*", "*.error" → flexible pattern routing
→ for: routing by topics/categories with wildcards (flexible pub/sub)
HEADERS → routes by message HEADER attributes (not the routing key) → less common