Medium WebClient & WebFlux

Chain Reactive Calls

Simulate two chained WebClient calls. First, fetch a user ID from getActiveUserId() which returns Mono<Int> with value 42. Then, use flatMap to fetch user details from getUserDetails(id) which returns Mono<String> with "User #42 - Active". Print the final result.

This pattern is fundamental for composing multiple async HTTP calls.

Expected

User #42 - Active

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Main.kt

Chain Reactive Calls

medium⏱ 15 minkotlinreactorchallengewebclient

This pattern is fundamental for composing multiple async HTTP calls.

Why this works

flatMap() is the key operator for chaining async calls. It takes each emitted value, passes it to a function that returns a Publisher, and subscribes to the inner Publisher. This is how you sequence dependent HTTP calls in WebFlux.

Expected output

User #42 - Active

Chain Reactive Calls

This pattern is fundamental for composing multiple async HTTP calls.

Expected

User #42 - Active

Chain Reactive Calls

medium⏱ 15 minkotlinreactorchallengewebclient

This pattern is fundamental for composing multiple async HTTP calls.

Why this works

Expected output

User #42 - Active