🎙️HttpChunk with Flow

on September 22, 2025

Processing HTTP responses in chunks is a recurring challenge:

  • Multiple requests must be run in parallel. * Some fail (404s, timeouts) and require retries. * Each user returns additional data (todos, posts), resulting in fan-out requests. * This quickly adds up to callback hell, manual state management, and difficult testing.

Problematic :

HTTP chunk processing is complex when it should be fluid.

The problem

In PHP, handling asynchronous HTTP streams has often been addressed in an imperative manner:

  • Nested callbacks. * Shared state variables. * Difficulty testing and maintaining.

These approaches make the code difficult to read, fragile and expensive to evolve.

The solution with Flow

The Flow Framework provides a functional and elegant response to this complexity.

  • Jobs: Pure functions that transform data. * Ips: Immutable objects that carry information between jobs. * Drivers: Amp, React, Swoole, or Fiber — abstracted behind Flow. * Y-Flow: Y-Combinator integration to handle recursion without explicit loops.

The result: a clear, composable, and testable pipeline that naturally orchestrates asynchronous flows.

The demo: httpchunkflow.php

The concrete example:

php examples/httpchunkflow.php

Procedure:

  1. Three initial queries (/users, /users/404, /todos). 2. Error handling: a 404 is automatically retried to /users/1. 3. Y-Combinator: each user automatically triggers additional queries (/todos, /posts). 4. Concurrent execution: queries run in parallel. 5. Final merge: consolidation of data into a structured result.

Excerpt from logs:

*. #1 GET /users ... started *. #2 GET /users/404 ... started *. #3 GET /todos ... started .* #2 404 -> retry /users/1 ..* #1 chunks: parsing via Y ...* #101 QUEUED /users/1/todos ...* #1101 QUEUED /users/1/posts .* #101 200 in 18ms .* #1101 200 in 16ms ....* merging data .....* finalizing results User #1: Leanne Graham ([email protected]) - Todos: 20 items - Posts: 10 items DONE driver=Flow\Driver\AmpDriver duration=7.99s users=200 retry=1 errors=0

The benefits

  • âś… Readability: No more callback hell. * âś… Purity: Each job is a testable function in isolation. * âś… Immutability: Clear and predictable data flows. * âś… Elegant recursion: Y-Combinator instead of imperative loops. * âś… Async by design: Flow orchestrates concurrency naturally.

Conclusion

With Flow and Y-Combinator, chunked HTTP processing goes from a mandatory nightmare to a smooth and functional solution. The result is code that:

  • more readable, * more testable, * more maintainable.

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