Post-processing Hook

Manael v3.1 adds a Go API hook for custom processing after image conversion. Use WithPostProcessor when you embed Manael as a library and need to inspect, cache, replace, or augment the converted bytes before they are sent to the client.

When the hook runs

The post-processing hook runs only after Manael has successfully converted an image.

• It receives the converted image bytes.
• It can return the same bytes unchanged.
• It can return replacement bytes if your application needs to modify the response.
• It is not called when Manael passes the upstream response through unchanged.

Basic example

proxy := manael.NewServeProxy(upstreamURL,
	manael.WithPostProcessor(func(data []byte) ([]byte, error) {
		// Store converted bytes in your cache, object store, or audit pipeline.
		return data, nil
	}),
)

Common use cases

• Store converted images in an external cache.
• Add application-specific response processing after format conversion.
• Integrate with downstream systems that need the final converted payload.

Error handling

If the hook returns an error, Manael logs the failure and falls back to the original upstream response instead of sending a partially processed result. This keeps request handling safe even when custom logic fails.

Important behavior

• The hook is a library API, not a command-line option or environment variable.
• The hook runs after format conversion, so it sees the final converted payload.
• If no conversion happens for the request, the hook is skipped.