pathway/get.go

package pathway

import (
	"io"
	"net/http"
	"sync/atomic"
)

func handleGet(pathID string, w http.ResponseWriter, r *http.Request) {
	queue := &Queue{ch: make(chan Transfer)}
	if p, loaded := paths.LoadOrStore(pathID, queue); loaded {
		queue = p.(*Queue)
		debug("%s [GET] Loads path", pathID)
	} else {
		debug("%s [GET] Created path", pathID)
	}
	atomic.AddInt32(&queue.gets, 1)

	select {
	case transfer := <-queue.ch:
		debug("%s [GET] Reads from path", pathID)
		if transfer.contentlength != "" {
			w.Header().Set("Content-Length", transfer.contentlength)
		}
		_, err := io.Copy(w, transfer.reader)
		if err != nil {
			transfer.reader.Close()
		}
		debug("%s [GET] Sends done", pathID)
		close(transfer.done)
	case <-r.Context().Done():
		debug("%s [GET] Cancels path", pathID)
	}

	if atomic.AddInt32(&queue.gets, -1) <= 0 {
		if atomic.LoadInt32(&queue.posts) <= 0 {
			paths.Delete(pathID)
			debug("%s [GET] Removes path", pathID)
		}
	}
	info("%s [GET] Finishes", pathID)
}