Go slow reader

go_slowreader.go

package main

import (
	"encoding/json"
	"fmt"
	"io"
	"log"
	"strings"
	"time"
)

const beSlow = true

// slowReader is a ... well ... slow reader.
type slowReader struct{ r io.Reader }

func (r slowReader) Read(data []byte) (int, error) {
	// wait for 250 ms before reading a single byte.
	time.Sleep(250 * time.Millisecond)
	n, err := r.r.Read(data[:1])
	if n > 0 {
		fmt.Printf("%s", data[:1])
	}
	return n, err
}

func main() {
	input := `{"Name":"A"}{"Name":"B"}{"Name":"C"}{"Name":"D"}{"Name":"E"}{"Name":"F"}{"Name":"G"}{"Name":"H"}`
	var p struct{ Name string }

	var r io.Reader = strings.NewReader(input)
	if beSlow {
		r = slowReader{r}
	}
	
	dec := json.NewDecoder(r)	
	for {
		// This will return as soon as a whole JSON object has been parsed.
		if err := dec.Decode(&p); err == io.EOF {
			break
		} else if err != nil {
			log.Fatal(err)
		}
		fmt.Printf(" -> %+v\n", p)
	}
}