如何在Go中重用原始的string.Reader？

Question

I have an input of type strings.Reader. Given the input, I am extracting the id from it and printing it out. I then pass the original input to a generic function that perform other tasks on it. The only way I can think of reusing the original is to read the content and pass it to a bytes.Reader twice.

Is the following the only way to achieve that in Go?

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io"
    "io/ioutil"
    "log"
    "strings"
)   

type Food struct {
    Id   int    `json:"id"`
    Name string `json:"name"`
}   

func genericFunction(body io.Reader) {
    content, err := ioutil.ReadAll(body)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(string(content))
}   

func main() {
    // Original input
    reader := strings.NewReader("{\"id\": 10, \"name\": \"Pie\"}")

    original, err := ioutil.ReadAll(reader)
    if err != nil {
        log.Fatal(err)
    }   

    foodReader := bytes.NewReader(original)
    decoder := json.NewDecoder(foodReader)
    var food Food
    decoder.Decode(&food)
    fmt.Println("About to eat food", food.Id)

    foodReader = bytes.NewReader(original)
    genericFunction(foodReader)
}   

Answer 1

You can seek back to the start of the string with either the strings.Reader or bytes.Reader

reader := bytes.NewReader([]byte("{\"id\": 10, \"name\": \"Pie\"}"))

decoder := json.NewDecoder(reader)
var food Food
decoder.Decode(&food)
fmt.Println("About to eat food", food.Id)

reader.Seek(0, 0)
genericFunction(reader)