How to Determine Data Availability in Stdin with Go

Question

In Go, is there a reliable way to check if the input stream (os.Stdin) contains data?

The conventional approach of reading from the stream blocks when no data is available, making it impractical for certain use cases.

Answer

Similar to other files, os.Stdin can be inspected to determine its size, offering a convenient method for data availability detection.

package main

import (
    "fmt"
    "os"
)

func main() {
    file := os.Stdin
    fi, err := file.Stat()
    if err != nil {
        fmt.Println("file.Stat()", err)
    }
    size := fi.Size()
    if size > 0 {
        fmt.Printf("%v bytes available in Stdin\n", size)
    } else {
        fmt.Println("Stdin is empty")
    }
}

By utilizing this technique, you can distinguish between empty and non-empty stdin inputs, allowing for a more flexible handling of data availability.