wrapreader

README

WrapReader

WrapReader is a Go library. It provides an io.ReadCloser that wraps an io.Reader and an io.Closer together.

It's useful when dealing with io.Reader implementations that wraps another io.ReadCloser, but will not close the underlying reader, such as gzip.Reader.

(Example code on godoc)

Documentation

Overview

Package wrapreader provides an io.ReadCloser that wraps an io.Reader and an io.Closer together.

It's useful when dealing with io.Reader implementations that wraps another io.ReadCloser, but will not close the underlying reader, such as GzipReader.

Index

• func Wrap(reader io.Reader, closer io.Closer) io.ReadCloser

Examples

• Wrap

Functions

func Wrap

func Wrap(reader io.Reader, closer io.Closer) io.ReadCloser

Wrap wraps reader and closer together to create an new io.ReadCloser.

The Read function will simply call the wrapped reader's Read function, while the Close function will call the wrapped closer's Close function.

If the wrapped reader is also an io.Closer, its Close function will be called in Close as well.

Example

package main

import (
	"compress/gzip"
	"fmt"
	"io/ioutil"
	"log"
	"os"
	"path/filepath"

	"github.com/fishy/wrapreader"
)

func main() {
	filename := filepath.Join(os.TempDir(), "_test.gz")
	content := "Hello, world!"
	defer os.Remove(filename)

	f, err := os.Create(filename)
	if err != nil {
		log.Fatal(err)
	}
	writer := gzip.NewWriter(f)
	func() {
		defer func() {
			writer.Close()
			f.Close()
		}()
		_, err = writer.Write([]byte(content))
		if err != nil {
			log.Fatal(err)
		}
	}()

	f, err = os.Open(filename)
	if err != nil {
		log.Fatal(err)
	}
	reader, err := gzip.NewReader(f)
	if err != nil {
		log.Fatal(err)
	}
	readCloser := wrapreader.Wrap(reader, f)
	// readCloser.Close() will close both f and reader
	defer readCloser.Close()
	// Read from readCloser is actually read from reader
	read, err := ioutil.ReadAll(readCloser)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(string(read))
}

Output:

Hello, world!