Current File : //usr/local/go119/src/compress/gzip/example_test.go
// Copyright 2016 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package gzip_test
import (
"bytes"
"compress/gzip"
"fmt"
"io"
"log"
"net/http"
"net/http/httptest"
"os"
"strings"
"time"
)
func Example_writerReader() {
var buf bytes.Buffer
zw := gzip.NewWriter(&buf)
// Setting the Header fields is optional.
zw.Name = "a-new-hope.txt"
zw.Comment = "an epic space opera by George Lucas"
zw.ModTime = time.Date(1977, time.May, 25, 0, 0, 0, 0, time.UTC)
_, err := zw.Write([]byte("A long time ago in a galaxy far, far away..."))
if err != nil {
log.Fatal(err)
}
if err := zw.Close(); err != nil {
log.Fatal(err)
}
zr, err := gzip.NewReader(&buf)
if err != nil {
log.Fatal(err)
}
fmt.Printf("Name: %s\nComment: %s\nModTime: %s\n\n", zr.Name, zr.Comment, zr.ModTime.UTC())
if _, err := io.Copy(os.Stdout, zr); err != nil {
log.Fatal(err)
}
if err := zr.Close(); err != nil {
log.Fatal(err)
}
// Output:
// Name: a-new-hope.txt
// Comment: an epic space opera by George Lucas
// ModTime: 1977-05-25 00:00:00 +0000 UTC
//
// A long time ago in a galaxy far, far away...
}
func ExampleReader_Multistream() {
var buf bytes.Buffer
zw := gzip.NewWriter(&buf)
var files = []struct {
name string
comment string
modTime time.Time
data string
}{
{"file-1.txt", "file-header-1", time.Date(2006, time.February, 1, 3, 4, 5, 0, time.UTC), "Hello Gophers - 1"},
{"file-2.txt", "file-header-2", time.Date(2007, time.March, 2, 4, 5, 6, 1, time.UTC), "Hello Gophers - 2"},
}
for _, file := range files {
zw.Name = file.name
zw.Comment = file.comment
zw.ModTime = file.modTime
if _, err := zw.Write([]byte(file.data)); err != nil {
log.Fatal(err)
}
if err := zw.Close(); err != nil {
log.Fatal(err)
}
zw.Reset(&buf)
}
zr, err := gzip.NewReader(&buf)
if err != nil {
log.Fatal(err)
}
for {
zr.Multistream(false)
fmt.Printf("Name: %s\nComment: %s\nModTime: %s\n\n", zr.Name, zr.Comment, zr.ModTime.UTC())
if _, err := io.Copy(os.Stdout, zr); err != nil {
log.Fatal(err)
}
fmt.Print("\n\n")
err = zr.Reset(&buf)
if err == io.EOF {
break
}
if err != nil {
log.Fatal(err)
}
}
if err := zr.Close(); err != nil {
log.Fatal(err)
}
// Output:
// Name: file-1.txt
// Comment: file-header-1
// ModTime: 2006-02-01 03:04:05 +0000 UTC
//
// Hello Gophers - 1
//
// Name: file-2.txt
// Comment: file-header-2
// ModTime: 2007-03-02 04:05:06 +0000 UTC
//
// Hello Gophers - 2
}
func Example_compressingReader() {
// This is an example of writing a compressing reader.
// This can be useful for an HTTP client body, as shown.
const testdata = "the data to be compressed"
// This HTTP handler is just for testing purposes.
handler := http.HandlerFunc(func(rw http.ResponseWriter, req *http.Request) {
zr, err := gzip.NewReader(req.Body)
if err != nil {
log.Fatal(err)
}
// Just output the data for the example.
if _, err := io.Copy(os.Stdout, zr); err != nil {
log.Fatal(err)
}
})
ts := httptest.NewServer(handler)
defer ts.Close()
// The remainder is the example code.
// The data we want to compress, as an io.Reader
dataReader := strings.NewReader(testdata)
// bodyReader is the body of the HTTP request, as an io.Reader.
// httpWriter is the body of the HTTP request, as an io.Writer.
bodyReader, httpWriter := io.Pipe()
// Make sure that bodyReader is always closed, so that the
// goroutine below will always exit.
defer bodyReader.Close()
// gzipWriter compresses data to httpWriter.
gzipWriter := gzip.NewWriter(httpWriter)
// errch collects any errors from the writing goroutine.
errch := make(chan error, 1)
go func() {
defer close(errch)
sentErr := false
sendErr := func(err error) {
if !sentErr {
errch <- err
sentErr = true
}
}
// Copy our data to gzipWriter, which compresses it to
// gzipWriter, which feeds it to bodyReader.
if _, err := io.Copy(gzipWriter, dataReader); err != nil && err != io.ErrClosedPipe {
sendErr(err)
}
if err := gzipWriter.Close(); err != nil && err != io.ErrClosedPipe {
sendErr(err)
}
if err := httpWriter.Close(); err != nil && err != io.ErrClosedPipe {
sendErr(err)
}
}()
// Send an HTTP request to the test server.
req, err := http.NewRequest("PUT", ts.URL, bodyReader)
if err != nil {
log.Fatal(err)
}
// Note that passing req to http.Client.Do promises that it
// will close the body, in this case bodyReader.
resp, err := ts.Client().Do(req)
if err != nil {
log.Fatal(err)
}
// Check whether there was an error compressing the data.
if err := <-errch; err != nil {
log.Fatal(err)
}
// For this example we don't care about the response.
resp.Body.Close()
// Output: the data to be compressed
}
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