Golang Writer.Close方法代碼示例

func (l *splunkLogger) tryPostMessages(messages []*splunkMessage) error {
	if len(messages) == 0 {
		return nil
	}
	var buffer bytes.Buffer
	var writer io.Writer
	var gzipWriter *gzip.Writer
	var err error
	// If gzip compression is enabled - create gzip writer with specified compression
	// level. If gzip compression is disabled, use standard buffer as a writer
	if l.gzipCompression {
		gzipWriter, err = gzip.NewWriterLevel(&buffer, l.gzipCompressionLevel)
		if err != nil {
			return err
		}
		writer = gzipWriter
	} else {
		writer = &buffer
	}
	for _, message := range messages {
		jsonEvent, err := json.Marshal(message)
		if err != nil {
			return err
		}
		if _, err := writer.Write(jsonEvent); err != nil {
			return err
		}
	}
	// If gzip compression is enabled, tell it, that we are done
	if l.gzipCompression {
		err = gzipWriter.Close()
		if err != nil {
			return err
		}
	}
	req, err := http.NewRequest("POST", l.url, bytes.NewBuffer(buffer.Bytes()))
	if err != nil {
		return err
	}
	req.Header.Set("Authorization", l.auth)
	// Tell if we are sending gzip compressed body
	if l.gzipCompression {
		req.Header.Set("Content-Encoding", "gzip")
	}
	res, err := l.client.Do(req)
	if err != nil {
		return err
	}
	defer res.Body.Close()
	if res.StatusCode != http.StatusOK {
		var body []byte
		body, err = ioutil.ReadAll(res.Body)
		if err != nil {
			return err
		}
		return fmt.Errorf("%s: failed to send event - %s - %s", driverName, res.Status, body)
	}
	io.Copy(ioutil.Discard, res.Body)
	return nil
}

// WriteBytes writes an encrypted/compressed stream to an io.Writer
func writeBytes(out io.Writer, key string, data []byte) error {
	var gzWriter *gzip.Writer  // compressed writer
	var iv [aes.BlockSize]byte // initialization vector
	var cb cipher.Block        // cipher block interface
	var err error              // general error holder

	// init cipher block
	if cb, err = aes.NewCipher(hashKey(key)); err != nil {
		return err
	}

	// init encrypted writer
	encWriter := &cipher.StreamWriter{
		S: cipher.NewOFB(cb, iv[:]),
		W: out,
	}

	// close when done
	defer encWriter.Close()

	// wrap encrypted writer
	gzWriter = gzip.NewWriter(encWriter)

	// close when done
	defer gzWriter.Close()

	// copy data to destination file compressing and encrypting along the way
	_, err = io.Copy(gzWriter, bytes.NewReader(data))

	// return copy error
	return err
}

func CreateGobsFile(targetFilePath string, recs *[]interface{}, getRecPtr GobRecPtrMaker, gzipped bool) {
	var file, err = os.Create(targetFilePath)
	var gobber *gob.Encoder
	var gzipper *gzip.Writer
	if file != nil {
		defer file.Close()
	}
	if err != nil {
		panic(err)
	}
	if gzipped {
		if gzipper, err = gzip.NewWriterLevel(file, gzip.BestCompression); gzipper != nil {
			defer gzipper.Close()
			gobber = gob.NewEncoder(gzipper)
		}
		if err != nil {
			panic(err)
		}
	} else {
		gobber = gob.NewEncoder(file)
	}
	for _, rec := range *recs {
		if err = gobber.Encode(coreutil.PtrVal(getRecPtr(rec))); err != nil {
			panic(err)
		}
	}
}

func NewDscout(waiter *sync.WaitGroup, filename string) *Dscout {
	d := new(Dscout)
	d.Operation.Waiter = waiter
	d.Operation.Waiter.Add(1)
	file, err := os.Create(filename)
	if err != nil {
		return nil
	}
	d.closer = func() {
		file.Close()
	}
	var writer io.WriteCloser = file
	var compressor *gzip.Writer
	if strings.HasSuffix(filename, ".gz") {
		compressor = gzip.NewWriter(file)
		d.closer = func() { compressor.Close(); file.Close() }
		writer = compressor
	}
	uncompressed_name := strings.TrimRight(filename, ".gz")
	switch {
	case strings.HasSuffix(uncompressed_name, ".gob"):
		d.marshaler = new(formats.GobMarshaler)
	case strings.HasSuffix(uncompressed_name, ".xml"):
		d.marshaler = new(formats.XmlMarshaler)
	}
	if d.marshaler != nil {
		d.marshaler.InitFile(writer)
	}
	return d
}

func webQuitHandler(diskwriter *csv.Writer, gzipwriter *gzip.Writer, csvfile *os.File) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		fmt.Fprintf(w, "flushing to disk and shutting down")
		diskwriter.Flush()
		if gzipwriter != nil {
			gzipwriter.Flush()
			gzipwriter.Close()
		}
		csvfile.Close()
		os.Exit(0)
	}
}

func (this *HtmlView) Publish(ctxt *web.Context) (err error) {
	names := mvc.GetMvcMeta(ctxt)
	if names[mvc.MVC_ACTION] == "" {
		names[mvc.MVC_ACTION] = "_"
	}

	var tmpl *template.Template
	tmpl, err = this.getTmpl(names)

	if err == nil {
		var method = ctxt.Method()

		ctxt.SetHeader("Content-Type", "text/html; charset=utf-8")

		if method != "HEAD" {
			var err error
			var tw io.Writer = ctxt.Response
			var gzipwriter *gzip.Writer

			if ctxt.ReqHeaderHas("Accept-Encoding", "gzip") {
				ctxt.SetHeader("Content-Encoding", "gzip")
				gzipwriter, _ = gzip.NewWriterLevel(ctxt.Response, gzip.BestSpeed)
				tw = gzipwriter
			}

			ctxt.SetHeader("Vary", "Accept-Encoding")
			ctxt.Response.WriteHeader(200)

			err = tmpl.Execute(tw, this.VM)

			if err != nil {
				// Header already sent... multiple write headers
				//panic(err)
				log.Println(err)
			}

			if gzipwriter != nil {
				gzipwriter.Close()
			}

			if flushw, ok := ctxt.Response.(http.Flusher); ok {
				flushw.Flush()
			}
		} else {
			ctxt.Response.WriteHeader(200)
		}
	} else {
		log.Println(err)
		ctxt.SetErrorCode(500)
	}

	return
}

func main() {
	var file *os.File
	var err error
	var writer *gzip.Writer
	var body []byte

	if file, err = os.Create("output/sample.tar.gz"); err != nil {
		log.Fatalln(err)
	}
	defer file.Close()

	// gzip.NewWriter()なら、エラーを返さないので便利
	if writer, err = gzip.NewWriterLevel(file, gzip.BestCompression); err != nil {
		log.Fatalln(err)
	}
	defer writer.Close()

	var filepaths = []string{
		"files/b0044482_1413812.jpg",
		"files/dart_flight_school.png",
		"files/golang.txt",
	}

	// Write()がio.Writerと同じなので、そのまま行ける。
	//	buf := new(bytes.Buffer)
	//	tw := tar.NewWriter(buf)
	tw := tar.NewWriter(writer)
	defer tw.Close()

	for _, filepath := range filepaths {
		if body, err = ioutil.ReadFile(filepath); err != nil {
			log.Fatalln(err)
		}

		if body != nil {
			hdr := &tar.Header{
				Name: path.Base(filepath),
				Size: int64(len(body)),
			}
			if err := tw.WriteHeader(hdr); err != nil {
				println(err)
			}
			if _, err := tw.Write(body); err != nil {
				println(err)
			}
		}
	}

	//	writer.Write(buf.Bytes())
	//	writer.Flush()
}

func (s *server) serveSync(rw http.ResponseWriter, req *http.Request) {
	memberID := s.validateConnection(rw, req)
	if memberID == "" {
		return
	}
	s.logger.Infof("Peer Member %s started synchronization from address %s", memberID, req.RemoteAddr)

	// Create a new channel for the new member synchronization
	syncChan := make(chan []byte)
	s.syncReqChannel <- syncChan

	// Send the response header to client side
	flusher := rw.(http.Flusher)

	gzipped := strings.Contains(req.Header.Get("Accept-Encoding"), "gzip")

	var gzipWriter *gzip.Writer
	var err error

	if gzipped {
		// override the response writer to be a gzipped writer
		if gzipWriter, err = gzip.NewWriterLevel(rw, gzip.DefaultCompression); err == nil {
			rw = gzipResponseWrapper{Writer: gzipWriter, ResponseWriter: rw}
			rw.Header().Set("Content-Encoding", "gzip")
			flusher = rw.(http.Flusher)
			defer func() {
				gzipWriter.Close()
			}()
		} else {
			s.logger.Warnf("Gzip wrapper creation for %s from %s failed: %v. Falling back to uncompressed HTTP", memberID, req.RemoteAddr, err)
		}
	}

	encoder := newEncoder(rw)
	var msgID uint64
	for data := range syncChan {
		ev := &sse{id: strconv.FormatUint(msgID, 10), event: "SYNC", data: string(data)}
		// Write to the ResponseWriter
		// Server Sent Events compatible
		if err := encoder.Encode(ev); err != nil {
			s.logger.WithFields(log.Fields{
				"error": err,
			}).Errorf("Failed to encode sync message to peer member %s", memberID)
			return
		}
		msgID++
	}
	flusher.Flush()
	s.logger.Infof("Peer Member %s synchronization has been completed successfully", memberID)
}

func createInvoiceFile(filename string) (io.WriteCloser, func(), error) {
	file, err := os.Create(filename)
	if err != nil {
		return nil, nil, err
	}
	closer := func() { file.Close() }
	var writer io.WriteCloser = file
	var compressor *gzip.Writer
	if strings.HasSuffix(filename, ".gz") {
		compressor = gzip.NewWriter(file)
		closer = func() { compressor.Close(); file.Close() }
		writer = compressor
	}
	return writer, closer, nil
}

func (nf *Netflow) NewFileWriter(filename string, mode int, compress bool) error {
	log.Debugln("NewFileWriter")
	if _, ok := nf.writers[filename]; ok {
		return fmt.Errorf("netflow writer %v already exists", filename)
	}

	f, err := os.Create(filename)
	if err != nil {
		return err
	}

	c := make(chan *Packet, BUFFER_DEPTH)
	go func() {
		var w *gzip.Writer
		if compress {
			log.Debugln("using compression")
			w = gzip.NewWriter(f)
		}
		for {
			d := <-c
			if d == nil {
				break
			}
			if mode == ASCII {
				if compress {
					w.Write([]byte(d.GoString()))
				} else {
					f.Write([]byte(d.GoString()))
				}
			} else {
				if compress {
					w.Write(d.Raw)
				} else {
					f.Write(d.Raw)
				}
			}
		}
		if compress {
			w.Close()
		}
		f.Close()
	}()

	nf.registerWriter(filename, c)
	return nil
}

func (e *Engine) gzip() error {
	var buf bytes.Buffer
	var level int
	var err error
	level, err = e.stack.PopInt()
	if err == nil {
		var w *gzip.Writer
		w, err = gzip.NewWriterLevel(&buf, level)
		if err == nil {
			_, err = w.Write(e.stack.Pop())
			w.Close()
		}
	}
	if err == nil {
		e.stack.Push(buf.Bytes())
	}
	return err
}

func writeSure(path string, info DirWalker) (err error) {
	file, err := os.Create(path)
	if err != nil {
		return
	}
	defer file.Close()

	var zfile io.Writer
	if strings.HasSuffix(path, ".gz") {
		var tmp *gzip.Writer
		tmp = gzip.NewWriter(file)
		defer tmp.Close()
		zfile = tmp
	} else {
		zfile = file
	}

	io.WriteString(zfile, magic)
	dumpDir(zfile, "__root__", info)
	return
}

func runPatchManifest(args []string) (exit int) {
	var fh *os.File
	var err error

	if patchReplace && patchOverwrite {
		stderr("patch-manifest: Cannot use both --replace and --overwrite")
		return 1
	}
	if !patchReplace && len(args) != 2 {
		stderr("patch-manifest: Must provide input and output files (or use --replace)")
		return 1
	}
	if patchReplace && len(args) != 1 {
		stderr("patch-manifest: Must provide one file")
		return 1
	}
	if patchManifestFile != "" && (patchName != "" || patchExec != "" || patchUser != "" || patchGroup != "" || patchCaps != "" || patchMounts != "") {
		stderr("patch-manifest: --manifest is incompatible with other manifest editing options")
		return 1
	}

	inputFile = args[0]

	// Prepare output writer

	if patchReplace {
		fh, err = ioutil.TempFile(path.Dir(inputFile), ".actool-tmp."+path.Base(inputFile)+"-")
		if err != nil {
			stderr("patch-manifest: Cannot create temporary file: %v", err)
			return 1
		}
	} else {
		outputFile = args[1]

		ext := filepath.Ext(outputFile)
		if ext != schema.ACIExtension {
			stderr("patch-manifest: Extension must be %s (given %s)", schema.ACIExtension, ext)
			return 1
		}

		mode := os.O_CREATE | os.O_WRONLY
		if patchOverwrite {
			mode |= os.O_TRUNC
		} else {
			mode |= os.O_EXCL
		}

		fh, err = os.OpenFile(outputFile, mode, 0644)
		if err != nil {
			if os.IsExist(err) {
				stderr("patch-manifest: Output file exists (try --overwrite)")
			} else {
				stderr("patch-manifest: Unable to open output %s: %v", outputFile, err)
			}
			return 1
		}
	}

	var gw *gzip.Writer
	var w io.WriteCloser = fh
	if !patchNocompress {
		gw = gzip.NewWriter(fh)
		w = gw
	}
	tw := tar.NewWriter(w)

	defer func() {
		tw.Close()
		if !patchNocompress {
			gw.Close()
		}
		fh.Close()
		if exit != 0 && !patchOverwrite {
			os.Remove(fh.Name())
		}
	}()

	// Prepare input reader

	input, err := os.Open(inputFile)
	if err != nil {
		stderr("patch-manifest: Cannot open %s: %v", inputFile, err)
		return 1
	}
	defer input.Close()

	tr, err := aci.NewCompressedTarReader(input)
	if err != nil {
		stderr("patch-manifest: Cannot extract %s: %v", inputFile, err)
		return 1
	}
	defer tr.Close()

	var newManifest []byte

	if patchManifestFile != "" {
		mr, err := os.Open(patchManifestFile)
		if err != nil {
			stderr("patch-manifest: Cannot open %s: %v", patchManifestFile, err)
			return 1
//.........這裏部分代碼省略.........

// Closes a gzip writer and returns it to the pool:
func ReturnGZipWriter(gz *gzip.Writer) {
	gz.Close()
	gzipWriterCache.Put(gz)
}

func main() {

	log.SetFlags(log.LstdFlags | log.Lshortfile)

	tr := &http.Transport{
		ResponseHeaderTimeout: time.Second * 500,
		DisableKeepAlives:     false,
		DisableCompression:    false,
	}

	var wXml *gzip.Writer = nil
	var ww *bufio.Writer = nil
	var xFile *os.File = nil

	meshFile, err2 := os.Create(meshFile)
	if err2 != nil {
		return
	}
	defer meshFile.Close()
	wwMesh := bufio.NewWriter(meshFile)
	wMesh := gzip.NewWriter(wwMesh)

	//w := bufio.NewWriter(file)

	numIdsPerUrl := findNumIdsPerUrl()
	pmids := make([]string, numIdsPerUrl)

	urlFetcher := gopubmed.Fetcher{
		Ssl: false,
		Transport: &http.Transport{
			ResponseHeaderTimeout: time.Second * 500,
			DisableKeepAlives:     false,
			DisableCompression:    false,
			//TLSClientConfig:       &tls.Config{InsecureSkipVerify: true},
		},
	}

	allCount := 0
	count := 0

	reader, err := makeReader()
	if err != nil {
		log.Fatal(err)
	}
	first := true
	chunkCount := 0
	for {
		thisNumIdsPerUrl := findNumIdsPerUrl()
		if numIdsPerUrl != thisNumIdsPerUrl {
			numIdsPerUrl = thisNumIdsPerUrl
			pmids = make([]string, numIdsPerUrl)
		}
		line, err := reader.ReadString('\n')
		if err != nil {
			// You may check here if err == io.EOF
			break
		}
		line = strings.TrimSpace(line)
		err = lineChecker(line)
		if err != nil {
			log.Fatal(err)
		}
		//log.Println(line)
		pmids[count] = line

		if wXml == nil {
			wXml, ww, xFile = makeXmlWriter(allCount, pmids[0])
		}

		count = count + 1
		// Collected enough pmids: get their XML from NIH
		if count == numIdsPerUrl {
			getPubmedRecords(&urlFetcher, first, wMesh, wXml, tr, pmids)
			checkTime()
			first = false
			count = 0
			zeroArray(pmids)
		} else {

		}
		allCount += 1
		chunkCount += 1
		// Start new xml file: close old one: open new one
		if chunkCount > recordsPerFile {
			fmt.Fprintln(wXml, endPubmedArticleSet)
			wXml.Flush()
			wXml.Close()
			ww.Flush()
			wXml, ww, xFile = makeXmlWriter(allCount, pmids[0])
			chunkCount = 0
			first = true
		}
		if allCount%500 == 0 {
			log.Println(allCount)
		}
	}
	if count != 0 {
		getPubmedRecords(&urlFetcher, first, wMesh, wXml, tr, pmids)
	}
	fmt.Fprintln(wXml, endPubmedArticleSet)
//.........這裏部分代碼省略.........