Golang Writer.Flush方法代碼示例

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 getPubmedRecords(urlFetcher *gopubmed.Fetcher, first bool, meshWriter *gzip.Writer, xmlWriter *gzip.Writer, transport *http.Transport, pmids []string) {
	preUrlTime := time.Now()

	articles, raw, err := urlFetcher.GetArticlesAndRaw(pmids)
	if err != nil {
		log.Fatal(err)
	}
	s := string(raw[:len(raw)])

	for i := 0; i < len(articles); i++ {
		pubmedArticle := articles[i]
		if pubmedArticle.MedlineCitation != nil && pubmedArticle.MedlineCitation.MeshHeadingList != nil && pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading != nil {
			fmt.Fprint(meshWriter, articles[i].MedlineCitation.PMID.Text)
			for j := 0; j < len(pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading); j++ {
				fmt.Fprint(meshWriter, "|")
				fmt.Fprint(meshWriter, pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading[j].DescriptorName.Attr_UI)
				fmt.Fprint(meshWriter, "::"+pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading[j].DescriptorName.Text)

				if len(pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading[j].QualifierName) > 0 {
					fmt.Fprint(meshWriter, "=")
					for q := 0; q < len(pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading[j].QualifierName); q++ {
						if q != 0 {
							fmt.Fprint(meshWriter, "&")
						}

						fmt.Fprint(meshWriter, pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading[j].QualifierName[q].Attr_UI)
						fmt.Fprint(meshWriter, "::"+pubmedArticle.MedlineCitation.MeshHeadingList.MeshHeading[j].QualifierName[q].Text)
					}
				}
			}
			fmt.Fprintln(meshWriter, "")
		}
	}
	meshWriter.Flush()
	if !first {
		s = strings.Replace(s, startXml, "", -1)
		s = strings.Replace(s, docType, "", -1)
		s = strings.Replace(s, startPubmedArticleSet, "", -1)
	}
	s = strings.Replace(s, endPubmedArticleSet, "<!-- breakset -->", -1)

	xmlWriter.Write([]byte(s))
	postUrlTime := time.Now()
	log.Println("Total request time:", postUrlTime.Sub(preUrlTime))
}

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.........

func (h *handler) sendContinuousChangesByWebSocket(inChannels base.Set, options db.ChangesOptions) (error, bool) {

	forceClose := false
	handler := func(conn *websocket.Conn) {
		h.logStatus(101, "Upgraded to WebSocket protocol")
		defer func() {
			conn.Close()
			base.LogTo("HTTP+", "#%03d:     --> WebSocket closed", h.serialNumber)
		}()

		// Read changes-feed options from an initial incoming WebSocket message in JSON format:
		var compress bool
		if msg, err := readWebSocketMessage(conn); err != nil {
			return
		} else {
			var channelNames []string
			var err error
			if _, options, _, channelNames, _, compress, err = h.readChangesOptionsFromJSON(msg); err != nil {
				return
			}
			if channelNames != nil {
				inChannels, _ = channels.SetFromArray(channelNames, channels.ExpandStar)
			}
		}

		// Set up GZip compression
		var writer *bytes.Buffer
		var zipWriter *gzip.Writer
		if compress {
			writer = bytes.NewBuffer(nil)
			zipWriter = GetGZipWriter(writer)
		}

		caughtUp := false
		_, forceClose = h.generateContinuousChanges(inChannels, options, func(changes []*db.ChangeEntry) error {
			var data []byte
			if changes != nil {
				data, _ = json.Marshal(changes)
			} else if !caughtUp {
				caughtUp = true
				data, _ = json.Marshal([]*db.ChangeEntry{})
			} else {
				data = []byte{}
			}
			if compress && len(data) > 8 {
				// Compress JSON, using same GZip context, and send as binary msg:
				zipWriter.Write(data)
				zipWriter.Flush()
				data = writer.Bytes()
				writer.Reset()
				conn.PayloadType = websocket.BinaryFrame
			} else {
				conn.PayloadType = websocket.TextFrame
			}
			_, err := conn.Write(data)
			return err
		})

		if zipWriter != nil {
			ReturnGZipWriter(zipWriter)
		}
	}
	server := websocket.Server{
		Handshake: func(*websocket.Config, *http.Request) error { return nil },
		Handler:   handler,
	}
	server.ServeHTTP(h.response, h.rq)
	return nil, forceClose
}

func (p Handler) processText(s *Session, w http.ResponseWriter, resp *http.Response) (err error) {
	var (
		zr      *gzip.Reader
		zw      *gzip.Writer
		body    []byte
		gzipped bool   = resp.Header.Get("Content-Encoding") == "gzip"
		reqHost string = resp.Request.URL.Host
		reqPath string = resp.Request.URL.Path
	)
	if resp.ContentLength != 0 && resp.Request.Method != "HEAD" {
		if gzipped {
			zr, err = gzip.NewReader(resp.Body)
			if err == nil {
				body, err = ioutil.ReadAll(zr)
				if !consumeError(&err) {
					return dumpError(err)
				}
			}
		} else {
			body, err = ioutil.ReadAll(resp.Body)
			if !consumeError(&err) {
				return dumpError(err)
			}
		}
	}

	w.Header().Del("Content-Length")
	w.Header().Set("Content-Encoding", "gzip")
	w.WriteHeader(resp.StatusCode)

	if len(body) <= 0 {
		return
	}

	var (
		rules           []ReRule
		bodyExtraHeader string
	)

	switch p {
	case HD_html:
		rules = reRules.Html
	case HD_javascript:
		rules = reRules.Js
	case HD_json:
		rules = reRules.Json
	case HD_css:
		rules = reRules.Css
	}

	if log.V(5) {
		log.Infof("Original entity %s\n%s", reqPath, string(body))
	}

	if s.abusing {
		imgSrc := fmt.Sprintf(`<img src="/!%s/sorry`, reqHost)
		body = bytes.Replace(body, []byte(`<img src="/sorry`), []byte(imgSrc), 1)
		rules = nil
	}

	for i, r := range rules {
		if r.PathRe != nil && r.PathRe.FindString(reqPath) == NULL {
			if log.V(4) {
				log.Infof("re.%d=[%s] pathRe=deny", i, r.ContentPattern.Pattern)
			}
			continue
		}
		if log.V(4) {
			log.Infof("re.%d=[%s] applied", i, r.ContentPattern.Pattern)
		}
		if r.Scheme&0xff > 0 {
			body = r.ContentRe.Replace(body, r.Replacement)
		}
		if r.Scheme&0xff00 > 0 {
			bodyExtraHeader += r.InsertHeader
		}
	}

	zw = gzip.NewWriter(w)
	if len(bodyExtraHeader) > 0 {
		zw.Write([]byte(bodyExtraHeader))
	}
	zw.Write(body)
	err = zw.Flush()
	return
}

//.........這裏部分代碼省略.........
		gzipwriter, _ = gzip.NewWriterLevel(csvfile, gzip.BestCompression)
		defer gzipwriter.Close()
		// wrap csv around gzipwriter
		diskwriter = csv.NewWriter(gzipwriter)
	} else {
		// create a diskwriter (appends to csv on disk)
		diskwriter = csv.NewWriter(csvfile)
	}

	// connect via telnet to the device and login
	conn, err := p.DialTimeout("tcp", p.device, time.Duration(time.Second*30))
	if err != nil {
		log.Fatal("can't connect")
	}

	// create http handlers
	http.HandleFunc("/quit", webQuitHandler(diskwriter, gzipwriter, csvfile))
	http.HandleFunc("/history", webHistoryHandler)
	http.HandleFunc("/stream", webStreamHandler)
	http.HandleFunc("/read.csv", webReadCsvHandler(p))
	http.HandleFunc("/read.json", webReadJsonHandler(p))

	// needed for occasionally flushing on a newline
	recordcount := 0

	// start infinite polling loop
	for {
		// measure how long it takes
		start := time.Now()

		// specify correct format for dygraph
		record := []string{start.Format("2006/01/02 15:04:05")}

		// get statistics from device and cleanup
		status := sendln(conn, plugGetInfoStats, '#')
		status = strings.Replace(status, plugGetInfoStats+"\r\n", "", 1)
		status = strings.Replace(status, "#", "", 1)
		// split up the 4 results a newline
		results := strings.SplitN(status, "\r\n", 4)

		re := regexp.MustCompile("01(I|V|W|E)[0-9]+ 0*([0-9]+)")
		// for each GetInfo result, do a regexp match, adjust value and create a CSV record
		for i, result := range results {
			match := re.FindStringSubmatch(result)
			value := "0"
			// check if we got the right size of slice
			if len(match) == 3 {
				value = match[2]
			}

			temp, _ := strconv.ParseFloat(value, 32)

			switch i {
			case 0:
				// mAmp/10 -> Amp
				value = strconv.FormatFloat(temp/10000, 'f', 2, 32)
			// centiWatt -> Watt
			case 1:
				value = strconv.FormatFloat(temp/100, 'f', 2, 32)
			// mWatt/h -> Watt/h | mVolt -> Volt
			case 2, 3:
				value = strconv.FormatFloat(temp/1000, 'f', 2, 32)
			}
			record = append(record, value)
			recordcount += 1
		}

		// latestentry is needed in JSON for the realtime streaming
		p.latestEntry, _ = json.Marshal(record)

		// write the record to disk
		err := diskwriter.Write(record)
		if err != nil {
			fmt.Println("Error:", err)
		}

		// write the record to buffer (in memory)
		err = bufferwriter.Write(record)
		if err != nil {
			fmt.Println("Error:", err)
		}

		// flush disk every 25 records
		if recordcount%100 == 0 {
			diskwriter.Flush()
			if strings.Contains(p.csvfile, ".gz") {
				gzipwriter.Flush()
			}
		}
		// flush memory immediately
		bufferwriter.Flush()

		if debug {
			fmt.Print(record)
			fmt.Println(" took", time.Since(start))
		}
		// sleep the right amount of time
		time.Sleep(time.Second*time.Duration(p.delay) - time.Since(start))
	}
}

func NewEventHandler(buildsDB BuildsDB, buildID int) http.Handler {
	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
		flusher := w.(http.Flusher)
		closed := w.(http.CloseNotifier).CloseNotify()

		w.Header().Add("Content-Type", "text/event-stream; charset=utf-8")
		w.Header().Add("Cache-Control", "no-cache, no-store, must-revalidate")
		w.Header().Add("Connection", "keep-alive")
		w.Header().Add(ProtocolVersionHeader, CurrentProtocolVersion)

		var start uint = 0
		if r.Header.Get("Last-Event-ID") != "" {
			_, err := fmt.Sscanf(r.Header.Get("Last-Event-ID"), "%d", &start)
			if err != nil {
				w.WriteHeader(http.StatusBadRequest)
				return
			}

			start++
		}

		var responseWriter io.Writer = w
		var responseFlusher *gzip.Writer

		w.Header().Add("Vary", "Accept-Encoding")
		if strings.Contains(r.Header.Get("Accept-Encoding"), "gzip") {
			w.Header().Set("Content-Encoding", "gzip")

			gz := gzip.NewWriter(w)
			defer gz.Close()

			responseWriter = gz
			responseFlusher = gz
		}

		events, err := buildsDB.GetBuildEvents(buildID, start)
		if err != nil {
			w.WriteHeader(http.StatusNotFound)
			return
		}

		defer events.Close()

		es := make(chan atc.Event)
		errs := make(chan error, 1)

		go func() {
			for {
				ev, err := events.Next()
				if err != nil {
					errs <- err
					return
				} else {
					select {
					case es <- ev:
					case <-closed:
						return
					}
				}
			}
		}()

		for {
			select {
			case ev := <-es:
				payload, err := json.Marshal(event.Message{ev})
				if err != nil {
					return
				}

				err = sse.Event{
					ID:   fmt.Sprintf("%d", start),
					Name: "event",
					Data: payload,
				}.Write(responseWriter)
				if err != nil {
					return
				}

				start++

				if responseFlusher != nil {
					err = responseFlusher.Flush()
					if err != nil {
						return
					}
				}

				flusher.Flush()
			case err := <-errs:
				if err == db.ErrEndOfBuildEventStream {
					err = sse.Event{Name: "end"}.Write(responseWriter)
					if err != nil {
						return
					}
				}

				return
			case <-closed:
				return
//.........這裏部分代碼省略.........