go并发版爬虫

并发版爬虫

代码实现

/crawler/main.go

package main

import (
	"learn/crawler/engine"
	"learn/crawler/scheduler"
	"learn/crawler/zhenai/parser"
)

func main() {
	e := engine.ConcurrentEngine{
		Scheduler: &scheduler.QueuedScheduler{},
		WorkerCount: 20,
	}
	e.Run(engine.Request{
		Url:       "http://www.zhenai.com/zhenghun",
		ParseFunc: parser.ParseCityList,
	})
	//测试上海单个城市
	//e.Run(engine.Request{
	//	Url:       "http://www.zhenai.com/zhenghun/shanghai",
	//	ParseFunc: parser.ParseCity,
	//})
}

/crawler/engine/simple.go

package engine

import (
	"learn/crawler/fetcher"
	"log"
)

type SimpleEngine struct {

}

func (e SimpleEngine) Run(seeds ...Request)  {
	var requests []Request
	for _, r := range seeds {
		requests = append(requests, r)
	}
	for len(requests) > 0 {
		r := requests[0]
		requests = requests[1:]

		parseResult, err := worker(r)
		if err != nil {
			continue
		}
		requests = append(requests, parseResult.Requests...)
		for _, item := range parseResult.Items{
			log.Printf("Got item %v", item)
		}
	}
}
func worker(r Request) (ParseResult, error) {
	log.Printf("Fetching %s", r.Url)
	body, err := fetcher.Fetch(r.Url)
	if err != nil {
		log.Printf("Fetcher: error" + "fetching url %s: %v", r.Url, err)
		return ParseResult{}, err
	}
	return r.ParseFunc(body), nil
}

/crawler/engine/concurrent.go

package engine

import (
	"log"
)

type ConcurrentEngine struct {
	Scheduler Scheduler
	WorkerCount int
}
type Scheduler interface {
	ReadyNotifier
	Submit(Request)
	WorkerChan() chan Request
	Run()
}
type ReadyNotifier interface {
	WorkerReady(chan Request)
}
func (e *ConcurrentEngine) Run(seeds ...Request)  {
	out := make(chan ParseResult)
	e.Scheduler.Run()

	for i := 0; i < e.WorkerCount; i++ {
		createWork(e.Scheduler.WorkerChan(), out, e.Scheduler)
	}
	for _, r := range seeds {
		e.Scheduler.Submit(r)
	}
	itemCount := 0
	for {
		result := <- out
		for _, item := range result.Items {
			log.Printf("Got item #%d: %v", itemCount, item)
			itemCount++
		}
		for _, request := range result.Requests {
			e.Scheduler.Submit(request)
		}
	}
}
func createWork(in chan Request, out chan ParseResult, ready ReadyNotifier)  {
	go func() {
		for  {
			ready.WorkerReady(in)
			request := <- in
			result, err := worker(request)
			if err != nil {
				continue
			}
			out <- result
		}
	}()
}

/crawler/engine/typers.go

package engine

type Request struct {
	Url string
	ParseFunc func([]byte) ParseResult
}
type ParseResult struct {
	Requests []Request
	Items []interface{}
}
func NilParser([]byte) ParseResult{
	return ParseResult{}
}

/crawler/fetcher/fetcher.go

package fetcher

import (
	"bufio"
	"fmt"
	"golang.org/x/net/html/charset"
	"golang.org/x/text/encoding"
	"golang.org/x/text/encoding/unicode"
	"golang.org/x/text/transform"
	"io/ioutil"
	"log"
	"net/http"
	"time"
)

var rateLimiter = time.Tick(100 * time.Millisecond)
func Fetch(url string) ([]byte, error)  {
	<- rateLimiter
	client := &http.Client{}
	req, err := http.NewRequest("GET", url, nil)
	if err != nil {
		return nil, err
	}
	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/66.0.3359.181 Safari/537.36")
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK {
		return nil, fmt.Errorf("Wrong status code: %d", resp.StatusCode)
	}
	bodyReader := bufio.NewReader(resp.Body)
	e := determineEncoding(bodyReader)
	utf8Reader := transform.NewReader(bodyReader, e.NewDecoder())
	return ioutil.ReadAll(utf8Reader)
}
func determineEncoding(r *bufio.Reader) encoding.Encoding  {
	bytes, err := r.Peek(1024)
	if err != nil {
		log.Printf("Fetcher error: %v", err)
		return unicode.UTF8
	}
	e, _, _ := charset.DetermineEncoding(bytes, "")
	return e
}

/crawler/zhenai/parser/citylist.go

package parser

import (
	"learn/crawler/engine"
	"regexp"
)

const cityListRe  = `<a href="(http://www.zhenai.com/zhenghun/[0-9a-z]+)" [^>]*>([^<]+)</a>`
func ParseCityList(contents []byte) engine.ParseResult {
	re := regexp.MustCompile(cityListRe)
	matches := re.FindAllSubmatch(contents, -1)
	result := engine.ParseResult{}
	for _, m := range matches {
		result.Items = append(result.Items, "City: "+string(m[2]))
		result.Requests = append(result.Requests, engine.Request{
			Url:       string(m[1]),
			ParseFunc: ParseCity,
		})
	}
	return result
}

/crawler/zhenai/parser/city.go

package parser

import (
	"learn/crawler/engine"
	"regexp"
)
var (
	profileRe = regexp.MustCompile(`<a href="(http://album.zhenai.com/u/[0-9]+)" [^>]*>([^<]+)</a>`)
	cityUrlRe = regexp.MustCompile(`href="(http://www.zhenai.com/zhenghun/[^"]+)"`)
)
func ParseCity(contents []byte) engine.ParseResult {
	matches := profileRe.FindAllSubmatch(contents, -1)
	result := engine.ParseResult{}
	for _, m := range matches {
		name := string(m[2])
		result.Items = append(result.Items, "User "+name)
		result.Requests = append(result.Requests, engine.Request{
			Url:       string(m[1]),
			ParseFunc: func(c []byte) engine.ParseResult {
				return ParseProfile(c, "name:"+name)
			},
		})
	}
	matches = cityUrlRe.FindAllSubmatch(contents, -1)
	for _, m := range matches {
		result.Requests = append(result.Requests, engine.Request{
			Url:       string(m[1]),
			ParseFunc: ParseCity,
		})
	}
	return result
}

/crawler/zhenai/parser/profile.go

package parser

import (
	"learn/crawler/engine"
	"learn/crawler/model"
	"regexp"
)

const all = `<div class="m-btn purple" data-v-8b1eac0c>([^<]+)</div>`
func ParseProfile(contents []byte, name string) engine.ParseResult {
	profile := model.Profile{}
	profile.User = append(profile.User, name)
	re := regexp.MustCompile(all)
	match := re.FindAllSubmatch(contents,-1)
	if match != nil {
		for _, m := range match {
			profile.User = append(profile.User, string(m[1]))
		}
	}

	result := engine.ParseResult{
		Items: []interface{}{profile},
	}
	return result
}

/crawler/model/profile.go

package model

type Profile struct {
	User []string
}

/crawler/scheduler/queued.go

package scheduler

import "learn/crawler/engine"

type QueuedScheduler struct {
	requestChan chan engine.Request
	workChan chan chan engine.Request
}

func (s *QueuedScheduler) WorkerChan() chan engine.Request {
	return make(chan engine.Request)
}

func (s *QueuedScheduler) Submit(r engine.Request) {
	s.requestChan <- r
}
func (s *QueuedScheduler) WorkerReady(w chan engine.Request){
	s.workChan <- w
}
func (s *QueuedScheduler) Run(){
	s.workChan = make(chan chan engine.Request)
	s.requestChan = make(chan engine.Request)
	go func() {
		var requestQ []engine.Request
		var workerQ []chan engine.Request
		for {
			var activeRequest engine.Request
			var activeWorker chan engine.Request
			if len(requestQ) > 0 && len(workerQ) > 0 {
				activeRequest = requestQ[0]
				activeWorker = workerQ[0]
			}
			select {
				case r := <-s.requestChan:
					requestQ = append(requestQ, r)
				case w := <-s.workChan:
					workerQ = append(workerQ, w)
				case activeWorker <- activeRequest:
					workerQ = workerQ[1:]
					requestQ = requestQ[1:]
			}
		}
	}()
}

/crawler/scheduler/simple.go

package scheduler

import "learn/crawler/engine"

type SimpleScheduler struct {
	workerChan chan engine.Request
}

func (s *SimpleScheduler) WorkerChan() chan engine.Request {
	return s.workerChan
}

func (s *SimpleScheduler) WorkerReady(chan engine.Request) {
}

func (s *SimpleScheduler) Run() {
	s.workerChan = make(chan engine.Request)
}

func (s *SimpleScheduler) Submit(r engine.Request) {
	go func() { s.workerChan <- r }()
}

完整项目

https://gitee.com/FenYiYuan/golang-cpdcrawler.git