golang简单爬虫示例

golang最简单的爬虫示例，爬取笔者的博客列表第一页面的数据。
仅为入门练习示例。

代码如下：

package main

import (
    "encoding/json"
    "io/ioutil"
    "log"
    "net/http"
    "os"
    "regexp"
    "strconv"
    "strings"
)

// golang抓取个人博客信息
// 作为示例，只抓取第一页的数据

const (
    blogUrl        = "https://blog.csdn.net/butterfly5211314/article/list/1"
    resultFilename = "csdnCrawler/result.json"
)

var (
    forgeHeaders = map[string]string{
        `User-Agent`: `Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/68.0.3440.106 Safari/537.36`,
    }

    // regexp of link & title & type
    //
    //
    //原        
    //git常用操作(不定期更新)      
    lttRe = regexp.MustCompile(`]*>\s*]*>([^<]*)([^<]+)`)

    postTimeRe     = regexp.MustCompile(`([^<]+)`)
    readCountRe    = regexp.MustCompile(`span class="read-num">阅读数：([^<]+)`)
    commentCountRe = regexp.MustCompile(`评论数：([^<]+)`)
)

type BlogItem struct {
    Link         string // 文章详情链接
    Type         string // 文章类型： 原创， 翻译等
    Title        string // 文章标题
    PostTime     string // 发表时间
    ReadCount    int    // 阅读数
    CommentCount int    // 评论数
}

// get all contents as []byte
func fetch(url string) ([]byte, error) {
    client := http.Client{}

    req, err := http.NewRequest("GET", blogUrl, nil)

    if err != nil {
        return nil, err
    }

    // add header
    for k, v := range forgeHeaders {
        req.Header.Add(k, v)
    }

    // send request
    resp, err := client.Do(req)

    if err != nil {
        return nil, err
    }

    // defer close
    defer resp.Body.Close()

    return ioutil.ReadAll(resp.Body)
}

// parse content to slice of BlogItem
func parse(html string) []BlogItem {
    ltts := lttRe.FindAllStringSubmatch(html, -1)
    postTime := postTimeRe.FindAllStringSubmatch(html, -1)
    readCount := readCountRe.FindAllStringSubmatch(html, -1)
    commentCount := commentCountRe.FindAllStringSubmatch(html, -1)

    var blogs []BlogItem

    for i, ltt := range ltts {

        blogs = append(blogs, BlogItem{
            Link:         ltt[1],
            Type:         strings.TrimSpace(ltt[2]),
            Title:        strings.TrimSpace(ltt[3]),
            PostTime:     postTime[i][1],
            ReadCount:    field2int(readCount[i][1]),
            CommentCount: field2int(commentCount[i][1]),
        })
    }

    return blogs
}

// string to int
func field2int(s string) int {
    ret, err := strconv.Atoi(s)
    if err != nil {
        ret = 0
    }

    return ret
}

func write2file(filename string, contents []byte) error {
    _, err := os.Stat(filename)
    if err == nil {
        log.Printf("file %s is existed, it will be truncated", filename)
    }
    return ioutil.WriteFile(filename, contents, 666)
}

func start() {
    contents, err := fetch(blogUrl)

    if err != nil {
        panic(err)
    }

    items := parse(string(contents))
    bytes, err := json.MarshalIndent(items, "", "    ")

    if err != nil {
        log.Printf("json error: %v", err)
        return
    }

    err = write2file(resultFilename, bytes)

    if err != nil {
        log.Printf("write2file error: %v", err)
        return
    }

    log.Printf("done!")
}

func main() {
    start()
}

抓取结果：

---

欢迎补充指正！