百度贴吧纵向爬取

上一个是横向爬取的，这个纵向爬取，具体怎么做的看代码

package main

import (
    "fmt"
    "io"
    "net/http"
    "os"
    "regexp"
    "strconv"
)

func httpgetdb(url string) (result string, err error) {
    resp, err1 := http.get(url)
    if err1 != nil {
        err = err1
        return
    }
    defer resp.body.close()

    buf := make([]byte, 4096)

    for {
        n, err2 := resp.body.read(buf)
        if n == 0 {
            break
        }
        if err2 != nil && err2 != io.eof {
            err = err2
            return
        }
        result += string(buf[:n])
    }

    return
}

func save2file(idx int, filename [][]string) {
    path := "第" + strconv.itoa(idx) + "页" + ".txt"
    f, err := os.create(path)
    if err != nil {
        fmt.println("os.create err", err)
        return
    }
    defer f.close()

    n := len(filename)

    f.writestring("名称\n")
    for i := 0; i < n; i++ {
        f.writestring(filename[i][1] + "\n")
    }
}

func spiderpagedb(idx int, page chan int) {
    //  url := "https://movie.douban.com/review/best/?start=" + strconv.itoa((idx-1)*20)
    //  url := "https://movie.douban.com/annual/2018?source=navigation#" + strconv.itoa(idx-1)
    //  https://movie.douban.com/review/best/?start=20

    url := "https://tieba.baidu.com/f?kw=vue&ie=utf-8&pn=" + strconv.itoa((idx-1)*50)

    result, err := httpgetdb(url)
    if err != nil {
        fmt.println("httpget2 err", err)
        return
    }
    //  fmt.println("result=", result)
    ret := regexp.mustcompile(`<span class="tb_icon_author_rely j_replyer" title="最后回复人:(?s:(.*?))"`)
    filename := ret.findallstringsubmatch(result, -1)
    //  for _, name := range filename {
    //      fmt.println("name", name[1])
    //  }
    save2file(idx, filename)

    page <- idx
}

func towork(start, end int) {
    fmt.printf("正在爬取%d到%d页。。。\n", start, end)

    page := make(chan int)
    for i := start; i <= end; i++ {
        go spiderpagedb(i, page)
    }

    for i := start; i <= end; i++ {
        fmt.print("第%d页爬取完成\n", <-page)
    }
}

func main() {
    var start, end int
    fmt.print("请输入起始页(>=1):")
    fmt.scan(&start)
    fmt.print("请输入终止页（>=start）:")
    fmt.scan(&end)

    towork(start, end)
}