我无法在Golang Colly的JSON数组中并排打印数据

Question

我正在使用来自亚马逊的golang colly拍照，我想将这些图片以JSON格式放入单个数组中（每个产品图像只有1个数组）。我抓取了我需要的图片，我只是JSON文件有问题。非常感谢你提前。package mainimport (    "encoding/json"    "fmt"    "io/ioutil"    "log"    "os"    "time"    "github.com/gocolly/colly")type Info struct {    ID     int      `json:"id"`    Images []string `json:"images"`}func main() {    AllInfos := make([]Info, 0)    start := time.Now()    co := colly.NewCollector(        colly.AllowedDomains("www.amazon.com", "amazon.com"),    )    // GET Images    Counter := 0    var info Info    var theArray [10]string    co.OnHTML("img[src]", func(e *colly.HTMLElement) {        imgsrc := e.Attr("src")        imgclass := e.Attr("class")        if imgsrc[0:49] == "https://images-na.ssl-images-amazon.com/images/I/" && imgclass == "" {            theArray[Counter] = imgsrc            fmt.Printf("The Array %d %v", Counter, theArray[Counter]+"\n")            Counter = Counter + 1            co.Visit(e.Request.AbsoluteURL(imgsrc))            info = Info{                Images: []string{                    theArray[0],                    theArray[1],                    theArray[2],                    theArray[3],                    theArray[4],                    theArray[5],                    theArray[6],                },            }            AllInfos = append(AllInfos, info)        }    })

Answer 1

我很难理解你想做什么，但这是我想到的：

package main

import (

    "encoding/json"

    "fmt"

    "io/ioutil"

    "log"

    "os"

    "strings"

    "time"

    "github.com/gocolly/colly"

)

type Info struct {

    ID     int      `json:"id"`

    Images []string `json:"images"`

}

func main() {

    allInfos := new(Info)

    start := time.Now()

    co := colly.NewCollector(

        colly.AllowedDomains("www.amazon.com", "amazon.com"),

    )

    // GET Images

    co.OnHTML("img[src]", func(e *colly.HTMLElement) {

        imgsrc := e.Attr("src")

        imgclass := e.Attr("class")

        if strings.HasPrefix(imgsrc, "https://images-na.ssl-images-amazon.com/images/I/") && imgclass == "" {

            fmt.Printf("The Array %d %v", len(allInfos.Images), imgsrc+"\n")

            allInfos.Images = append(allInfos.Images, imgsrc)

            co.Visit(e.Request.AbsoluteURL(imgsrc))

        }

    })

    co.Visit("https://www.amazon.com/Bluetooth-FM-Transmitter-Compatible-Smartphones/dp/B088TCSH8T/ref=sr_1_1_sspa?dchild=1&keywords=transmitter&qid=1623860482&sr=8-1-spons&psc=1&smid=A2XMGHKVCX40WB&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFGVEgxTjJLRFdLSkUmZW5jcnlwdGVkSWQ9QTAyNDE0ODkyRlNDWlAzUktPQzJSJmVuY3J5cHRlZEFkSWQ9QTA5MTkwNjgyWVUzQ0RUMTBCTEFFJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==WDY4VktWQlImd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl")

    co.OnRequest(func(r *colly.Request) {

        fmt.Println("Visiting: ", r.URL.String())

    })

    enc := json.NewEncoder(os.Stdout)

    enc.SetIndent("", " ")

    enc.Encode(allInfos)

    writeJson(allInfos)

    duration := time.Since(start)

    fmt.Println(duration.Seconds())

}

func writeJson(data *Info) {

    dataFile, err := json.MarshalIndent(data, "", " ")

    if err != nil {

        log.Println("Could not create JSON", err)

    }

    ioutil.WriteFile("stocky.json", dataFile, 0666)

}

正如@Flimzy建议的那样，我只将new附加到信息结构的自有实例中。看起来您的预期输出是包含所有图像的长度为1的切片。imagesrc

我还使用了一个来清理切片检查。这是等效的，但我认为它更干净，所以这是一个可选的更改。strings.HasPrefix

如果您还有其他问题，请告诉我。

编辑，如果您需要继续使用切片，如下所示的内容可能会起作用。从您的问题中，很难判断何时需要清除新信息：

package main

import (

    "encoding/json"

    "fmt"

    "io/ioutil"

    "log"

    "os"

    "strings"

    "time"

    "github.com/gocolly/colly"

)

type Info struct {

    ID     int      `json:"id"`

    Images []string `json:"images"`

}

func main() {

    allInfos := make([]Info, 1)

    start := time.Now()

    co := colly.NewCollector(

        colly.AllowedDomains("www.amazon.com", "amazon.com"),

    )

    // GET Images

    co.OnHTML("img[src]", func(e *colly.HTMLElement) {

        imgsrc := e.Attr("src")

        imgclass := e.Attr("class")

        if strings.HasPrefix(imgsrc, "https://images-na.ssl-images-amazon.com/images/I/") && imgclass == "" {

            fmt.Printf("The Array %d %v", len(allInfos[0].Images), imgsrc+"\n")

            allInfos[0].Images = append(allInfos[0].Images, imgsrc)

            co.Visit(e.Request.AbsoluteURL(imgsrc))

        }

    })

    co.Visit("https://www.amazon.com/Bluetooth-FM-Transmitter-Compatible-Smartphones/dp/B088TCSH8T/ref=sr_1_1_sspa?dchild=1&keywords=transmitter&qid=1623860482&sr=8-1-spons&psc=1&smid=A2XMGHKVCX40WB&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUFGVEgxTjJLRFdLSkUmZW5jcnlwdGVkSWQ9QTAyNDE0ODkyRlNDWlAzUktPQzJSJmVuY3J5cHRlZEFkSWQ9QTA5MTkwNjgyWVUzQ0RUMTBCTEFFJndpZGdldE5hbWU9c3BfYXRmJmFjdGlvbj1jbGlja1JlZGlyZWN0JmRvTm90TG9nQ2xpY2s9dHJ1ZQ==WDY4VktWQlImd2lkZ2V0TmFtZT1zcF9kZXRhaWwmYWN0aW9uPWNsaWNrUmVkaXJlY3QmZG9Ob3RMb2dDbGljaz10cnVl")

    co.OnRequest(func(r *colly.Request) {

        fmt.Println("Visiting: ", r.URL.String())

    })

    enc := json.NewEncoder(os.Stdout)

    enc.SetIndent("", " ")

    enc.Encode(allInfos)

    writeJson(allInfos)

    duration := time.Since(start)

    fmt.Println(duration.Seconds())

}

func writeJson(data []Info) {

    dataFile, err := json.MarshalIndent(data, "", " ")

    if err != nil {

        log.Println("Could not create JSON", err)

    }

    ioutil.WriteFile("stocky.json", dataFile, 0666)

}