How to solve golang crawler garbled code

With the continuous development of Internet technology, crawlers have become a very important technology. In crawler technology, the Go language crawler library is becoming more and more popular among developers.

However, when using golang to crawl, we may encounter garbled characters. So how to solve it?

First of all, it needs to be clear that the occurrence of garbled characters is caused by encoding problems. Therefore, before dealing with the garbled code problem, we first need to understand the relevant knowledge of encoding.

In golang, we usually use utf-8 encoding for data transmission and storage. During the crawler process, the data we obtain may contain data in other encoding formats, such as gbk, gb2312, etc.

So, if we do not perform encoding conversion correctly when processing data, garbled characters will appear.

So, how to perform correct encoding conversion?

The Go language provides the strings package and strconv package, which are used to handle the conversion of string and numerical type data respectively. In the crawler, we can use these two packages for encoding conversion.

Specifically, when we obtain the data, we need to first determine its encoding format. You can use the go-iconv package to help us determine the encoding format of the text.

Assuming that the obtained data encoding format is gbk, we can follow the following steps to perform encoding conversion:

1. Convert the obtained data to []byte type.

   data := []byte(获取到的数据)

2. Use the external library go-iconv to identify the encoding format.

   import "github.com/djimenez/iconv-go"
   
   utf8Data, err := iconv.ConvertString(string(data), "gbk", "utf-8")
   if err == nil {
   
    // 处理 utf8Data 数据
   
   }

In the above code, we imported the go-iconv package through import, and then used the ConvertString method to convert gbk encoding into utf-8 encoding.

Finally, we need to note that when crawling web pages, the encoding format of some websites may change dynamically, and we need to dynamically determine the encoding format. You can use regular expressions to match page content and dynamically determine the encoding format. Here is a piece of code for dynamic judgment encoding.

import (
    "golang.org/x/net/html/charset"
    "golang.org/x/text/encoding"
    "golang.org/x/text/transform"
)

// 获取网页编码
func getCharset(reader io.Reader) (e encoding.Encoding, name string, certain bool, err error) {
    result, err := bufio.NewReader(reader).Peek(1024)
    if err != nil {
        return
    }
    e, name, certain = charset.DetermineEncoding(result, "")
    return
}

// 编码转换
func convertEncoding(encodedReader io.Reader, e encoding.Encoding) io.Reader {
    if e != nil && e != encoding.Nop {
        encodedReader = transform.NewReader(encodedReader, e.NewDecoder())
    }
    return encodedReader
}

// 获取网页内容并进行编码转换
func getHtmlContent(url string) (string, error) {
    resp, err := http.Get(url)
    if err != nil {
        return "", err
    }
    defer resp.Body.Close()

    reader := bufio.NewReader(resp.Body)

    e, _, _, err := getCharset(reader)
    if err != nil {
        return "", err
    }

    utf8Reader := convertEncoding(reader, e)
    htmlContent, err := ioutil.ReadAll(utf8Reader)
    if err != nil {
        return "", err
    }

    return string(htmlContent), nil
}

In the above code, we first determine the encoding format of the web page through the DetermineEncoding method, then convert the web page content into utf-8 encoding through the NewDecoder method, and return the converted content.

Using the above method, we can solve the problem of garbled characters in the crawler.

To sum up, golang encounters garbled code problems when writing crawlers. Generally speaking, it is caused by coding problems. Solutions include using the iconv package for encoding conversion or using libraries such as go-x/net/html/charset and golang.org/x/text/encoding to dynamically determine the encoding format and convert the encoding. As long as we are proficient in these methods, we can crawl happily in golang.

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