Files
SamWaf/wafenginecore/content_encoding.go
T
2026-03-31 13:48:00 +08:00

307 lines
9.6 KiB
Go

package wafenginecore
import (
"SamWaf/common/zlog"
"SamWaf/utils"
"bufio"
"bytes"
"compress/flate"
"compress/gzip"
"errors"
"fmt"
"github.com/andybalholm/brotli"
"github.com/klauspost/compress/zstd"
"golang.org/x/net/html/charset"
"golang.org/x/text/encoding"
"golang.org/x/text/encoding/simplifiedchinese"
"golang.org/x/text/encoding/unicode"
"golang.org/x/text/transform"
"io"
"net/http"
"strings"
)
// 返回内容前依据情况进行返回压缩数据
func (waf *WafEngine) compressContent(res *http.Response, isStaticAssist bool, inputBytes []byte, encodeType string) (respBytes []byte, err error) {
// 如果是静态资源响应或资源类型请求,直接返回原始内容
if isStaticAssist {
return inputBytes, errors.New("静态资源或资源类型请求,跳过编码转换")
}
// 首先检查Content-Type头中是否明确指定了字符集
contentType := res.Header.Get("Content-Type")
var encodedBytes []byte = inputBytes
charsetName := encodeType
// 如果Content-Type中指定了字符集,需要将UTF-8编码的内容转换回原始编码
if charsetName == "" && strings.Contains(contentType, "charset=") {
parts := strings.Split(contentType, ";")
for _, part := range parts {
part = strings.TrimSpace(part)
if strings.HasPrefix(part, "charset=") {
charsetName = strings.TrimPrefix(part, "charset=")
charsetName = strings.Trim(charsetName, `"'`)
break
}
}
}
// 根据字符集进行编码转换
if charsetName != "" && !strings.EqualFold(charsetName, "utf-8") && !strings.EqualFold(charsetName, "utf8") {
switch strings.ToLower(charsetName) {
case "gbk", "gb2312":
// 将UTF-8转换为GBK
encoder := simplifiedchinese.GBK.NewEncoder()
encodedBytes, err = encoder.Bytes(inputBytes)
if err != nil {
zlog.Warn("编码转换失败(UTF-8 -> GBK): %v", err)
// 转换失败时使用原始UTF-8内容
encodedBytes = inputBytes
}
// 可以根据需要添加其他编码的支持
default:
zlog.Debug("不支持的字符集编码转换: %s,保持UTF-8编码", charsetName)
}
}
// 根据Content-Encoding进行压缩
switch res.Header.Get("Content-Encoding") {
case "gzip":
respBytes, err = utils.GZipEncode(encodedBytes)
case "deflate":
respBytes, err = utils.DeflateEncode(encodedBytes)
case "br":
respBytes, err = utils.BrotliEncode(encodedBytes)
case "zstd":
respBytes, err = utils.ZstdEncode(encodedBytes)
default:
respBytes = encodedBytes
}
return
}
// 获取原始内容
func (waf *WafEngine) getOrgContent(resp *http.Response, isStaticAssist bool, defaultEncoding string) (cntBytes []byte, encodeType string, err error) {
bodyBytes, err := io.ReadAll(resp.Body)
if err != nil {
return bodyBytes, "", fmt.Errorf("读取原始响应体失败: %v", err)
}
charsetNameFinal := ""
// 重新设置响应体,以便后续处理
resp.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
// 如果是静态资源响应或资源类型请求,直接返回原始内容
if isStaticAssist {
return bodyBytes, "", errors.New("静态资源或资源类型请求,跳过编码转换")
}
// 根据内容编码处理压缩
var bodyReader io.Reader
switch resp.Header.Get("Content-Encoding") {
case "gzip":
gzipReader, gzipErr := gzip.NewReader(resp.Body)
if gzipErr != nil {
zlog.Warn("gzip解压失败: %v", gzipErr)
// 失败时返回错误
return bodyBytes, "", fmt.Errorf("gzip解压失败: %v", gzipErr)
}
bodyReader = gzipReader
defer gzipReader.Close()
case "deflate":
deflateReader := flate.NewReader(resp.Body)
bodyReader = deflateReader
defer deflateReader.Close()
case "br":
brotliReader := brotli.NewReader(resp.Body)
bodyReader = brotliReader
case "zstd":
zstdReader, zstdErr := zstd.NewReader(resp.Body)
if zstdErr != nil {
zlog.Warn("zstd解压失败: %v", zstdErr)
return bodyBytes, "", fmt.Errorf("zstd解压失败: %v", zstdErr)
}
bodyReader = zstdReader
defer zstdReader.Close()
default:
bodyReader = resp.Body
}
// 创建缓冲读取器
bufReader := bufio.NewReader(bodyReader)
// 首先检查Content-Type头中是否明确指定了字符集
contentType := resp.Header.Get("Content-Type")
var currentEncoding encoding.Encoding
if defaultEncoding != "" {
switch strings.ToLower(defaultEncoding) {
case "utf-8", "utf8":
currentEncoding = unicode.UTF8
charsetNameFinal = "utf-8"
break
case "gbk", "gb2312":
currentEncoding = simplifiedchinese.GBK
charsetNameFinal = "gbk"
break
default:
}
} else if strings.Contains(contentType, "charset=") {
charsetName := ""
parts := strings.Split(contentType, ";")
for _, part := range parts {
part = strings.TrimSpace(part)
if strings.HasPrefix(part, "charset=") {
charsetName = strings.TrimPrefix(part, "charset=")
charsetName = strings.Trim(charsetName, `"'`)
break
}
}
// 如果找到了字符集
if charsetName != "" {
zlog.Debug("从Content-Type中检测到字符集: %s", charsetName)
switch strings.ToLower(charsetName) {
case "utf-8", "utf8":
currentEncoding = unicode.UTF8
charsetNameFinal = "utf-8"
break
case "gbk", "gb2312":
currentEncoding = simplifiedchinese.GBK
charsetNameFinal = "gbk"
break
default:
currentEncoding = nil // 使用自动检测
}
}
}
// 如果没有从Content-Type中获取到编码或获取的编码不支持,则使用自动检测
if currentEncoding == nil {
// 增加检测字节数到1024,提高准确性
peekBytes, peekErr := bufReader.Peek(1024)
if peekErr != nil && peekErr != io.EOF {
return bodyBytes, "", errors.New(fmt.Sprintf("编码检测错误,Peek失败: %v", peekErr))
} else {
// 先尝试用系统自带的自动检测
detectedEncoding, name, certain := charset.DetermineEncoding(peekBytes, contentType)
if !certain {
// 自动检测不确定时,尝试从HTML头部meta标签或DOCTYPE中提取编码
htmlHead := string(peekBytes)
metaCharset := ""
// 1. 检查meta标签
metaIdx := strings.Index(strings.ToLower(htmlHead), "charset=")
if metaIdx != -1 {
// 提取charset=后面的内容
substr := htmlHead[metaIdx+8:]
// 只取等号后面第一个非字母数字下划线的内容
for i, c := range substr {
if !(c == '-' || c == '_' || (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z') || (c >= '0' && c <= '9')) {
metaCharset = substr[:i]
break
}
}
if metaCharset == "" {
metaCharset = substr
}
metaCharset = strings.Trim(metaCharset, "\"' />")
}
// 2. 检查DOCTYPE声明
if metaCharset == "" && strings.Contains(htmlHead, "xhtml1-transitional.dtd") {
// XHTML 1.0 通常默认utf-8或iso-8859-1
metaCharset = "utf-8"
}
if metaCharset != "" {
zlog.Debug("通过HTML头部meta/doctype辅助检测到字符集: %s", metaCharset)
switch strings.ToLower(metaCharset) {
case "utf-8", "utf8":
currentEncoding = unicode.UTF8
charsetNameFinal = "utf-8"
break
case "gbk", "gb2312":
currentEncoding = simplifiedchinese.GBK
charsetNameFinal = "gbk"
break
default:
zlog.Debug("meta标签检测到未知字符集: %s,保持UTF-8", metaCharset)
return bodyBytes, "", errors.New(fmt.Sprintf("编码检测不确定,且未能从HTML头部meta/doctype提取到编码"))
}
} else {
return bodyBytes, "", errors.New(fmt.Sprintf("编码检测不确定,且未能从HTML头部meta/doctype提取到编码"))
}
} else {
zlog.Debug("编码检测确定为: %s", name)
currentEncoding = detectedEncoding
}
}
}
// 使用检测到的编码创建转换读取器
reader := transform.NewReader(bufReader, currentEncoding.NewDecoder())
// 读取全部内容
resBodyBytes, readErr := io.ReadAll(reader)
if readErr != nil {
zlog.Warn("读取响应体失败: %v", readErr)
return bodyBytes, "", fmt.Errorf("读取响应体失败: %v", readErr)
}
return resBodyBytes, charsetNameFinal, nil
}
// 处理请求的Content-Encoding解压
func (waf *WafEngine) decompressRequestContent(req *http.Request) ([]byte, error) {
if req.Body == nil || req.Body == http.NoBody {
return nil, nil
}
// 读取原始请求体
bodyBytes, err := io.ReadAll(req.Body)
if err != nil {
return nil, fmt.Errorf("读取请求体失败: %v", err)
}
// 重新设置请求体
req.Body = io.NopCloser(bytes.NewBuffer(bodyBytes))
// 根据Content-Encoding进行解压
var bodyReader io.Reader
switch req.Header.Get("Content-Encoding") {
case "gzip":
gzipReader, gzipErr := gzip.NewReader(bytes.NewReader(bodyBytes))
if gzipErr != nil {
zlog.Warn("请求gzip解压失败: %v", gzipErr)
return bodyBytes, fmt.Errorf("请求gzip解压失败: %v", gzipErr)
}
bodyReader = gzipReader
defer gzipReader.Close()
case "deflate":
deflateReader := flate.NewReader(bytes.NewReader(bodyBytes))
bodyReader = deflateReader
defer deflateReader.Close()
case "br":
brotliReader := brotli.NewReader(bytes.NewReader(bodyBytes))
bodyReader = brotliReader
case "zstd":
zstdReader, zstdErr := zstd.NewReader(bytes.NewReader(bodyBytes))
if zstdErr != nil {
zlog.Warn("请求zstd解压失败: %v", zstdErr)
return bodyBytes, fmt.Errorf("请求zstd解压失败: %v", zstdErr)
}
bodyReader = zstdReader
defer zstdReader.Close()
default:
// 没有压缩或不支持的压缩格式,直接返回原始内容
return bodyBytes, nil
}
// 读取解压后的内容
decompressedBytes, readErr := io.ReadAll(bodyReader)
if readErr != nil {
zlog.Warn("读取解压后的请求体失败: %v", readErr)
return bodyBytes, fmt.Errorf("读取解压后的请求体失败: %v", readErr)
}
return decompressedBytes, nil
}