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decoder.go
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decoder.go
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package traefiklogger
import (
"bytes"
"compress/flate"
"compress/gzip"
"compress/lzw"
"io"
"log"
)
// HTTPBodyDecoderFactory selects which decoder should run.
type HTTPBodyDecoderFactory struct {
rawDecoder *RawHTTPDecoder
gzipDecoder *GZipHTTPDecoder
compressDecoder *CompressHTTPDecoder
deflateHTTPDecoder *DeflateHTTPDecoder
}
func (f *HTTPBodyDecoderFactory) create(encoding string) HTTPBodyDecoder {
if encoding == "gzip" {
return f.gzipDecoder
}
if encoding == "compress" {
return f.compressDecoder
}
if encoding == "deflate" {
return f.deflateHTTPDecoder
}
return f.rawDecoder // identity and any unsupported encoding
}
func createHTTPBodyDecoderFactory(logger *log.Logger) *HTTPBodyDecoderFactory {
return &HTTPBodyDecoderFactory{
rawDecoder: &RawHTTPDecoder{},
gzipDecoder: &GZipHTTPDecoder{logger: logger},
compressDecoder: &CompressHTTPDecoder{logger: logger},
deflateHTTPDecoder: &DeflateHTTPDecoder{logger: logger},
}
}
// HTTPBodyDecoder a body decoder strategy.
type HTTPBodyDecoder interface {
// decodes the content
decode(content *bytes.Buffer) (string, error)
}
// RawHTTPDecoder just returns the content as-is.
type RawHTTPDecoder struct{}
func (d *RawHTTPDecoder) decode(content *bytes.Buffer) (string, error) {
return content.String(), nil
}
// GZipHTTPDecoder extracts the Lempel-Ziv coding (LZ77) with a 32-bit CRC.
type GZipHTTPDecoder struct {
logger *log.Logger
}
func (d *GZipHTTPDecoder) decode(content *bytes.Buffer) (string, error) {
gzReader, err := gzip.NewReader(content)
if err != nil {
d.logger.Printf("Failed to create gzip reader: %s", err)
return "", err
}
defer tryClose(gzReader, d.logger)
result, err := io.ReadAll(gzReader)
if err != nil {
d.logger.Printf("Failed to read gzip: %s", err)
return "", err
}
return string(result), nil
}
// CompressHTTPDecoder extracts with the Lempel-Ziv-Welch (LZW) algorithm.
type CompressHTTPDecoder struct {
logger *log.Logger
}
func (d *CompressHTTPDecoder) decode(content *bytes.Buffer) (string, error) {
reader := lzw.NewReader(content, lzw.MSB, 8)
defer tryClose(reader, d.logger)
result, err := io.ReadAll(reader)
if err != nil {
d.logger.Printf("Failed to read compress: %s", err)
return "", err
}
return string(result), nil
}
// DeflateHTTPDecoder extracts the zlib structure with the deflate compression algorithm.
type DeflateHTTPDecoder struct {
logger *log.Logger
}
func (d *DeflateHTTPDecoder) decode(content *bytes.Buffer) (string, error) {
reader := flate.NewReader(content)
defer tryClose(reader, d.logger)
result, err := io.ReadAll(reader)
if err != nil {
d.logger.Printf("Failed to read deflate: %s", err)
return "", err
}
return string(result), nil
}