WIP

Author: Snawoot

cmd/main.go

@@ -4,12 +4,13 @@ import (
 	"bufio"
 	"bytes"
 	"encoding/hex"
-	"errors"
 	"flag"
 	"fmt"
 	"io"
 	"log"
 	"os"
+
+	"github.com/SenseUnit/basic_hmac_auth/handler"
 )
 
 var version = "undefined"
@@ -52,8 +53,8 @@ func run() int {
 	}
 
 	if hs == "" {
-		log.Print(`secret is not specified! Please set "-secret" or "-secret-file"`+
-		` command line options or `+envKeySecret+` environment variable.`)
+		log.Print(`secret is not specified! Please set "-secret" or "-secret-file"` +
+			` command line options or ` + envKeySecret + ` environment variable.`)
 		return 2
 	}
 
@@ -63,8 +64,13 @@ func run() int {
 		return 3
 	}
 
-	log.Printf("secret=%x\n", secret)
-
+	err = (&handler.BasicHMACAuthHandler{
+		Secret: secret,
+	}).Run(os.Stdin, os.Stdout)
+	if err != nil {
+		log.Printf("auth handler terminated with error: %v", err)
+		return 1
+	}
 	return 0
 }
 
@@ -77,7 +83,7 @@ func readSecretFromFile(filename string) (string, error) {
 
 	rd := bufio.NewReader(f)
 	buf, err := rd.ReadBytes('\n')
-	if err != nil && !errors.Is(err, io.EOF) {
+	if err != nil && err != io.EOF {
 		return "", fmt.Errorf("secret file reading failed: %w", err)
 	}
 

handler/handler.go

@@ -0,0 +1,34 @@
+package handler
+
+import (
+	"bufio"
+	"io"
+	"log"
+
+	"github.com/SenseUnit/basic_hmac_auth/proto"
+)
+
+const (
+	// Sufficient for anything what might come from 64KB basic auth header
+	DefaultBufferSize = 150 * 1024
+)
+
+type BasicHMACAuthHandler struct {
+	Secret     []byte
+	BufferSize int
+}
+
+func (a *BasicHMACAuthHandler) Run(input io.Reader, output io.Writer) error {
+	bufSize := a.BufferSize
+	if bufSize <= 0 {
+		bufSize = DefaultBufferSize
+	}
+	rd := bufio.NewReaderSize(input, bufSize)
+	scanner := proto.NewElasticLineScanner(rd, '\n')
+
+	for scanner.Scan() {
+		log.Printf("line=%q", string(scanner.Bytes()))
+	}
+
+	return scanner.Err()
+}

proto/scanner.go

@@ -0,0 +1,55 @@
+package proto
+
+import "io"
+
+type BytesReader interface {
+	ReadBytes(byte) ([]byte, error)
+}
+
+type ElasticLineScanner struct {
+	line    []byte
+	reader  BytesReader
+	lastErr error
+	done    bool
+	delim   byte
+}
+
+func NewElasticLineScanner(reader BytesReader, delim byte) *ElasticLineScanner {
+	return &ElasticLineScanner{
+		reader: reader,
+		delim:  delim,
+	}
+}
+
+func (els *ElasticLineScanner) Err() error {
+	if els.lastErr == io.EOF {
+		return nil
+	}
+	return els.lastErr
+}
+
+func (els *ElasticLineScanner) Bytes() []byte {
+	return els.line
+}
+
+func (els *ElasticLineScanner) Scan() bool {
+	if els.done {
+		return false
+	}
+
+	data, err := els.reader.ReadBytes(els.delim)
+	if err != nil {
+		els.done = true
+		els.lastErr = err
+		if len(data) == 0 {
+			return false
+		}
+	} else {
+		// strip delimiter if needed
+		if len(data) > 0 && data[len(data)-1] == els.delim {
+			data = data[:len(data)-1]
+		}
+	}
+	els.line = data
+	return true
+}