Added JSON encoder (#21)

* Add new lines to printed error messages

* Added JSON encoder and decoder

* Fixed error handling in jsondecode.go

* Changed from json 'encode' to json 'escape'

* README.md changes - added json escaper info

README.md

@@ -25,6 +25,8 @@ Available encoders:
   b64encode         - Base64 encoder
   hexdecode         - Hex string decoder
   hexencode         - Hex string encoder
+  jsonescape        - JSON escape
+  jsonunescape      - JSON unescape
   unicodedecode     - Unicode escape string decode
   unicodeencodeall  - Unicode escape string encode (all characters)
   urldecode         - URL decode
@@ -47,6 +49,8 @@ $ echo 'what%ever'|pencode urlencode b64encode hexencode
 - Base64 decoder
 - Hex string encoder
 - Hex string decoder
+- JSON escape encoder (reserved characters)
+- JSON escape decoder
 - Unicode escape string encoder
 - Unicode escape string decoder
 - URL encoder (reserved characters)

cmd/pencode/main.go

@@ -38,14 +38,14 @@ func main() {
 	err := chain.Initialize(os.Args[1:])
 	if err != nil {
 		flag.Usage()
-		fmt.Printf("\n[!] %s", err)
+		fmt.Printf("\n[!] %s\n", err)
 		os.Exit(1)
 	}
 
 	input := readInput()
 	output, err := chain.Encode([]byte(input))
 	if err != nil {
-		fmt.Printf("  [!] %s", err)
+		fmt.Printf("  [!] %s\n", err)
 	}
 	fmt.Print(string(output))
 }

pkg/pencode/encoders.go

@@ -10,6 +10,8 @@ var availableEncoders = map[string]Encoder{
 	"b64decode":        Base64Decoder{},
 	"hexencode":        HexEncoder{},
 	"hexdecode":        HexDecoder{},
+	"jsonescape":       JSONEscaper{},
+	"jsonunescape":     JSONUnescaper{},
 	"unicodedecode":    UnicodeDecode{},
 	"unicodeencodeall": UnicodeEncodeAll{},
 	"urlencode":        URLEncoder{},

pkg/pencode/jsondecode.go

@@ -0,0 +1,24 @@
+package pencode
+
+import "encoding/json"
+
+type JSONUnescaper struct{}
+
+type JSONInput struct {
+	Input string `json:"input"`
+}
+
+func (u JSONUnescaper) Encode(input []byte) ([]byte, error) {
+	inputJson := `{"input":"` + string(input) + `"}`
+
+	var out JSONInput
+	if err := json.Unmarshal([]byte(inputJson), &out); err != nil {
+		return []byte{}, err
+	}
+
+	return []byte(out.Input), nil
+}
+
+func (u JSONUnescaper) HelpText() string {
+	return "JSON unescape"
+}

pkg/pencode/jsonencode.go

@@ -0,0 +1,25 @@
+package pencode
+
+import (
+	"bytes"
+	"encoding/json"
+)
+
+type JSONEscaper struct{}
+
+func (u JSONEscaper) Encode(input []byte) ([]byte, error) {
+	buf := &bytes.Buffer{}
+	enc := json.NewEncoder(buf)
+	enc.SetEscapeHTML(false) // prevents encoding of < and > characters
+	err := enc.Encode(string(input))
+	if err != nil {
+		return []byte{}, err
+	}
+
+	output := buf.Bytes()
+	return output[1 : len(output)-2], nil
+}
+
+func (u JSONEscaper) HelpText() string {
+	return "JSON escape"
+}