Evaluate backslash n in message content

Author: jmattheis

README.md

@@ -105,12 +105,13 @@ DESCRIPTION:
    echo my text | gotify push
 
 OPTIONS:
-   --priority value, -p value  Set the priority (default: 0)
-   --title value, -t value     Set the title (empty for app name)
-   --token value               Override the app token
-   --url value                 Override the Gotify URL
-   --quiet, -q                 Do not output anything (on success)
-   --contentType value         The content type of the message. See https://gotify.net/docs/msgextras#client-display
+   --priority value, -p value    Set the priority (default: 0)
+   --title value, -t value       Set the title (empty for app name)
+   --token value                 Override the app token
+   --url value                   Override the Gotify URL
+   --quiet, -q                   Do not output anything (on success)
+   --contentType value           The content type of the message. See https://gotify.net/docs/msgextras#client-display
+   --disable-unescape-backslash  Disable evaluating \n and \t (if set, \n and \t will be seen as a string)
 ```
 
 ## Configuration

command/push.go

@@ -16,6 +16,7 @@ import (
 	"gopkg.in/urfave/cli.v1"
 )
 
+
 func Push() cli.Command {
 	return cli.Command{
 		Name:        "push",
@@ -30,6 +31,7 @@ func Push() cli.Command {
 			cli.StringFlag{Name: "url", Usage: "Override the Gotify URL"},
 			cli.BoolFlag{Name: "quiet,q", Usage: "Do not output anything (on success)"},
 			cli.StringFlag{Name: "contentType", Usage: "The content type of the message. See https://gotify.net/docs/msgextras#client-display"},
+			cli.BoolFlag{Name: "disable-unescape-backslash", Usage: "Disable evaluating \\n and \\t (if set, \\n and \\t will be seen as a string)"},
 		},
 		Action: doPush,
 	}
@@ -39,6 +41,9 @@ func doPush(ctx *cli.Context) {
 	conf, confErr := config.ReadConfig(config.GetLocations())
 
 	msgText := readMessage(ctx)
+	if !ctx.Bool("disable-unescape-backslash") {
+		msgText = utils.Evaluate(msgText)
+	}
 
 	priority := ctx.Int("priority")
 	title := ctx.String("title")

utils/evaluate.go

@@ -0,0 +1,34 @@
+package utils
+
+import (
+	"bytes"
+	"io"
+)
+
+func Evaluate(s string) string {
+	res := bytes.NewBuffer([]byte{})
+	sourceReader := bytes.NewBufferString(s)
+	for {
+		r, _, err := sourceReader.ReadRune()
+		if err == io.EOF {
+			break
+		}
+		if r == '\\' {
+			nextRune, _, err := sourceReader.ReadRune()
+			if err == nil {
+				switch nextRune {
+				case '\\':
+					// ignore
+				case 't':
+					r = '\t'
+				case 'n':
+					r = '\n'
+				default:
+					sourceReader.UnreadRune()
+				}
+			}
+		}
+		res.WriteRune(r)
+	}
+	return res.String()
+}

utils/evaluate_test.go

@@ -0,0 +1,29 @@
+package utils
+
+import "testing"
+
+func TestEvaluate(t *testing.T) {
+	items := []struct {
+		str      string
+		expected string
+	}{
+		{str: "test\\ntest", expected: "test\ntest"},
+		{str: "test\ntest", expected: "test\ntest"},
+		{str: "test\\\\ntest", expected: "test\\ntest"},
+		{str: "\\n", expected: "\n"},
+		{str: "\\\\n\\n", expected: "\\n\n"},
+		{str: "\\n", expected: "\n"},
+		{str: "\n", expected: "\n"},
+		{str: "\\n\\thi", expected: "\n\thi"},
+		{str: "\\n\t\\n\\t\n\n", expected: "\n\t\n\t\n\n"},
+		{str: "\\\\n\\\\thallo\\\\t\\\\n", expected: "\\n\\thallo\\t\\n"},
+	}
+	for _, item := range items {
+		t.Run(item.str, func(t *testing.T) {
+			eval := Evaluate(item.str)
+			if eval != item.expected {
+				t.Fatalf("str '%s' should be evaluated to '%s' but was '%s'.", item.str, item.expected, eval)
+			}
+		})
+	}
+}