[templating] Add b64urldec and b64urlenc functions

Signed-off-by: Knut Ahlers <knut@ahlers.me>

docs/content/configuration/templating.md

@@ -47,6 +47,32 @@ Example:
 < @tester please refrain from BSG
 ```
 
+### `b64urldec`
+
+Decodes the input using base64 URL-encoding (like `b64dec` but using `URLEncoding` instead of `StdEncoding`)
+
+Syntax: `b64urldec <input>`
+
+Example:
+
+```
+# {{ b64urldec "bXlzdHJpbmc=" }}
+< mystring
+```
+
+### `b64urlenc`
+
+Encodes the input using base64 URL-encoding (like `b64enc` but using `URLEncoding` instead of `StdEncoding`)
+
+Syntax: `b64urlenc <input>`
+
+Example:
+
+```
+# {{ b64urlenc "mystring" }}
+< bXlzdHJpbmc=
+```
+
 ### `botHasBadge`
 
 Checks whether bot has the given badge in the current channel

internal/template/strings/strings.go

@@ -0,0 +1,27 @@
+package strings
+
+import (
+	"encoding/base64"
+
+	"github.com/pkg/errors"
+
+	"github.com/Luzifer/twitch-bot/v3/plugins"
+)
+
+func Register(args plugins.RegistrationArguments) error {
+	args.RegisterTemplateFunction("b64urlenc", plugins.GenericTemplateFunctionGetter(base64URLEncode))
+	args.RegisterTemplateFunction("b64urldec", plugins.GenericTemplateFunctionGetter(base64URLDecode))
+	return nil
+}
+
+func base64URLEncode(v string) string {
+	return base64.URLEncoding.EncodeToString([]byte(v))
+}
+
+func base64URLDecode(v string) (string, error) {
+	data, err := base64.URLEncoding.DecodeString(v)
+	if err != nil {
+		return "", errors.Wrap(err, "decoding string")
+	}
+	return string(data), nil
+}

plugins_core.go

@@ -46,6 +46,7 @@ import (
 	"github.com/Luzifer/twitch-bot/v3/internal/template/numeric"
 	"github.com/Luzifer/twitch-bot/v3/internal/template/random"
 	"github.com/Luzifer/twitch-bot/v3/internal/template/slice"
+	"github.com/Luzifer/twitch-bot/v3/internal/template/strings"
 	"github.com/Luzifer/twitch-bot/v3/internal/template/subscriber"
 	"github.com/Luzifer/twitch-bot/v3/pkg/database"
 	"github.com/Luzifer/twitch-bot/v3/pkg/twitch"
@@ -90,6 +91,7 @@ var (
 		numeric.Register,
 		random.Register,
 		slice.Register,
+		strings.Register,
 		subscriber.Register,
 
 		// API-only modules