From a39dc5e4c67ab2172bf824a7a790b1cd667c2ab3 Mon Sep 17 00:00:00 2001
From: Knut Ahlers <knut@ahlers.me>
Date: Fri, 25 Aug 2023 13:14:23 +0200
Subject: [PATCH] [templating] Add `b64urldec` and `b64urlenc` functions

Signed-off-by: Knut Ahlers <knut@ahlers.me>
---
 docs/content/configuration/templating.md | 26 +++++++++++++++++++++++
 internal/template/strings/strings.go     | 27 ++++++++++++++++++++++++
 plugins_core.go                          |  2 ++
 3 files changed, 55 insertions(+)
 create mode 100644 internal/template/strings/strings.go

diff --git a/docs/content/configuration/templating.md b/docs/content/configuration/templating.md
index b4a1335..015acd7 100644
--- a/docs/content/configuration/templating.md
+++ b/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
diff --git a/internal/template/strings/strings.go b/internal/template/strings/strings.go
new file mode 100644
index 0000000..b43a870
--- /dev/null
+++ b/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
+}
diff --git a/plugins_core.go b/plugins_core.go
index 353af84..69f8294 100644
--- a/plugins_core.go
+++ b/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