Add support mCaptcha as captcha provider (#20458)

https://mcaptcha.org/

Co-authored-by: Felipe Leopoldo Sologuren Gutiérrez <fsologureng@users.noreply.github.com>

modules/mcaptcha/mcaptcha.go

@@ -0,0 +1,27 @@
+// Copyright 2022 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package mcaptcha
+
+import (
+	"context"
+	"fmt"
+
+	"code.gitea.io/gitea/modules/setting"
+
+	"codeberg.org/gusted/mcaptcha"
+)
+
+func Verify(ctx context.Context, token string) (bool, error) {
+	valid, err := mcaptcha.Verify(ctx, &mcaptcha.VerifyOpts{
+		InstanceURL: setting.Service.McaptchaURL,
+		Sitekey:     setting.Service.McaptchaSitekey,
+		Secret:      setting.Service.McaptchaSecret,
+		Token:       token,
+	})
+	if err != nil {
+		return false, fmt.Errorf("wasn't able to verify mCaptcha: %v", err)
+	}
+	return valid, nil
+}

modules/setting/service.go

@@ -47,6 +47,9 @@ var Service = struct {
 	RecaptchaURL                            string
 	HcaptchaSecret                          string
 	HcaptchaSitekey                         string
+	McaptchaSecret                          string
+	McaptchaSitekey                         string
+	McaptchaURL                             string
 	DefaultKeepEmailPrivate                 bool
 	DefaultAllowCreateOrganization          bool
 	DefaultUserIsRestricted                 bool
@@ -133,6 +136,9 @@ func newService() {
 	Service.RecaptchaURL = sec.Key("RECAPTCHA_URL").MustString("https://www.google.com/recaptcha/")
 	Service.HcaptchaSecret = sec.Key("HCAPTCHA_SECRET").MustString("")
 	Service.HcaptchaSitekey = sec.Key("HCAPTCHA_SITEKEY").MustString("")
+	Service.McaptchaURL = sec.Key("MCAPTCHA_URL").MustString("https://demo.mcaptcha.org/")
+	Service.McaptchaSecret = sec.Key("MCAPTCHA_SECRET").MustString("")
+	Service.McaptchaSitekey = sec.Key("MCAPTCHA_SITEKEY").MustString("")
 	Service.DefaultKeepEmailPrivate = sec.Key("DEFAULT_KEEP_EMAIL_PRIVATE").MustBool()
 	Service.DefaultAllowCreateOrganization = sec.Key("DEFAULT_ALLOW_CREATE_ORGANIZATION").MustBool(true)
 	Service.DefaultUserIsRestricted = sec.Key("DEFAULT_USER_IS_RESTRICTED").MustBool(false)

modules/setting/setting.go

@@ -59,6 +59,7 @@ const (
 	ImageCaptcha = "image"
 	ReCaptcha    = "recaptcha"
 	HCaptcha     = "hcaptcha"
+	MCaptcha     = "mcaptcha"
 )
 
 // settings