Prevent incorrect HTML escaping in swagger.json (#14957)

* Prevent incorrect HTML escaping in swagger.json

Fix #14706

Signed-off-by: Andrew Thornton <art27@cantab.net>

* oops add it to the helper

Signed-off-by: Andrew Thornton <art27@cantab.net>

* try again

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: 6543 <6543@obermui.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

Makefile

 #To update swagger use: GO111MODULE=on go get -u github.com/go-swagger/go-swagger/cmd/swagger
 SWAGGER := $(GO) run -mod=vendor github.com/go-swagger/go-swagger/cmd/swagger
 SWAGGER_SPEC := templates/swagger/v1_json.tmpl
-SWAGGER_SPEC_S_TMPL := s|"basePath": *"/api/v1"|"basePath": "{{AppSubUrl}}/api/v1"|g
-SWAGGER_SPEC_S_JSON := s|"basePath": *"{{AppSubUrl}}/api/v1"|"basePath": "/api/v1"|g
+SWAGGER_SPEC_S_TMPL := s|"basePath": *"/api/v1"|"basePath": "{{AppSubUrl \| JSEscape \| Safe}}/api/v1"|g
+SWAGGER_SPEC_S_JSON := s|"basePath": *"{{AppSubUrl \| JSEscape \| Safe}}/api/v1"|"basePath": "/api/v1"|g
 SWAGGER_EXCLUDE := code.gitea.io/sdk
 SWAGGER_NEWLINE_COMMAND := -e '$$a\'
 

modules/templates/helper.go

 		},
 		"Safe":          Safe,
 		"SafeJS":        SafeJS,
+		"JSEscape":      JSEscape,
 		"Str2html":      Str2html,
 		"TimeSince":     timeutil.TimeSince,
 		"TimeSinceUnix": timeutil.TimeSinceUnix,
 	return html.EscapeString(raw)
 }
 
+// JSEscape escapes a JS string
+func JSEscape(raw string) string {
+	return template.JSEscapeString(raw)
+}
+
 // List traversings the list
 func List(l *list.List) chan interface{} {
 	e := l.Front()

routers/api/v1/api.go

 //
 //     Schemes: http, https
 //     BasePath: /api/v1
-//     Version: {{AppVer}}
+//     Version: {{AppVer | JSEscape | Safe}}
 //     License: MIT http://opensource.org/licenses/MIT
 //
 //     Consumes:

templates/swagger/v1_json.tmpl

       "name": "MIT",
       "url": "http://opensource.org/licenses/MIT"
     },
-    "version": "{{AppVer}}"
+    "version": "{{AppVer | JSEscape | Safe}}"
   },
-  "basePath": "{{AppSubUrl}}/api/v1",
+  "basePath": "{{AppSubUrl | JSEscape | Safe}}/api/v1",
   "paths": {
     "/admin/cron": {
       "get": {