notifier: add support for 'attach' property

Signed-off-by: Pieter Willekens <me@pataar.nl>

docs/configuration.md

@@ -1686,7 +1686,7 @@ Enables the notification service. Multiple "notifiers" may be configured,
 each with their own section, ie: `[notifier my_discord_server]`, `[notifier my_phone]`.
 
 All notifiers require an url for a service to be set up. Moonraker uses [Apprise](https://github.com/caronc/apprise) internally.
-You can find the available services and their corresponding urls here: https://github.com/caronc/apprise/wiki.
+You can find the available services and their corresponding urls here: [https://github.com/caronc/apprise/wiki](https://github.com/caronc/apprise/wiki).
 
 ```ini
 # moonraker.conf
@@ -1708,7 +1708,10 @@ body: "Your printer status has changed to {event_name}"
 #   the arguments that came with it.
 title:
 #   The optional title of the notification. Just as the body, this option accepts Jinja2 templates.
-
+attach:
+#   An optional attachment. Can be an url of a webcam for example. Note: this isn't available for all
+#   notification services. You can check if it's supported on the Apprise Wiki. Be aware that links in
+#   your internal network can only be viewed within your network.
 ```
 
 #### An example:
@@ -1720,6 +1723,17 @@ url: tgram://{bottoken}/{ChatID}
 events: started
 body: Your printer started printing '{event_args[1].filename}'
 
+[notifier print_completed]
+url: tgram://{bottoken}/{ChatID}
+events: completed
+body: Your printer completed printing '{event_args[1].filename}'
+attach: http://192.168.1.100/webcam/?action=snapshot
+
+[notifier print_error]
+url: tgram://{bottoken}/{ChatID}
+events: error
+body: {event_args[1].message}
+attach: http://192.168.1.100/webcam/?action=snapshot
 ```
 
 ## Jinja2 Templates

moonraker/components/notifier.py

@@ -17,6 +17,7 @@ from typing import (
     Dict,
     Any,
     List,
+    Union,
 )
 
 if TYPE_CHECKING:
@@ -112,6 +113,14 @@ class NotifierInstance:
         self.server = config.get_server()
         self.name = name_parts[1]
         self.apprise = apprise.Apprise()
+        self.warned = False
+
+        self.attach_requires_file_system_check = True
+        self.attach = config.get("attach", None)
+        if self.attach is None or \
+            (self.attach.startswith("http://") or
+             self.attach.startswith("https://")):
+            self.attach_requires_file_system_check = False
 
         url_template = config.gettemplate('url')
         self.url = url_template.render()
@@ -139,9 +148,23 @@ class NotifierInstance:
             event_name if self.body is None else self.body.render(context)
         )
 
+        # Verify the attachment
+        if self.attach_requires_file_system_check and self.attach is not None:
+            fm = self.server.lookup_component("file_manager")
+            if not fm.can_access_path(self.attach):
+                if not self.warned:
+                    self.server.add_warning(
+                        f"Attachment of notifier '{self.name}' is not "
+                        "valid. The location of the "
+                        "attachment is not "
+                        "accessible.")
+                    self.warned = True
+                self.attach = None
+
         await self.apprise.async_notify(
             rendered_body.strip(),
-            rendered_title.strip()
+            rendered_title.strip(),
+            attach=self.attach
         )
 
     def get_name(self) -> str: