SocialPostDispatchingNotification

Published before a due post is handed to a channel’s automation, once per channel and attempt. A handler can change what is sent, for example to add campaign tags to the link, or hold the post back.

The following properties are available within the notification

Property Name	Type	Use
Target	OutgoingSocialPost	What is about to be sent to this channel.
Messages	EventMessages	Add the message to record when you cancel.
Cancel	bool	Set to true to cancel without a message.

OutgoingSocialPost has these properties:

Property Name	Type	Settable	Use
TargetId	int	No	The post’s target on this channel.
PostId	int	No	The post’s id.
ChannelKey	Guid	No	The channel.
Network	string	No	The channel’s network id, for example linkedin.
Attempt	int	No	The attempt number (0 for the first).
Text	string	Yes	The text the network receives: the channel’s own text or the main text, with the link already added for networks that take it in the text.
LinkUrl	string?	Yes	The link.
LinkTitle	string?	Yes	The link’s title.
LinkDescription	string?	Yes	The link’s description.
ImageUrl	string?	Yes	The image’s absolute public URL (a JPEG version for Instagram).
ImageAltText	string?	Yes	The image’s alt text.

Cancelling

Call CancelOperation(new EventMessage(category, message, EventMessageType.Error)). Nothing is sent, the target is Failed with the error dispatch.cancelled:<message>, and SocialPostTargetFailedNotification is published. A person can retry it later.

Rules

• LinkUrl and ImageUrl must stay absolute https URLs. If a handler leaves anything else, nothing is sent and the target is Failed with dispatch.invalid_url.
• The text is counted again after the handlers. If it no longer fits the network’s limit (see Network limits), nothing is sent and the target fails with text.too_long:<network>.
• For X, Bluesky and Mastodon, the link is already in Text. Changing LinkUrl doesn’t change it there: change Text too.
• Changes apply to what is sent this time only. They aren’t stored on the post.
• The notification runs on the background server that sends posts, outside any request.

See Extending UmbSocial for an example.