Returnning arbitrary data to the client

[barkanido]

Hi, In addition to signals sent to the client like logs and notifications, I need to return some custom data to the client. What is pygls api for returning, say, a nested dict? Should i return a response or there is a wrapping api fot that? What will the client expect then? A raw json? Or the languages specific desirialization of the related json?

[alcarney]

Many objects have a field like CompletionItem.data where you can store arbitrary data - which may or may not be useful to you.

Alternatively you can send custom messages to the client.

• notify is probably the easiest to get started with as it allows you to send a one off message to the client. Here is an example of a custom notification message
• However, if you need the client to reply to your message then send_request or send_request_async will handle waiting for the response for you. Here you can find examples of using those

What happens client side is ultimately up to the language and/or framework that the client is written in. In VSCode/TypeScript for example I'm able to define an interface that describes the structure of the custom message coming from the server and then reference it in the handler definition - at the lowest level though it's all JSON :)

Hope that helps!