Add support for URL previews in matrix-rust-sdk

[satrujit11]

Description

We need to add support for URL previews in the matrix-rust-sdk, specifically using the matrix_sdk::ruma::api::client::media::get_media_preview endpoint. URL previews are essential for clients like Fractal, and these previews should be handled server-side as per the Matrix specification.

The API should handle two different endpoints, depending on the Matrix version supported by the homeserver (similar to how get_media_content works). This ensures backward compatibility with older versions of the Matrix protocol.

Requirements

• Implement API support for URL previews using the get_media_preview endpoint.
• Handle compatibility with multiple Matrix versions by supporting both relevant endpoints (similar to how get_media_content is handled).
• Ensure that URL previews are done server-side, not client-side, as specified by the Matrix protocol.

Additional Context

This feature is important for integrating URL preview functionality into Fractal, so it would be ideal to implement the API in the matrix-rust-sdk first and then use it within Fractal. This ensures a proper and standardized implementation of URL previews.

Thanks @afranke for the help with this suggestion.

[satrujit11]

Hi Everyone,

I am currently working on a binding for the get_media_preview functionality. I will be utilizing two endpoints: api::client::authenticated_media::get_media_preview and api::client::media::get_media_preview depending oon the matrix version.

My plan is to handle the extraction of URLs from messages using the SDK. Then, I will use the API to get previews for one or more links and send that information back in a single call.

Could you please advise whether I should use regex for URL extraction, or are there specific methods or crates available in the codebase that would be more appropriate?

Additionally, I welcome any suggestions regarding the path I intend to follow.

Thank you!