add receive and send link prototype

[windmemory]

See #1539

[huan]

Thanks for the PR.

However, please move all the discussion to an issue before you create a PR, and only keep the issue number in the PR content, which I think it's better to show what's happened in the CHANGELOG.

[windmemory]

Got it, will create issue next time.

[huan]

Thanks for the prototyping.

I had added a new class named UrlLink and it should be used for sending/receiving Url Type Messages.

Merged.

[windmemory]

It seems like the current design for UrlLink is that, once the link is created, the content(title, description, url, thumbnail url) can not be modified. Can we make the properties modifiable? I think people might want to have control on that.

[huan]

The best practice is to keep the date immutable as possible as we can.

If you want to change those values, you can do that by creating a new UrlLink.

Or could you provide a scenario that can prove we have to support mutation?

[windmemory]

But even create a new UrlLink, the title, thumbnailurl and description is immutable.

I think either we support modifying the link or creating new UrlLink with full control.

I can not come up with use cases modifying the UrlLink, but create a customize link should be common scenario.

What do you think?

[huan]

Please file another issue for this immutable discuss because this is a closed PR, and let's track it more clear.

[windmemory]

Okay, issue created: #1541