Add XEP-0070: Verifying HTTP Requests via XMPP support

[cmeng-git]

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[Flowdalic]

I usually do not add new features to stable Smack branches, so please adjust the target branch to master.

[Flowdalic]

First round of review. I think especially the manager design needs to be changed.

[Flowdalic]

Suggested change

	private final String url;
	private final URI url;

I believe this member should be of type URI.

[cmeng-git]

Can this variable be handled as a string all the ways. Otherwise need to do extract steps during xml phrase() and in toXML() method.
In aTalk app implementation, the value is used as string in prompting user to accept or reject the auth request. Do not see the need for app to access the URL directly.

[stokito]

The URI class is not intended to be in fields. So please keep as a string

[Flowdalic]

The URI class is not intended to be in fields.

Care to elaborate on that?

[stokito]

The URI class has a lot of internal fields, the object size itself is 80 bytes and each internal string adds more and more e.g. URI.create("https://github.com/igniterealtime/Smack/pull/557") took 400 bytes in memory (checked with JOL).
And the parsing itself also needs for CPU.
But there is no any logic that needs the parsed URI. We just need to show the link to a user.

[stokito]

The URI class is not intended to be in fields. So please keep as a string