isSane (line 144)

Is this trust root sane?

A trust root is sane if it is syntactically valid and it has a reasonable domain name. Specifically, the domain name must be more than one level below a standard TLD or more than two levels below a two-letter tld.

For example, '*.com' is not a sane trust root, but '*.foo.com' is. '*.co.uk' is not sane, but '*.bbc.co.uk' is.

This check is not always correct, but it attempts to err on the side of marking sane trust roots insane instead of marking insane trust roots sane. For example, 'kink.fm' is marked as insane even though it "should" (for some meaning of should) be marked sane.

This function should be used when creating OpenID servers to alert the users of the server when a consumer attempts to get the user to accept a suspicious trust root.

• return: Whether the trust root looks OK

• string $trust_root: The trust root to check