Implement "sendtoname" in Qt UI

[domob1812]

This patch implements an equivalent of the "sendtoname" functionality in the Qt UI. You can now enter a name in the "Pay To" field, and have the coins sent to the address holding the name. This only works if the name is not expired and 1-25 characters long. The latter constraint is to prevent "typo squatting" on Namecoin addresses.

This may make live easier for "ordinary users" who don't like the cryptic addresses - and it can be used to tip websites or identities.

[phelixbtc]

I get a "transaction creation failed" error. But I manually merged with the Qt5 patch, maybe I got something wrong. Will give it another look.

[phelixnmc]

[regarding the namespace behaviour]

Another alternative might be to red out names without a namespace prepended.

I agree that it sendtoname should behave the same.

Options: 1.) Accept names without namespace: id/name d/name name

• easy use without namespace
• transparent to the user

2.) Translate names without namespace to id/: id/name d/name name-->id/name

• easy use without namespace
• intransparent to the user? Query box will display it correctly. Maybe query box could say: NAME HAS BEEN TRANSLATED TO id/ namespace id/name: (address)

3.) Do not accept names without namespace: id/name d/name name-->(bail)

• must always prepend namespace
• transparent to the user

One more thing: Only characters a-b0-9 should be allowed. With everything else it is too easy to trick the user. E.g. large characters or spaces at the end.

[domob1812]

Updated. Now only names with a namespace are accepted, and only with characters a-z, 0-9, dash and space (not as first or last character and not double). This is inspired by a combination of the rules for d/ and id/ names. The rule with 25 characters is gone, since addresses can't be valid names in any way due to these new rules. Ok?

[phelixbtc]

Hmm the single space in the middle still seems odd to me. But might be nice to allow "firstname lastname"...
For the record: I can create an all lower case Bitcoin address in a minute. Namecoin needs a capital M or N as first character and there still is the namespace check, though. It works now for me, too - seems my testing wallet is broken as I can not send to addresses, either. ACK

[phelixbtc]

One more thing: What about adding " or id/namecoin" to the sendcoinsentry example text?

[domob1812]

Good idea, done!

[domob1812]

Regarding single space in the middle: This is allowed according to the wiki page. (Which I created myself, but the rules for valid names were copied from the old Wiki in turn.) We could actually also allow upper-case characters for real names (like "id/Satoshi Nakamoto" similar to the previously proposed p/ namespace), but I don't think this is important for now.

[phelixbtc]

Created a forum post to get some more input on this: https://forum.namecoin.info/viewtopic.php?f=5&t=1893