Add validation of CID in Subdomains

[lidel]

(Parent issues: ipfs/ipfs-companion#526, ipfs/in-web-browsers#89, https://github.com/ipfs/ipfs/issues/337)

This PR adds below utility methods:

isIPFS.multibase('bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va') // 'base32'
isIPFS.multibase('zdj7WWeQ43G6JJvLWQWZpyHuAMq6uYWRjkBXFad11vE2LHhQ7') // 'base58btc'
isIPFS.multibase('QmYjtig7VJQ6XsnUjqqJvj7QaMcCAwtrgNdahSiFofrE7o') // false (no multibase prefix in CIDv0)
isIPFS.multibase('noop') // false

isIPFS.base32cid('bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va') // true
isIPFS.base32cid('QmYjtig7VJQ6XsnUjqqJvj7QaMcCAwtrgNdahSiFofrE7o') // false

isIPFS.subdomain('http://bafybeiabc2xofh6tdi6vutusorpumwcikw3hf3st4ecjugo6j52f6xwc6q.ipns.dweb.link') // true
isIPFS.subdomain('http://www.bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va.ipfs.dweb.link') // false
isIPFS.subdomain('http://bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va.dweb.link') // false

isIPFS.ipfsSubdomain('http://bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va.ipfs.dweb.link') // true
isIPFS.ipfsSubdomain('http://bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va.dweb.link') // false

isIPFS.ipnsSubdomain('http://bafybeiabc2xofh6tdi6vutusorpumwcikw3hf3st4ecjugo6j52f6xwc6q.ipns.dweb.link') // true
isIPFS.ipnsSubdomain('http://bafybeiabc2xofh6tdi6vutusorpumwcikw3hf3st4ecjugo6j52f6xwc6q.dweb.link') // false
isIPFS.ipnsSubdomain('http://QmcNioXSC1bfJj1dcFErhUfyjFzoX2HodkRccsFFVJJvg8.ipns.dweb.link') // false
isIPFS.ipnsSubdomain('http://foo-bar.ipns.dweb.link') // false (not a PeerID)

• Closes Detect CID in Subdomains #19 (and Closes Should be part of the IPFS org + needs a Lead Maintainer + needs to have Jenkins run. #17)
• Subdomain validation follows FQDN convention of cidv1b32.ip(f|n)s.domain.tld suggested in Detect CID in subdomains ipfs/ipfs-companion#526 (comment)
• IPNS support is limited to PeerID represented as cidv1b32
  • (not sure how to represent dnslink, reverse notation makes little sense, so we don't allow it in subdomains for now)
• Subdomain checks are not included in already existing isIPFS.url on purpose.
  People already use it and we don't want to change its meaning, because isIPFS.url == true means it is safe to take URLs pathname as-is, which is not the case when subdomain is used.
• I think we will have a separate isIPFS.nativeUrl for ipfs:// for the same reason
  • .. and a catch-all check (path || url || subdomain || nativeUrl) could be named isIPFS.any

cc @lgierth @kyledrake – thoughts?
(We need this for Companion to support cidv1b32 and subdomains, and I want to ship it before DWEB)

[alanshaw]

Super cool. Really nice to see this module getting some ❤️

[alanshaw]

This feels out of place to me. The rest of the API returns true/false. This is a simple call-through to multibase.isEncoded.

[lidel]

Should it be changed to true/false or just removed? Not sure how useful it is, maybe just remove it?
(I think I've added it only because isIPFS.base32cid introduced multibase as a dependency)

[alanshaw]

Personally, I'd remove it. I considered that isIPFS.base32cid uses multibase as a dependency, and was thinking of suggesting to check like:

typeof cid === 'string' && cid.slice(0, 4) === 'bafy' && isCID(cid)

...but js-cid depends on multibase so you're not saving any bundle bytes by depending on it and using it.

[alanshaw]

Is this true for http://bafybeie5gq4jxvzmsym6hjlwxej4rwdoxt7wadqvmmwbqi7r27fclha2va.ipfs.dweb.link also? Maybe add an example here :D

[lidel]

@alanshaw removed multibase, Jenkins works as expected. Ok to merge?

[alanshaw]

You still depend directly on multibase - it should be in dependencies

[fsdiogo]

...that provides...

[fsdiogo]

As you're calling (ipfsSubdomain || ipnsSubdomain), you should declare them before the module.exports. That way if any of those change, you won't need to change that code in two places.

To make things clearer:

const ipfsSubdomain = (url) => isIpfs(url, fqdnPattern, fqdnProtocolMatch, fqdnHashMatch)
const ipnsSubdomain = (url) => isIpns(url, fqdnPattern, fqdnProtocolMatch, fqdnHashMatch)

module.exports = {
	multihash: isMultihash,
	cid: isCID,
	base32cid: (cid) => (isMultibase(cid) === 'base32' && isCID(cid)),
	ipfsSubdomain: ipfsSubdomain,
	ipnsSubdomain: ipnsSubdomain,
	subdomain: (url) => (ipfsSubdomain(url) || ipnsSubdomain(url)),
	...
}