feat: add /accounts/:address/validate endpoint

[TarikGul]

This endpoint will validate the address for the given chain.

Response

/accounts/:address/validate

{
    isValid: boolean;
    ss58: number | null
}

• isValid: Whether or not this address is valid ss58 address.
• ss58: The ss58 prefix for the address.

TODO

• Unit Tests
• Docs
• e2e Tests (Only need one test per chain). Should be a follow up PR as well to keep this clean and easily readable.

[emostov]

I think we should change this to ss58Prefix for clarity. SS58 is the name of the address format

[emostov]

And specify what happens when an address has no prefix

[TarikGul]

And specify what happens when an address has no prefix

I think any valid base58 will provide a "ss58Prefix" that we plug into checkAddressChecksum,

const ss58Length = (decoded[0] & 0b0100_0000) ? 2 : 1;
// ss58Decoded is the prefix
const ss58Decoded = ss58Length === 1
    ? decoded[0]
    : ((decoded[0] & 0b0011_1111) << 2) | (decoded[1] >> 6) | ((decoded[1] & 0b0011_1111) << 8);

so in this case do you think we should just say if the address is not valid a prefix may still be returned.

[TarikGul]

Or if we receive a non valid address we just return null for the ss58Prefix

[emostov]

should have a test for a hex value with no prefix and a ss58 value with no prefix to show it works and what the expected prefix is (null?)

[TarikGul]

Is an ss58 address with no prefix just a base58 address?

[emostov]

I think

[TarikGul]

Yea so to build on that too, every base58 address will always have a prefix as well

[emostov]

Just add a couple of the mentioned tests, maybe consider my recommendations for what we consider valid and excluding network id from response, and then I think its good to go

[TarikGul]

@dvdplm Via this comment I changed the returned error for the catch, and added a test for it.