examples: fix (2022-03)

[maiha]

Let's catch up examples before Crystal 1.4 😃

• checker: https://github.com/maiha/crystal-examples
• compiler: Crystal 1.4.0-dev [458595f] (2022-03-23)
• last commit: 458595f

Best regards,

[maiha]

Also, there is an error in crypto/bcrypt, but I don't know how to fix it, so I am leaving it alone.
https://github.com/crystal-lang/crystal/blob/master/src/crypto/bcrypt.cr#L69

require "crypto/bcrypt"
password = Crypto::Bcrypt.new "secret", "salt_of_16_chars"

Unhandled exception: Invalid salt size (Crypto::Bcrypt::Error)
  from crystal/src/crypto/bcrypt.cr:93:5 in 'initialize'
  from crystal/src/crypto/bcrypt.cr:91:3 in 'new'

[straight-shoota]

The second argument needs to be a base64 encoded string that represents a byte slice with size 16.

For example:

Crypto::Bcrypt.new("secret", "AQIDBAUGBwgJCgsMDQ4PEA==") # => $2a$11$AQIDBAUGBwgJCgsMDQ4PE.jO8j7sDnyP0tyPC/HrVgzzeEvGdmSN2

[straight-shoota]

On second thought... maybe we shouldn't provide an actually working salt value in the example. I'm sure there would be people who just copy the example code and never change the salt...
In any case, the documentation should also mention the base64 encoding. So I think we need to improve that, but it's out of scope for this PR. It's fine if you leave it at the last commit or revert that. We can merge it either way and improve the documentation in a separate PR.

[Blacksmoke16]

On second thought... maybe we shouldn't provide an actually working salt value in the example.

I'd go as far as saying:

You probably want to use Crypto::Bcrypt.hash_secret instead.

given there is really no reason to supply your own salt. PHP's docs even say:

[maiha]

maybe we shouldn't provide an actually working salt value in the example

Agreed.

I want to correct only the ones that are definitely wrong, so I will leave the others as they are.

[beta-ziliani]

Thanks!