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Elixir ruby-like SecureRandom
# UPD from 2018:
# This gist was written for pre-1.0 version of Elixir and won't work on post-1.0 versions.
# You probably consider using something else!
defmodule SecureRandom do
@moduledoc """
Ruby-like SecureRandom module.
## Examples
iex> SecureRandom.base64
"xhTcitKZI8YiLGzUNLD+HQ=="
iex> SecureRandom.urlsafe_base64(4)
"pLSVJw"
"""
@default_length 16
@doc """
Returns random Base64 encoded string.
## Examples
iex> SecureRandom.base64
"rm/JfqH8Y+Jd7m5SHTHJoA=="
iex> SecureRandom.base64(8)
"2yDtUyQ5Xws="
"""
def base64(n // @default_length) when is_integer n do
random_bytes(n)
|> :base64.encode_to_string
|> to_string
end
@doc """
Returns random urlsafe Base64 encoded string.
## Examples
iex> SecureRandom.urlsafe_base64
"xYQcVfWuq6THMY_ZVmG0mA"
iex> SecureRandom.urlsafe_base64(8)
"8cN__l-6wNw"
"""
def urlsafe_base64(n // @default_length) when is_integer n do
random_bytes(n)
|> :base64.encode_to_string
|> to_string
|> String.replace(%r/[\n\=]/, "")
|> String.replace(%r/\+/, "-")
|> String.replace(%r/\//, "_")
end
@doc """
Returns random hex string.
## Examples
iex> SecureRandom.hex
"c3d3b6cdab81a7382fbbae33407b3272"
iex> SecureRandom.hex(8)
"125583e32b698259"
"""
def hex(n // @default_length) when is_integer n do
random_bytes(n)
|> bitstring_to_list
|> Enum.map(fn (x) -> integer_to_binary(x, 16) end)
|> Enum.join
|> String.downcase
end
@doc """
Returns UUID v4. Not implemented yet.
"""
def uuid do
raise NotImplemented
end
@doc """
Returns random number.
## Examples
iex> SecureRandom.random_number
0.11301116455519611
iex> SecureRandom.random_number(42)
31
iex> SecureRandom.random_number(14, 42)
18
iex> SecureRandom.random_number(14..42)
28
"""
def random_number do
:random.seed({:crypto.rand_uniform(1, 99999), :crypto.rand_uniform(1, 99999), :crypto.rand_uniform(1, 99999)})
:random.uniform
end
def random_number(x) when is_integer x do
:crypto.rand_uniform(1, x)
end
def random_number(range) when is_range range do
:crypto.rand_uniform(Range.first(range), Range.last(range))
end
def random_number(x, y) when is_integer(x) and is_integer(y) do
:crypto.rand_uniform(x, y)
end
@doc """
Returns random bytes.
## Examples
iex> SecureRandom.random_bytes
<<202, 104, 227, 197, 25, 7, 132, 73, 92, 186, 242, 13, 170, 115, 135, 7>>
iex> SecureRandom.random_bytes(8)
<<231, 123, 252, 174, 156, 112, 15, 29>>
"""
def random_bytes(n // @default_length) when is_integer n do
:crypto.strong_rand_bytes(n)
end
end
@robconery
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robconery commented Sep 30, 2015

Default args use \\ - otherwise you'll have a compilation error.

@lucidstack
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lucidstack commented Jun 7, 2016

Also, the regular expressions in urlsafe_base64 won't even make this compile. Correct version is:

  def urlsafe_base64(n // @default_length) when is_integer n do
    random_bytes(n)
    |> :base64.encode_to_string
    |> to_string
    |> String.replace(~r/[\n\=]/, "")
    |> String.replace(~r/\+/, "-")
    |> String.replace(~r/\//, "_")
  end

All in all, I discourage all future visitors from using this gist.

@Myuzu
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Author

Myuzu commented Aug 15, 2018

@lucidstack and @robconery, wow, I just saw this comments during my gists "maintenance". Guys it was naive implementation wrote for pre-1.0 version of Elixir. Since then base syntax of the language changed, so it definitely won't work on post-1.0 versions of Elixir.

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