34 lines
863 B
Elixir
34 lines
863 B
Elixir
defmodule RecycledCloud.Captcha do
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# We can't use a graphical-only captcha library such as
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# https://hex.pm/packages/captcha since it would break accessibility for
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# blind people. Let's make it simple maths instead!
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# Captcha expression tuning:
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@terms 1..6
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@operands ["+", "-", "*"]
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def validate(changeset, expected_result) do
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result = Ecto.Changeset.get_field(changeset, :captcha)
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if result == expected_result do
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changeset
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else
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Ecto.Changeset.add_error(changeset, :captcha, "does not match")
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end
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end
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def generate do
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left = @terms |> Enum.random
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right = @terms |> Enum.random
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operation = @operands |> Enum.random
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text = "#{left} #{operation} #{right}"
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value = case operation do
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"+" -> left + right
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"-" -> left - right
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"*" -> left * right
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end
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{text, value}
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end
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end
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