51 lines
1.2 KiB
Elixir
51 lines
1.2 KiB
Elixir
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defmodule Zoeyscomputer.IdGenerator do
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@moduledoc """
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Generates URL-friendly unique IDs
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"""
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@alphabet "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
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@size 7
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@doc """
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Generates a random ID with default length of 7 characters using URL-friendly characters.
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## Examples
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iex> IdGenerator.generate()
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"f3k9m4z"
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"""
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def generate(size \\ @size) do
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alphabet_length = String.length(@alphabet)
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1..size
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|> Enum.reduce([], fn _, acc ->
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position = :rand.uniform(alphabet_length) - 1
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char = String.at(@alphabet, position)
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[char | acc]
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end)
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|> Enum.join("")
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end
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@doc """
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Generates a random ID and ensures it's unique by checking against a provided function.
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## Examples
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iex> IdGenerator.generate_unique(&MyApp.id_exists?/1)
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"x7k9m4z"
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"""
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def generate_unique(exists_fn, attempts \\ 0)
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def generate_unique(exists_fn, attempts) when attempts < 5 do
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id = generate()
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if exists_fn.(id) do
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generate_unique(exists_fn, attempts + 1)
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else
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id
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end
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end
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def generate_unique(_exists_fn, _attempts) do
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raise "Failed to generate unique ID after 5 attempts"
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end
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end
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