defmodule Infer do
@moduledoc """
A dependency free library to infer file and MIME type by checking the [magic number](https://en.wikipedia.org/wiki/Magic_number_(programming)) signature.
An elixir adaption of the [`infer`](https://github.com/bojand/infer) rust library.
"""
defmodule Type do
defstruct [:matcher_type, :mime_type, :extension, :matcher]
@type matcher_type() :: :app | :archive | :audio | :book | :image | :font | :text
@type mime_type() :: binary()
@type extension() :: binary()
@type matcher_fun() :: (binary() -> boolean())
@type t() :: %{matcher_type: matcher_type(), mime_type: mime_type(), extension: extension(), matcher: matcher_fun()}
end
# Load matchers on compilation
@matchers Infer.Matchers.list()
@doc """
Takes the binary file contents as argument and returns the `t:Infer.Type.t/0` if the file matches one of the supported types. Returns `nil` otherwise.
## Examples
iex> binary = File.read!("test/images/sample.png")
iex> Infer.get(binary)
%Infer.Type{extension: "png", matcher: &Infer.Image.png?/1, matcher_type: :image, mime_type: "image/png"}
"""
@spec get(binary()) :: Infer.Type.t() | nil
def get(binary), do: Enum.find(@matchers, & &1.matcher.(binary))
@doc """
Same as `Infer.get/1`, but takes the file path and byte size as argument.
## Examples
iex> Infer.get_from_path("test/images/sample.png", 128)
%Infer.Type{extension: "png", matcher: &Infer.Image.png?/1, matcher_type: :image, mime_type: "image/png"}
iex> Infer.get_from_path("test/docs/sample.pptx")
%Infer.Type{extension: "pptx", matcher: &Infer.Doc.pptx?/1, matcher_type: :doc, mime_type: "application/vnd.openxmlformats-officedocument.presentationml.presentation"}
iex> Infer.get_from_path("test/docs/unknown.path")
nil
"""
@spec get_from_path(binary()) :: Infer.Type.t() | nil
def get_from_path(path, byte_size \\ 2048) do
result = File.open(path, [:binary, :read], fn io_device ->
case IO.binread(io_device, byte_size) do
binary when is_binary(binary) -> Enum.find(@matchers, & &1.matcher.(binary))
_other -> nil
end
end)
case result do
{:ok, %Infer.Type{} = type} -> type
_other -> nil
end
end
@doc """
Takes the binary content and the file extension as arguments. Returns whether the file content is
of the given extension.
## Examples
iex> binary = File.read!("test/images/sample.png")
iex> Infer.is?(binary, "png")
true
"""
@spec is?(binary(), Infer.Type.extension()) :: boolean()
def is?(binary, extension), do: Enum.any?(@matchers, &(&1.extension == extension && &1.matcher.(binary)))
@doc """
Takes the binary content and the file extension as arguments. Returns whether the file content is
of the given mime type.
## Examples
iex> binary = File.read!("test/images/sample.png")
iex> Infer.mime?(binary, "image/png")
true
"""
@spec mime?(binary(), Infer.Type.mime_type()) :: boolean()
def mime?(binary, mime_type), do: Enum.any?(@matchers, &(&1.mime_type == mime_type && &1.matcher.(binary)))
@doc """
Returns whether the given extension is supported.
## Examples
iex> Infer.supported?("png")
true
"""
@spec supported?(Infer.Type.extension()) :: boolean()
def supported?(extension), do: Enum.any?(@matchers, &(&1.extension == extension))
@doc """
Returns whether the given mime type is supported.
## Examples
iex> Infer.mime_supported?("image/png")
true
"""
@spec mime_supported?(Infer.Type.mime_type()) :: boolean()
def mime_supported?(mime_type), do: Enum.any?(@matchers, &(&1.mime_type == mime_type))
@doc """
Takes the binary file contents as argument and returns whether the file is an application or not.
## Examples
iex> binary = File.read!("test/app/sample.wasm")
iex> Infer.app?(binary)
true
iex> binary = File.read!("test/images/sample.png")
iex> Infer.app?(binary)
false
"""
@spec app?(binary()) :: boolean()
def app?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :app && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is an archive or not.
## Examples
iex> binary = File.read!("test/archives/sample.zip")
iex> Infer.archive?(binary)
true
iex> binary = File.read!("test/images/sample.png")
iex> Infer.archive?(binary)
false
"""
@spec archive?(binary()) :: boolean()
def archive?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :archive && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is an archive or not.
## Examples
iex> binary = File.read!("test/audio/sample.mp3")
iex> Infer.audio?(binary)
true
iex> binary = File.read!("test/images/sample.png")
iex> Infer.audio?(binary)
false
"""
@spec audio?(binary()) :: boolean()
def audio?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :audio && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is an book (epub or mobi) or not.
## Examples
iex> binary = File.read!("test/books/sample.epub")
iex> Infer.book?(binary)
true
iex> binary = File.read!("test/images/sample.png")
iex> Infer.book?(binary)
false
"""
@spec book?(binary()) :: boolean()
def book?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :book && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is a document (microsoft office, open office)
## Examples
iex> binary = File.read!("test/docs/sample.xlsx")
iex> Infer.document?(binary)
true
iex> binary = File.read!("test/docs/sample.pptx")
iex> Infer.document?(binary)
true
iex> binary = File.read!("test/docs/sample.odp")
iex> Infer.document?(binary)
true
iex> binary = File.read!("test/images/sample.png")
iex> Infer.document?(binary)
false
"""
@spec document?(binary()) :: boolean()
def document?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :doc && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is a font or not.
## Examples
iex> binary = File.read!("test/fonts/sample.ttf")
iex> Infer.font?(binary)
true
iex> binary = File.read!("test/app/sample.wasm")
iex> Infer.font?(binary)
false
"""
@spec font?(binary()) :: boolean()
def font?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :font && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is an image or not.
## Examples
iex> binary = File.read!("test/images/sample.png")
iex> Infer.image?(binary)
true
iex> binary = File.read!("test/app/sample.wasm")
iex> Infer.image?(binary)
false
"""
@spec image?(binary()) :: boolean()
def image?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :image && &1.matcher.(binary)))
@doc """
Takes the binary file contents as argument and returns whether the file is a video or not.
## Examples
iex> binary = File.read!("test/videos/sample.mp4")
iex> Infer.video?(binary)
true
iex> binary = File.read!("test/app/sample.wasm")
iex> Infer.video?(binary)
false
"""
@spec video?(binary()) :: boolean()
def video?(binary), do: Enum.any?(@matchers, &(&1.matcher_type == :video && &1.matcher.(binary)))
end
