MMDB2 Decoder v3.0.0 MMDB2Decoder View Source

MMDB2 file format decoder.

Usage

To prepare lookups in a given database you need to parse it and hold the result available for later usage:

iex(1)> database = File.read!("/path/to/database.mmdb")
iex(2)> {:ok, meta, tree, data} = MMDB2Decoder.parse_database(database)

Using the returned database contents you can start looking up individual entries:

iex(3)> {:ok, ip} = :inet.parse_address(String.to_charlist("127.0.0.1"))
iex(4)> MMDB2Decoder.lookup(ip, meta, tree, data)
{:ok, %{...}}

For more details on the lookup methods (and a function suitable for direct piping) please see the individual function documentations.

Lookup Options

The behaviour of the decoder can be adjusted by passing an option map as the last argument to the lookup functions:

iex> MMDB2Decoder.lookup(ip, meta, tree, data, %{map_keys: :atoms!})

The following options are available:

:map_keys defines the type of the keys in a decoded map:
- :strings is the default value
- :atoms uses String.to_atom/1
- :atoms! uses String.to_existing_atom/1
:double_precision defines the precision of decoded Double values
- nil is the default for "unlimited" precision
- any value from Float.precision_range/0 to round the precision to
:float_precision defines the precision of decoded Float values
- nil is the default for "unlimited" precision
- any value from Float.precision_range/0 to round the precision to

Link to this section Summary

Types

decode_options()

decoded_value()

lookup_result()

lookup_value()

parse_result()

tree_result()

Functions

find_pointer(ip, meta, tree)

Fetches the pointer of an IP in the data if available.

find_pointer!(ip, meta, tree)

Calls find_pointer/3 and raises if an error occurs.

lookup(ip, meta, tree, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Looks up the data associated with an IP tuple.

lookup!(ip, meta, tree, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Calls lookup/4 and raises if an error occurs.

lookup_pointer(pointer, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Fetches the data at a given pointer position.

lookup_pointer!(pointer, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Calls lookup_pointer/3 and unrolls the return tuple.

parse_database(contents)

Parses a database binary and splits it into metadata, lookup tree and data.

pipe_lookup(parse_result, ip, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Utility method to pipe parse_database/1 directly to lookup/4.

pipe_lookup!(parse_result, ip, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Calls pipe_lookup/2 and raises if an error from parse_database/1 is given or occurs during lookup/4.

Link to this section Types

decode_options()

Specs

decode_options() :: %{
  optional(:double_precision) => nil | Float.precision_range(),
  optional(:float_precision) => nil | Float.precision_range(),
  optional(:map_keys) => nil | :atoms | :atoms! | :strings
}

decoded_value()

Specs

decoded_value() ::
  :cache_container
  | :end_marker
  | binary()
  | boolean()
  | list()
  | map()
  | number()

lookup_result()

Specs

lookup_result() :: {:ok, lookup_value()} | {:error, term()}

lookup_value()

Specs

lookup_value() :: decoded_value() | nil

parse_result()

Specs

parse_result() ::
  {:ok, MMDB2Decoder.Metadata.t(), binary(), binary()} | {:error, term()}

tree_result()

Specs

tree_result() :: {:ok, non_neg_integer()} | {:error, term()}

Link to this section Functions

find_pointer(ip, meta, tree)

Specs

find_pointer(:inet.ip_address(), MMDB2Decoder.Metadata.t(), binary()) ::
  tree_result()

Fetches the pointer of an IP in the data if available.

The pointer will be calculated to be relative to the start of the binary data.

Usage

iex> MMDB2Decoder.find_pointer({127, 0, 0, 1}, meta, tree)
123456

find_pointer!(ip, meta, tree)

Specs

find_pointer!(:inet.ip_address(), MMDB2Decoder.Metadata.t(), binary()) ::
  non_neg_integer() | no_return()

Calls find_pointer/3 and raises if an error occurs.

lookup(ip, meta, tree, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Specs

lookup(
  :inet.ip_address(),
  MMDB2Decoder.Metadata.t(),
  binary(),
  binary(),
  decode_options()
) :: lookup_result()

Looks up the data associated with an IP tuple.

This is probably the main function you will use. The ip address is expected to be a 4- or 8-element tuple describing an IPv4 or IPv6 address. To obtain this tuple from a string you can use :inet.parse_address/1.

Usage

iex> MMDB2Decoder.lookup({127, 0, 0, 1}, meta, tree, data)
{
  :ok,
  %{
    "continent" => %{...},
    "country" => %{...},
    "registered_country" => %{...}
  }
}

The values for meta, tree and data can be obtained by parsing the file contents of a database using parse_database/1.

lookup!(ip, meta, tree, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Specs

lookup!(
  :inet.ip_address(),
  MMDB2Decoder.Metadata.t(),
  binary(),
  binary(),
  decode_options()
) :: lookup_value() | no_return()

Calls lookup/4 and raises if an error occurs.

lookup_pointer(pointer, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Specs

lookup_pointer(non_neg_integer(), binary(), decode_options()) ::
  {:ok, lookup_value()}

Fetches the data at a given pointer position.

The pointer is expected to be relative to the start of the binary data.

Usage

iex> MMDB2Decoder.lookup_pointer(123456, data)
{
  :ok,
  %{
    "continent" => %{...},
    "country" => %{...},
    "registered_country" => %{...}
  }
}

lookup_pointer!(pointer, data, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Specs

lookup_pointer!(non_neg_integer(), binary(), decode_options()) :: lookup_value()

Calls lookup_pointer/3 and unrolls the return tuple.

parse_database(contents)

Specs

parse_database(binary()) :: parse_result()

Parses a database binary and splits it into metadata, lookup tree and data.

It is expected that you pass the real contents of the file, not the name of the database or the path to it.

Usage

iex> MMDB2Decoder.parse_database(File.read!("/path/to/database.mmdb"))
{
  :ok,
  %MMDB2Decoder.Metadata{...},
  <<...>>,
  <<...>>
}

If parsing the database fails you will receive an appropriate error tuple:

iex> MMDB2Decoder.parse_database("invalid-database-contents")
{:error, :no_metadata}

pipe_lookup(parse_result, ip, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Specs

pipe_lookup(parse_result(), :inet.ip_address(), decode_options()) ::
  lookup_result()

Utility method to pipe parse_database/1 directly to lookup/4.

Usage

Depending on how you handle the parsed database contents you may want to pass the results directly to the lookup.

iex> "/path/to/database.mmdb"
...> |> File.read!()
...> |> MMDB2Decoder.parse_database()
...> |> MMDB2Decoder.pipe_lookup({127, 0, 0, 1})
{:ok, %{...}}

pipe_lookup!(parse_result, ip, options \\ %{double_precision: nil, float_precision: nil, map_keys: :strings})

Specs

pipe_lookup!(parse_result(), :inet.ip_address(), decode_options()) ::
  lookup_value() | no_return()

Calls pipe_lookup/2 and raises if an error from parse_database/1 is given or occurs during lookup/4.