Tempo.SQL.JSON (Tempo SQL v0.2.0)

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Shim module that adapts Erlang's built-in :json (OTP 27+) to Postgrex's expected JSON-library interface.

Postgrex's jsonb extension calls library.encode_to_iodata!/1 and library.decode!/1 (the shapes Jason exposes). Erlang's :json exposes encode/2 and decode/3, so this module bridges the two. It also configures nil ↔ JSON null translation in both directions, sparing application code from the :null atom the raw :json module returns.

Use from Postgrex

Postgrex.Types.define(MyApp.PostgresTypes, [], json: Tempo.SQL.JSON)

Summary

Functions

decode!(binary)

Decodes a JSON binary, in the shape Postgrex expects of a JSON library.

encode_to_iodata!(term)

Encodes a term as JSON iodata, in the shape Postgrex expects of a JSON library.

Functions

decode!(binary)

Decodes a JSON binary, in the shape Postgrex expects of a JSON library.

Arguments

  • binary is the JSON document to decode.

Returns

  • The decoded term, with JSON null becoming nil rather than the :null atom.

Examples

iex> Tempo.SQL.JSON.decode!(~s({"hours":8}))
%{"hours" => 8}

iex> Tempo.SQL.JSON.decode!(~s({"ends":null}))
%{"ends" => nil}

encode_to_iodata!(term)

Encodes a term as JSON iodata, in the shape Postgrex expects of a JSON library.

Arguments

  • term is any JSON-serialisable term.

Returns

  • The encoded JSON as iodata. nil encodes as JSON null rather than as the :null atom the raw :json module uses.

Examples

iex> Tempo.SQL.JSON.encode_to_iodata!(%{"hours" => 8})
...> |> IO.iodata_to_binary()
~s({"hours":8})

iex> Tempo.SQL.JSON.encode_to_iodata!(%{"ends" => nil})
...> |> IO.iodata_to_binary()
~s({"ends":null})