Hi,

I’ve created a small helper library called PostgrexTextExt. It allows users to enable text protocol encoding/decoding in Postgrex for any PostgeSQL data type they choose, even if Postgrex doesn’t currently support it.

Github: GitHub - greg-rychlewski/postgrex_text_ext · GitHub
Hex: PostgrexTextExt — PostgrexTextExt v0.1.0

I created it based on some edge cases I saw while helping with Ecto over the past year. In particular, it seems like it helps in the following cases:

• Text search functions requiring OIDs: Error interpolating `ts_vector` Ecto - is this a bug?. It avoids the double casting oid::text::regconfig.

• Extensions that don’t have a binary protocol version. For example, ltree didn’t have a binary protocol under somewhat recently

• Using Postgrex directly instead of Ecto and preferring the text versions of certain types (i.e. UUID): pass uuid as string by OleMchls · Pull Request #271 · elixir-ecto/postgrex · GitHub

I started off wanting to make an extension just for OIDs, but then I realized with very little effort you can make it work for any type.

How it’s used:

1. Specify the data types in your configuration

  config :postgrex_text_ext,
    type_names: ["regconfig", "ltree"],
    type_outputs: ["range_out"]

There are 2 levels of granularity: type name and type output. These correspond to the typname and typoutput columns in the pg_type system catalog.

A list of type names and outputs is provided here. You may also use the pg_type system catalog: SELECT typname, typoutput FROM pg_type;.

2. Define a custom type module, as needed by Postgrex

Postgrex.Types.define(MyApp.PostgrexTypes, [PostgrexTextExt], [])