Poison support

[ppatrzyk]

Setting Poison as json_library in config leads to the following error in queries:

[error] ** (UndefinedFunctionError) function Poison.encode_to_iodata!/1 is undefined or private

This is due to the following change: #282 . Unfortunately function encode_to_iodata!/1 is no longer present in the latest version of Poison (5.0.0).

For now I found a workaround by having a custom module that maps these names to Poison calls, i.e. doing just the following and putting it as json_library in configuration.

def encode_to_iodata!(data) do
  Poison.encode!(data)
end

But would it be maybe possible to set this properly in config - i.e. set exact function for decode / encode? Something like:

config :postgrex,
  json_decode: Poison.decode!/1
  json_encode: Poison.encode!/1

thanks

[josevalim]

My suggestion is to update Poison to add the new function or have a wrapper module. It is a bad practice to have functions in config because they cannot be copied to Erlang configs when assembling a release. :)

[ppatrzyk]

@josevalim thank you for a very fast reply, I will continue using a wrapper module then