Cep

A package to query Brazilian zip (CEP) codes.

Has support for multiple source APIs (Correios, ViaCep, Postmon, etc). It can query one specific source or query until one source returns a valid result.

Table of Contents
Installation
Usage
Configuration
- Sources
Future

Installation

It's is available as an Hex package and thus can be installed as:

Add cep to your list of dependencies in mix.exs:

def deps do
  [{:cep, "~> 0.0.2"}]
end

Usage

To query for the address of any given Brazilian CEP code:

{:ok, address} = Cep.Client.get_address("29375-000")
IO.inspect address

The default Cep.Client.get_address will first try to access the official Brazilian Post Office web service to get the information. If the web service is down, timeout or doesn't have information about one specific CEP the next source will be automatically and transparently used. If none of the sources give good reply it will return a proper error, as in the following example:

{status, reason} = Cep.Client.get_address("00000-000")
IO.inspect status
IO.inspect reason

You can modify the sources that a query will use by using the sources keyword argument and sending as its value any combination of the element from Cep.sources as follows:

available_sources = Keyword.delete(Cep.sources, :correios)
{:ok, address} = Cep.Client.get_address("28016-811", sources: available_sources)

To query just one specific source there is a sugar: just send the source with the desired source:

Cep.Client.get_address("28016-811", source: :viacep)

Configuration

Sources

You can change the default sources used when no source or sources keywords are sent to Cep.Client.get_address by modifying your config file like this:

config :cep, sources: [:correios, :viacep]

IMPORTANT: even if you add the default sources in config file, the source and sources keywords can override this configuration.

Add a custom source

defmodule Cep.Sources.Custom.YourNewGreateSource do
  import Cep.Sources.Base

  @behaviour Cep.Source

  def get_address(cep) do
    # implement your source returning:
    # { :ok, %Cep.Address{...} }
    # or
    # { :error, "reason" }
    # or
    # { :not_found, _ }
  end
end

and then pass it as the default sources in config file or as sources keywords.

config :cep, sources: [:correios, Cep.Sources.Custom.YourNewGreateSource]
# or
client.get_address("00010-100", sources: [:correios, Cep.Sources.Custom.YourNewGreateSource])

Future

Future features that are planned:

Use the circuit breaker pattern to avoid querying sources that return unexpected errors too often.
Use Mox in the specs

sumup-bank/cep