I've created a JSON api using Elixir and the Phoenix
I have an endpoint for a create action in my controller that takes json data which looks like this:
[{"opens_detail"=>
[{"ua"=>"Linux/Ubuntu/Chrome/Chrome 28.0.1500.53",
"ip"=>"55.55.55.55",
"ts"=>1365190001,
"location"=>"Georgia, US"}],
"template"=>"example-template",
"metadata"=>{"user_id"=>"123", "website"=>"www.example.com"},
"clicks"=>42,
"ts"=>1365190000,
"state"=>"sent",
"clicks_detail"=>
[{"ua"=>"Linux/Ubuntu/Chrome/Chrome 28.0.1500.53",
"ip"=>"55.55.55.55",
"ts"=>1365190001,
"url"=>"http://www.example.com",
"location"=>"Georgia, US"}],
"email"=>"recipient.email@example.com",
"subject"=>"example subject",
"sender"=>"sender@example.com",
"_id"=>"abc123abc123abc123abc123",
"tags"=>["password-reset"],
"opens"=>42}]
My goal is to take this json and create a new one from it where some keys and values are renamed to match my schema below:
in web/models/messages.ex
...
schema "messages" do
field :sender, :string
field :uniq_id, :string # equal to '_id' in the payload
field :ts, :utc_datetime
field :template, :string
field :subject, :string
field :email, :string
field :tags, {:array, :string}
field :opens, :integer
field :opens_ip, :string # equal to nested 'ip' value in 'open_details'
field :opens_location, :string # equal to nested 'location' value in 'open_details'
field :clicks, :integer
field :clicks_ip, :string # equal to nested 'ip' value in 'click_details'
field :clicks_location, :string # equal to nested 'location' value in 'click_details'
field :status, :string # equal to the "state" in the payload
timestamps()
end
...
This is what I tried:
in web/controller/message_controller.ex:
def create(conn, payload) do
%{ payload |
"uniq_id" => payload["_id"],
"status" => payload["type"]
"open_ips" => Enum.at(payload["opens_detail"], 0)['ip'],
"open_location" => Enum.at(payload["opens_detail"], 0)['location'],
"click_ips" => Enum.at(payload["clicks_detail"], 0)['ip'],
"click_location" => Enum.at(payload["clicks_detail"], 0)['location'],
}
changeset = Message.changeset(%Message{}, payload)
...
end
but it quickly became clear that it wouldn't work also because I would still need to remove some keys.
I'm coming from Ruby/Python (Rails/Django) and don't want to start polluting my learning of functional programming, specifically elixir/phoenix, with my OO knowledge.
How would you solve this problem?
How would you solve this problem?
I would create a new map from scratch instead of updating the original map. You can use get_in to simplify the logic to access nested fields. Here's an example:
map = %{
uniq_id: get_in(payload, ["_id"]),
open_ips: get_in(payload, ["opens_detail", Access.at(0), "ip"]),
open_locations: get_in(payload, ["opens_detail", Access.at(0), "location"]),
}
If you want to pick a subset of fields from the original map, you can use Map.merge and Map.take:
Map.merge(Map.take(payload, [:sender, ...]), %{uniq_id: ...})
But if it's only a couple of fields I'd rather write them out manually.