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Allow specifying custom type field
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@mathieuprog
mathieuprog committed Dec 25, 2020
1 parent 41f5d6c commit 7488273
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Showing 3 changed files with 74 additions and 61 deletions.
120 changes: 66 additions & 54 deletions lib/polymorphic_embed.ex
View file
Original file line number Diff line number Diff line change
Expand Up @@ -10,37 +10,36 @@ defmodule PolymorphicEmbed do
raise("`:on_replace` option for polymorphic embed must be set to `:update` (single embed) or `:delete` (list of embeds)")
end

metadata =
types_metadata =
Keyword.fetch!(opts, :types)
|> Enum.map(fn
{type_name, type_opts} when is_list(type_opts) ->
module = Keyword.fetch!(type_opts, :module)
identify_by_fields = Keyword.fetch!(type_opts, :identify_by_fields)

%{
type: type_name |> to_string(),
module: module,
identify_by_fields: identify_by_fields |> Enum.map(&to_string/1)
}
{type_name, type_opts}

{type_name, module} ->
{type_name, module: module}
end)
|> Enum.map(fn
{type_name, type_opts} when is_list(type_opts) ->
%{
type: type_name |> to_string(),
module: module,
identify_by_fields: []
module: Keyword.fetch!(type_opts, :module),
identify_by_fields: Keyword.get(type_opts, :identify_by_fields, []) |> Enum.map(&to_string/1)
}
end)

%{
metadata: metadata,
types_metadata: types_metadata,
on_type_not_found: Keyword.get(opts, :on_type_not_found, :changeset_error),
type_field: Keyword.get(opts, :type_field, :__type__) |> to_string(),
on_replace: Keyword.fetch!(opts, :on_replace)
}
end

def cast_polymorphic_embed(changeset, field) do
%{array?: array?, metadata: metadata, on_type_not_found: on_type_not_found, on_replace: on_replace} =
get_options(changeset.data.__struct__, field)
options = get_options(changeset.data.__struct__, field)

%{array?: array?, on_replace: on_replace} = options

if array? and on_replace != :delete do
raise "`:on_replace` option for field #{inspect field} must be set to `:update`"
Expand All @@ -65,25 +64,27 @@ defmodule PolymorphicEmbed do
{:ok, params_for_field} ->
cond do
array? and is_list(params_for_field) ->
cast_polymorphic_embeds_many(changeset, field, params_for_field, metadata, on_type_not_found)
cast_polymorphic_embeds_many(changeset, field, params_for_field, options)

not array? and is_map(params_for_field) ->
cast_polymorphic_embeds_one(changeset, field, params_for_field, metadata, on_type_not_found)
cast_polymorphic_embeds_one(changeset, field, params_for_field, options)
end
end
end

defp cast_polymorphic_embeds_one(changeset, field, params, metadata, on_type_not_found) do
defp cast_polymorphic_embeds_one(changeset, field, params, options) do
%{types_metadata: types_metadata, on_type_not_found: on_type_not_found, type_field: type_field} = options

params =
Map.fetch!(changeset.data, field)
|> case do
nil -> %{}
struct -> map_from_struct(struct, metadata)
struct -> map_from_struct(struct, type_field, types_metadata)
end
|> Map.merge(params)
|> convert_map_keys_to_string()

case do_get_polymorphic_module(params, metadata) do
case do_get_polymorphic_module_from_map(params, type_field, types_metadata) do
nil when on_type_not_found == :raise ->
raise_cannot_infer_type_from_data(params)

Expand All @@ -108,10 +109,12 @@ defmodule PolymorphicEmbed do
end
end

defp cast_polymorphic_embeds_many(changeset, field, list_params, metadata, on_type_not_found) do
defp cast_polymorphic_embeds_many(changeset, field, list_params, options) do
%{types_metadata: types_metadata, on_type_not_found: on_type_not_found, type_field: type_field} = options

embeds =
Enum.map(list_params, fn params ->
case do_get_polymorphic_module(params, metadata) do
case do_get_polymorphic_module_from_map(params, type_field, types_metadata) do
nil when on_type_not_found == :raise ->
raise_cannot_infer_type_from_data(params)

Expand Down Expand Up @@ -156,8 +159,8 @@ defmodule PolymorphicEmbed do
@impl true
def load(nil, _loader, _params), do: {:ok, nil}

def load(data, _loader, %{metadata: metadata}) do
case do_get_polymorphic_module(data, metadata) do
def load(data, _loader, %{types_metadata: types_metadata, type_field: type_field}) do
case do_get_polymorphic_module_from_map(data, type_field, types_metadata) do
nil -> raise_cannot_infer_type_from_data(data)
module when is_atom(module) -> {:ok, Ecto.embedded_load(module, data, :json)}
end
Expand All @@ -168,64 +171,73 @@ defmodule PolymorphicEmbed do
raise "cannot dump invalid changeset"
end

def dump(%_module{} = struct, dumper, %{metadata: metadata}) do
dumper.(:map, map_from_struct(struct, metadata))
def dump(%_module{} = struct, dumper, %{types_metadata: types_metadata, type_field: type_field}) do
dumper.(:map, map_from_struct(struct, type_field, types_metadata))
end

def dump(nil, dumper, _params) do
dumper.(:map, nil)
end

defp map_from_struct(%module{} = struct, metadata) do
defp map_from_struct(%module{} = struct, type_field, types_metadata) do
struct
|> Ecto.embedded_dump(:json)
|> Map.put(:__type__, do_get_polymorphic_type(module, metadata))
|> Map.put(type_field, do_get_polymorphic_type(module, types_metadata))
end

def get_polymorphic_module(schema, field, type_or_data) do
%{metadata: metadata} = get_options(schema, field)
do_get_polymorphic_module(type_or_data, metadata)
end
%{types_metadata: types_metadata, type_field: type_field} = get_options(schema, field)

defp do_get_polymorphic_module(%{:__type__ => type}, metadata),
do: do_get_polymorphic_module(type, metadata)
case type_or_data do
map when is_map(map) -> do_get_polymorphic_module_from_map(map, type_field, types_metadata)
type when is_atom(type) or is_binary(type) -> do_get_polymorphic_module_for_type(type, types_metadata)
end
end

defp do_get_polymorphic_module(%{"__type__" => type}, metadata),
do: do_get_polymorphic_module(type, metadata)
defp do_get_polymorphic_module_from_map(%{} = attrs, type_field, types_metadata) do
type = Enum.find_value(attrs, fn {key, value} -> to_string(key) == type_field && value end)

defp do_get_polymorphic_module(%{} = attrs, metadata) do
# check if one list is contained in another
# Enum.count(contained -- container) == 0
# contained -- container == []
metadata
|> Enum.filter(&([] != &1.identify_by_fields))
|> Enum.find(&([] == &1.identify_by_fields -- Map.keys(attrs)))
|> (&(&1 && Map.fetch!(&1, :module))).()
if type do
do_get_polymorphic_module_for_type(type, types_metadata)
else
# check if one list is contained in another
# Enum.count(contained -- container) == 0
# contained -- container == []
types_metadata
|> Enum.filter(&([] != &1.identify_by_fields))
|> Enum.find(&([] == &1.identify_by_fields -- Map.keys(attrs)))
|> (&(&1 && Map.fetch!(&1, :module))).()
end
end

defp do_get_polymorphic_module(type, metadata) do
type = to_string(type)

metadata
|> Enum.find(&(type == &1.type))
defp do_get_polymorphic_module_for_type(type, types_metadata) do
get_metadata_for_type(type, types_metadata)
|> (&(&1 && Map.fetch!(&1, :module))).()
end

def get_polymorphic_type(schema, field, module_or_struct) do
%{metadata: metadata} = get_options(schema, field)
do_get_polymorphic_type(module_or_struct, metadata)
%{types_metadata: types_metadata} = get_options(schema, field)
do_get_polymorphic_type(module_or_struct, types_metadata)
end

defp do_get_polymorphic_type(%module{}, metadata),
do: do_get_polymorphic_type(module, metadata)
defp do_get_polymorphic_type(%module{}, types_metadata),
do: do_get_polymorphic_type(module, types_metadata)

defp do_get_polymorphic_type(module, metadata) do
metadata
|> Enum.find(&(module == &1.module))
defp do_get_polymorphic_type(module, types_metadata) do
get_metadata_for_module(module, types_metadata)
|> Map.fetch!(:type)
|> String.to_atom()
end

defp get_metadata_for_module(module, types_metadata) do
Enum.find(types_metadata, &(module == &1.module))
end

defp get_metadata_for_type(type, types_metadata) do
type = to_string(type)
Enum.find(types_metadata, &(type == &1.type))
end

defp get_options(schema, field) do
try do
schema.__schema__(:type, field)
Expand Down
12 changes: 6 additions & 6 deletions test/polymorphic_embed_test.exs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -23,7 +23,7 @@ defmodule PolymorphicEmbedTest do
date: ~U[2020-05-28 02:57:19Z],
text: "This is an SMS reminder #{polymorphic?}",
channel: %{
__type__: "sms",
my_type_field: "sms",
number: "02/807.05.53",
country_code: 1,
result: %{success: true},
Expand Down Expand Up @@ -77,7 +77,7 @@ defmodule PolymorphicEmbedTest do
date: ~U[2020-05-28 02:57:19Z],
text: "This is an SMS reminder",
channel: %{
__type__: "sms"
my_type_field: "sms"
}
}

Expand Down Expand Up @@ -370,7 +370,7 @@ defmodule PolymorphicEmbedTest do
reminder
|> reminder_module.changeset(%{
"channel" => %{
"__type__" => "sms",
"my_type_field" => "sms",
"number" => "54"
}
})
Expand Down Expand Up @@ -432,7 +432,7 @@ defmodule PolymorphicEmbedTest do
date: ~U[2020-05-28 02:57:19Z],
text: "This is an SMS reminder",
channel: %{
__type__: "sms",
my_type_field: "sms",
number: "02/807.05.53",
country_code: 1,
result: %{success: true},
Expand Down Expand Up @@ -479,7 +479,7 @@ defmodule PolymorphicEmbedTest do

Ecto.Adapters.SQL.query!(
Repo,
"UPDATE reminders SET channel = jsonb_set(channel, '{__type__}', '\"foo\"')",
"UPDATE reminders SET channel = jsonb_set(channel, '{my_type_field}', '\"foo\"')",
[]
)

Expand All @@ -501,7 +501,7 @@ defmodule PolymorphicEmbedTest do
date: ~U[2020-05-28 02:57:19Z],
text: "This is a reminder with multiple contexts #{polymorphic?}",
channel: %{
__type__: "sms",
my_type_field: "sms",
number: "02/807.05.53",
country_code: 1
},
Expand Down
3 changes: 2 additions & 1 deletion test/support/models/polymorphic/reminder.ex
View file
Original file line number Diff line number Diff line change
Expand Up @@ -16,7 +16,8 @@ defmodule PolymorphicEmbed.Reminder do
identify_by_fields: [:address, :confirmed]
]
],
on_replace: :update
on_replace: :update,
type_field: :my_type_field
)

field(:contexts, {:array, PolymorphicEmbed},
Expand Down

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