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lib/ecto_shortcuts.ex
defmodule EctoShortcuts do
@moduledoc """
Shortcuts for Ecto gets, insertions, deletes, updates, where clauses, counts, etc.
This module is strictly meant to simplify common Ecto usecases and you should
defer to the Ecto way for more complicated logic that these shortcuts can't handle.
Examples are in the [README](README.html).
"""
require Ecto.Query
defmacro __using__(opts) do
unless repo = Keyword.get(opts, :repo) do
raise ArgumentError,
"""
expected :repo to be given as an option. Example:
use EctoShortcuts, repo: MyApp.Repo
"""
end
quote do
def repo do
unquote repo
end
######### INSERTS ##########
defp new_changeset(attributes) do
__MODULE__.changeset struct(__MODULE__), attributes
end
@doc """
Inserts a new record. It returns {:ok, struct} if the struct has been
successfully inserted or {:error, changeset} if there was a validation
or a known constraint error.
## Examples
iex> MyApp.User.insert name: "bob"
"""
def insert(attributes) do
repo.insert new_changeset(Enum.into(attributes, %{}))
end
@doc """
Inserts a new record. Same as insert/1 but returns the struct or raises
if the changeset is invalid.
## Examples
iex> MyApp.User.insert! name: "bob"
"""
def insert!(attributes) do
repo.insert! new_changeset(Enum.into(attributes, %{}))
end
######### UPDATES ##########
@doc """
Updates all records
## Examples
iex> MyApp.User.update_all set: [status_id: 3]
"""
def update_all(updates, opts \\ []) do
repo.update_all(__MODULE__, updates, opts)
end
defp apply_filter(key, value, query) do
from f in query,
where: field(f, ^key) == ^value
end
defp reduce_filters(filters) do
ecto_query = Ecto.Query.from x in __MODULE__
Enum.reduce(filters, ecto_query, fn(filter, ecto_query) ->
ecto_query = apply_filter(elem(filter, 0), elem(filter, 1), ecto_query)
end)
end
@doc """
Updates all records matching filters
## Examples
iex> MyApp.User.update_by [mode: 3], set: [status_id: 4]
"""
def update_by(filters, updates, opts \\ []) do
reduce_filters(filters) |> repo.update_all(updates, opts)
end
######## DELETES ##########
@doc """
Deletes all records
## Examples
iex> MyApp.User.delete_all
"""
def delete_all do
repo.delete_all __MODULE__
end
@doc """
Deletes all records matching filters
## Examples
iex> MyApp.User.delete_by mode: 3
"""
def delete_by(filters, opts \\ []) do
reduce_filters(filters) |> repo.delete_all(opts)
end
######### GETS ############
@doc """
Fetches a single struct from the data store where the primary key matches
the given id. Returns nil if no result was found. An ArgumentError will be
raised if more than one primary key exist.
## Examples
iex> MyApp.User.get 3
"""
def get(id, opts \\ []) do
repo.get __MODULE__, id, opts
end
@doc """
Similar to get/2 but raises Ecto.NoResultsError if no record was found.
## Examples
iex> MyApp.User.get! 3
"""
def get!(id, opts \\ []) do
repo.get! __MODULE__, id, opts
end
@doc """
Fetches a single record that matches filters. Returns nil if no result was found.
## Examples
iex> MyApp.User.get_by name: "Sally"
"""
def get_by(filters, opts \\ []) do
repo.get_by __MODULE__, filters, opts
end
@doc """
Similar to get_by/2 but raises Ecto.NoResultsError if no record was found.
## Examples
iex> MyApp.User.get_by! name: "Sally"
"""
def get_by!(clauses, opts \\ []) do
repo.get_by! __MODULE__, clauses, opts
end
@doc """
Retrieves first record from datastore.
## Examples
iex> MyApp.User.first
"""
def first do
__MODULE__ |> Ecto.Query.first |> repo.one
end
@doc """
Retrieves records matching attributes with optional order and limit
## Examples
iex> MyApp.User.where status: 3
iex> MyApp.User.where [status: 3], limit: 10, order_by: [desc: :created_at]
"""
def where(attributes, options \\ []) do
ecto_query = if options[:limit] && options[:order_by] do
limit_order_by_where options[:limit], options[:order_by]
else
if options[:limit] do
limit_where options[:limit]
else
if options[:order_by] do
order_by_where options[:order_by]
else
nil
end
end
end
ecto_query = ecto_query || __MODULE__
ecto_query
|> Ecto.Query.where(^attributes)
|> repo.all
end
# silly method needed due to macro hell
defp limit_where(limit) do
Ecto.Query.from(__MODULE__, [limit: ^limit])
end
# silly method needed due to macro hell
defp order_by_where(order_by) do
Ecto.Query.from(__MODULE__, [order_by: ^order_by])
end
# silly method needed due to macro hell
defp limit_order_by_where(limit, order_by) do
Ecto.Query.from(__MODULE__, [limit: ^limit, order_by: ^order_by])
end
@doc """
Retrieves first record matching attributes
## Examples
iex> MyApp.User.first_where status: 3
"""
def first_where(attributes) do
__MODULE__
|> Ecto.Query.where(^attributes)
|> Ecto.Query.first
|> repo.one
end
@doc """
Finds record matching attributes or inserts it if it does not exist.
## Examples
iex> MyApp.User.get_or_insert first_name: "John", last_name: "Smith"
"""
def get_or_insert(attributes) do
record = first_where(attributes)
if record do
record
else
insert attributes
end
end
@doc """
Finds record matching attributes or inserts it if it does not exist.
## Examples
iex> MyApp.User.get_or_insert! first_name: "John", last_name: "Smith"
"""
def get_or_insert!(attributes) do
record = first_where(attributes)
if record do
record
else
insert! attributes
end
end
@doc """
Retrieves all records from dataset.
## Examples
iex> MyApp.User.all
"""
def all do
__MODULE__ |> repo.all
end
@doc """
Retrieves count of all records in dataset.
## Examples
iex> MyApp.User.count
"""
def count do
repo.one(Ecto.Query.from p in __MODULE__, select: count("id"))
end
@doc """
Retrieves count of all records in dataset matching filters
## Examples
iex> MyApp.User.count_where status_id: 4
"""
def count_where(filters) do
Ecto.Query.from(p in __MODULE__, select: count("id"))
|> Ecto.Query.where(^filters)
|> repo.one
end
end
end
end