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lib/ecto_rut.ex
defmodule Ecto.Rut do
@moduledoc """
Provides simple, sane and terse shortcuts for Ecto models.
Ecto.Rut is a wrapper around `Ecto.Repo` methods that usually require you to pass
the module as the subject and sometimes even require you do extra work before hand,
(as in the case of `Repo.insert/3`) to perform operations on your database. Ecto.Rut
tries to reduce code repetition by following the "Convention over Configuration"
ideology.
For example, once set up, it allows you to do this on a model called `Post`:
```
# Create a Post
Post.insert(title: "Introduction to Elixir", categories: ["Elixir", "Programming"])
# Get all Posts
Post.all
# Get a Post with its id
Post.get(3)
# Get a Post with another attribute
Post.get_by(published_date: "2016-02-24")
# Delete a Post
Post.delete(lame_post)
```
## Installation
Once added to your mix dependencies, all you need to do is call `use Ecto.Rut` in
your Ecto models:
```
defmodule YourApp.Post do
use Ecto.Schema
use Ecto.Rut
# Schema, Changeset and other stuff...
end
```
### Phoenix Projects
If you're using Ecto with a Phoenix project, instead of calling `use Ecto.Rut` in all of
your models, you can just call it once in the `model/0` method of your `web/web.ex` file:
```
# web/web.ex
def model do
quote do
use Ecto.Schema
use Ecto.Rut
# Other stuff...
end
end
```
## Configuration
You can also pass options to Ecto.Rut when calling `use` on it. These values are inferred
automatically by Ecto.Rut, but you can set them yourself in those special cases where it
can't. The two options are:
- `:model`
You set this when your Ecto Model is different from the module where you are calling `use`
- `:repo`
You set this when your app's Ecto.Repo module is set differently.
```
defmodule YourApp.OtherNamespace.Post do
use Ecto.Schema
use Ecto.Rut, model: YourApp.Post, repo: YourApp.CustomEcto.Repo
# Other Stuff
end
```
## Export Changeset
Methods like `c:insert/1` or `c:update/2` depend on your model exporting a public function called
`changeset(struct, params)` with all your desired validations and constraints applied to
the casted struct.
Ecto.Rut uses this function to convert maps, keyword lists and other types into `Ecto.Changeset`,
before updating or inserting them into the database.
Phoenix projects generate them for your models automatically, but for other Elixir projects,
you can [see an example here](https://hexdocs.pm/ecto/Ecto.Changeset.html).
"""
@doc false
defmacro __using__(opts \\ []) do
quote bind_quoted: [opts: opts] do
@model opts[:model] || __MODULE__
@app opts[:app] || @model |> Module.split |> Enum.drop(-1) |> Module.concat
@repo opts[:repo] || @app |> Module.concat("Repo")
# Default Changeset method
def changeset(struct, params) do
Ecto.Changeset.cast(struct, params, [])
end
defoverridable [changeset: 2]
# Simple Methods
def all, do: call(:all, [@model])
def delete_all, do: call(:delete_all, [@model])
def get(id), do: call(:get, [@model, id])
def get!(id), do: call(:get!, [@model, id])
def get_by(clauses), do: call(:get_by, [@model, clauses])
def get_by!(clauses), do: call(:get_by!, [@model, clauses])
def delete(struct), do: call(:delete, [struct])
def delete!(struct), do: call(:delete!, [struct])
# Insert and Insert!
Enum.each [:insert, :insert!], fn method ->
def unquote(method)(%{__struct__: Ecto.Changeset} = changeset) do
call(unquote(method), [changeset])
end
def unquote(method)(%{__struct__: @model} = struct) do
struct
|> Map.from_struct
|> unquote(method)()
end
def unquote(method)(map) when is_map(map) do
@model
|> Kernel.struct
|> changeset(map)
|> unquote(method)()
end
def unquote(method)(keywords) do
keywords
|> ExUtils.Keyword.to_map
|> unquote(method)()
end
end
# Update and Update!
Enum.each [:update, :update!], fn method ->
def unquote(method)(%{__struct__: Ecto.Changeset} = changeset) do
call(unquote(method), [changeset])
end
def unquote(method)(%{__struct__: @model} = struct, new \\ nil) do
[struct, map] =
cond do
is_nil(new) -> [get!(struct.id), Map.from_struct(struct)]
ExUtils.is_struct?(new) -> [struct, Map.from_struct(new)]
ExUtils.is_pure_map?(new) -> [struct, new]
Keyword.keyword?(new) -> [struct, ExUtils.Keyword.to_map(new)]
end
struct
|> changeset(map)
|> unquote(method)()
end
end
# Private Methods
defp call(method, args \\ []) do
apply(@repo, method, args)
end
end
end
@doc """
Fetches all entries from the Datastore for the Model
See `c:Ecto.Repo.all/2`.
## Example
```
Post.all
```
"""
@callback all :: [Ecto.Schema.t] | no_return
@doc """
Fetches a single struct from the data store where the primary key matches the given id.
Returns nil if no result was found. If the struct in the queryable has no or more than one
primary key, it will raise an argument error. See `c:Ecto.Repo.get/3`.
## Example
```
Post.get(3)
Post.get("0e531047-6bd2-4ab1-94c3-817fba988dbe")
```
"""
@callback get(id :: term) :: Ecto.Schema.t | nil | no_return
@doc """
Similar to `c:get/1` but raises `Ecto.NoResultsError` if no record was found.
Also see `c:Ecto.Repo.get!/3`.
"""
@callback get!(id :: term) :: Ecto.Schema.t | nil | no_return
@doc """
Fetches a single struct from the data store that matches the passed clauses.
Returns `nil` if no result was found. See `c:Ecto.Repo.get_by/3`.
## Example
```
Post.get_by(title: "Introduction to Elixir")
Post.get_by(published_date: "2015-10-15")
```
"""
@callback get_by(clauses :: Keyword.t) :: Ecto.Schema.t | nil | no_return
@doc """
Similar to `c:get_by/1` but raises `Ecto.NoResultsError` if no record was found.
Also see `c:Ecto.Repo.get_by!/3`.
"""
@callback get_by!(clauses :: Keyword.t) :: Ecto.Schema.t | nil | no_return
@doc """
Deletes a struct using its primary key.
Returns `{:ok, struct}` if the struct was successfully deleted or `{:error, changeset}`
if there was a validation or a known constraint error.
See `c:Ecto.Repo.delete/2`.
## Example
```
case Post.delete(post) do
{:ok, struct} -> # Deleted with success
{:error, changeset} -> # Something went wrong
end
```
"""
@callback delete(struct_or_changeset :: Ecto.Schema.t | Ecto.Changeset.t) :: {:ok, Ecto.Schema.t} | {:error, Ecto.Changeset.t}
@doc """
Similar to `c:delete/1` but returns the struct or raises if the changeset is invalid.
Also see `c:Ecto.Repo.delete!/2`.
"""
@callback delete!(struct_or_changeset :: Ecto.Schema.t | Ecto.Changeset.t) :: Ecto.Schema.t | no_return
@doc """
Deletes all entries of the model
Returns a tuple containing the number of items deleted. Also see `c:Ecto.Repo.delete_all/2`.
## Example
```
Post.delete_all
# => {34, nil}
```
"""
@callback delete_all :: {integer, nil | [term]} | no_return
@doc """
Inserts a new record (Can be a struct, changeset, keyword list or a map).
In case a changeset is given, the changes in the changeset are merges with the struct fields
and all of them are sent to the database.
In case a struct, keyword list or a map is given, they are first converted to a changeset, with
all non-nil fields as part of the changeset and inserted into the database if it's valid.
Returns a {:ok, struct} if it was successfully inserted, or a {:error, changeset} is there was a
validation or a known constraint error.
Also see `c:Ecto.Repo.insert/2`.
## Requires a changeset method
This method depends on your model exporting a public changeset function. [See this for more
details](#module-export-changeset).
## Example
```
Post.insert(title: "Introduction to Elixir")
Post.insert(%{title: "Building your first Phoenix app"})
Post.insert(%Post{title: "Concurrency in Elixir", categories: ["programming", "elixir"]})
Post.changeset(%Post{}, %{title: "Ecto for dummies"}) |> Post.insert
```
"""
@callback insert(struct :: Ecto.Schema.t | Ecto.Changeset.t | Map.t | Keyword.t) :: {:ok, Ecto.Schema.t} | {:error, Ecto.Changeset.t}
@doc """
Similar to `c:insert/1` but returns the struct or raises if the changeset is invalid.
Also see `c:Ecto.Repo.insert!/2`.
"""
@callback insert!(struct :: Ecto.Schema.t | Ecto.Changeset.t | Map.t | Keyword.t) :: Ecto.Schema.t | no_return
@doc """
Updates the database record using a modified struct or a changeset.
This method only accepts one argument; either a modified struct or a changeset. It uses the
struct or changeset's primary key to update the correct record in the database. If no primary
key is found, `Ecto.NoPrimaryKeyFieldError` will be raised.
Returns `{:ok, struct}` if the struct has been successfully updated or `{:error, changeset}`
if there was a validation or a known constraint error.
## Requires a changeset method
This method depends on your model exporting a public changeset function. [See this for more
details](#module-export-changeset).
## Example
```
post = Post.get_by!(id: 3)
post = %{ post | title: "Updated post title"}
Post.update(post)
```
"""
@callback update(modified_struct_or_changeset :: Ecto.Schema.t | Ecto.Changeset.t) :: {:ok, Ecto.Schema.t} | {:error, Ecto.Changeset.t}
@doc """
Updates the database record using a Keyword list or a Map and a Struct for comparison.
This method accepts two arguments, the first being the struct that has to be updated, and
the second being a Map or a Keyword List of the new values.
Returns `{:ok, struct}` if the struct has been successfully updated or `{:error, changeset}`
if there was a validation or a known constraint error. Also see `c:Ecto.Repo.update/2`.
## Requires a changeset method
This method depends on your model exporting a public changeset function. [See this for more
details](#module-export-changeset).
## Example
```
post = Post.get_by!(id: 3)
Post.update(post, title: "New post title", author_id: new_author_id)
```
"""
@callback update(struct :: Ecto.Schema.t, params :: Map.t | Keyword.t) :: {:ok, Ecto.Schema.t} | {:error, Ecto.Changeset.t}
@doc """
Similar to `c:update/1` but returns the struct or raises if the changeset is invalid.
"""
@callback update!(modified_struct_or_changeset :: Ecto.Schema.t | Ecto.Changeset.t) :: Ecto.Schema.t | no_return
@doc """
Similar to `c:update/2` but returns the struct or raises if the changeset is invalid.
"""
@callback update!(struct :: Ecto.Schema.t, params :: Map.t | Keyword.t) :: Ecto.Schema.t | no_return
end