Packages
ash
3.4.72
3.29.3
3.29.2
3.29.1
3.29.0
3.28.0
3.27.8
3.27.7
3.27.6
3.27.5
3.27.4
3.27.3
3.27.2
3.27.1
3.27.0
3.26.0
3.25.2
3.25.1
3.25.0
retired
3.24.7
3.24.6
3.24.5
3.24.4
3.24.3
3.24.2
3.24.1
3.24.0
3.23.1
3.23.0
3.22.2
3.22.1
3.22.0
3.21.3
3.21.2
3.21.1
3.21.0
3.20.0
3.19.3
3.19.2
3.19.1
3.19.0
3.18.0
3.17.1
3.17.0
3.16.0
3.15.0
3.14.1
3.14.0
retired
3.13.2
3.13.1
3.13.0
3.12.0
3.11.3
3.11.2
3.11.1
3.11.0
3.10.1
3.10.0
3.9.0
3.8.0
3.7.6
3.7.5
3.7.4
3.7.3
3.7.2
3.7.1
3.7.0
retired
3.6.3
retired
3.6.2
3.6.1
3.6.0
3.5.43
3.5.42
3.5.41
3.5.40
3.5.39
3.5.38
3.5.37
3.5.36
3.5.35
3.5.34
3.5.33
3.5.32
3.5.31
3.5.30
3.5.29
3.5.28
3.5.27
3.5.26
3.5.25
3.5.24
3.5.23
3.5.22
3.5.21
3.5.20
3.5.19
3.5.18
3.5.17
3.5.16
3.5.15
3.5.14
3.5.13
3.5.12
3.5.11
3.5.10
3.5.9
3.5.8
3.5.7
3.5.6
3.5.5
3.5.4
3.5.3
3.5.2
3.5.1
3.5.0
3.4.74
retired
3.4.73
3.4.72
3.4.71
3.4.70
3.4.69
3.4.68
3.4.67
3.4.66
3.4.65
3.4.64
3.4.63
3.4.62
3.4.61
3.4.60
3.4.59
3.4.58
3.4.57
3.4.56
3.4.55
3.4.54
3.4.53
3.4.52
3.4.51
3.4.50
3.4.49
3.4.48
3.4.47
3.4.46
3.4.45
3.4.44
3.4.43
3.4.42
3.4.41
3.4.40
3.4.39
3.4.38
3.4.37
3.4.36
3.4.35
3.4.34
3.4.33
3.4.32
3.4.31
3.4.30
3.4.29
3.4.28
3.4.27
3.4.26
3.4.25
3.4.24
3.4.23
3.4.22
3.4.21
3.4.20
3.4.19
3.4.18
3.4.17
3.4.16
3.4.15
3.4.14
3.4.13
3.4.12
3.4.11
3.4.10
3.4.9
3.4.8
3.4.7
3.4.6
3.4.5
3.4.4
3.4.3
3.4.2
3.4.1
3.4.0
3.3.3
3.3.2
3.3.1
3.3.0
3.2.6
3.2.5
3.2.4
3.2.3
3.2.2
3.2.1
3.2.0
3.1.8
3.1.7
3.1.6
3.1.5
3.1.4
3.1.3
3.1.2
3.1.1
3.1.0
3.0.16
3.0.15
3.0.14
3.0.13
3.0.12
3.0.11
3.0.10
3.0.9
3.0.8
3.0.7
3.0.6
3.0.5
3.0.4
3.0.3
3.0.2
3.0.1
3.0.0
3.0.0-rc.46
3.0.0-rc.45
3.0.0-rc.44
3.0.0-rc.43
3.0.0-rc.42
3.0.0-rc.41
3.0.0-rc.40
3.0.0-rc.39
3.0.0-rc.38
3.0.0-rc.37
3.0.0-rc.36
3.0.0-rc.35
3.0.0-rc.34
3.0.0-rc.33
3.0.0-rc.32
3.0.0-rc.31
3.0.0-rc.29
3.0.0-rc.28
3.0.0-rc.27
3.0.0-rc.26
3.0.0-rc.25
3.0.0-rc.24
3.0.0-rc.23
3.0.0-rc.22
3.0.0-rc.21
3.0.0-rc.20
3.0.0-rc.19
3.0.0-rc.18
3.0.0-rc.17
3.0.0-rc.16
3.0.0-rc.15
3.0.0-rc.14
3.0.0-rc.13
3.0.0-rc.12
3.0.0-rc.11
3.0.0-rc.10
3.0.0-rc.9
3.0.0-rc.8
3.0.0-rc.7
3.0.0-rc.6
3.0.0-rc.5
3.0.0-rc.4
3.0.0-rc.3
3.0.0-rc.1
3.0.0-rc.0
2.21.15
2.21.14
2.21.13
2.21.12
2.21.11
2.21.10
2.21.9
2.21.8
2.21.7
2.21.6
2.21.5
2.21.4
2.21.3
2.21.2
2.21.1
2.21.0
2.20.3
2.20.2
2.20.1
2.20.0
2.19.14
2.19.13
2.19.12
2.19.11
2.19.10
2.19.9
2.19.8
2.19.7
2.19.6
2.19.5
2.19.4
2.19.3
retired
2.19.2
retired
2.19.1
retired
2.19.0
retired
2.18.2
2.18.1
2.18.0
2.17.24
2.17.23
2.17.22
2.17.21
2.17.20
2.17.19
2.17.18
2.17.17
2.17.16
2.17.15
2.17.14
2.17.13
2.17.12
2.17.11
2.17.10
2.17.9
2.17.8
2.17.7
2.17.6
2.17.5
2.17.4
2.17.3
2.17.2
2.17.1
2.17.0
2.16.1
2.16.0
2.15.20
2.15.19
2.15.18
2.15.17
2.15.16
2.15.15
2.15.14
2.15.13
2.15.12
2.15.11
2.15.10
2.15.9
2.15.8
2.15.7
2.15.6
2.15.5
2.15.4
2.15.2
2.15.1
2.15.0
2.14.21
2.14.20
2.14.19
2.14.18
2.14.17
2.14.16
2.14.15
2.14.14
2.14.13
2.14.12
2.14.11
2.14.10
2.14.9
2.14.8
2.14.7
2.14.6
2.14.5
2.14.4
2.14.3
2.14.2
2.14.1
2.14.0
2.13.4
retired
2.13.3
2.13.2
2.13.1
2.13.0
2.12.1
2.12.0
2.11.11
2.11.10
2.11.9
2.11.8
2.11.7
2.11.6
2.11.5
2.11.4
2.11.3
2.11.2
2.11.1
2.11.0
2.11.0-rc.3
2.11.0-rc.2
2.11.0-rc.1
2.11.0-rc.0
2.10.2
2.10.1
2.10.0
2.9.29
2.9.28
2.9.27
2.9.26
2.9.25
2.9.24
2.9.23
2.9.22
2.9.21
2.9.20
2.9.19
2.9.18
2.9.17
2.9.16
2.9.15
2.9.14
2.9.13
2.9.12
2.9.11
2.9.10
2.9.9
2.9.8
2.9.7
2.9.6
2.9.5
2.9.4
2.9.3
2.9.2
2.9.1
2.9.0
2.8.1
2.8.0
2.7.1
2.7.0
2.6.31
2.6.30
2.6.29
2.6.28
2.6.27
2.6.26
2.6.25
2.6.24
2.6.23
2.6.22
2.6.21
2.6.20
2.6.19
2.6.18
2.6.17
2.6.16
2.6.15
2.6.14
2.6.13
2.6.11
2.6.10
2.6.9
2.6.8
2.6.7
2.6.6
2.6.5
2.6.4
2.6.3
2.6.2
2.6.1
2.6.0
2.5.16
2.5.15
2.5.14
2.5.13
2.5.12
2.5.11
2.5.10
2.5.9
2.5.8
2.5.7
2.5.6
2.5.5
2.5.4
2.5.3
2.5.2
2.5.1
2.5.0
2.5.0-rc.6
2.5.0-rc.5
2.5.0-rc.4
2.5.0-rc.3
2.5.0-rc.2
2.5.0-rc.1
2.5.0-rc.0
2.4.30
2.4.29
2.4.28
2.4.27
2.4.26
2.4.25
2.4.24
2.4.23
2.4.22
2.4.21
2.4.20
2.4.19
2.4.18
2.4.17
2.4.16
2.4.15
2.4.14
2.4.13
2.4.12
2.4.11
2.4.10
2.4.9
2.4.8
2.4.7
2.4.6
2.4.5
2.4.4
2.4.3
2.4.2
2.4.1
2.4.0
2.3.0
2.2.0
2.1.0
2.0.0
2.0.0-rc.15
2.0.0-rc.14
2.0.0-rc.13
2.0.0-rc.12
2.0.0-rc.11
2.0.0-rc.10
2.0.0-rc.9
2.0.0-rc.8
2.0.0-rc.7
2.0.0-rc.6
2.0.0-rc.5
2.0.0-rc.4
2.0.0-rc.3
2.0.0-rc.2
2.0.0-rc.1
2.0.0-rc.0
2.0.0-pre.8
2.0.0-pre.7
2.0.0-pre.6
2.0.0-pre.5
2.0.0-pre.4
2.0.0-pre.3
2.0.0-pre.2
2.0.0-pre.1
2.0.0-pre.0
1.53.3
1.53.2
1.53.0
1.52.0-rc.22
1.52.0-rc.21
1.52.0-rc.20
1.52.0-rc.19
1.52.0-rc.18
1.52.0-rc.17
1.52.0-rc.16
1.52.0-rc.15
1.52.0-rc.14
1.52.0-rc.13
1.52.0-rc.12
1.52.0-rc.11
1.52.0-rc.10
1.52.0-rc.9
1.52.0-rc.8
1.52.0-rc.7
1.52.0-rc.6
1.52.0-rc.5
1.52.0-rc.4
1.52.0-rc.3
1.52.0-rc.2
1.52.0-rc.1
1.52.0-rc.0
1.51.2
1.51.1
retired
1.51.0
1.50.21
1.50.20
1.50.19
1.50.18
1.50.17
1.50.16
1.50.15
1.50.14
1.50.13
1.50.12
1.50.11
1.50.10
1.50.9
1.50.8
1.50.7
1.50.6
1.50.5
1.50.4
1.50.3
1.50.2
1.50.1
1.50.0
1.49.0
1.48.0-rc.30
1.48.0-rc.29
1.48.0-rc.28
1.48.0-rc.27
1.48.0-rc.26
1.48.0-rc.25
1.48.0-rc.24
1.48.0-rc.23
1.48.0-rc.22
1.48.0-rc.21
1.48.0-rc.20
1.48.0-rc.19
1.48.0-rc.18
1.48.0-rc.17
1.48.0-rc.16
1.48.0-rc.15
1.48.0-rc.14
1.48.0-rc.13
1.48.0-rc.12
1.48.0-rc.11
1.48.0-rc.10
1.48.0-rc.9
1.48.0-rc.8
1.48.0-rc.7
1.48.0-rc.6
1.48.0-rc.5
1.48.0-rc.4
1.48.0-rc.3
1.48.0-rc.2
1.48.0-rc.1
1.48.0-rc.0
1.47.12
1.47.11
1.47.10
1.47.9
1.47.8
1.47.7
1.47.6
1.47.5
1.47.4
1.47.3
1.47.2
1.47.1
1.47.0
1.46.13
1.46.12
1.46.11
1.46.10
1.46.9
1.46.8
1.46.7
1.46.6
1.46.5
1.46.4
1.46.3
1.46.2
1.46.1
1.46.0
1.45.0-rc9
1.45.0-rc8
1.45.0-rc7
1.45.0-rc6
1.45.0-rc5
1.45.0-rc4
1.45.0-rc3
1.45.0-rc20
1.45.0-rc2
1.45.0-rc19
1.45.0-rc18
1.45.0-rc17
1.45.0-rc16
1.45.0-rc15
1.45.0-rc14
1.45.0-rc13
1.45.0-rc12
1.45.0-rc11
1.45.0-rc10
1.45.0-rc1
1.45.0-rc0
1.44.13
1.44.12
1.44.11
1.44.10
1.44.9
1.44.8
1.44.7
1.44.6
1.44.5
1.44.4
1.44.3
1.44.2
1.44.1
1.44.0
1.43.12
1.43.11
1.43.10
1.43.9
1.43.8
1.43.7
1.43.6
1.43.5
1.43.4
1.43.3
1.43.2
1.43.1
1.43.0
1.42.0
1.41.12
1.41.11
1.41.10
1.41.9
1.41.8
1.41.7
1.41.6
1.41.5
1.41.4
1.41.3
1.41.2
1.41.1
1.41.0
1.40.0
1.39.7
1.39.6
1.39.5
1.39.4
1.39.3
1.39.2
1.39.1
1.39.0
1.38.0
1.37.2
1.37.1
1.37.0
1.36.22
1.36.21
1.36.19
1.36.18
1.36.17
1.36.16
1.36.15
1.36.14
1.36.13
1.36.12
1.36.11
1.36.10
1.36.9
1.36.8
1.36.7
1.36.6
1.36.5
1.36.4
1.36.3
1.36.2
1.36.0
1.35.1
1.35.0
1.34.9
1.34.8
1.34.7
1.34.6
1.34.5
1.34.4
1.34.3
1.34.2
1.34.1
1.34.0
1.33.0
1.32.2
1.32.1
1.32.0
1.31.1
1.31.0
1.30.2
1.30.1
1.29.0-rc1
1.29.0-rc0
1.28.1
1.28.0
1.27.1
1.27.0
1.26.13
1.26.12
1.26.11
1.26.10
1.26.9
1.26.8
1.26.7
1.26.6
1.26.5
1.26.4
1.26.2
1.26.1
1.26.0
1.25.8
1.25.7
1.25.6
1.25.5
1.25.4
1.25.3
1.25.2
1.25.1
1.25.0
1.24.2
1.24.1
1.24.0
1.23.3
1.23.2
1.23.1
1.23.0
1.22.1
1.22.0
1.20.1
1.20.0
1.19.1
1.19.0
1.18.1
1.18.0
1.17.1
1.17.0
1.16.2
1.15.1
1.15.0
1.14.0
1.13.4
1.13.3
1.13.2
1.13.1
1.13.0
1.12.0
1.11.1
1.11.0
1.10.0
1.9.0
1.8.0
1.7.0
1.6.8
1.6.7
1.6.6
1.6.5
1.6.4
1.6.3
1.6.2
1.6.1
1.6.0
1.5.1
1.5.0
1.4.1
1.4.0
1.3.1
1.3.0
1.2.1
1.2.0
1.1.3
1.1.2
1.1.0
1.0.3
1.0.2
1.0.1
1.0.0
0.13.1
0.13.0
0.12.0
0.10.0
0.9.1
0.9.0
0.8.0
0.7.0
0.6.5
0.6.4
0.6.3
0.6.2
0.6.1
0.6.0
0.5.2
0.5.1
0.5.0
0.4.0
0.3.0
0.2.0
0.1.9
0.1.8
0.1.3
0.1.1
0.1.0
A declarative, extensible framework for building Elixir applications.
Security advisory:
This version has known vulnerabilities.
View advisories
Current section
Files
Jump to
Current section
Files
documentation/topics/resources/preparations.md
# Preparations
Preparations are the primary way of customizing read action behavior. If you are familiar with `Plug`, you can think of an `Ash.Resource.Preparation` as the equivalent of a `Plug` for queries. At its most basic, a preparation will take a query and return a new query. Queries can be simple, like adding a filter or a sort, or more complex, attaching hooks to be executed within the lifecycle of the action.
## Builtin Preparations
There are builtin preparations that can be used, and are automatically imported into your resources. See `Ash.Resource.Preparation.Builtins` for more.
The primary preparation you will use is `build/1`, which passes the arguments through to `Ash.Query.build/2` when the preparation is run. See that function for what options can be provided.
Some examples of usage of builtin preparations
```elixir
# sort by inserted at descending
prepare build(sort: [inserted_at: :desc])
# only show the top 5 results
prepare build(sort: [total_points: :desc], limit: 5)
```
## Custom Preparations
```elixir
defmodule MyApp.Preparations.Top5 do
use Ash.Resource.Preparation
# transform and validate opts
@impl true
def init(opts) do
if is_atom(opts[:attribute]) do
{:ok, opts}
else
{:error, "attribute must be an atom!"}
end
end
@impl true
def prepare(query, opts, _context) do
attribute = opts[:attribute]
query
|> Ash.Query.sort([{attribute, :desc}])
|> Ash.Query.limit(5)
end
end
```
This could then be used in a resource via:
```elixir
prepare {MyApp.Preparations.Top5, attribute: :foo}
```
## Anonymous Function Queries
You can also use anonymous functions for preparations. This is great for prototyping, but we generally recommend using a module for organizational purposes.
```elixir
prepare fn query, _context ->
# put your code here
end
```
## Action vs Global Preparations
You can place a preparation on a read action, like so:
```elixir
actions do
read :read do
prepare {Top5, attribute: :name}
end
end
```
Or you can use the global preparations block to apply to all read actions.
```elixir
preparations do
prepare {Top5, attribute: :name}
end
```
The preparations section allows you to add preparations across multiple actions of a resource.