View Source Goal ⚽
A library for parsing and validating parameters. Goal takes the params
(e.g. from an Phoenix controller), validates them against a schema, and returns an atom-based map or an error changeset. It's based on Ecto, so every validation that you have for database fields can be applied in validating parameters.
Goal is different from other validation libraries because of its syntax, being Ecto-based, and validating data using functions from Ecto.Changeset
instead of building embedded Ecto.Schema
s in the background.
Additionally, Goal allows you to configure your own regexes. This is helpful in case of backward compatibility, where Goal's defaults might not match your production system's behavior.
installation
Installation
Add goal
to the list of dependencies in mix.exs
:
def deps do
[
{:goal, "~> 0.1.1"}
]
end
usage
Usage
Goal's entry point is Goal.validate_params/2
, which receives the parameters and a validation schema. The parameters must be a map, and can be string-based or atom-based. Goal needs a validation schema (also a map) to parse and validate the parameters. You can build one with the defschema
macro:
defmodule MyApp.SomeController do
import Goal
import Goal.Syntax
def create(conn, params) do
with {:ok, attrs} <- validate_params(params, schema()) do
...
end
end
defp schema do
defschema do
required :uuid, :string, format: :uuid
required :name, :string, min: 3, max: 3
optional :age, :integer, min: 0, max: 120
optional :gender, :enum, values: ["female", "male", "non-binary"]
optional :data, :map do
required :color, :string
optional :money, :decimal
optional :height, :float
end
end
end
end
The defschema
macro converts the given structure into a validation schema at compile-time. You can also use the basic syntax like in the example below. The basic syntax is what defschema
compiles to.
defmodule MyApp.SomeController do
import Goal
@schema %{
id: [format: :uuid, required: true],
name: [min: 3, max: 20, required: true],
age: [type: :integer, min: 0, max: 120],
gender: [type: :enum, values: ["female", "male", "non-binary"]],
data: [
type: :map,
properties: %{
color: [required: true],
money: [type: :decimal],
height: [type: :float]
}
]
}
def create(conn, params) do
with {:ok, attrs} <- validate_params(params, @schema) do
...
end
end
end
features
Features
bring-your-own-regex
Bring your own regex
Goal has sensible defaults for string format validation. If you'd like to use your own regex, e.g. for validating email addresses or passwords, then you can add your own regex in the configuration:
config :goal,
uuid_regex: ~r/^[[:alpha:]]+$/,
email_regex: ~r/^[[:alpha:]]+$/,
password_regex: ~r/^[[:alpha:]]+$/,
url_regex: ~r/^[[:alpha:]]+$/
deeply-nested-maps
Deeply nested maps
Goal efficiently builds error changesets for nested maps, and has support for lists of nested maps. There is no limitation on depth.
params = %{
"nested_map" => %{
"map" => %{
"inner_map" => %{
"id" => 123,
"list" => [1, 2, 3]
}
}
}
}
schema = %{
nested_map: [
type: :map,
properties: %{
inner_map: [
type: :map,
properties: %{
map: [
type: :map,
properties: %{
id: [type: :integer, required: true],
list: [type: {:array, :integer}]
}
]
}
]
}
]
}
iex(3)> Goal.validate_params(params, schema)
{:ok, %{nested_map: %{inner_map: %{map: %{id: 123, list: [1, 2, 3]}}}}}
use-defschema-to-reduce-boilerplate
Use defschema to reduce boilerplate
Goal provides a macro called Goal.Syntax.defschema/1
to build validation schemas without all
the boilerplate code. The previous example of deeply nested maps can be rewritten to:
import Goal.Syntax
params = %{...}
schema =
defschema do
optional :nested_map, :map do
optional :inner_map, :map do
optional :map, :map do
required :id, :integer
optional :list, {:array, :integer}
end
end
end
end
iex(3)> Goal.validate_params(params, schema)
{:ok, %{nested_map: %{inner_map: %{map: %{id: 123, list: [1, 2, 3]}}}}}
readable-error-messages
Readable error messages
Use Goal.traverse_errors/2
to build readable errors. Phoenix by default uses Ecto.Changeset.traverse_errors/2
, which works for embedded Ecto schemas but not for the plain nested maps used by Goal. Goal's traverse_errors/2
is compatible with (embedded) Ecto.Schema
s, so you don't have to make any changes to your existing logic.
def translate_errors(changeset) do
Goal.traverse_errors(changeset, &translate_error/1)
end
available-validations
Available validations
The field types and available validations are:
Field type | Validations | Description |
---|---|---|
:string | :equals | string value |
:is | string length | |
:min | minimum string length | |
:max | maximum string length | |
:trim | oolean to remove leading and trailing spaces | |
:squish | boolean to trim and collapse spaces | |
:format | :uuid , :email , :password , :url | |
:subset | list of required strings | |
:included | list of allowed strings | |
:excluded | list of disallowed strings | |
:integer | :equals | integer value |
:is | integer value | |
:min | minimum integer value | |
:max | maximum integer value | |
:greater_than | minimum integer value | |
:less_than | maximum integer value | |
:greater_than_or_equal_to | minimum integer value | |
:less_than_or_equal_to | maximum integer value | |
:equal_to | integer value | |
:not_equal_to | integer value | |
:subset | list of required integers | |
:included | list of allowed integers | |
:excluded | list of disallowed integers | |
:float | all of the integer validations | |
:decimal | all of the integer validations | |
:boolean | :equals | boolean value |
:date | :equals | date value |
:time | :equals | time value |
:enum | :values | list of allowed values |
:map | :properties | use :properties to define the fields |
{:array, :map} | :properties | use :properties to define the fields |
{:array, inner_type} | inner_type can be any of the basic types | |
More basic types | See Ecto.Schema for the full list |
The default basic type is :string
. You don't have to define this field if you are using the basic syntax.
All field types, exluding :map
and {:array, :map}
, can use :equals
, :subset
, :included
, :excluded
validations.
roadmap
Roadmap
- [x] Bring your own regex
- [x] ExDoc documentation
- [x] Basic syntax optimizations
- [x] Macro for generating schemas without boilerplate
- [x] Release v0.1.0 on Hex.pm
- [ ] Convert incoming params from
camelCase
tosnake_case
credits
Credits
This library is based on Ecto and I had to copy and adapt Ecto.Changeset.traverse_errors/2
. Thanks for making such an awesome library! 🙇