# Joi
[](https://hex.pm/packages/joi)
[](https://hexdocs.pm/joi/readme.html)
This project is inspired by [sideway/joi](https://github.com/sideway/joi) and [lob/litmus](https://github.com/lob/litmus).
And the code of this repository is based on [lob/litmus](https://github.com/lob/litmus), but the API of this repository is completely different from litmus.
<!-- MDOC !-->
## Background
The community already has a lot of verification-related libraries, such as skooma, vex, but why write a new one?
The api of vex is very much like Rails ActiveModel Validations, and it feels too complex for me, especially when it comes to customizing some validation modules, which is not convenient and flexible enough. Skooma, on the other hand, is very flexible and I find it particularly useful when validating non-map data structures.
So the **goal** of this repository is:
1. Support most of the types supported by the native [sideway/joi](https://github.com/sideway/joi)
2. Nested validation support.
3. Easy internationalization
4. Easy to extend
## Installation
```elixir
def deps do
[
{:joi, "~> 0.2.0"},
]
end
```
## Usage
Joi validates data against a predefined schema with the `Joi.validate/2` function.
If the data is valid, the function returns `{:ok, data}`. The returned data will perform the transformation according to the provided schema.
if the passed data does not match the type defined in the schema, the function returns `{:error, errors}`, the `errors` is a list of `Joi.Error`, that a struct contains four fields:
* `context`: map providing context of the error containing:
+ `key`: key of the value that erred, equivalent to the last element of path.
+ `value`: the value that failed validation.
+ other error specific properties as described for each error code.
* `message`: string with a description of the error.
* `path`: list where each element is the accessor to the value where the error happened.
* `type`: type of the error.
, When a field is received that is not specified in the provided schema, it does nothing and returns `{:ok, data}`.
```elixir
iex> schema = %{a: [:integer]}
%{a: [:integer]}
iex> data1 = %{a: 1}
%{a: 1}
iex> Joi.validate(data1, schema)
{:ok, %{a: 1}}
iex> data2 = %{a: <<123>>}
iex> Joi.validate(data2, schema)
{:error,
[
%Joi.Error{
context: %{key: :a, value: "{"},
message: "a must be a integer",
path: [:a],
type: "integer.base"
}
]}
```
### Supported Types
* [`atom`](#Atom)
* [`boolean`](#Boolean)
* [`date`](#Date)
* [`datetime`](#Datetime)
* [`decimal`](#Decimal)
* [`float`](#Float)
* [`integer`](#Integer)
* [`list`](#List)
* [`map`](#Map)
* [`string`](#String)
#### Atom
error types
* `atom.base`
* `atom.inclusion`
Additional local context properties:
```elixir
%{inclusion: list()}
```
* `atom.required`
#### Boolean
error types
* `boolean.base`
* `boolean.required`
#### Date
error types
* `date.base`
Examples:
```elixir
iex> schema = %{day: [:date]}
%{day: [:date]}
iex> Joi.validate(%{day: "2021-07-20"}, schema)
{:ok, %{day: ~D[2021-07-20]}}
iex> Joi.validate(%{day: "20210720"}, schema)
{:error,
[
%Joi.Error{
context: %{key: :day, value: "20210720"},
message: "day must be a valid ISO-8601 date",
path: [:day],
type: "date.base"
}
]}
```
* `date.required`
#### Datetime
error types
* `datetime.base`
Examples:
```elixir
iex> schema = %{t: [:datetime]}
%{t: [:datetime]}
iex> d = %{t: ~U[2021-08-27 00:30:59.783833Z]}
%{t: ~U[2021-08-27 00:30:59.783833Z]}
iex> Joi.validate(d, schema)
{:ok, %{t: ~U[2021-08-27 00:30:59.783833Z]}}
iex> d2 = %{t: "2021-08-27 00:30:59.783833Z"}
%{t: "2021-08-27 00:30:59.783833Z"}
iex> Joi.validate(d2, schema)
{:ok, %{t: ~U[2021-08-27 00:30:59.783833Z]}}
iex> d3 = %{t: "2021-08-27 00:30:59"}
%{t: "2021-08-27 00:30:59"}
iex> Joi.validate(d3, schema)
{:error,
[
%Joi.Error{
context: %{key: :t, value: "2021-08-27 00:30:59"},
message: "t must be a valid ISO-8601 datetime",
path: [:t],
type: "datetime.base"
}
]}
```
* `datetime.required`
#### Decimal
error types
* `decimal.base`
* `decimal.inclusion`
Additional local context properties:
```elixir
%{inclusion: list()}
```
Examples:
```elixir
iex> schema = %{d: [:decimal, inclusion: [Decimal.new(1)]]}
%{d: [:decimal, {:inclusion, [Decimal.new(1)]}]}
iex> Joi.validate(%{d: Decimal.new(2)}, schema)
{:error,
[
%Joi.Error{
context: %{inclusion: [Decimal.new(1)], key: :d, value: Decimal.new(2)},
message: "d must be one of #{inspect [Decimal.new(1)]}",
path: [:d],
type: "decimal.inclusion"
}
]}
```
* `decimal.max`
Additional local context properties:
```elixir
%{limit: Decimal.t()}
```
Examples:
```elixir
iex> schema = %{n: [:decimal, max: 1]}
%{n: [:decimal, {:max, 1}]}
iex> Joi.validate(%{n: 0}, schema)
{:ok, %{n: Decimal.new(0)}}
iex> Joi.validate(%{n: "2"}, schema)
{:error,
[
%Joi.Error{
# string value will be converted to a float
context: %{key: :n, limit: Decimal.new(1), value: Decimal.from_float(2.0)},
message: "n must be less than or equal to 1",
path: [:n],
type: "decimal.max"
}
]}
iex> # max also support Decimal.t()
iex> schema = %{n: [:decimal, max: Decimal.new(1)]}
%{n: [:decimal, {:max, Decimal.new(1)}]}
iex> Joi.validate(%{n: 2}, schema)
{:error,
[
%Joi.Error{
context: %{key: :n, limit: Decimal.new(1), value: Decimal.new(2)},
message: "n must be less than or equal to 1",
path: [:n],
type: "decimal.max"
}
]}
iex> # max also support float
iex> schema = %{n: [:decimal, max: 1.1]}
%{n: [:decimal, {:max, 1.1}]}
iex> Joi.validate(%{n: 2}, schema)
{:error,
[
%Joi.Error{
context: %{key: :n, limit: Decimal.from_float(1.1), value: Decimal.new(2)},
message: "n must be less than or equal to 1.1",
path: [:n],
type: "decimal.max"
}
]}
```
* `decimal.min`
Additional local context properties:
```elixir
%{limit: Decimal.t()}
```
* `decimal.greater`
Additional local context properties:
```elixir
%{limit: Decimal.t()}
```
Examples:
```elixir
iex> schema = %{n: [:decimal, greater: 0]}
%{n: [:decimal, {:greater, 0}]}
iex> Joi.validate(%{n: 2}, schema)
{:ok, %{n: Decimal.new(2)}}
iex> Joi.validate(%{n: 0}, schema)
{:error,
[
%Joi.Error{
context: %{key: :n, limit: Decimal.new(0), value: Decimal.new(0)},
message: "n must be greater than 0",
path: [:n],
type: "decimal.greater"
}
]}
```
* `decimal.less`
Additional local context properties:
```elixir
%{limit: Decimal.t()}
```
Examples:
```elixir
iex> schema = %{n: [:decimal, less: 0]}
%{n: [:decimal, {:less, 0}]}
iex> Joi.validate(%{n: -1}, schema)
{:ok, %{n: Decimal.new(-1)}}
iex> Joi.validate(%{n: 0}, schema)
{:error,
[
%Joi.Error{
context: %{key: :n, limit: Decimal.new(0), value: Decimal.new(0)},
message: "n must be less than 0",
path: [:n],
type: "decimal.less"
}
]}
```
* `decimal.required`
#### Float
error types
* `float.base`
* `float.inclusion`
Additional local context properties:
```elixir
%{inclusion: list()}
```
* `float.max`
Additional local context properties:
```elixir
%{limit: float() | integer()}
```
* `float.min`
Additional local context properties:
```elixir
%{limit: float() | integer()}
```
* `float.greater`
Additional local context properties:
```elixir
%{limit: float() | integer()}
```
* `float.less`
Additional local context properties:
```elixir
%{limit: float() | integer()}
```
* `float.required`
#### Integer
error types
* `integer.base`
* `integer.inclusion`
Additional local context properties:
```elixir
%{inclusion: list()}
```
* `integer.max`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `integer.min`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `integer.greater`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `integer.less`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `integer.required`
#### List
list supports some special features, such as validation for each element:
```elixir
iex> schema = %{l: [:list, type: :integer]}
%{l: [:list, {:type, :integer}]}
iex> Joi.validate(%{l: [<<123>>]}, schema)
{:error,
[
%Joi.Error{
context: %{key: :l, value: ["{"]},
message: "l must be a list of integer",
path: [:l],
type: "list.integer"
}
]}
```
or a sub schema:
```elixir
iex> sub_schema = %{key: [:integer]}
%{key: [:integer]}
iex> schema = %{l: [:list, schema: sub_schema]}
%{l: [:list, {:schema, %{key: [:integer]}}]}
iex> Joi.validate(%{l: [%{key: 1}, %{key: <<123>>}]}, schema)
{:error,
[
%Joi.Error{
context: %{key: :key, value: "{"},
message: "key must be a integer",
path: [:l, 1, :key],
type: "integer.base"
}
]}
```
error types
* `list.base`
* `list.length`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `list.max_length`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `list.min_length`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `list.required`
* `list.schema`
* `list.type`
#### Map
`:map` also supports validation with sub schema:
```elixir
iex> sub_schema = %{sub_key: [:integer]}
%{sub_key: [:integer]}
iex> schema = %{m: [:map, schema: sub_schema]}
%{m: [:map, {:schema, %{sub_key: [:integer]}}]}
iex> Joi.validate(%{m: %{sub_key: <<123>>}}, schema)
{:error,
[
%Joi.Error{
context: %{key: :sub_key, value: "{"},
message: "sub_key must be a integer",
path: [:m, :sub_key],
type: "integer.base"
}
]}
```
error types
* `map.base`
* `map.required`
#### String
error types
* `string.base`
* `string.format`
* `string.inclusion`
Additional local context properties:
```elixir
%{inclusion: list()}
```
* `string.length`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `string.max_length`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `string.min_length`
Additional local context properties:
```elixir
%{limit: integer()}
```
* `string.required`
* `string.uuid`
### Custom functions
There is nothing magical about custom functions, you just need to return the same format as Joi's type, and then use `:f` as the key for the custom function in the schema, so you can use one or more custom functions inside a type.
```elixir
iex> import Joi.Util
iex> func = fn field, data ->
...> case data[field] == 1 do
...> true -> {:ok, data}
...> false -> error("custom", path: [field], value: data[field], message: "does not match the custom function")
...> end
...> end
iex> schema = %{id: [:integer, f: func]}
iex> data = %{id: 2}
iex> Joi.validate(data, schema)
{:error, [
%Joi.Error{
context: %{key: :id, message: "does not match the custom function", value: 2},
message: "does not match the custom function",
path: [:id],
type: "custom"
}
]}
```
<!-- MDOC !-->
## Contributing
Feel free to dive in! [Open an issue](https://github.com/scottming/joi/issues/new) or submit PRS.
Joi follows the [Contributor Covenant](https://www.contributor-covenant.org/version/1/3/0/code-of-conduct/) Code of Conduct.
