Data.Swagger.Schema

Types and functions for working with Swagger schema.

Encoding

class ToSchema a where

Convert a type into Schema.

An example type and instance:

{-# LANGUAGE OverloadedStrings #-}   -- allows to write Text literals
{-# LANGUAGE OverloadedLists #-}     -- allows to write Map and HashMap as lists

import Control.Lens

data Coord = Coord { x :: Double, y :: Double }

instance ToSchema Coord where
  declareNamedSchema = pure (Just "Coord", schema)
   where
     schema = mempty
       & type_ .~ SwaggerObject
       & properties .~
           [ ("x", toSchemaRef (Proxy :: Proxy Double))
           , ("y", toSchemaRef (Proxy :: Proxy Double))
           ]
       & required .~ [ "x", "y" ]

Instead of manually writing your ToSchema instance you can use a default generic implementation of declareNamedSchema.

To do that, simply add deriving Generic clause to your datatype and declare a ToSchema instance for your datatype without giving definition for declareNamedSchema.

For instance, the previous example can be simplified into this:

{-# LANGUAGE DeriveGeneric #-}

import GHC.Generics (Generic)

data Coord = Coord { x :: Double, y :: Double } deriving Generic

instance ToSchema Coord

Minimal complete definition

Nothing

Methods

declareNamedSchema :: proxy a -> Declare (Definitions Schema) NamedSchema

Convert a type into an optionally named schema together with all used definitions. Note that the schema itself is included in definitions only if it is recursive (and thus needs its definition in scope).

Instances

ToSchema Bool

ToSchema Char

ToSchema Double

ToSchema Float

ToSchema Int

ToSchema Int8

ToSchema Int16

ToSchema Int32

ToSchema Int64

ToSchema Integer

ToSchema Word

ToSchema Word8

ToSchema Word16

ToSchema Word32

ToSchema Word64

ToSchema String

ToSchema ()

ToSchema Scientific

ToSchema Text

ToSchema UTCTime

>>> toSchema (Proxy :: Proxy UTCTime) ^. format
Just "yyyy-mm-ddThh:MM:ssZ"

ToSchema Text

ToSchema All

ToSchema Any

ToSchema IntSet

ToSchema LocalTime

>>> toSchema (Proxy :: Proxy LocalTime) ^. format
Just "yyyy-mm-ddThh:MM:ss"

ToSchema ZonedTime

Format "date" corresponds to yyyy-mm-ddThh:MM:ss(Z|+hh:MM) format.

ToSchema NominalDiffTime

ToSchema Day

Format "date" corresponds to yyyy-mm-dd format.

ToSchema a => ToSchema [a]

ToSchema a => ToSchema (Maybe a)

ToSchema a => ToSchema (Dual a)

ToSchema a => ToSchema (Sum a)

ToSchema a => ToSchema (Product a)

ToSchema a => ToSchema (First a)

ToSchema a => ToSchema (Last a)

ToSchema a => ToSchema (IntMap a)

NOTE: This schema does not account for the uniqueness of keys.

ToSchema a => ToSchema (Set a)

ToSchema a => ToSchema (Vector a)

ToSchema a => ToSchema (Vector a)

ToSchema a => ToSchema (Vector a)

ToSchema a => ToSchema (Vector a)

ToSchema a => ToSchema (HashSet a)

(ToSchema a, ToSchema b) => ToSchema (Either a b)

(ToSchema a, ToSchema b) => ToSchema (a, b)

ToSchema a => ToSchema (HashMap String a)

ToSchema a => ToSchema (HashMap Text a)

ToSchema a => ToSchema (HashMap Text a)

ToSchema a => ToSchema (Map String a)

ToSchema a => ToSchema (Map Text a)

ToSchema a => ToSchema (Map Text a)

(ToSchema a, ToSchema b, ToSchema c) => ToSchema (a, b, c)

(ToSchema a, ToSchema b, ToSchema c, ToSchema d) => ToSchema (a, b, c, d)

(ToSchema a, ToSchema b, ToSchema c, ToSchema d, ToSchema e) => ToSchema (a, b, c, d, e)

(ToSchema a, ToSchema b, ToSchema c, ToSchema d, ToSchema e, ToSchema f) => ToSchema (a, b, c, d, e, f)

(ToSchema a, ToSchema b, ToSchema c, ToSchema d, ToSchema e, ToSchema f, ToSchema g) => ToSchema (a, b, c, d, e, f, g)

declareSchema :: ToSchema a => proxy a -> Declare (Definitions Schema) Schema

Convert a type into a schema and declare all used schema definitions.

declareSchemaRef :: ToSchema a => proxy a -> Declare (Definitions Schema) (Referenced Schema)

Convert a type into a referenced schema if possible and declare all used schema definitions. Only named schemas can be referenced, nameless schemas are inlined.

Schema definitions are typically declared for every referenced schema. If declareSchemaRef returns a reference, a corresponding schema will be declared (regardless of whether it is recusive or not).

toSchema :: ToSchema a => proxy a -> Schema

Convert a type into a schema.

>>> encode $ toSchema (Proxy :: Proxy Int8)
"{\"maximum\":127,\"minimum\":-128,\"type\":\"integer\"}"

>>> encode $ toSchema (Proxy :: Proxy [Day])
"{\"items\":{\"$ref\":\"#/definitions/Day\"},\"type\":\"array\"}"

toSchemaRef :: ToSchema a => proxy a -> Referenced Schema

Convert a type into a referenced schema if possible. Only named schemas can be referenced, nameless schemas are inlined.

>>> encode $ toSchemaRef (Proxy :: Proxy Integer)
"{\"type\":\"integer\"}"

>>> encode $ toSchemaRef (Proxy :: Proxy Day)
"{\"$ref\":\"#/definitions/Day\"}"

schemaName :: ToSchema a => proxy a -> Maybe Text

Get type's schema name according to its ToSchema instance.

>>> schemaName (Proxy :: Proxy Int)
Nothing

>>> schemaName (Proxy :: Proxy UTCTime)
Just "UTCTime"

toInlinedSchema :: ToSchema a => proxy a -> Schema

Convert a type into a schema without references.

>>> encode $ toInlinedSchema (Proxy :: Proxy [Day])
"{\"items\":{\"format\":\"date\",\"type\":\"string\"},\"type\":\"array\"}"

WARNING: toInlinedSchema will produce infinite schema when inlining recursive schemas.

Generic schema encoding

genericDeclareNamedSchema :: forall a proxy. (Generic a, GToSchema (Rep a)) => SchemaOptions -> proxy a -> Declare (Definitions Schema) NamedSchema

A configurable generic NamedSchema creator. This function applied to defaultSchemaOptions is used as the default for declareNamedSchema when the type is an instance of Generic.

genericDeclareSchema :: (Generic a, GToSchema (Rep a)) => SchemaOptions -> proxy a -> Declare (Definitions Schema) Schema

A configurable generic Schema creator.

genericToNamedSchemaBoundedIntegral :: forall a d f proxy. (Bounded a, Integral a, Generic a, Rep a ~ D1 d f, Datatype d) => SchemaOptions -> proxy a -> NamedSchema

Default generic named schema for Bounded, Integral types.

toSchemaBoundedIntegral :: forall a proxy. (Bounded a, Integral a) => proxy a -> Schema

Default schema for Bounded, Integral types.

>>> encode $ toSchemaBoundedIntegral (Proxy :: Proxy Int16)
"{\"maximum\":32767,\"minimum\":-32768,\"type\":\"integer\"}"

paramSchemaToNamedSchema :: forall a d f proxy. (ToParamSchema a, Generic a, Rep a ~ D1 d f, Datatype d) => SchemaOptions -> proxy a -> NamedSchema

Lift a plain ParamSchema into a model NamedSchema.

paramSchemaToSchema :: forall a proxy. ToParamSchema a => proxy a -> Schema

Lift a plain ParamSchema into a model Schema.

Schema templates

passwordSchema :: Schema

Default schema for password string. "password" format is used to hint UIs the input needs to be obscured.

binarySchema :: Schema

Default schema for binary data (any sequence of octets).

byteSchema :: Schema

Default schema for binary data (base64 encoded).

Sketching Schemas using ToJSON

sketchSchema :: ToJSON a => a -> Schema

Make an unrestrictive sketch of a Schema based on a ToJSON instance. Produced schema can be used for further refinement.

>>> encode $ sketchSchema "hello"
"{\"example\":\"hello\",\"type\":\"string\"}"

>>> encode $ sketchSchema (1, 2, 3)
"{\"example\":[1,2,3],\"items\":{\"type\":\"number\"},\"type\":\"array\"}"

>>> encode $ sketchSchema ("Jack", 25)
"{\"example\":[\"Jack\",25],\"items\":[{\"type\":\"string\"},{\"type\":\"number\"}],\"type\":\"array\"}"

>>> data Person = Person { name :: String, age :: Int } deriving (Generic)
>>> instance ToJSON Person
>>> encode $ sketchSchema (Person "Jack" 25)
"{\"example\":{\"age\":25,\"name\":\"Jack\"},\"required\":[\"age\",\"name\"],\"type\":\"object\",\"properties\":{\"age\":{\"type\":\"number\"},\"name\":{\"type\":\"string\"}}}"

sketchStrictSchema :: ToJSON a => a -> Schema

Make a restrictive sketch of a Schema based on a ToJSON instance. Produced schema uses as much constraints as possible.

>>> encode $ sketchStrictSchema "hello"
"{\"maxLength\":5,\"pattern\":\"hello\",\"minLength\":5,\"type\":\"string\",\"enum\":[\"hello\"]}"

>>> encode $ sketchStrictSchema (1, 2, 3)
"{\"minItems\":3,\"uniqueItems\":true,\"items\":[{\"maximum\":1,\"minimum\":1,\"multipleOf\":1,\"type\":\"number\",\"enum\":[1]},{\"maximum\":2,\"minimum\":2,\"multipleOf\":2,\"type\":\"number\",\"enum\":[2]},{\"maximum\":3,\"minimum\":3,\"multipleOf\":3,\"type\":\"number\",\"enum\":[3]}],\"maxItems\":3,\"type\":\"array\",\"enum\":[[1,2,3]]}"

>>> encode $ sketchStrictSchema ("Jack", 25)
"{\"minItems\":2,\"uniqueItems\":true,\"items\":[{\"maxLength\":4,\"pattern\":\"Jack\",\"minLength\":4,\"type\":\"string\",\"enum\":[\"Jack\"]},{\"maximum\":25,\"minimum\":25,\"multipleOf\":25,\"type\":\"number\",\"enum\":[25]}],\"maxItems\":2,\"type\":\"array\",\"enum\":[[\"Jack\",25]]}"

>>> data Person = Person { name :: String, age :: Int } deriving (Generic)
>>> instance ToJSON Person
>>> encode $ sketchStrictSchema (Person "Jack" 25)
"{\"minProperties\":2,\"required\":[\"age\",\"name\"],\"maxProperties\":2,\"type\":\"object\",\"enum\":[{\"age\":25,\"name\":\"Jack\"}],\"properties\":{\"age\":{\"maximum\":25,\"minimum\":25,\"multipleOf\":25,\"type\":\"number\",\"enum\":[25]},\"name\":{\"maxLength\":4,\"pattern\":\"Jack\",\"minLength\":4,\"type\":\"string\",\"enum\":[\"Jack\"]}}}"

Inlining Schemas

inlineNonRecursiveSchemas :: Data s => Definitions Schema -> s -> s

Inline all non-recursive schemas for which the definition can be found in Definitions.

inlineAllSchemas :: Data s => Definitions Schema -> s -> s

Inline all schema references for which the definition can be found in Definitions.

WARNING: inlineAllSchemas will produce infinite schemas when inlining recursive schemas.

inlineSchemas :: Data s => [Text] -> Definitions Schema -> s -> s

Inline any referenced schema if its name is in the given list.

NOTE: if a referenced schema is not found in definitions it stays referenced even if it appears in the list of names.

WARNING: inlineSchemas will produce infinite schemas when inlining recursive schemas.

inlineSchemasWhen :: Data s => (Text -> Bool) -> Definitions Schema -> s -> s

Inline any referenced schema if its name satisfies given predicate.

NOTE: if a referenced schema is not found in definitions the predicate is ignored and schema stays referenced.

WARNING: inlineSchemasWhen will produce infinite schemas when inlining recursive schemas.

Generic encoding configuration

data SchemaOptions

Options that specify how to encode your type to Swagger schema.

Constructors

SchemaOptions

Fields

fieldLabelModifier :: String -> String

Function applied to field labels. Handy for removing common record prefixes for example.

constructorTagModifier :: String -> String

Function applied to constructor tags which could be handy for lower-casing them for example.

datatypeNameModifier :: String -> String

Function applied to datatype name.

allNullaryToStringTag :: Bool

If True the constructors of a datatype, with all nullary constructors, will be encoded to a string enumeration schema with the constructor tags as possible values.

unwrapUnaryRecords :: Bool

Hide the field name when a record constructor has only one field, like a newtype.

defaultSchemaOptions :: SchemaOptions

Default encoding SchemaOptions.

SchemaOptions
{ fieldLabelModifier     = id
, constructorTagModifier = id
, datatypeNameModifier   = id
, allNullaryToStringTag  = True
, unwrapUnaryRecords     = False
}