Convert a type into a plain Schema.

In previous versions of the package there was a separate type called ParamSchema, which was included in a greater Schema. Now this is a single class, but distinction for schema generators for "simple" types is preserved.

ToParamSchema is suited only for primitive-like types without nested fields and such.

An example type and instance:

{-# LANGUAGE OverloadedStrings #-}   -- allows to write Text literals

import Control.Lens

data Direction = Up | Down

instance ToParamSchema Direction where
  toParamSchema _ = mempty
     & type_ ?~ OpenApiString
     & enum_ ?~ [ "Up", "Down" ]

Instead of manually writing your ToParamSchema instance you can use a default generic implementation of toParamSchema.

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

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

{-# LANGUAGE DeriveGeneric #-}

import GHC.Generics (Generic)

data Direction = Up | Down deriving Generic

instance ToParamSchema Direction

A configurable generic Schema creator.

>>> :set -XDeriveGeneric
>>> data Color = Red | Blue deriving Generic
>>> BSL.putStrLn $ encodePretty $ genericToParamSchema defaultSchemaOptions (Proxy :: Proxy Color)
{
    "enum": [
        "Red",
        "Blue"
    ],
    "type": "string"
}

Default plain schema for Bounded, Integral types.

>>> BSL.putStrLn $ encodePretty $ toParamSchemaBoundedIntegral (Proxy :: Proxy Int8)
{
    "maximum": 127,
    "minimum": -128,
    "type": "integer"
}

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

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

Default schema for binary data (base64 encoded).

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

Default encoding SchemaOptions.

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