Servant.Swagger Data.Bson.ObjectId 的 ToSchema

Question

我正在尝试为我的 Servant 项目构建 Swagger 规范。

我的 API 定义的一部分包含具有 _id 类型 Data.Bson.ObjectId

字段的内部模型对象

type API = rest
      :<|> "signup" :> ReqBody '[JSON] Credentials :> Post '[JSON] Account
      :<|> "signin" :> ReqBody '[JSON] Credentials :> Post '[JSON] Session

所以我需要为 Account 和 Session 定义 ToSchema 以避免添加额外的层，这些层将具有 String 字段而不是 ObjectId，因为例如。

data Account = Account
    { _id       :: ObjectId
    , user      :: User
    , createdAt :: UTCTime
    , updatedAt :: UTCTime
    } deriving (Generic, Typeable, Show, Read, Eq, Ord)

instance ToBSON Account
instance FromBSON Account

instance ToJSON Account where
    toJSON (Account oid user createdAt updatedAt) =
        object [ "_id"       .= show oid
               , "user"      .= toJSON user
               , "createdAt" .= iso8601Show createdAt
               , "updatedAt" .= iso8601Show updatedAt ]

instance FromJSON Account where
    parseJSON (Object o) =
        Account <$> o .: "_id"
                <*> o .: "user"
                <*> o .: "createdAt"
                <*> o .: "updatedAt"

instance ToSchema Account where
  declareNamedSchema proxy = genericDeclareNamedSchema defaultSchemaOptions proxy
    & mapped.schema.description ?~ "This is an example of a Account"
    & mapped.schema.example ?~ toJSON Model_Account.demo

instance ToSchema User where
  declareNamedSchema proxy = genericDeclareNamedSchema defaultSchemaOptions proxy
    & mapped.schema.description ?~ "This is an example of a User"
    & mapped.schema.example ?~ toJSON Model_User.demo

instance ToSchema Session where
  declareNamedSchema proxy = genericDeclareNamedSchema defaultSchemaOptions proxy
    & mapped.schema.description ?~ "This is an example of a Session"
    & mapped.schema.example ?~ toJSON Model_Session.demo

我还必须为 ObjectId 实施 ToSchema，但我不知道该怎么做。

instance ToSchema ObjectId where
  declareNamedSchema proxy = genericDeclareNamedSchema defaultSchemaOptions proxy
    & mapped.schema.description ?~ "This is an example of ObjectId"
    & mapped.schema.example ?~ "5e8da2d2393d8b1acd000001"

我收到以下错误

Data.Swagger.Internal.Schema.genericDeclareNamedSchema
:: SchemaOptions
-> Proxy ObjectId -> Declare (Definitions Schema) NamedSchema
Defined in ‘Data.Swagger.Internal.Schema’

Server.hs:210:30: error:
    • Could not deduce: Data.Swagger.Internal.TypeShape.GenericHasSimpleShape
                          ObjectId
                          "genericDeclareNamedSchemaUnrestricted"
                          (Data.Swagger.Internal.TypeShape.GenericShape (Rep ObjectId))
        arising from a use of ‘genericDeclareNamedSchema’
    • In the first argument of ‘(&)’, namely
        ‘genericDeclareNamedSchema defaultSchemaOptions proxy’
      In the first argument of ‘(&)’, namely
        ‘genericDeclareNamedSchema defaultSchemaOptions proxy
           & mapped . schema . description
               ?~ "This is an example of ObjectId"’
      In the expression:
        genericDeclareNamedSchema defaultSchemaOptions proxy
          & mapped . schema . description ?~ "This is an example of ObjectId"
          & mapped . schema . example ?~ "5e8da2d2393d8b1acd000001"
Server.hs:210:30: error:
    • No instance for (Generic ObjectId)
        arising from a use of ‘genericDeclareNamedSchema’
    • In the first argument of ‘(&)’, namely
        ‘genericDeclareNamedSchema defaultSchemaOptions proxy’
      In the first argument of ‘(&)’, namely
        ‘genericDeclareNamedSchema defaultSchemaOptions proxy
           & mapped . schema . description
               ?~ "This is an example of ObjectId"’
      In the expression:
        genericDeclareNamedSchema defaultSchemaOptions proxy
          & mapped . schema . description ?~ "This is an example of ObjectId"
          & mapped . schema . example ?~ "5e8da2d2393d8b1acd000001"

我如何为像 ObjectId 这样的自定义类型添加 ToSchema 实现，它可以很容易地转换为 String，因为它实现了 show/read ？

Answer 1

• No instance for (Generic ObjectId)

顾名思义，genericDeclareNamedSchema 仅适用于具有 Generic. ObjectId does not implement it, so your only option is to declare the schema entirely by hand, see the documentation of ToSchema 实例的数据类型。

Servant.Swagger Data.Bson.ObjectId 的 ToSchema

Servant.Swagger ToSchema for Data.Bson.ObjectId

haskell

bson

swagger