jsonrpc (empty) → 0.2.0.0
raw patch · 6 files changed
+1239/−0 lines, 6 filesdep +aesondep +basedep +hspec
Dependencies added: aeson, base, hspec, jsonrpc, text
Files
- CHANGELOG.md +15/−0
- LICENSE +373/−0
- README.md +41/−0
- jsonrpc.cabal +88/−0
- src/JSONRPC.hs +498/−0
- test/Main.hs +224/−0
+ CHANGELOG.md view
@@ -0,0 +1,15 @@+# Changelog++## 0.2.0++### Added+- Initial release.+- Core JSON-RPC 2.0 types: `JSONRPCRequest`, `JSONRPCResponse`, `JSONRPCError`,+ `JSONRPCNotification`, `JSONRPCMessage`, `JSONRPCErrorInfo`, `RequestId`.+- Type classes for deriving JSON-RPC serialisation: `IsJSONRPCRequest`,+ `IsJSONRPCNotification` with `ViaJSONRPCRequest` / `ViaJSONRPCNotification`+ newtype wrappers for `DerivingVia`.+- Standard JSON-RPC 2.0 error codes: `pARSE_ERROR`, `iNVALID_REQUEST`,+ `mETHOD_NOT_FOUND`, `iNVALID_PARAMS`, `iNTERNAL_ERROR`.+- `rPC_VERSION` constant (`"2.0"`).+- `EmptyParams` placeholder type for methods with no parameters.
+ LICENSE view
@@ -0,0 +1,373 @@+Mozilla Public License Version 2.0+==================================++1. Definitions+--------------++1.1. "Contributor"+ means each individual or legal entity that creates, contributes to+ the creation of, or owns Covered Software.++1.2. "Contributor Version"+ means the combination of the Contributions of others (if any) used+ by a Contributor and that particular Contributor's Contribution.++1.3. "Contribution"+ means Covered Software of a particular Contributor.++1.4. "Covered Software"+ means Source Code Form to which the initial Contributor has attached+ the notice in Exhibit A, the Executable Form of such Source Code+ Form, and Modifications of such Source Code Form, in each case+ including portions thereof.++1.5. "Incompatible With Secondary Licenses"+ means++ (a) that the initial Contributor has attached the notice described+ in Exhibit B to the Covered Software; or++ (b) that the Covered Software was made available under the terms of+ version 1.1 or earlier of the License, but not also under the+ terms of a Secondary License.++1.6. "Executable Form"+ means any form of the work other than Source Code Form.++1.7. "Larger Work"+ means a work that combines Covered Software with other material, in+ a separate file or files, that is not Covered Software.++1.8. "License"+ means this document.++1.9. "Licensable"+ means having the right to grant, to the maximum extent possible,+ whether at the time of the initial grant or subsequently, any and+ all of the rights conveyed by this License.++1.10. "Modifications"+ means any of the following:++ (a) any file in Source Code Form that results from an addition to,+ deletion from, or modification of the contents of Covered+ Software; or++ (b) any new file in Source Code Form that contains any Covered+ Software.++1.11. "Patent Claims" of a Contributor+ means any patent claim(s), including without limitation, method,+ process, and apparatus claims, in any patent Licensable by such+ Contributor that would be infringed, but for the grant of the+ License, by the making, using, selling, offering for sale, having+ made, import, or transfer of either its Contributions or its+ Contributor Version.++1.12. "Secondary License"+ means either the GNU General Public License, Version 2.0, the GNU+ Lesser General Public License, Version 2.1, the GNU Affero General+ Public License, Version 3.0, or any later versions of those+ licenses.++1.13. "Source Code Form"+ means the form of the work preferred for making modifications.++1.14. "You" (or "Your")+ means an individual or a legal entity exercising rights under this+ License. For legal entities, "You" includes any entity that+ controls, is controlled by, or is under common control with You. For+ purposes of this definition, "control" means (a) the power, direct+ or indirect, to cause the direction or management of such entity,+ whether by contract or otherwise, or (b) ownership of more than+ fifty percent (50%) of the outstanding shares or beneficial+ ownership of such entity.++2. License Grants and Conditions+--------------------------------++2.1. Grants++Each Contributor hereby grants You a world-wide, royalty-free,+non-exclusive license:++(a) under intellectual property rights (other than patent or trademark)+ Licensable by such Contributor to use, reproduce, make available,+ modify, display, perform, distribute, and otherwise exploit its+ Contributions, either on an unmodified basis, with Modifications, or+ as part of a Larger Work; and++(b) under Patent Claims of such Contributor to make, use, sell, offer+ for sale, have made, import, and otherwise transfer either its+ Contributions or its Contributor Version.++2.2. Effective Date++The licenses granted in Section 2.1 with respect to any Contribution+become effective for each Contribution on the date the Contributor first+distributes such Contribution.++2.3. Limitations on Grant Scope++The licenses granted in this Section 2 are the only rights granted under+this License. No additional rights or licenses will be implied from the+distribution or licensing of Covered Software under this License.+Notwithstanding Section 2.1(b) above, no patent license is granted by a+Contributor:++(a) for any code that a Contributor has removed from Covered Software;+ or++(b) for infringements caused by: (i) Your and any other third party's+ modifications of Covered Software, or (ii) the combination of its+ Contributions with other software (except as part of its Contributor+ Version); or++(c) under Patent Claims infringed by Covered Software in the absence of+ its Contributions.++This License does not grant any rights in the trademarks, service marks,+or logos of any Contributor (except as may be necessary to comply with+the notice requirements in Section 3.4).++2.4. Subsequent Licenses++No Contributor makes additional grants as a result of Your choice to+distribute the Covered Software under a subsequent version of this+License (see Section 10.2) or under the terms of a Secondary License (if+permitted under the terms of Section 3.3).++2.5. Representation++Each Contributor represents that the Contributor believes its+Contributions are its original creation(s) or it has sufficient rights+to grant the rights to its Contributions conveyed by this License.++2.6. Fair Use++This License is not intended to limit any rights You have under+applicable copyright doctrines of fair use, fair dealing, or other+equivalents.++2.7. Conditions++Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted+in Section 2.1.++3. Responsibilities+-------------------++3.1. Distribution of Source Form++All distribution of Covered Software in Source Code Form, including any+Modifications that You create or to which You contribute, must be under+the terms of this License. You must inform recipients that the Source+Code Form of the Covered Software is governed by the terms of this+License, and how they can obtain a copy of this License. You may not+attempt to alter or restrict the recipients' rights in the Source Code+Form.++3.2. Distribution of Executable Form++If You distribute Covered Software in Executable Form then:++(a) such Covered Software must also be made available in Source Code+ Form, as described in Section 3.1, and You must inform recipients of+ the Executable Form how they can obtain a copy of such Source Code+ Form by reasonable means in a timely manner, at a charge no more+ than the cost of distribution to the recipient; and++(b) You may distribute such Executable Form under the terms of this+ License, or sublicense it under different terms, provided that the+ license for the Executable Form does not attempt to limit or alter+ the recipients' rights in the Source Code Form under this License.++3.3. Distribution of a Larger Work++You may create and distribute a Larger Work under terms of Your choice,+provided that You also comply with the requirements of this License for+the Covered Software. If the Larger Work is a combination of Covered+Software with a work governed by one or more Secondary Licenses, and the+Covered Software is not Incompatible With Secondary Licenses, this+License permits You to additionally distribute such Covered Software+under the terms of such Secondary License(s), so that the recipient of+the Larger Work may, at their option, further distribute the Covered+Software under the terms of either this License or such Secondary+License(s).++3.4. Notices++You may not remove or alter the substance of any license notices+(including copyright notices, patent notices, disclaimers of warranty,+or limitations of liability) contained within the Source Code Form of+the Covered Software, except that You may alter any license notices to+the extent required to remedy known factual inaccuracies.++3.5. Application of Additional Terms++You may choose to offer, and to charge a fee for, warranty, support,+indemnity or liability obligations to one or more recipients of Covered+Software. However, You may do so only on Your own behalf, and not on+behalf of any Contributor. You must make it absolutely clear that any+such warranty, support, indemnity, or liability obligation is offered by+You alone, and You hereby agree to indemnify every Contributor for any+liability incurred by such Contributor as a result of warranty, support,+indemnity or liability terms You offer. You may include additional+disclaimers of warranty and limitations of liability specific to any+jurisdiction.++4. Inability to Comply Due to Statute or Regulation+---------------------------------------------------++If it is impossible for You to comply with any of the terms of this+License with respect to some or all of the Covered Software due to+statute, judicial order, or regulation then You must: (a) comply with+the terms of this License to the maximum extent possible; and (b)+describe the limitations and the code they affect. Such description must+be placed in a text file included with all distributions of the Covered+Software under this License. Except to the extent prohibited by statute+or regulation, such description must be sufficiently detailed for a+recipient of ordinary skill to be able to understand it.++5. Termination+--------------++5.1. The rights granted under this License will terminate automatically+if You fail to comply with any of its terms. However, if You become+compliant, then the rights granted under this License from a particular+Contributor are reinstated (a) provisionally, unless and until such+Contributor explicitly and finally terminates Your grants, and (b) on an+ongoing basis, if such Contributor fails to notify You of the+non-compliance by some reasonable means prior to 60 days after You have+come back into compliance. Moreover, Your grants from a particular+Contributor are reinstated on an ongoing basis if such Contributor+notifies You of the non-compliance by some reasonable means, this is the+first time You have received notice of non-compliance with this License+from such Contributor, and You become compliant prior to 30 days after+Your receipt of the notice.++5.2. If You initiate litigation against any entity by asserting a patent+infringement claim (excluding declaratory judgment actions,+counter-claims, and cross-claims) alleging that a Contributor Version+directly or indirectly infringes any patent, then the rights granted to+You by any and all Contributors for the Covered Software under Section+2.1 of this License shall terminate.++5.3. In the event of termination under Sections 5.1 or 5.2 above, all+end user license agreements (excluding distributors and resellers) which+have been validly granted by You or Your distributors under this License+prior to termination shall survive termination.++************************************************************************+* *+* 6. Disclaimer of Warranty *+* ------------------------- *+* *+* Covered Software is provided under this License on an "as is" *+* basis, without warranty of any kind, either expressed, implied, or *+* statutory, including, without limitation, warranties that the *+* Covered Software is free of defects, merchantable, fit for a *+* particular purpose or non-infringing. The entire risk as to the *+* quality and performance of the Covered Software is with You. *+* Should any Covered Software prove defective in any respect, You *+* (not any Contributor) assume the cost of any necessary servicing, *+* repair, or correction. This disclaimer of warranty constitutes an *+* essential part of this License. No use of any Covered Software is *+* authorized under this License except under this disclaimer. *+* *+************************************************************************++************************************************************************+* *+* 7. Limitation of Liability *+* -------------------------- *+* *+* Under no circumstances and under no legal theory, whether tort *+* (including negligence), contract, or otherwise, shall any *+* Contributor, or anyone who distributes Covered Software as *+* permitted above, be liable to You for any direct, indirect, *+* special, incidental, or consequential damages of any character *+* including, without limitation, damages for lost profits, loss of *+* goodwill, work stoppage, computer failure or malfunction, or any *+* and all other commercial damages or losses, even if such party *+* shall have been informed of the possibility of such damages. This *+* limitation of liability shall not apply to liability for death or *+* personal injury resulting from such party's negligence to the *+* extent applicable law prohibits such limitation. Some *+* jurisdictions do not allow the exclusion or limitation of *+* incidental or consequential damages, so this exclusion and *+* limitation may not apply to You. *+* *+************************************************************************++8. Litigation+-------------++Any litigation relating to this License may be brought only in the+courts of a jurisdiction where the defendant maintains its principal+place of business and such litigation shall be governed by laws of that+jurisdiction, without reference to its conflict-of-law provisions.+Nothing in this Section shall prevent a party's ability to bring+cross-claims or counter-claims.++9. Miscellaneous+----------------++This License represents the complete agreement concerning the subject+matter hereof. If any provision of this License is held to be+unenforceable, such provision shall be reformed only to the extent+necessary to make it enforceable. Any law or regulation which provides+that the language of a contract shall be construed against the drafter+shall not be used to construe this License against a Contributor.++10. Versions of the License+---------------------------++10.1. New Versions++Mozilla Foundation is the license steward. Except as provided in Section+10.3, no one other than the license steward has the right to modify or+publish new versions of this License. Each version will be given a+distinguishing version number.++10.2. Effect of New Versions++You may distribute the Covered Software under the terms of the version+of the License under which You originally received the Covered Software,+or under the terms of any subsequent version published by the license+steward.++10.3. Modified Versions++If you create software not governed by this License, and you want to+create a new license for such software, you may create and use a+modified version of this License if you rename the license and remove+any references to the name of the license steward (except to note that+such modified license differs from this License).++10.4. Distributing Source Code Form that is Incompatible With Secondary+Licenses++If You choose to distribute Source Code Form that is Incompatible With+Secondary Licenses under the terms of this version of the License, the+notice described in Exhibit B of this License must be attached.++Exhibit A - Source Code Form License Notice+-------------------------------------------++ This Source Code Form is subject to the terms of the Mozilla Public+ License, v. 2.0. If a copy of the MPL was not distributed with this+ file, You can obtain one at https://mozilla.org/MPL/2.0/.++If it is not possible or desirable to put the notice in a particular+file, then You may include the notice in a location (such as a LICENSE+file in a relevant directory) where a recipient would be likely to look+for such a notice.++You may add additional accurate notices of copyright ownership.++Exhibit B - "Incompatible With Secondary Licenses" Notice+---------------------------------------------------------++ This Source Code Form is "Incompatible With Secondary Licenses", as+ defined by the Mozilla Public License, v. 2.0.
+ README.md view
@@ -0,0 +1,41 @@+# jsonrpc++A lightweight Haskell implementation of+[JSON-RPC 2.0](https://www.jsonrpc.org/specification) protocol types with+[Aeson](https://hackage.haskell.org/package/aeson) serialisation.++## Features++- Core message types: requests, responses, notifications, and errors+- `IsJSONRPCRequest` / `IsJSONRPCNotification` type classes for automatic+ method dispatch via `DerivingVia`+- Standard error codes from the specification+- Spec-compliant JSON encoding (optional `params`, error `data` field, etc.)++## Quick start++```haskell+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE DerivingVia #-}+{-# LANGUAGE DuplicateRecordFields #-}+{-# LANGUAGE TypeFamilies #-}++import JSONRPC+import Data.Aeson (FromJSON, ToJSON)+import GHC.Generics (Generic)++-- Define your request type+data PingRequest = PingRequest+ { id :: RequestId+ , params :: Maybe ()+ }+ deriving stock (Show, Eq, Generic)+ deriving (ToJSON, FromJSON) via ViaJSONRPCRequest PingRequest++instance IsJSONRPCRequest PingRequest where+ requestMethod _ = "ping"+```++## License++[MPL-2.0](LICENSE)
+ jsonrpc.cabal view
@@ -0,0 +1,88 @@+cabal-version: 2.2+name: jsonrpc+version: 0.2.0.0+license: MPL-2.0+license-file: LICENSE+copyright: (c) 2026 DPella AB+author: DPella AB+tested-with: ghc ==9.12.2+extra-doc-files:+ README.md+ CHANGELOG.md++maintainer:+ matti@dpella.io,+ lobo@dpella.io++synopsis: JSON-RPC 2.0 types and type classes for Haskell+description:+ A lightweight implementation of the JSON-RPC 2.0 protocol types for Haskell+ with Aeson serialisation. Provides the core request, response, notification,+ and error types along with type classes for deriving JSON-RPC method dispatch+ via @DerivingVia@.+ .+ Implements the specification at <https://www.jsonrpc.org/specification>.++homepage: https://github.com/DPella/jsonrpc+bug-reports: https://github.com/DPella/jsonrpc/issues+category: Web, Network++source-repository head+ type: git+ location: https://github.com/DPella/jsonrpc.git++library+ default-language:+ Haskell2010++ default-extensions:+ DataKinds+ FlexibleInstances+ GADTs+ GeneralizedNewtypeDeriving+ ImportQualifiedPost+ OverloadedStrings+ PolyKinds+ RankNTypes+ TypeApplications+ TypeFamilies++ hs-source-dirs:+ src++ exposed-modules:+ JSONRPC++ build-depends:+ aeson >=2.1 && <2.3,+ base >=4.18 && <4.22,+ text >=2.0 && <2.2,++test-suite test-jsonrpc+ type: exitcode-stdio-1.0+ default-language:+ Haskell2010++ default-extensions:+ DataKinds+ FlexibleInstances+ GADTs+ GeneralizedNewtypeDeriving+ ImportQualifiedPost+ OverloadedStrings+ PolyKinds+ RankNTypes+ TypeApplications+ TypeFamilies++ hs-source-dirs:+ test++ main-is:+ Main.hs++ build-depends:+ aeson >=2.1 && <2.3,+ base >=4.18 && <4.22,+ hspec >=2.10 && <2.12,+ jsonrpc,
+ src/JSONRPC.hs view
@@ -0,0 +1,498 @@+{-# LANGUAGE DefaultSignatures #-}+{-# LANGUAGE DeriveAnyClass #-}+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE DerivingVia #-}+{-# LANGUAGE DuplicateRecordFields #-}+{-# LANGUAGE FlexibleContexts #-}+{-# LANGUAGE FunctionalDependencies #-}+{-# LANGUAGE InstanceSigs #-}+{-# LANGUAGE LambdaCase #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE RecordWildCards #-}+{-# LANGUAGE ScopedTypeVariables #-}+{-# LANGUAGE TypeFamilies #-}+{-# LANGUAGE TypeOperators #-}+{-# LANGUAGE UndecidableInstances #-}++{- |+Module : JSONRPC+Description : JSON-RPC 2.0 types and type classes+Copyright : (c) 2026 DPella AB+License : MPL-2.0+Maintainer : matti@dpella.io, lobo@dpella.io+Stability : experimental+Portability : GHC++An implementation of the [JSON-RPC 2.0](https://www.jsonrpc.org/specification)+protocol types for Haskell, with Aeson serialisation.++= Core types++The four message kinds defined by the specification:++* 'JSONRPCRequest' — a method call expecting a response+* 'JSONRPCResponse' — a successful response+* 'JSONRPCError' — an error response+* 'JSONRPCNotification' — a one-way message (no response)++'JSONRPCMessage' is a tagged union of all four, useful when reading messages+off the wire without knowing the kind in advance.++= Deriving support++'IsJSONRPCRequest' and 'IsJSONRPCNotification' let you define strongly-typed+request\/notification types and derive their JSON-RPC encoding via+@DerivingVia@:++@+data PingRequest = PingRequest+ { id :: RequestId, params :: Maybe () }+ deriving (ToJSON, FromJSON) via ViaJSONRPCRequest PingRequest++instance IsJSONRPCRequest PingRequest where+ requestMethod _ = \"ping\"+@+-}+module JSONRPC (+ -- * Request identifiers+ RequestId (..),++ -- * Type classes+ IsJSONRPCRequest (..),+ IsJSONRPCNotification (..),++ -- * Deriving-via wrappers+ ViaJSONRPCRequest (..),+ ViaJSONRPCNotification (..),++ -- * JSON-RPC message types+ JSONRPCRequest (..),+ JSONRPCResponse (..),+ JSONRPCError (..),+ JSONRPCNotification (..),+ JSONRPCMessage (..),+ JSONRPCErrorInfo (..),++ -- * Helpers+ EmptyParams,++ -- * Standard JSON-RPC 2.0 error codes+ pARSE_ERROR,+ iNVALID_REQUEST,+ mETHOD_NOT_FOUND,+ iNVALID_PARAMS,+ iNTERNAL_ERROR,++ -- * Constants+ rPC_VERSION,+) where++import Control.Applicative ((<|>))+import Data.Aeson+import Data.Aeson qualified as Aeson+import Data.Data (Proxy (..), Typeable, typeRep)+import Data.Kind (Type)+import Data.Text (Text)+import GHC.Generics+import GHC.Records (HasField (getField))+import GHC.TypeError (ErrorMessage (..), TypeError)++-- ---------------------------------------------------------------------------+-- RequestId+-- ---------------------------------------------------------------------------++{- | A uniquely identifying ID for a request in JSON-RPC.++The JSON-RPC 2.0 specification requires that each request has a unique+identifier. The ID can be a string, number, or null value. Numbers+SHOULD NOT contain fractional parts.+-}+newtype RequestId = RequestId Value+ deriving stock (Show, Eq)+ deriving newtype (ToJSON, FromJSON)++-- ---------------------------------------------------------------------------+-- Constants+-- ---------------------------------------------------------------------------++{- | JSON-RPC protocol version string (@\"2.0\"@).++Every request, response, and notification includes a @jsonrpc@ field+that MUST be exactly this value.+-}+rPC_VERSION :: Text+rPC_VERSION = "2.0"++-- ---------------------------------------------------------------------------+-- EmptyParams+-- ---------------------------------------------------------------------------++{- | Placeholder type for methods that take no parameters.++'EmptyParams' serialises to JSON @null@ and always fails to parse+(it is only used as a type-level marker; the 'FromJSON' instance for+'JSONRPCRequest' defaults missing params to 'Null').+-}+data EmptyParams+ deriving stock (Generic)++instance Show EmptyParams where+ show :: EmptyParams -> String+ show _ = show Aeson.Null++instance Eq EmptyParams where+ (==) :: EmptyParams -> EmptyParams -> Bool+ _ == _ = True++instance ToJSON EmptyParams where+ toJSON :: EmptyParams -> Value+ toJSON _ = Aeson.Null++instance FromJSON EmptyParams where+ parseJSON _ = fail "EmptyParams can only be used as a placeholder for empty params"++-- ---------------------------------------------------------------------------+-- JSON-RPC error information+-- ---------------------------------------------------------------------------++{- | Structured error information inside a JSON-RPC error response.++@+{ "code": -32601, "message": "Method not found", "data": ... }+@++The @code@ and @message@ fields are mandatory; @data@ is optional and may+contain any additional information about the error.+-}+data JSONRPCErrorInfo = JSONRPCErrorInfo+ { code :: Int+ -- ^ A number indicating the error type that occurred.+ , message :: Text+ -- ^ A short description of the error.+ , errorData :: Maybe Value+ -- ^ Additional information about the error (serialised as @\"data\"@ in JSON).+ }+ deriving stock (Show, Eq, Generic)++-- | Custom 'ToJSON' that maps the Haskell field @errorData@ to the JSON key @\"data\"@+-- as required by the JSON-RPC 2.0 specification.+instance ToJSON JSONRPCErrorInfo where+ toJSON (JSONRPCErrorInfo c m d) =+ object $+ [ "code" .= c+ , "message" .= m+ ]+ <> maybe [] (\v -> ["data" .= v]) d++-- | Custom 'FromJSON' that reads the JSON key @\"data\"@ into the Haskell field @errorData@.+instance FromJSON JSONRPCErrorInfo where+ parseJSON = withObject "JSONRPCErrorInfo" $ \o ->+ JSONRPCErrorInfo+ <$> o .: "code"+ <*> o .: "message"+ <*> o .:? "data"++-- ---------------------------------------------------------------------------+-- Core message types+-- ---------------------------------------------------------------------------++{- | A JSON-RPC request that expects a response.++@+{ "jsonrpc": "2.0", "id": 1, "method": "foo", "params": { ... } }+@+-}+data JSONRPCRequest = JSONRPCRequest+ { jsonrpc :: Text+ -- ^ Always @\"2.0\"@.+ , id :: RequestId+ -- ^ A unique identifier for the request.+ , method :: Text+ -- ^ The method to invoke.+ , params :: Value+ -- ^ The method parameters (defaults to 'Null' if omitted).+ }+ deriving stock (Show, Eq, Generic)+ deriving anyclass (ToJSON)++-- | Custom 'FromJSON' instance that treats a missing @params@ key as 'Null'.+-- JSON-RPC 2.0 allows the @params@ field to be omitted.+instance FromJSON JSONRPCRequest where+ parseJSON = withObject "JSONRPCRequest" $ \o ->+ JSONRPCRequest+ <$> o .: "jsonrpc"+ <*> o .: "id"+ <*> o .: "method"+ <*> o .:? "params" .!= Null++{- | A successful (non-error) response to a request.++@+{ "jsonrpc": "2.0", "id": 1, "result": { ... } }+@+-}+data JSONRPCResponse = JSONRPCResponse+ { jsonrpc :: Text+ -- ^ Always @\"2.0\"@.+ , id :: RequestId+ -- ^ Must match the @id@ of the corresponding request.+ , result :: Value+ -- ^ The result of the method invocation.+ }+ deriving stock (Show, Eq, Generic)+ deriving anyclass (FromJSON, ToJSON)++{- | A response to a request that indicates an error occurred.++@+{ "jsonrpc": "2.0", "id": 1, "error": { "code": -32601, "message": "..." } }+@+-}+data JSONRPCError = JSONRPCError+ { jsonrpc :: Text+ -- ^ Always @\"2.0\"@.+ , id :: RequestId+ -- ^ Must match the @id@ of the corresponding request (or 'Null' for parse errors).+ , error :: JSONRPCErrorInfo+ -- ^ Structured error information.+ }+ deriving stock (Show, Eq, Generic)+ deriving anyclass (FromJSON, ToJSON)++{- | A notification which does not expect a response.++@+{ "jsonrpc": "2.0", "method": "update", "params": { ... } }+@++Notifications have no @id@ field. The server MUST NOT reply to a notification.+-}+data JSONRPCNotification = JSONRPCNotification+ { jsonrpc :: Text+ -- ^ Always @\"2.0\"@.+ , method :: Text+ -- ^ The method name.+ , params :: Value+ -- ^ The method parameters (omitted from JSON when 'Null').+ }+ deriving stock (Show, Eq, Generic)++-- | Custom 'ToJSON' instance that omits @params@ when it is 'Null'.+instance ToJSON JSONRPCNotification where+ toJSON (JSONRPCNotification j m Null) =+ object ["jsonrpc" .= j, "method" .= m]+ toJSON (JSONRPCNotification j m p) =+ object ["jsonrpc" .= j, "method" .= m, "params" .= p]++-- | Custom 'FromJSON' instance that treats a missing @params@ key as 'Null'.+-- JSON-RPC 2.0 allows notifications to omit the @params@ field entirely.+instance FromJSON JSONRPCNotification where+ parseJSON = withObject "JSONRPCNotification" $ \o ->+ JSONRPCNotification+ <$> o .: "jsonrpc"+ <*> o .: "method"+ <*> o .:? "params" .!= Null++{- | Any valid JSON-RPC message that can be decoded off the wire.++Useful when reading from a transport where the message kind is unknown.+-}+data JSONRPCMessage+ = RequestMessage JSONRPCRequest+ | ResponseMessage JSONRPCResponse+ | ErrorMessage JSONRPCError+ | NotificationMessage JSONRPCNotification+ deriving stock (Show, Eq, Generic)++instance ToJSON JSONRPCMessage where+ toJSON (RequestMessage r) = toJSON r+ toJSON (ResponseMessage r) = toJSON r+ toJSON (ErrorMessage e) = toJSON e+ toJSON (NotificationMessage n) = toJSON n++instance FromJSON JSONRPCMessage where+ parseJSON v =+ (RequestMessage <$> parseJSON v)+ <|> (ResponseMessage <$> parseJSON v)+ <|> (ErrorMessage <$> parseJSON v)+ <|> (NotificationMessage <$> parseJSON v)++-- ---------------------------------------------------------------------------+-- IsJSONRPCRequest+-- ---------------------------------------------------------------------------++-- | Type family to extract the type of the @params@ field from a generic representation.+type family RequestParamType (rep :: Type -> Type) :: Type where+ RequestParamType (D1 _ (C1 _ (S1 _ (K1 _ RequestId) :*: S1 _ (K1 _ p)))) = p+ RequestParamType (D1 ('MetaData nm _ _ _) _) =+ TypeError+ ( ('Text "Error when defining IsJSONRPCRequest for " :<>: 'Text nm :<>: 'Text ":")+ :$$: 'Text "The request datatype must be a record with fields 'id' and 'params'"+ )++{- | Type class for Haskell types that represent a specific JSON-RPC request method.++Instances define the method name via 'requestMethod'. Serialisation and+deserialisation are provided by default using GHC Generics: the type must+be a two-field record with @id :: RequestId@ and @params :: SomeParamsType@.++Use 'ViaJSONRPCRequest' for @DerivingVia@-based 'ToJSON'\/'FromJSON' instances.+-}+class+ ( HasField "id" a RequestId+ , HasField "params" a (RequestParams a)+ , Typeable a+ , ToJSON (RequestParams a)+ , FromJSON (RequestParams a)+ ) =>+ IsJSONRPCRequest a+ where+ -- | The type of the @params@ field.+ type RequestParams a+ type RequestParams a = RequestParamType (Rep a)++ -- | The JSON-RPC method name (e.g. @\"initialize\"@, @\"tools\/list\"@).+ requestMethod :: Proxy a -> Text++ -- | Convert a typed request to a raw 'JSONRPCRequest'.+ toJSONRPCRequest :: a -> JSONRPCRequest+ toJSONRPCRequest (req :: a) =+ JSONRPCRequest rPC_VERSION (getField @"id" req) (requestMethod (Proxy @a)) (toJSON (getField @"params" req))++ -- | Parse a raw 'JSONRPCRequest' into a typed request.+ fromJSONRPCRequest :: JSONRPCRequest -> Either String a+ default fromJSONRPCRequest ::+ ( Generic a+ , Rep a ~ D1 c0 (C1 i0 (S1 s0 (K1 i1 RequestId) :*: S1 s1 (K1 i30 (RequestParams a))))+ ) =>+ JSONRPCRequest ->+ Either String a+ fromJSONRPCRequest JSONRPCRequest{id = req_id, params = req_params} =+ case fromJSON @(RequestParams a) req_params of+ Success p -> Right $ to $ M1 (M1 (M1 (K1 req_id) :*: M1 (K1 p)))+ Aeson.Error err -> Left err++-- | Newtype wrapper for deriving 'ToJSON' and 'FromJSON' via 'IsJSONRPCRequest'.+newtype ViaJSONRPCRequest a = ViaJSONRPCRequest {unViaJSONRPCRequest :: a}++instance (IsJSONRPCRequest a) => ToJSON (ViaJSONRPCRequest a) where+ toJSON = toJSON . toJSONRPCRequest . unViaJSONRPCRequest++instance (IsJSONRPCRequest a) => FromJSON (ViaJSONRPCRequest a) where+ parseJSON = withObject (show $ typeRep (Proxy @a)) $ \o -> do+ m <- o .: "method"+ req_id <- o .: "id"+ if m == requestMethod (Proxy @a)+ then do+ p <- o .:? "params" .!= Null+ case fromJSONRPCRequest (JSONRPCRequest rPC_VERSION req_id m p) of+ Right r -> return (ViaJSONRPCRequest r)+ Left err -> fail $ "Failed to parse params for " <> show (typeRep (Proxy @a)) <> ": " <> err+ else fail $ "Expected method '" <> show (requestMethod (Proxy @a)) <> "'"++-- ---------------------------------------------------------------------------+-- IsJSONRPCNotification+-- ---------------------------------------------------------------------------++-- | Type family to extract the type of the @params@ field from a notification's generic representation.+type family NotificationParamType (rep :: Type -> Type) :: Type where+ NotificationParamType (D1 _ (C1 _ (S1 _ (K1 _ p)))) = p+ NotificationParamType (D1 ('MetaData nm _ _ _) _) =+ TypeError+ ( ('Text "Error when defining IsJSONRPCNotification for " :<>: 'Text nm :<>: 'Text ":")+ :$$: 'Text "The notification datatype must be a record with a single field 'params'"+ )++{- | Type class for Haskell types that represent a specific JSON-RPC notification method.++Similar to 'IsJSONRPCRequest' but for notifications (no @id@ field).+Use 'ViaJSONRPCNotification' for @DerivingVia@-based instances.+-}+class+ ( HasField "params" a (NotificationParams a)+ , Typeable a+ , ToJSON (NotificationParams a)+ , FromJSON (NotificationParams a)+ ) =>+ IsJSONRPCNotification a+ where+ -- | The type of the @params@ field.+ type NotificationParams a+ type NotificationParams a = NotificationParamType (Rep a)++ -- | The JSON-RPC method name.+ notificationsMethod :: Proxy a -> Text++ -- | Convert a typed notification to a raw 'JSONRPCNotification'.+ toJSONRPCNotification :: a -> JSONRPCNotification+ toJSONRPCNotification (req :: a) =+ JSONRPCNotification rPC_VERSION (notificationsMethod (Proxy @a)) (toJSON (getField @"params" req))++ -- | Parse a raw 'JSONRPCNotification' into a typed notification.+ fromJSONRPCNotification :: JSONRPCNotification -> Either String a+ default fromJSONRPCNotification ::+ ( Generic a+ , Rep a ~ D1 c0 (C1 i0 (S1 s1 (K1 i30 (NotificationParams a))))+ ) =>+ JSONRPCNotification ->+ Either String a+ fromJSONRPCNotification JSONRPCNotification{params = notification_params} =+ case fromJSON @(NotificationParams a) notification_params of+ Success p -> Right $ to $ M1 (M1 (M1 (K1 p)))+ Aeson.Error err -> Left err++-- | Newtype wrapper for deriving 'ToJSON' and 'FromJSON' via 'IsJSONRPCNotification'.+newtype ViaJSONRPCNotification a = ViaJSONRPCNotification {unViaJSONRPCNotification :: a}++instance (IsJSONRPCNotification a) => ToJSON (ViaJSONRPCNotification a) where+ toJSON = toJSON . toJSONRPCNotification . unViaJSONRPCNotification++instance (IsJSONRPCNotification a) => FromJSON (ViaJSONRPCNotification a) where+ parseJSON = withObject (show $ typeRep (Proxy @a)) $ \o -> do+ m <- o .: "method"+ if m == notificationsMethod (Proxy @a)+ then do+ p <- o .:? "params" .!= Null+ case fromJSONRPCNotification (JSONRPCNotification rPC_VERSION m p) of+ Right r -> return (ViaJSONRPCNotification r)+ Left err -> fail $ "Failed to parse params for " <> show (typeRep (Proxy @a)) <> ": " <> err+ else fail $ "Expected method '" <> show (notificationsMethod (Proxy @a)) <> "'"++-- ---------------------------------------------------------------------------+-- Standard JSON-RPC 2.0 error codes+-- ---------------------------------------------------------------------------++{- | Parse error (@-32700@).++Invalid JSON was received by the server.+-}+pARSE_ERROR :: Int+pARSE_ERROR = -32700++{- | Invalid request (@-32600@).++The JSON sent is not a valid Request object.+-}+iNVALID_REQUEST :: Int+iNVALID_REQUEST = -32600++{- | Method not found (@-32601@).++The method does not exist or is not available.+-}+mETHOD_NOT_FOUND :: Int+mETHOD_NOT_FOUND = -32601++{- | Invalid params (@-32602@).++Invalid method parameter(s).+-}+iNVALID_PARAMS :: Int+iNVALID_PARAMS = -32602++{- | Internal error (@-32603@).++Internal JSON-RPC error.+-}+iNTERNAL_ERROR :: Int+iNTERNAL_ERROR = -32603
+ test/Main.hs view
@@ -0,0 +1,224 @@+{-# LANGUAGE DataKinds #-}+{-# LANGUAGE DeriveGeneric #-}+{-# LANGUAGE DerivingVia #-}+{-# LANGUAGE DuplicateRecordFields #-}+{-# LANGUAGE OverloadedStrings #-}+{-# LANGUAGE TypeFamilies #-}++module Main (main) where++import Data.Aeson+import Data.Aeson.KeyMap qualified as KM+import Data.Maybe (isNothing)+import GHC.Generics (Generic)+import JSONRPC+import Test.Hspec+import Prelude hiding (error, id)+import Prelude qualified++-- ---------------------------------------------------------------------------+-- Example types for DerivingVia tests+-- ---------------------------------------------------------------------------++data PingRequest = PingRequest+ { id :: RequestId+ , params :: Maybe Value+ }+ deriving stock (Show, Eq, Generic)+ deriving (ToJSON, FromJSON) via ViaJSONRPCRequest PingRequest++instance IsJSONRPCRequest PingRequest where+ requestMethod _ = "ping"++data InitNotification = InitNotification+ { params :: Maybe Value+ }+ deriving stock (Show, Eq, Generic)+ deriving (ToJSON, FromJSON) via ViaJSONRPCNotification InitNotification++instance IsJSONRPCNotification InitNotification where+ notificationsMethod _ = "notifications/initialized"++-- | Helper to extract an Object from a Value, failing on non-objects.+asObject :: Value -> KM.KeyMap Value+asObject (Object o) = o+asObject _ = Prelude.error "expected object"++-- ---------------------------------------------------------------------------+-- Tests+-- ---------------------------------------------------------------------------++main :: IO ()+main = hspec $ do+ describe "JSONRPC" $ do+ describe "Constants" $ do+ it "rPC_VERSION is \"2.0\"" $+ rPC_VERSION `shouldBe` "2.0"++ describe "Error codes" $ do+ it "pARSE_ERROR is -32700" $+ pARSE_ERROR `shouldBe` (-32700)+ it "iNVALID_REQUEST is -32600" $+ iNVALID_REQUEST `shouldBe` (-32600)+ it "mETHOD_NOT_FOUND is -32601" $+ mETHOD_NOT_FOUND `shouldBe` (-32601)+ it "iNVALID_PARAMS is -32602" $+ iNVALID_PARAMS `shouldBe` (-32602)+ it "iNTERNAL_ERROR is -32603" $+ iNTERNAL_ERROR `shouldBe` (-32603)++ describe "RequestId" $ do+ it "round-trips a numeric id" $ do+ let rid = RequestId (Number 42)+ decode (encode rid) `shouldBe` Just rid++ it "round-trips a string id" $ do+ let rid = RequestId (String "abc-123")+ decode (encode rid) `shouldBe` Just rid++ it "round-trips a null id" $ do+ let rid = RequestId Null+ decode (encode rid) `shouldBe` Just rid++ describe "JSONRPCErrorInfo" $ do+ it "serialises errorData as \"data\" (spec compliance)" $ do+ let info = JSONRPCErrorInfo (-32601) "Method not found" (Just (String "details"))+ obj = asObject (toJSON info)+ KM.member "data" obj `shouldBe` True+ KM.member "errorData" obj `shouldBe` False++ it "omits \"data\" when errorData is Nothing" $ do+ let info = JSONRPCErrorInfo (-32601) "Method not found" Nothing+ obj = asObject (toJSON info)+ KM.member "data" obj `shouldBe` False++ it "round-trips with data" $ do+ let info = JSONRPCErrorInfo (-32700) "Parse error" (Just (String "unexpected"))+ decode (encode info) `shouldBe` Just info++ it "round-trips without data" $ do+ let info = JSONRPCErrorInfo (-32600) "Invalid Request" Nothing+ decode (encode info) `shouldBe` Just info++ it "parses JSON with \"data\" key into errorData field" $ do+ let json = "{\"code\":-32601,\"message\":\"Method not found\",\"data\":\"extra\"}"+ case decode json :: Maybe JSONRPCErrorInfo of+ Just info -> errorData info `shouldBe` Just (String "extra")+ Nothing -> expectationFailure "Failed to parse JSONRPCErrorInfo"++ it "parses JSON without \"data\" key as Nothing" $ do+ let json = "{\"code\":-32601,\"message\":\"Method not found\"}"+ case decode json :: Maybe JSONRPCErrorInfo of+ Just info -> isNothing (errorData info) `shouldBe` True+ Nothing -> expectationFailure "Failed to parse JSONRPCErrorInfo"++ describe "JSONRPCRequest" $ do+ it "round-trips a request with params" $ do+ let req = JSONRPCRequest "2.0" (RequestId (Number 1)) "test" (object ["x" .= (1 :: Int)])+ decode (encode req) `shouldBe` Just req++ it "defaults missing params to Null" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"ping\"}"+ case decode json :: Maybe JSONRPCRequest of+ Just (JSONRPCRequest _ _ _ p) -> p `shouldBe` Null+ Nothing -> expectationFailure "Failed to parse JSONRPCRequest"++ it "accepts explicit null params" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"ping\",\"params\":null}"+ case decode json :: Maybe JSONRPCRequest of+ Just (JSONRPCRequest _ _ _ p) -> p `shouldBe` Null+ Nothing -> expectationFailure "Failed to parse JSONRPCRequest"++ describe "JSONRPCResponse" $ do+ it "round-trips a response" $ do+ let resp = JSONRPCResponse "2.0" (RequestId (Number 1)) (String "ok")+ decode (encode resp) `shouldBe` Just resp++ describe "JSONRPCError" $ do+ it "round-trips an error" $ do+ let err = JSONRPCError "2.0" (RequestId (Number 1)) (JSONRPCErrorInfo (-32601) "Not found" Nothing)+ decode (encode err) `shouldBe` Just err++ it "round-trips an error with data" $ do+ let err = JSONRPCError "2.0" (RequestId Null) (JSONRPCErrorInfo pARSE_ERROR "Parse error" (Just (String "detail")))+ decode (encode err) `shouldBe` Just err++ describe "JSONRPCNotification" $ do+ it "round-trips a notification with params" $ do+ let notif = JSONRPCNotification "2.0" "update" (object ["key" .= ("val" :: String)])+ decode (encode notif) `shouldBe` Just notif++ it "omits params when Null in serialised JSON" $ do+ let notif = JSONRPCNotification "2.0" "update" Null+ obj = asObject (toJSON notif)+ KM.member "params" obj `shouldBe` False++ it "defaults missing params to Null on parse" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"method\":\"update\"}"+ case decode json :: Maybe JSONRPCNotification of+ Just (JSONRPCNotification _ _ p) -> p `shouldBe` Null+ Nothing -> expectationFailure "Failed to parse JSONRPCNotification"++ describe "JSONRPCMessage" $ do+ it "parses a request as RequestMessage" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"foo\",\"params\":{}}"+ case decode json :: Maybe JSONRPCMessage of+ Just (RequestMessage _) -> pure ()+ other -> expectationFailure $ "Expected RequestMessage, got: " <> show other++ it "parses a response as ResponseMessage" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"id\":1,\"result\":42}"+ case decode json :: Maybe JSONRPCMessage of+ Just (ResponseMessage _) -> pure ()+ other -> expectationFailure $ "Expected ResponseMessage, got: " <> show other++ it "parses an error as ErrorMessage" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"id\":1,\"error\":{\"code\":-32601,\"message\":\"not found\"}}"+ case decode json :: Maybe JSONRPCMessage of+ Just (ErrorMessage _) -> pure ()+ other -> expectationFailure $ "Expected ErrorMessage, got: " <> show other++ it "parses a notification as NotificationMessage" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"method\":\"update\"}"+ case decode json :: Maybe JSONRPCMessage of+ Just (NotificationMessage _) -> pure ()+ other -> expectationFailure $ "Expected NotificationMessage, got: " <> show other++ it "round-trips all message types" $ do+ let msgs =+ [ RequestMessage $ JSONRPCRequest "2.0" (RequestId (Number 1)) "test" Null+ , ResponseMessage $ JSONRPCResponse "2.0" (RequestId (Number 2)) (String "ok")+ , ErrorMessage $ JSONRPCError "2.0" (RequestId (Number 3)) (JSONRPCErrorInfo (-32600) "Bad" Nothing)+ , NotificationMessage $ JSONRPCNotification "2.0" "ping" Null+ ]+ mapM_ (\m -> decode (encode m) `shouldBe` Just m) msgs++ describe "ViaJSONRPCRequest (DerivingVia)" $ do+ it "serialises a typed request with correct method" $ do+ let req = PingRequest (RequestId (Number 1)) Nothing+ obj = asObject (toJSON req)+ KM.lookup "method" obj `shouldBe` Just (String "ping")+ KM.lookup "jsonrpc" obj `shouldBe` Just (String "2.0")++ it "round-trips a typed request" $ do+ let req = PingRequest (RequestId (Number 7)) (Just (object ["foo" .= True]))+ decode (encode req) `shouldBe` Just req++ it "rejects a request with wrong method" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"wrong\",\"params\":null}"+ (decode json :: Maybe PingRequest) `shouldBe` Nothing++ describe "ViaJSONRPCNotification (DerivingVia)" $ do+ it "serialises a typed notification with correct method" $ do+ let notif = InitNotification Nothing+ obj = asObject (toJSON notif)+ KM.lookup "method" obj `shouldBe` Just (String "notifications/initialized")+ KM.lookup "jsonrpc" obj `shouldBe` Just (String "2.0")++ it "round-trips a typed notification" $ do+ let notif = InitNotification (Just (object ["meta" .= (1 :: Int)]))+ decode (encode notif) `shouldBe` Just notif++ it "rejects a notification with wrong method" $ do+ let json = "{\"jsonrpc\":\"2.0\",\"method\":\"wrong\",\"params\":null}"+ (decode json :: Maybe InitNotification) `shouldBe` Nothing