Documentation
¶
Overview ¶
Package jsonrpc2 is a minimal implementation of the JSON RPC 2 spec. https://www.jsonrpc.org/specification It is intended to be compatible with other implementations at the wire level.
Index ¶
- Constants
- Variables
- func EncodeMessage(msg Message) ([]byte, error)
- func NewError(code int64, message string) error
- func SetDebug(flags dbgFlags)
- type AsyncCall
- type Binder
- type BinderFunc
- type Connection
- func (c *Connection) Call(ctx context.Context, method string, params interface{}) *AsyncCall
- func (c *Connection) Cancel(id ID)
- func (c *Connection) Close() error
- func (c *Connection) Notify(ctx context.Context, method string, params interface{}) (err error)
- func (c *Connection) Respond(id ID, result interface{}, err error) error
- func (c *Connection) Wait() error
- type ConnectionOptions
- type Dialer
- type Framer
- type Handler
- type HandlerFunc
- type ID
- type Listener
- type Message
- type Preempter
- type PreempterFunc
- type Reader
- type Request
- type Response
- type Server
- type Writer
Constants ¶
const ( DbgFlagVerbose dbgFlags = 1 << iota DbgFlagCall DbgFlagAll = DbgFlagVerbose | DbgFlagCall )
Variables ¶
var ( // ErrIdleTimeout is returned when serving timed out waiting for new connections. ErrIdleTimeout = errors.New("timed out waiting for new connections") // ErrNotHandled is returned from a Handler or Preempter to indicate it did // not handle the request. // // If a Handler returns ErrNotHandled, the server replies with // ErrMethodNotFound. ErrNotHandled = errors.New("JSON RPC not handled") // ErrAsyncResponse is returned from a handler to indicate it will generate a // response asynchronously. // // ErrAsyncResponse must not be returned for notifications, // which do not receive responses. ErrAsyncResponse = errors.New("JSON RPC asynchronous response") )
var ( // ErrParse is used when invalid JSON was received by the server. ErrParse = NewError(-32700, "JSON RPC parse error") // ErrInvalidRequest is used when the JSON sent is not a valid Request object. ErrInvalidRequest = NewError(-32600, "JSON RPC invalid request") // ErrMethodNotFound should be returned by the handler when the method does // not exist / is not available. ErrMethodNotFound = NewError(-32601, "JSON RPC method not found") // ErrInvalidParams should be returned by the handler when method // parameter(s) were invalid. ErrInvalidParams = NewError(-32602, "JSON RPC invalid params") // ErrInternal indicates a failure to process a call correctly ErrInternal = NewError(-32603, "JSON RPC internal error") // ErrServerOverloaded is returned when a message was refused due to a // server being temporarily unable to accept any new messages. ErrServerOverloaded = NewError(-32000, "JSON RPC overloaded") // ErrUnknown should be used for all non coded errors. ErrUnknown = NewError(-32001, "JSON RPC unknown error") // ErrServerClosing is returned for calls that arrive while the server is closing. ErrServerClosing = NewError(-32002, "JSON RPC server is closing") // ErrClientClosing is a dummy error returned for calls initiated while the client is closing. ErrClientClosing = NewError(-32003, "JSON RPC client is closing") )
var (
Verbose bool
)
Functions ¶
func EncodeMessage ¶
Types ¶
type AsyncCall ¶
type AsyncCall struct {
// contains filtered or unexported fields
}
func (*AsyncCall) Await ¶
Await waits for (and decodes) the results of a Call. The response will be unmarshaled from JSON into the result.
type Binder ¶
type Binder interface {
// Bind returns the ConnectionOptions to use when establishing the passed-in
// Connection.
//
// The connection is not ready to use when Bind is called,
// but Bind may close it without reading or writing to it.
Bind(context.Context, *Connection) ConnectionOptions
}
Binder builds a connection configuration. This may be used in servers to generate a new configuration per connection. ConnectionOptions itself implements Binder returning itself unmodified, to allow for the simple cases where no per connection information is needed.
type BinderFunc ¶
type BinderFunc func(context.Context, *Connection) ConnectionOptions
A BinderFunc implements the Binder interface for a standalone Bind function.
func (BinderFunc) Bind ¶
func (f BinderFunc) Bind(ctx context.Context, c *Connection) ConnectionOptions
type Connection ¶
type Connection struct {
// contains filtered or unexported fields
}
Connection manages the jsonrpc2 protocol, connecting responses back to their calls. Connection is bidirectional; it does not have a designated server or client end.
func Dial ¶
Dial uses the dialer to make a new connection, wraps the returned reader and writer using the framer to make a stream, and then builds a connection on top of that stream using the binder.
The returned Connection will operate independently using the Preempter and/or Handler provided by the Binder, and will release its own resources when the connection is broken, but the caller may Close it earlier to stop accepting (or sending) new requests.
func (*Connection) Call ¶
func (c *Connection) Call(ctx context.Context, method string, params interface{}) *AsyncCall
Call invokes the target method and returns an object that can be used to await the response. The params will be marshaled to JSON before sending over the wire, and will be handed to the method invoked. You do not have to wait for the response, it can just be ignored if not needed. If sending the call failed, the response will be ready and have the error in it.
func (*Connection) Cancel ¶
func (c *Connection) Cancel(id ID)
Cancel cancels the Context passed to the Handle call for the inbound message with the given ID.
Cancel will not complain if the ID is not a currently active message, and it will not cause any messages that have not arrived yet with that ID to be cancelled.
func (*Connection) Close ¶
func (c *Connection) Close() error
Close stops accepting new requests, waits for in-flight requests and enqueued Handle calls to complete, and then closes the underlying stream.
After the start of a Close, notification requests (that lack IDs and do not receive responses) will continue to be passed to the Preempter, but calls with IDs will receive immediate responses with ErrServerClosing, and no new requests (not even notifications!) will be enqueued to the Handler.
func (*Connection) Notify ¶
func (c *Connection) Notify(ctx context.Context, method string, params interface{}) (err error)
Notify invokes the target method but does not wait for a response. The params will be marshaled to JSON before sending over the wire, and will be handed to the method invoked.
func (*Connection) Respond ¶
func (c *Connection) Respond(id ID, result interface{}, err error) error
Respond delivers a response to an incoming Call.
Respond must be called exactly once for any message for which a handler returns ErrAsyncResponse. It must not be called for any other message.
func (*Connection) Wait ¶
func (c *Connection) Wait() error
Wait blocks until the connection is fully closed, but does not close it.
type ConnectionOptions ¶
type ConnectionOptions struct {
// Framer allows control over the message framing and encoding.
// If nil, HeaderFramer will be used.
Framer Framer
// Preempter allows registration of a pre-queue message handler.
// If nil, no messages will be preempted.
Preempter Preempter
// Handler is used as the queued message handler for inbound messages.
// If nil, all responses will be ErrNotHandled.
Handler Handler
// OnInternalError, if non-nil, is called with any internal errors that occur
// while serving the connection, such as protocol errors or invariant
// violations. (If nil, internal errors result in panics.)
OnInternalError func(error)
}
ConnectionOptions holds the options for new connections.
type Dialer ¶
type Dialer interface {
// Dial returns a new communication byte stream to a listening server.
Dial(ctx context.Context) (io.ReadWriteCloser, error)
}
Dialer is used by clients to dial a server.
type Framer ¶
type Framer interface {
// Reader wraps a byte reader into a message reader.
Reader(rw io.Reader) Reader
// Writer wraps a byte writer into a message writer.
Writer(rw io.Writer) Writer
}
Framer wraps low level byte readers and writers into jsonrpc2 message readers and writers. It is responsible for the framing and encoding of messages into wire form.
func HeaderFramer ¶
func HeaderFramer() Framer
HeaderFramer returns a new Framer. The messages are sent with HTTP content length and MIME type headers. This is the format used by LSP and others.
type Handler ¶
type Handler interface {
// Handle is invoked sequentially for each incoming request that has not
// already been handled by a Preempter.
//
// If the Request has a nil ID, Handle must return a nil result,
// and any error may be logged but will not be reported to the caller.
//
// If the Request has a non-nil ID, Handle must return either a
// non-nil, JSON-marshalable result, or a non-nil error.
//
// The Context passed to Handle will be canceled if the
// connection is broken or the request is canceled or completed.
// (If Handle returns ErrAsyncResponse, ctx will remain uncanceled
// until either Cancel or Respond is called for the request's ID.)
Handle(ctx context.Context, req *Request) (result interface{}, err error)
}
Handler handles messages on a connection.
type HandlerFunc ¶
A HandlerFunc implements the Handler interface for a standalone Handle function.
type ID ¶
type ID struct {
// contains filtered or unexported fields
}
ID is a Request identifier.
type Listener ¶
type Listener interface {
// Accept accepts an inbound connection to a server.
// It blocks until either an inbound connection is made, or the listener is closed.
Accept(context.Context) (io.ReadWriteCloser, error)
// Close closes the listener.
// Any blocked Accept or Dial operations will unblock and return errors.
Close() error
// Dialer returns a dialer that can be used to connect to this listener
// locally.
// If a listener does not implement this it will return nil.
Dialer() Dialer
}
Listener is implemented by protocols to accept new inbound connections.
func NewIdleListener ¶
NewIdleListener wraps a listener with an idle timeout.
When there are no active connections for at least the timeout duration, calls to Accept will fail with ErrIdleTimeout.
A connection is considered inactive as soon as its Close method is called.
type Message ¶
type Message interface {
// contains filtered or unexported methods
}
Message is the interface to all jsonrpc2 message types. They share no common functionality, but are a closed set of concrete types that are allowed to implement this interface. The message types are *Request and *Response.
func DecodeMessage ¶
type Preempter ¶
type Preempter interface {
// Preempt is invoked for each incoming request before it is queued for handling.
//
// If Preempt returns ErrNotHandled, the request will be queued,
// and eventually passed to a Handle call.
//
// Otherwise, the result and error are processed as if returned by Handle.
//
// Preempt must not block. (The Context passed to it is for Values only.)
Preempt(ctx context.Context, req *Request) (result interface{}, err error)
}
Preempter handles messages on a connection before they are queued to the main handler. Primarily this is used for cancel handlers or notifications for which out of order processing is not an issue.
type PreempterFunc ¶
A PreempterFunc implements the Preempter interface for a standalone Preempt function.
type Reader ¶
type Reader interface {
// Read gets the next message from the stream.
Read(context.Context) (Message, int64, error)
}
Reader abstracts the transport mechanics from the JSON RPC protocol. A Conn reads messages from the reader it was provided on construction, and assumes that each call to Read fully transfers a single message, or returns an error. A reader is not safe for concurrent use, it is expected it will be used by a single Conn in a safe manner.
type Request ¶
type Request struct {
// ID of this request, used to tie the Response back to the request.
// This will be nil for notifications.
ID ID
// Method is a string containing the method name to invoke.
Method string
// Params is either a struct or an array with the parameters of the method.
Params json.RawMessage
}
Request is a Message sent to a peer to request behavior. If it has an ID it is a call, otherwise it is a notification.
func NewNotification ¶
NewNotification constructs a new Notification message for the supplied method and parameters.
type Response ¶
type Response struct {
// result is the content of the response.
Result json.RawMessage
// err is set only if the call failed.
Error error
// id of the request this is a response to.
ID ID
}
Response is a Message used as a reply to a call Request. It will have the same ID as the call it is a response to.
type Server ¶
type Server struct {
// contains filtered or unexported fields
}
Server is a running server that is accepting incoming connections.
func NewServer ¶
NewServer starts a new server listening for incoming connections and returns it. This returns a fully running and connected server, it does not block on the listener. You can call Wait to block on the server, or Shutdown to get the sever to terminate gracefully. To notice incoming connections, use an intercepting Binder.
type Writer ¶
type Writer interface {
// Write sends a message to the stream.
Write(context.Context, Message) (int64, error)
}
Writer abstracts the transport mechanics from the JSON RPC protocol. A Conn writes messages using the writer it was provided on construction, and assumes that each call to Write fully transfers a single message, or returns an error. A writer is not safe for concurrent use, it is expected it will be used by a single Conn in a safe manner.
Source Files
Directories