61 lines
1.9 KiB
Go
61 lines
1.9 KiB
Go
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package jsonrpc2
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import (
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"context"
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"encoding/json"
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"errors"
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"io"
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)
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// ReadWriterServer wraps an io.ReadWriter so that it can handle RPC calls.
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//
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// The HandleNext method will process a single request and response. It should
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// be called in a loop until it returns an error.
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type ReadWriterServer struct {
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handler Handler
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enc *json.Encoder
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dec *json.Decoder
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}
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// NewReadWriterServer returns a ReadWriterServer which will read/write on the
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// given io.ReadWriter.
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//
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// All methods exported from rpcInterface which accept a context and one other
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// value, and return a value and an error, will be considered to be available
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// RPC methods, and the ReadWriterServer will execute calls to those methods
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// against the given rpcInterface instance.
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func NewReadWriterServer(handler Handler, rw io.ReadWriter) *ReadWriterServer {
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return &ReadWriterServer{
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handler: handler,
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enc: json.NewEncoder(rw),
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dec: json.NewDecoder(rw),
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}
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}
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// HandleNext blocks until a single RPC call has been handled. If an error is
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// returned, including context errors, then the ReadWriterServer should be
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// considered in an unusable state and discarded.
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func (h *ReadWriterServer) HandleNext(ctx context.Context) error {
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req, decErr := decodeRequest(h.dec)
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if decErr.Code != 0 {
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encErr := encodeErrorResponse(h.enc, req.ID, decErr)
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return errors.Join(decErr, encErr)
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}
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var rpcErr Error
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res, err := h.handler.ServeRPC(ctx, req)
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if err != nil && !errors.As(err, &rpcErr) {
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// We deliberately don't include the actual error in the response. If
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// doing so is desired this can be achieved using a middleware which
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// translates the non-Error into an Error prior to it reaching this
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// point.
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rpcErr = NewError(errCodeServerError, "unexpected server-side error")
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}
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if rpcErr.Code != 0 {
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return encodeErrorResponse(h.enc, req.ID, rpcErr)
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}
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return encodeResponse(h.enc, req.ID, res)
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}
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