New APIs added:
    client.RegisterName(namespace, service) // makes service available to server
    client.Notify(ctx, method, args...)     // sends a notification
    ClientFromContext(ctx)                  // to get a client in handler method
This is essentially a rewrite of the server-side code. JSON-RPC
processing code is now the same on both server and client side. Many
minor issues were fixed in the process and there is a new test suite for
JSON-RPC spec compliance (and non-compliance in some cases).
List of behavior changes:
- Method handlers are now called with a per-request context instead of a
  per-connection context. The context is canceled right after the method
  returns.
- Subscription error channels are always closed when the connection
  ends. There is no need to also wait on the Notifier's Closed channel
  to detect whether the subscription has ended.
- Client now omits "params" instead of sending "params": null when there
  are no arguments to a call. The previous behavior was not compliant
  with the spec. The server still accepts "params": null.
- Floating point numbers are allowed as "id". The spec doesn't allow
  them, but we handle request "id" as json.RawMessage and guarantee that
  the same number will be sent back.
- Logging is improved significantly. There is now a message at DEBUG
  level for each RPC call served.
		
	
			
		
			
				
	
	
		
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			108 lines
		
	
	
		
			3.3 KiB
		
	
	
	
		
			Go
		
	
	
	
	
	
// Copyright 2015 The go-ethereum Authors
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// This file is part of the go-ethereum library.
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//
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// The go-ethereum library is free software: you can redistribute it and/or modify
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// it under the terms of the GNU Lesser General Public License as published by
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// the Free Software Foundation, either version 3 of the License, or
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// (at your option) any later version.
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//
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// The go-ethereum library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU Lesser General Public License for more details.
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//
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// You should have received a copy of the GNU Lesser General Public License
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// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
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package rpc
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import (
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	"context"
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	"fmt"
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	"math"
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	"strings"
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	"github.com/ethereum/go-ethereum/common/hexutil"
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)
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// API describes the set of methods offered over the RPC interface
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type API struct {
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	Namespace string      // namespace under which the rpc methods of Service are exposed
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	Version   string      // api version for DApp's
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	Service   interface{} // receiver instance which holds the methods
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	Public    bool        // indication if the methods must be considered safe for public use
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}
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// Error wraps RPC errors, which contain an error code in addition to the message.
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type Error interface {
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	Error() string  // returns the message
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	ErrorCode() int // returns the code
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}
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// ServerCodec implements reading, parsing and writing RPC messages for the server side of
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// a RPC session. Implementations must be go-routine safe since the codec can be called in
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// multiple go-routines concurrently.
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type ServerCodec interface {
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	Read() (msgs []*jsonrpcMessage, isBatch bool, err error)
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	Close()
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	jsonWriter
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}
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// jsonWriter can write JSON messages to its underlying connection.
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// Implementations must be safe for concurrent use.
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type jsonWriter interface {
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	Write(context.Context, interface{}) error
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	// Closed returns a channel which is closed when the connection is closed.
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	Closed() <-chan interface{}
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	// RemoteAddr returns the peer address of the connection.
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	RemoteAddr() string
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}
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type BlockNumber int64
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const (
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	PendingBlockNumber  = BlockNumber(-2)
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	LatestBlockNumber   = BlockNumber(-1)
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	EarliestBlockNumber = BlockNumber(0)
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)
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// UnmarshalJSON parses the given JSON fragment into a BlockNumber. It supports:
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// - "latest", "earliest" or "pending" as string arguments
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// - the block number
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// Returned errors:
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// - an invalid block number error when the given argument isn't a known strings
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// - an out of range error when the given block number is either too little or too large
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func (bn *BlockNumber) UnmarshalJSON(data []byte) error {
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	input := strings.TrimSpace(string(data))
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	if len(input) >= 2 && input[0] == '"' && input[len(input)-1] == '"' {
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		input = input[1 : len(input)-1]
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	}
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	switch input {
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	case "earliest":
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		*bn = EarliestBlockNumber
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		return nil
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	case "latest":
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		*bn = LatestBlockNumber
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		return nil
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	case "pending":
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		*bn = PendingBlockNumber
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		return nil
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	}
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	blckNum, err := hexutil.DecodeUint64(input)
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	if err != nil {
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		return err
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	}
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	if blckNum > math.MaxInt64 {
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		return fmt.Errorf("Blocknumber too high")
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	}
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	*bn = BlockNumber(blckNum)
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	return nil
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}
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func (bn BlockNumber) Int64() int64 {
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	return (int64)(bn)
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}
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