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-rw-r--r--src/net/rpc/jsonrpc/server.go134
1 files changed, 134 insertions, 0 deletions
diff --git a/src/net/rpc/jsonrpc/server.go b/src/net/rpc/jsonrpc/server.go
new file mode 100644
index 0000000..40e4e6f
--- /dev/null
+++ b/src/net/rpc/jsonrpc/server.go
@@ -0,0 +1,134 @@
+// Copyright 2010 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package jsonrpc
+
+import (
+ "encoding/json"
+ "errors"
+ "io"
+ "net/rpc"
+ "sync"
+)
+
+var errMissingParams = errors.New("jsonrpc: request body missing params")
+
+type serverCodec struct {
+ dec *json.Decoder // for reading JSON values
+ enc *json.Encoder // for writing JSON values
+ c io.Closer
+
+ // temporary work space
+ req serverRequest
+
+ // JSON-RPC clients can use arbitrary json values as request IDs.
+ // Package rpc expects uint64 request IDs.
+ // We assign uint64 sequence numbers to incoming requests
+ // but save the original request ID in the pending map.
+ // When rpc responds, we use the sequence number in
+ // the response to find the original request ID.
+ mutex sync.Mutex // protects seq, pending
+ seq uint64
+ pending map[uint64]*json.RawMessage
+}
+
+// NewServerCodec returns a new rpc.ServerCodec using JSON-RPC on conn.
+func NewServerCodec(conn io.ReadWriteCloser) rpc.ServerCodec {
+ return &serverCodec{
+ dec: json.NewDecoder(conn),
+ enc: json.NewEncoder(conn),
+ c: conn,
+ pending: make(map[uint64]*json.RawMessage),
+ }
+}
+
+type serverRequest struct {
+ Method string `json:"method"`
+ Params *json.RawMessage `json:"params"`
+ Id *json.RawMessage `json:"id"`
+}
+
+func (r *serverRequest) reset() {
+ r.Method = ""
+ r.Params = nil
+ r.Id = nil
+}
+
+type serverResponse struct {
+ Id *json.RawMessage `json:"id"`
+ Result interface{} `json:"result"`
+ Error interface{} `json:"error"`
+}
+
+func (c *serverCodec) ReadRequestHeader(r *rpc.Request) error {
+ c.req.reset()
+ if err := c.dec.Decode(&c.req); err != nil {
+ return err
+ }
+ r.ServiceMethod = c.req.Method
+
+ // JSON request id can be any JSON value;
+ // RPC package expects uint64. Translate to
+ // internal uint64 and save JSON on the side.
+ c.mutex.Lock()
+ c.seq++
+ c.pending[c.seq] = c.req.Id
+ c.req.Id = nil
+ r.Seq = c.seq
+ c.mutex.Unlock()
+
+ return nil
+}
+
+func (c *serverCodec) ReadRequestBody(x interface{}) error {
+ if x == nil {
+ return nil
+ }
+ if c.req.Params == nil {
+ return errMissingParams
+ }
+ // JSON params is array value.
+ // RPC params is struct.
+ // Unmarshal into array containing struct for now.
+ // Should think about making RPC more general.
+ var params [1]interface{}
+ params[0] = x
+ return json.Unmarshal(*c.req.Params, &params)
+}
+
+var null = json.RawMessage([]byte("null"))
+
+func (c *serverCodec) WriteResponse(r *rpc.Response, x interface{}) error {
+ c.mutex.Lock()
+ b, ok := c.pending[r.Seq]
+ if !ok {
+ c.mutex.Unlock()
+ return errors.New("invalid sequence number in response")
+ }
+ delete(c.pending, r.Seq)
+ c.mutex.Unlock()
+
+ if b == nil {
+ // Invalid request so no id. Use JSON null.
+ b = &null
+ }
+ resp := serverResponse{Id: b}
+ if r.Error == "" {
+ resp.Result = x
+ } else {
+ resp.Error = r.Error
+ }
+ return c.enc.Encode(resp)
+}
+
+func (c *serverCodec) Close() error {
+ return c.c.Close()
+}
+
+// ServeConn runs the JSON-RPC server on a single connection.
+// ServeConn blocks, serving the connection until the client hangs up.
+// The caller typically invokes ServeConn in a go statement.
+func ServeConn(conn io.ReadWriteCloser) {
+ rpc.ServeCodec(NewServerCodec(conn))
+}