micro/client/rpc_codec.go

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package client
import (
"bytes"
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"errors"
"github.com/micro/go-micro/codec"
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"github.com/micro/go-micro/codec/jsonrpc"
"github.com/micro/go-micro/codec/protorpc"
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"github.com/micro/go-micro/transport"
)
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const (
lastStreamResponseError = "EOS"
)
// serverError represents an error that has been returned from
// the remote side of the RPC connection.
type serverError string
func (e serverError) Error() string {
return string(e)
}
// errShutdown holds the specific error for closing/closed connections
var (
errShutdown = errors.New("connection is shut down")
)
type rpcPlusCodec struct {
client transport.Client
codec codec.Codec
req *transport.Message
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buf *readWriteCloser
}
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type readWriteCloser struct {
wbuf *bytes.Buffer
rbuf *bytes.Buffer
}
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type clientCodec interface {
WriteRequest(*request, interface{}) error
ReadResponseHeader(*response) error
ReadResponseBody(interface{}) error
Close() error
}
type request struct {
Service string
ServiceMethod string // format: "Service.Method"
Seq uint64 // sequence number chosen by client
next *request // for free list in Server
}
type response struct {
ServiceMethod string // echoes that of the Request
Seq uint64 // echoes that of the request
Error string // error, if any.
next *response // for free list in Server
}
var (
defaultContentType = "application/octet-stream"
defaultCodecs = map[string]codec.NewCodec{
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"application/json": jsonrpc.NewCodec,
"application/json-rpc": jsonrpc.NewCodec,
"application/protobuf": protorpc.NewCodec,
"application/proto-rpc": protorpc.NewCodec,
"application/octet-stream": protorpc.NewCodec,
}
)
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func (rwc *readWriteCloser) Read(p []byte) (n int, err error) {
return rwc.rbuf.Read(p)
}
func (rwc *readWriteCloser) Write(p []byte) (n int, err error) {
return rwc.wbuf.Write(p)
}
func (rwc *readWriteCloser) Close() error {
rwc.rbuf.Reset()
rwc.wbuf.Reset()
return nil
}
func newRpcPlusCodec(req *transport.Message, client transport.Client, c codec.NewCodec) *rpcPlusCodec {
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rwc := &readWriteCloser{
wbuf: bytes.NewBuffer(nil),
rbuf: bytes.NewBuffer(nil),
}
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r := &rpcPlusCodec{
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buf: rwc,
client: client,
codec: c(rwc),
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req: req,
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}
return r
}
func (c *rpcPlusCodec) WriteRequest(req *request, body interface{}) error {
c.buf.wbuf.Reset()
m := &codec.Message{
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Id: req.Seq,
Target: req.Service,
Method: req.ServiceMethod,
Type: codec.Request,
Headers: map[string]string{},
}
if err := c.codec.Write(m, body); err != nil {
return err
}
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c.req.Body = c.buf.wbuf.Bytes()
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for k, v := range m.Headers {
c.req.Header[k] = v
}
return c.client.Send(c.req)
}
func (c *rpcPlusCodec) ReadResponseHeader(r *response) error {
var m transport.Message
if err := c.client.Recv(&m); err != nil {
return err
}
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c.buf.rbuf.Reset()
c.buf.rbuf.Write(m.Body)
var me codec.Message
err := c.codec.ReadHeader(&me, codec.Response)
r.ServiceMethod = me.Method
r.Seq = me.Id
r.Error = me.Error
return err
}
func (c *rpcPlusCodec) ReadResponseBody(b interface{}) error {
return c.codec.ReadBody(b)
}
func (c *rpcPlusCodec) Close() error {
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c.buf.Close()
c.codec.Close()
return c.client.Close()
}