Improve the errors returned from ReadJSON.

The JSON decoder returns io.EOF when a message is empty or all
whitespace. Convert io.EOF return values from the JSON decoder to
io.ErrUnexpectedEOF so that applications can distinguish between an
error reading the JSON value and the connection closing.
This commit is contained in:
Gary Burd 2015-03-09 12:10:02 -07:00
parent ab5b3a61f5
commit 2dbddebb82
2 changed files with 65 additions and 1 deletions

10
json.go
View File

@ -6,6 +6,7 @@ package websocket
import ( import (
"encoding/json" "encoding/json"
"io"
) )
// WriteJSON is deprecated, use c.WriteJSON instead. // WriteJSON is deprecated, use c.WriteJSON instead.
@ -45,5 +46,12 @@ func (c *Conn) ReadJSON(v interface{}) error {
if err != nil { if err != nil {
return err return err
} }
return json.NewDecoder(r).Decode(v) err = json.NewDecoder(r).Decode(v)
if err == io.EOF {
// Decode returns io.EOF when the message is empty or all whitespace.
// Convert to io.ErrUnexpectedEOF so that application can distinguish
// between an error reading the JSON value and the connection closing.
err = io.ErrUnexpectedEOF
}
return err
} }

View File

@ -6,6 +6,8 @@ package websocket
import ( import (
"bytes" "bytes"
"encoding/json"
"io"
"reflect" "reflect"
"testing" "testing"
) )
@ -36,6 +38,60 @@ func TestJSON(t *testing.T) {
} }
} }
func TestPartialJsonRead(t *testing.T) {
var buf bytes.Buffer
c := fakeNetConn{&buf, &buf}
wc := newConn(c, true, 1024, 1024)
rc := newConn(c, false, 1024, 1024)
var v struct {
A int
B string
}
v.A = 1
v.B = "hello"
messageCount := 0
// Partial JSON values.
data, err := json.Marshal(v)
if err != nil {
t.Fatal(err)
}
for i := len(data) - 1; i >= 0; i-- {
if err := wc.WriteMessage(TextMessage, data[:i]); err != nil {
t.Fatal(err)
}
messageCount++
}
// Whitespace.
if err := wc.WriteMessage(TextMessage, []byte(" ")); err != nil {
t.Fatal(err)
}
messageCount++
// Close.
if err := wc.WriteMessage(CloseMessage, FormatCloseMessage(CloseNormalClosure, "")); err != nil {
t.Fatal(err)
}
for i := 0; i < messageCount; i++ {
err := rc.ReadJSON(&v)
if err != io.ErrUnexpectedEOF {
t.Error("read", i, err)
}
}
err = rc.ReadJSON(&v)
if err != io.EOF {
t.Error("final", err)
}
}
func TestDeprecatedJSON(t *testing.T) { func TestDeprecatedJSON(t *testing.T) {
var buf bytes.Buffer var buf bytes.Buffer
c := fakeNetConn{&buf, &buf} c := fakeNetConn{&buf, &buf}