pgproto3.go (1629B)
1 package pgproto3 2 3 import ( 4 "encoding/hex" 5 "errors" 6 "fmt" 7 ) 8 9 // Message is the interface implemented by an object that can decode and encode 10 // a particular PostgreSQL message. 11 type Message interface { 12 // Decode is allowed and expected to retain a reference to data after 13 // returning (unlike encoding.BinaryUnmarshaler). 14 Decode(data []byte) error 15 16 // Encode appends itself to dst and returns the new buffer. 17 Encode(dst []byte) []byte 18 } 19 20 type FrontendMessage interface { 21 Message 22 Frontend() // no-op method to distinguish frontend from backend methods 23 } 24 25 type BackendMessage interface { 26 Message 27 Backend() // no-op method to distinguish frontend from backend methods 28 } 29 30 type AuthenticationResponseMessage interface { 31 BackendMessage 32 AuthenticationResponse() // no-op method to distinguish authentication responses 33 } 34 35 type invalidMessageLenErr struct { 36 messageType string 37 expectedLen int 38 actualLen int 39 } 40 41 func (e *invalidMessageLenErr) Error() string { 42 return fmt.Sprintf("%s body must have length of %d, but it is %d", e.messageType, e.expectedLen, e.actualLen) 43 } 44 45 type invalidMessageFormatErr struct { 46 messageType string 47 } 48 49 func (e *invalidMessageFormatErr) Error() string { 50 return fmt.Sprintf("%s body is invalid", e.messageType) 51 } 52 53 // getValueFromJSON gets the value from a protocol message representation in JSON. 54 func getValueFromJSON(v map[string]string) ([]byte, error) { 55 if v == nil { 56 return nil, nil 57 } 58 if text, ok := v["text"]; ok { 59 return []byte(text), nil 60 } 61 if binary, ok := v["binary"]; ok { 62 return hex.DecodeString(binary) 63 } 64 return nil, errors.New("unknown protocol representation") 65 }