/
conn.go
268 lines (248 loc) · 6.49 KB
/
conn.go
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package ws
import (
"bytes"
"encoding/json"
"errors"
"fmt"
"net/http"
"sync"
"github.com/eduhenke/go-ocpp/internal/log"
"github.com/eduhenke/go-ocpp/messages"
"github.com/eduhenke/go-ocpp/messages/req"
"github.com/google/uuid"
"github.com/eduhenke/go-ocpp"
"github.com/gorilla/websocket"
)
type CallResponse struct {
response messages.Response
err error
}
type Conn struct {
*websocket.Conn
sendMux sync.Mutex
sentMessages map[MessageID]*CallMessage
requests chan struct {
messages.Request
MessageID
}
responsesOf map[MessageID]chan CallResponse
}
func newConn(socket *websocket.Conn) *Conn {
return &Conn{
Conn: socket,
sentMessages: make(map[MessageID]*CallMessage, 0),
requests: make(chan struct {
messages.Request
MessageID
}, 0),
responsesOf: make(map[MessageID]chan CallResponse),
}
}
func Dial(identity, csURL string, version ocpp.Version) (*Conn, error) {
dialer := websocket.Dialer{
Subprotocols: []string{"ocpp" + string(version)},
}
socket, _, err := dialer.Dial(csURL+"/"+identity, http.Header{})
if err != nil {
return nil, err
}
return newConn(socket), err
}
var upgrader = websocket.Upgrader{
ReadBufferSize: 1024,
WriteBufferSize: 1024,
CheckOrigin: func(r *http.Request) bool {
return true
},
}
func Handshake(w http.ResponseWriter, r *http.Request, supportedVersions []ocpp.Version) (*Conn, error) {
upgraderHeader := http.Header{}
for _, v := range supportedVersions {
upgraderHeader.Add("Sec-WebSocket-Protocol", "ocpp"+string(v))
}
socket, err := upgrader.Upgrade(w, r, upgraderHeader)
conn := newConn(socket)
return conn, err
}
func (c *Conn) WriteJSON(data interface{}) error {
c.sendMux.Lock()
defer c.sendMux.Unlock()
return c.Conn.WriteJSON(data)
}
var (
newline = []byte{'\n'}
space = []byte{' '}
)
func UnmarshalMessage(msg []byte) (Message, error) {
var frame []interface{}
err := json.Unmarshal(msg, &frame)
if err != nil {
return nil, fmt.Errorf("on unmarshalling websocket message: %w", err)
}
msgType, ok := frame[0].(float64)
if !ok {
return nil, fmt.Errorf("first field is not a message type: %w", err)
}
idStr, ok := frame[1].(string)
if !ok {
return nil, fmt.Errorf("second field is not a message ID: %w", err)
}
id := MessageID(idStr)
switch MessageType(msgType) {
case Call:
actionStr, ok := frame[2].(string)
if !ok {
return nil, fmt.Errorf("third field is not action: %w", err)
}
action := Action(actionStr)
payload, ok := frame[3].(map[string]interface{})
if !ok {
return nil, fmt.Errorf("fourth field is not payload: %w", err)
}
return &CallMessage{id, action, payload}, nil
case CallResult:
payload, ok := frame[2].(map[string]interface{})
if !ok {
return nil, fmt.Errorf("third field is not payload: %w", err)
}
return &CallResultMessage{id, payload}, nil
case CallError:
codeStr, ok := frame[2].(string)
if !ok {
return nil, fmt.Errorf("third field is not error code: %w", err)
}
description, ok := frame[3].(string)
if !ok {
return nil, fmt.Errorf("fourth field is not error description: %w", err)
}
details, ok := frame[4].(map[string]interface{})
if !ok {
return nil, fmt.Errorf("fifth field is not error details: %w", err)
}
return &CallErrorMessage{id, ErrorCode(codeStr), description, details}, nil
}
return nil, nil
}
func (c *Conn) ReadMessage() error {
_, messageBytes, err := c.Conn.ReadMessage()
if err != nil {
return err
}
messageBytes = bytes.TrimSpace(bytes.Replace(messageBytes, newline, space, -1))
log.Debug("Received a message, raw: %v", string(messageBytes))
msg, err := UnmarshalMessage(messageBytes)
if err != nil {
return err
}
log.Debug("Received a message, parsed: %v", msg)
if msg.Type() == CallResult || msg.Type() == CallError {
_, ok := c.sentMessages[msg.ID()]
if !ok {
return errors.New("received call error/result without sending any call message")
}
}
var wserr ErrorCode
switch m := msg.(type) {
case *CallMessage:
var req messages.Request
req, wserr = c.callToRequest(m)
if wserr != Nil {
msg := NewCallErrorMessage(msg.ID(), wserr, "on handling message")
return c.sendMessage(msg)
}
c.requests <- struct {
messages.Request
MessageID
}{req, msg.ID()}
case *CallResultMessage:
var resp messages.Response
resp, wserr = c.callResultToResponse(m)
c.responsesOf[m.ID()] <- CallResponse{
response: resp,
err: wserr,
}
case *CallErrorMessage:
c.responsesOf[m.ID()] <- CallResponse{
response: nil,
err: m,
}
}
return nil
}
func (c *Conn) callToRequest(call *CallMessage) (messages.Request, ErrorCode) {
req := req.FromActionName(string(call.Action))
if req == nil {
return nil, NotSupported
}
originalPayload, err := json.Marshal(call.Payload)
if err != nil {
return nil, GenericError
}
err = json.Unmarshal(originalPayload, req)
if err != nil {
return nil, FormationViolation
}
return req, Nil
}
func (c *Conn) callResultToResponse(result *CallResultMessage) (messages.Response, ErrorCode) {
id := result.ID()
call, ok := c.sentMessages[id]
if !ok {
return nil, GenericError
}
if call == nil {
return nil, NotSupported
}
resp := req.FromActionName(string(call.Action)).GetResponse()
originalPayload, err := json.Marshal(result.Payload)
if err != nil {
return nil, GenericError
}
err = json.Unmarshal(originalPayload, resp)
if err != nil {
return nil, FormationViolation
}
return resp, Nil
}
func (c *Conn) SendResponse(id MessageID, response messages.Response, err error) error {
return c.sendMessage(unmarshalResponse(id, response, err))
}
func (c *Conn) sendMessage(msg Message) error {
bts, err := json.Marshal(msg)
if err != nil {
return fmt.Errorf("on marshalling message: %w", err)
}
log.Debug("Sending message [raw]: %v", string(bts))
err = c.Conn.WriteMessage(websocket.TextMessage, bts)
if err != nil {
return fmt.Errorf("on sending message: %w", err)
}
log.Debug("Sent message!")
return nil
}
func (c *Conn) Requests() <-chan struct {
messages.Request
MessageID
} {
return c.requests
}
func (c *Conn) SendRequest(request messages.Request) (messages.Response, error) {
id := MessageID(uuid.New().String())
msg, err := UnmarshalRequest(id, request)
if err != nil {
return nil, err
}
c.sentMessages[id] = msg
c.responsesOf[id] = make(chan CallResponse)
err = c.sendMessage(msg)
if err != nil {
return nil, err
}
callResponse := <-c.responsesOf[id]
delete(c.sentMessages, id)
delete(c.responsesOf, id)
if callResponse.err != Nil {
return nil, callResponse.err
}
return callResponse.response, nil
}