WebSocketClient.h

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/*
WebSocketClient, a websocket implementation for Arduino
Copyright 2020 Patrick Moffitt

Based on previous implementations by
Copyright 2015 William Blommaert
and
Copyright 2010 Ben Swanson
and
Copyright 2010 Randall Brewer
and
Copyright 2010 Oliver Smith
and
Copyright 2011 Branden Hall
and
Copyright 2011 Per Ejeklint

Some code and concept based off of Webduino library
Copyright 2009 Ben Combee, Ran Talbott

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/

#ifndef WEBSOCKETCLIENT_H_
#define WEBSOCKETCLIENT_H_

#include <Arduino.h>
#include <Stream.h>
#include "Client.h"

// CRLF characters to terminate lines/handshakes in headers.
#define CRLF "\r\n"

// Amount of time in ms to wait for server to have characters available after making a request.
#define AVAILABLE_TIMEOUT_MS 500

// Amount of time (in ms) a user may be connected before getting disconnected 
// for timing out (i.e. not sending any data to the server).
#define TIMEOUT_IN_MS 10000

// ACTION_SPACE is how many actions are allowed in a program. Defaults to 
// 5 unless overwritten by user.
#ifndef CALLBACK_FUNCTIONS
#define CALLBACK_FUNCTIONS 1
#endif

// Don't allow the client to send big frames of data. This will flood the Arduinos
// memory and might even crash it.
#ifndef MAX_FRAME_LENGTH
#define MAX_FRAME_LENGTH 256
#endif

#define SIZE(array) (sizeof(array) / sizeof(*array))

// WebSocket protocol constants
// First byte
#define WS_FIN            0x80
#define WS_OPCODE_TEXT    0x1
#define WS_OPCODE_BINARY  0x2
#define WS_OPCODE_CLOSE   0x8
#define WS_OPCODE_PING    0x9
#define WS_OPCODE_PONG    0xa
// Second byte
#define WS_MASK           0x80
#define WS_SIZE16         126
#define WS_SIZE64         127

class WebSocketClient {
public:

    // Handle connection requests to validate and process/refuse
    // connections.
    bool handshake(Client &client);
    
    // Get data off of the stream
    String getData();

    // Write data to the stream
    void sendData(const char *str);
    void sendData(String str);
    // Write data to the stream with frame masking, this is required!
    void sendData(const char *str, uint8_t opcode);
    void sendData(String str, uint8_t opcode);

    char *path;
    char *host;
    char *origin;

private:
    Client *socket_client;
    unsigned long _startMillis;

    const char *socket_urlPrefix;

    // Discovers if the client's header is requesting an upgrade to a
    // websocket connection.
    bool analyzeRequest();

    String handleStream();    
    
    // Disconnect user gracefully.
    void disconnectStream();
    
    int timedRead();

    void sendEncodedData(char *str);
    void sendEncodedData(String str);
    // Write data to the stream with frame masking, this is required!
    void sendEncodedData(char *str, uint8_t opcode);
    void sendEncodedData(String str, uint8_t opcode);
};
#endif