ESP32-Websocket arduino library

readme.md

Websocket Client and Server for ESP-8266

This is a simple library that implements a Websocket client and server running on an ESP-8266.

Getting started

The example WebSocketServer.html file should be served from any web server you have access to. Remember to change the URL in it to your Arduino. The examples are based on using a WiFly wireless card to connect. If you're using ethernet instead you'll need to swap out the client class.

Install the library to "libraries" folder in your Arduino sketchbook folder. For example, on a mac that's ~/Documents/Arduino/libraries.

Try the examples to ensure that things work.

Start playing with your own code!

Notes

Inside of the WebSocketServer class there is a compiler directive to turn on support for the older "Hixie76" standard. If you don't need it, leave it off as it greatly increases the memory required.

Because of limitations of the current Arduino platform (Uno at the time of this writing), this library does not support messages larger than 65535 characters. In addition, this library only supports single-frame text frames. It currently does not recognize continuation frames, binary frames, or ping/pong frames.

Credits

Thank you to github user ejeklint for the excellent starting point for this library. From his original Hixie76-only code I was able to add support for RFC 6455 and create the WebSocket client.

• Branden

ESP32 port

Some light changes were incorporated to this library to make it compatible with ESP32. First of all MD5 code was removed, because it was in conflict with ESP32 MD5 implementation, WebSocketClient::sendEncodedData was altered so it transfers the data as single packet instead of per byte transmission. Function WebSocketClient::analyzeRequest exits when there is no response in 30s interval.

Base64.cpp

#include "Base64.h"

const char b64_alphabet[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
		"abcdefghijklmnopqrstuvwxyz"
		"0123456789+/";

/* 'Private' declarations */
inline void a3_to_a4(unsigned char * a4, unsigned char * a3);
inline void a4_to_a3(unsigned char * a3, unsigned char * a4);
inline unsigned char b64_lookup(char c);

int base64_encode(char *output, char *input, int inputLen) {
	int i = 0, j = 0;
	int encLen = 0;
	unsigned char a3[3];
	unsigned char a4[4];

	while(inputLen--) {
		a3[i++] = *(input++);
		if(i == 3) {
			a3_to_a4(a4, a3);

			for(i = 0; i < 4; i++) {
				output[encLen++] = b64_alphabet[a4[i]];
			}

			i = 0;
		}
	}

	if(i) {
		for(j = i; j < 3; j++) {
			a3[j] = '\0';
		}

		a3_to_a4(a4, a3);

		for(j = 0; j < i + 1; j++) {
			output[encLen++] = b64_alphabet[a4[j]];
		}

		while((i++ < 3)) {
			output[encLen++] = '=';
		}
	}
	output[encLen] = '\0';
	return encLen;
}

int base64_decode(char * output, char * input, int inputLen) {
	int i = 0, j = 0;
	int decLen = 0;
	unsigned char a3[3];
	unsigned char a4[4];


	while (inputLen--) {
		if(*input == '=') {
			break;
		}

		a4[i++] = *(input++);
		if (i == 4) {
			for (i = 0; i <4; i++) {
				a4[i] = b64_lookup(a4[i]);
			}

			a4_to_a3(a3,a4);

			for (i = 0; i < 3; i++) {
				output[decLen++] = a3[i];
			}
			i = 0;
		}
	}

	if (i) {
		for (j = i; j < 4; j++) {
			a4[j] = '\0';
		}

		for (j = 0; j <4; j++) {
			a4[j] = b64_lookup(a4[j]);
		}

		a4_to_a3(a3,a4);

		for (j = 0; j < i - 1; j++) {
			output[decLen++] = a3[j];
		}
	}
	output[decLen] = '\0';
	return decLen;
}

int base64_enc_len(int plainLen) {
	int n = plainLen;
	return (n + 2 - ((n + 2) % 3)) / 3 * 4;
}

int base64_dec_len(char * input, int inputLen) {
	int i = 0;
	int numEq = 0;
	for(i = inputLen - 1; input[i] == '='; i--) {
		numEq++;
	}

	return ((6 * inputLen) / 8) - numEq;
}

inline void a3_to_a4(unsigned char * a4, unsigned char * a3) {
	a4[0] = (a3[0] & 0xfc) >> 2;
	a4[1] = ((a3[0] & 0x03) << 4) + ((a3[1] & 0xf0) >> 4);
	a4[2] = ((a3[1] & 0x0f) << 2) + ((a3[2] & 0xc0) >> 6);
	a4[3] = (a3[2] & 0x3f);
}

inline void a4_to_a3(unsigned char * a3, unsigned char * a4) {
	a3[0] = (a4[0] << 2) + ((a4[1] & 0x30) >> 4);
	a3[1] = ((a4[1] & 0xf) << 4) + ((a4[2] & 0x3c) >> 2);
	a3[2] = ((a4[2] & 0x3) << 6) + a4[3];
}

inline unsigned char b64_lookup(char c) {
	int i;
	for(i = 0; i < 64; i++) {
		if(b64_alphabet[i] == c) {
			return i;
		}
	}

	return -1;
}

Base64.h

#ifndef _BASE64_H
#define _BASE64_H

/* b64_alphabet:
 * 		Description: Base64 alphabet table, a mapping between integers
 * 					 and base64 digits
 * 		Notes: This is an extern here but is defined in Base64.c
 */
extern const char b64_alphabet[];

/* base64_encode:
 * 		Description:
 * 			Encode a string of characters as base64
 * 		Parameters:
 * 			output: the output buffer for the encoding, stores the encoded string
 * 			input: the input buffer for the encoding, stores the binary to be encoded
 * 			inputLen: the length of the input buffer, in bytes
 * 		Return value:
 * 			Returns the length of the encoded string
 * 		Requirements:
 * 			1. output must not be null or empty
 * 			2. input must not be null
 * 			3. inputLen must be greater than or equal to 0
 */
int base64_encode(char *output, char *input, int inputLen);

/* base64_decode:
 * 		Description:
 * 			Decode a base64 encoded string into bytes
 * 		Parameters:
 * 			output: the output buffer for the decoding,
 * 					stores the decoded binary
 * 			input: the input buffer for the decoding,
 * 				   stores the base64 string to be decoded
 * 			inputLen: the length of the input buffer, in bytes
 * 		Return value:
 * 			Returns the length of the decoded string
 * 		Requirements:
 * 			1. output must not be null or empty
 * 			2. input must not be null
 * 			3. inputLen must be greater than or equal to 0
 */
int base64_decode(char *output, char *input, int inputLen);

/* base64_enc_len:
 * 		Description:
 * 			Returns the length of a base64 encoded string whose decoded
 * 			form is inputLen bytes long
 * 		Parameters:
 * 			inputLen: the length of the decoded string
 * 		Return value:
 * 			The length of a base64 encoded string whose decoded form
 * 			is inputLen bytes long
 * 		Requirements:
 * 			None
 */
int base64_enc_len(int inputLen);

/* base64_dec_len:
 * 		Description:
 * 			Returns the length of the decoded form of a
 * 			base64 encoded string
 * 		Parameters:
 * 			input: the base64 encoded string to be measured
 * 			inputLen: the length of the base64 encoded string
 * 		Return value:
 * 			Returns the length of the decoded form of a
 * 			base64 encoded string
 * 		Requirements:
 * 			1. input must not be null
 * 			2. input must be greater than or equal to zero
 */
int base64_dec_len(char *input, int inputLen);

#endif // _BASE64_H

sha1.cpp

/*
 *  sha1.c
 *
 *  Description:
 *      This file implements the Secure Hashing Algorithm 1 as
 *      defined in FIPS PUB 180-1 published April 17, 1995.
 *
 *      The SHA-1, produces a 160-bit message digest for a given
 *      data stream.  It should take about 2**n steps to find a
 *      message with the same digest as a given message and
 *      2**(n/2) to find any two messages with the same digest,
 *      when n is the digest size in bits.  Therefore, this
 *      algorithm can serve as a means of providing a
 *      "fingerprint" for a message.
 *
 *  Portability Issues:
 *      SHA-1 is defined in terms of 32-bit "words".  This code
 *      uses <stdint.h> (included via "sha1.h" to define 32 and 8
 *      bit unsigned integer types.  If your C compiler does not
 *      support 32 bit unsigned integers, this code is not
 *      appropriate.
 *
 *  Caveats:
 *      SHA-1 is designed to work with messages less than 2^64 bits
 *      long.  Although SHA-1 allows a message digest to be generated
 *      for messages of any number of bits less than 2^64, this
 *      implementation only works with messages with a length that is
 *      a multiple of the size of an 8-bit character.
 *
 */

#include "sha1.h"

/*
 *  Define the SHA1 circular left shift macro
 */
#define SHA1CircularShift(bits,word) \
(((word) << (bits)) | ((word) >> (32-(bits))))

/* Local Function Prototyptes */
void SHA1PadMessage(SHA1Context *);
void SHA1ProcessMessageBlock(SHA1Context *);

/*
 *  SHA1Reset
 *
 *  Description:
 *      This function will initialize the SHA1Context in preparation
 *      for computing a new SHA1 message digest.
 *
 *  Parameters:
 *      context: [in/out]
 *          The context to reset.
 *
 *  Returns:
 *      sha Error Code.
 *
 */
int SHA1Reset(SHA1Context *context)
{
    if (!context)
    {
        return shaNull;
    }
    
    context->Length_Low             = 0;
    context->Length_High            = 0;
    context->Message_Block_Index    = 0;
    
    context->Intermediate_Hash[0]   = 0x67452301;
    context->Intermediate_Hash[1]   = 0xEFCDAB89;
    context->Intermediate_Hash[2]   = 0x98BADCFE;
    context->Intermediate_Hash[3]   = 0x10325476;
    context->Intermediate_Hash[4]   = 0xC3D2E1F0;
    
    context->Computed   = 0;
    context->Corrupted  = 0;
    
    return shaSuccess;
}

/*
 *  SHA1Result
 *
 *  Description:
 *      This function will return the 160-bit message digest into the
 *      Message_Digest array  provided by the caller.
 *      NOTE: The first octet of hash is stored in the 0th element,
 *            the last octet of hash in the 19th element.
 *
 *  Parameters:
 *      context: [in/out]
 *          The context to use to calculate the SHA-1 hash.
 *      Message_Digest: [out]
 *          Where the digest is returned.
 *
 *  Returns:
 *      sha Error Code.
 *
 */
int SHA1Result( SHA1Context *context,
               uint8_t Message_Digest[SHA1HashSize])
{
    int i;
    
    if (!context || !Message_Digest)
    {
        return shaNull;
    }
    
    if (context->Corrupted)
    {
        return context->Corrupted;
    }
    
    if (!context->Computed)
    {
        SHA1PadMessage(context);
        for(i=0; i<64; ++i)
        {
            /* message may be sensitive, clear it out */
            context->Message_Block[i] = 0;
        }
        context->Length_Low = 0;    /* and clear length */
        context->Length_High = 0;
        context->Computed = 1;
        
    }
    
    for(i = 0; i < SHA1HashSize; ++i)
    {
        Message_Digest[i] = context->Intermediate_Hash[i>>2]
        >> 8 * ( 3 - ( i & 0x03 ) );
    }
    
    return shaSuccess;
}

/*
 *  SHA1Input
 *
 *  Description:
 *      This function accepts an array of octets as the next portion
 *      of the message.
 *
 *  Parameters:
 *      context: [in/out]
 *          The SHA context to update
 *      message_array: [in]
 *          An array of characters representing the next portion of
 *          the message.
 *      length: [in]
 *          The length of the message in message_array
 *
 *  Returns:
 *      sha Error Code.
 *
 */
int SHA1Input(    SHA1Context    *context,
              const uint8_t  *message_array,
              unsigned       length)
{
    if (!length)
    {
        return shaSuccess;
    }
    
    if (!context || !message_array)
    {
        return shaNull;
    }
    
    if (context->Computed)
    {
        context->Corrupted = shaStateError;
        
        return shaStateError;
    }
    
    if (context->Corrupted)
    {
        return context->Corrupted;
    }
    while(length-- && !context->Corrupted)
    {
        context->Message_Block[context->Message_Block_Index++] =
        (*message_array & 0xFF);
        
        context->Length_Low += 8;
        if (context->Length_Low == 0)
        {
            context->Length_High++;
            if (context->Length_High == 0)
            {
                /* Message is too long */
                context->Corrupted = 1;
            }
        }
        
        if (context->Message_Block_Index == 64)
        {
            SHA1ProcessMessageBlock(context);
        }
        
        message_array++;
    }
    
    return shaSuccess;
}

/*
 *  SHA1ProcessMessageBlock
 *
 *  Description:
 *      This function will process the next 512 bits of the message
 *      stored in the Message_Block array.
 *
 *  Parameters:
 *      None.
 *
 *  Returns:
 *      Nothing.
 *
 *  Comments:
 
 *      Many of the variable names in this code, especially the
 *      single character names, were used because those were the
 *      names used in the publication.
 *
 *
 */
void SHA1ProcessMessageBlock(SHA1Context *context)
{
    const uint32_t K[] =    {       /* Constants defined in SHA-1   */
        0x5A827999,
        0x6ED9EBA1,
        0x8F1BBCDC,
        0xCA62C1D6
    };
    int           t;                 /* Loop counter                */
    uint32_t      temp;              /* Temporary word value        */
    uint32_t      W[80];             /* Word sequence               */
    uint32_t      A, B, C, D, E;     /* Word buffers                */
    
    /*
     *  Initialize the first 16 words in the array W
     */
    for(t = 0; t < 16; t++)
    {
        W[t] = context->Message_Block[t * 4] << 24;
        W[t] |= context->Message_Block[t * 4 + 1] << 16;
        W[t] |= context->Message_Block[t * 4 + 2] << 8;
        W[t] |= context->Message_Block[t * 4 + 3];
    }
    
    for(t = 16; t < 80; t++)
    {
        W[t] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
    }
    
    A = context->Intermediate_Hash[0];
    B = context->Intermediate_Hash[1];
    C = context->Intermediate_Hash[2];
    D = context->Intermediate_Hash[3];
    E = context->Intermediate_Hash[4];
    
    for(t = 0; t < 20; t++)
    {
        temp =  SHA1CircularShift(5,A) +
        ((B & C) | ((~B) & D)) + E + W[t] + K[0];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        
        B = A;
        A = temp;
    }
    
    for(t = 20; t < 40; t++)
    {
        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    
    for(t = 40; t < 60; t++)
    {
        temp = SHA1CircularShift(5,A) +
        ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    
    for(t = 60; t < 80; t++)
    {
        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
        E = D;
        D = C;
        C = SHA1CircularShift(30,B);
        B = A;
        A = temp;
    }
    
    context->Intermediate_Hash[0] += A;
    context->Intermediate_Hash[1] += B;
    context->Intermediate_Hash[2] += C;
    context->Intermediate_Hash[3] += D;
    context->Intermediate_Hash[4] += E;
    
    context->Message_Block_Index = 0;
}

/*
 *  SHA1PadMessage
 *
 
 *  Description:
 *      According to the standard, the message must be padded to an even
 *      512 bits.  The first padding bit must be a '1'.  The last 64
 *      bits represent the length of the original message.  All bits in
 *      between should be 0.  This function will pad the message
 *      according to those rules by filling the Message_Block array
 *      accordingly.  It will also call the ProcessMessageBlock function
 *      provided appropriately.  When it returns, it can be assumed that
 *      the message digest has been computed.
 *
 *  Parameters:
 *      context: [in/out]
 *          The context to pad
 *      ProcessMessageBlock: [in]
 *          The appropriate SHA*ProcessMessageBlock function
 *  Returns:
 *      Nothing.
 *
 */

void SHA1PadMessage(SHA1Context *context)
{
    /*
     *  Check to see if the current message block is too small to hold
     *  the initial padding bits and length.  If so, we will pad the
     *  block, process it, and then continue padding into a second
     *  block.
     */
    if (context->Message_Block_Index > 55)
    {
        context->Message_Block[context->Message_Block_Index++] = 0x80;
        while(context->Message_Block_Index < 64)
        {
            context->Message_Block[context->Message_Block_Index++] = 0;
        }
        
        SHA1ProcessMessageBlock(context);
        
        while(context->Message_Block_Index < 56)
        {
            context->Message_Block[context->Message_Block_Index++] = 0;
        }
    }
    else
    {
        context->Message_Block[context->Message_Block_Index++] = 0x80;
        while(context->Message_Block_Index < 56)
        {
            
            context->Message_Block[context->Message_Block_Index++] = 0;
        }
    }
    
    /*
     *  Store the message length as the last 8 octets
     */
    context->Message_Block[56] = context->Length_High >> 24;
    context->Message_Block[57] = context->Length_High >> 16;
    context->Message_Block[58] = context->Length_High >> 8;
    context->Message_Block[59] = context->Length_High;
    context->Message_Block[60] = context->Length_Low >> 24;
    context->Message_Block[61] = context->Length_Low >> 16;
    context->Message_Block[62] = context->Length_Low >> 8;
    context->Message_Block[63] = context->Length_Low;
    
    SHA1ProcessMessageBlock(context);
}

sha1.h

/*
 *  sha1.h
 *
 *  Description:
 *      This is the header file for code which implements the Secure
 *      Hashing Algorithm 1 as defined in FIPS PUB 180-1 published
 *      April 17, 1995.
 *
 *      Many of the variable names in this code, especially the
 *      single character names, were used because those were the names
 *      used in the publication.
 *
 *      Please read the file sha1.c for more information.
 *
 */

#ifndef _SHA1_H_
#define _SHA1_H_

#include <stdint.h>
/*
 * If you do not have the ISO standard stdint.h header file, then you
 * must typdef the following:
 *    name              meaning
 *  uint32_t         unsigned 32 bit integer
 *  uint8_t          unsigned 8 bit integer (i.e., unsigned char)
 *  int_least16_t    integer of >= 16 bits
 *
 */

#ifndef _SHA_enum_
#define _SHA_enum_
enum
{
    shaSuccess = 0,
    shaNull,            /* Null pointer parameter */
    shaInputTooLong,    /* input data too long */
    shaStateError       /* called Input after Result */
};
#endif
#define SHA1HashSize 20

/*
 *  This structure will hold context information for the SHA-1
 *  hashing operation
 */
typedef struct SHA1Context
{
    uint32_t Intermediate_Hash[SHA1HashSize/4]; /* Message Digest  */
    
    uint32_t Length_Low;            /* Message length in bits      */
    uint32_t Length_High;           /* Message length in bits      */
    
    /* Index into message block array   */
    int_least16_t Message_Block_Index;
    uint8_t Message_Block[64];      /* 512-bit message blocks      */
    
    int Computed;               /* Is the digest computed?         */
    int Corrupted;             /* Is the message digest corrupted? */
} SHA1Context;

/*
 *  Function Prototypes
 */

int SHA1Reset(  SHA1Context *);
int SHA1Input(  SHA1Context *,
              const uint8_t *,
              unsigned int);
int SHA1Result( SHA1Context *,
               uint8_t Message_Digest[SHA1HashSize]);

#endif