节点：如何发送16位二进制信息

Question

I have a server program which reads binary commands from a socket. The buffer that is sent to the socket needs to have its data ordered very specifically. This is some C-code from an example client application provided, which shows the ordering and size of the data which needs to be sent.

typedef   unsigned char     u8;
typedef   unsigned short    u16;
typedef   unsigned int      u32;

typedef struct JobNodeInfo_s {
    u16  jNodeInfoType;                          /* per END device, per router, whole system */
    u8  value[32];        /* mac address / barcode value / Location  */
} JobNodeInfo_t;

typedef struct JobHdrFormat_s {
    u16                 jPreamble;
    JobCommandType_t    jCmd;
    u16                 jBatchID;       /* for logging */
    u16                 jSeq;
    u16                 priority;
    u16                 option;         /* option field could be reserved for future extension */
    JobNodeInfo_t       jNodeInfo;
    u16                 jLen;

} JobHdrFormat_t;

The JobHdrFormat_s struct is passed as a void pointer to the socket:

send(connfd, (void*)jFormat, sizeof(JobHdrFormat_t) + jFormat->jLen , 0);

Now, I need to replicate this buffer in Node.js. I've looked into the Node Buffer class but have noticed it only supports Octets. As you can see, most of the memory slots are reserved for 16-bit integers. Is it possible to arrange the data is Node.js the way I need like this C-code? I have taken a first shot at it here:

var net = require( 'net' );
var client = new net.Socket();
client.connect( 13929, '192.168.2.2', function() {
    var mac_addr = "041511000960",
        outgoing_str = "FE9C00020000001100000004"
            + mac_addr
            + "0000",
        outgoing_buf = new Buffer( outgoing_str.length, "hex" );
var new_buff_arr = [];
for ( var i = 0, il = outgoing_str.length; i < il; i += 2 ) {
    var cmd_substr = "0x" + outgoing_str.substring( i, i + 2 ),
        i_cmd_substr = parseInt( cmd_substr );
        console.log( "substr: " + cmd_substr + " int: " +  i_cmd_substr );
        new_buff_arr.push(i_cmd_substr);
}
const buf = new Buffer(new_buff_arr);
    client.write( buf ,
        function() {
            console.log( "data is written" );
        }
    );
});

client.on('data', function( data ) {
    console.log('Received: ' + data.toString( "hex" ));
});

client.on('close', function() {
    console.log( 'Connection closed' );
});

More or less I've attempted to write the buffer as a string, loop through it, write each two 'bytes' as a single hex values, and then convert those back into the numbers and write the buffer out. Is any of this possible if Node can only work with Octets? Let me know if you need any more information.

Answer 1

Look at this :

[The] jBinary [is a] library for working with binary data in JavaScript, allows loading data from any source with automatically detected best supported way on current browser or Node.js

And then also look at jBinary library Typesets ...

I have no experience with jBinary and Node.js. But I'm interested in such features to, and I have found this solution right now.