serialization

#Data Serialization

Data serialization, for our purposes, simply refers to taking a block of data and transmitting it one byte at a time over some interface. This tutorial will give an example using sockets and the C programming language, but the concepts are the same for Java.

Serializing text/numerical data

One common application for this technique is in sending a mix of quantitative and qualitative information all at once in a big string of characters. The following C example transmits a number of fields over a TCP socket.

char buf[] = "Time: 15:05CST,\n
              Temperature: 50F,\n
              Unit ID: 15105,\n
              Status: OK";
write(socketfd, buf, sizeof(buf));  

Serializing an image

In this C example, a .png image is read into a program as its individual bytes and then transmitted in order over a TCP socket.

FILE* fp = fopen("image.png","rb"); //open image.png for binary reading
char buf[32768]; //allocate 32K buffer for serializing image data (watch out for RAM usage)
int bytes_read = 0;
while(!feof(fp)) //keep going until we reach the end of the file
{
    bytes_read = fread(buf, sizeof(char), sizeof(buf), fp); //read as many bytes as possible from the image
    write(socketfd, buf, bytes_read); //serially write as many bytes as we have in the buffer to the socket
}  

Example Code

These example programs transmit a serialized screenshot image from the server to the client over a TCP socket.
Server
Client