Send files via network I want to send a file from an Arduino to the server or another Arduino. 

I wrote a code that's open the file then write the content of the text on an array and then send it.

That would work if the data is small, but when i try to send, .wav it will takes lots of time if i do it that why (storing each byte in array).
I want to send the whole file at on time.
Is there a way or a library helps ?  

#include &lt;SPI.h&gt;
#include &lt;Ethernet.h&gt;
#include &lt;EthernetUdp.h&gt;
#include &lt;SD.h&gt;


const int push1 = 2;

File myFile;
char a[400];
int c= 0; 


// network parameters
byte mac[] = { 0x90, 0xA2, 0xDA, 0x0E, 0x05, 0x02 };  // ethernet interface MAC address
IPAddress localIp(10,131,41,72);    // local ip address
IPAddress destIp(10,131,41,74);      // destination ip address
unsigned int port = 9631;               // destination port

// EthernetUDP to send and receive messages.
EthernetUDP Udp;


// timing

// setup the arduino and shields
void setup() {

    pinMode(push1, INPUT); 


  //Initialize serial and wait for port to open:
  Serial.begin(9600); // 19200
  while (!Serial) {
    ; // wait for serial port to connect. Needed for Leonardo only
  }

  Serial.print("Initializing SD card...");

  if (!SD.begin(4)) {
    Serial.println("initialization failed!");
    while (1);
  }
  Serial.println("initialization done.");


  // start ethernet and udp
  Ethernet.begin(mac, localIp);   // static ip version
  //if(Ethernet.begin(mac) == 0) {     // dhcp version
  // report failure to obtain network parameters
  // Serial.println("DHCP error");

  // no point in carrying on, loop indefinitely:
  // while(true)
  // ;
  //}

  // open UDP port
  Udp.begin(port);

  // show the local ip address (useful for dhcp)
  Serial.print("Local IP: ");
  Serial.println(Ethernet.localIP());

  // initialize previous millis variables



}

// do tasks
void loop() {

if(digitalRead(push1) == LOW){

   myFile = SD.open("R.wav" , FILE_READ);

  if (myFile) {
    // read from the file until there's nothing else in it:
    Serial.println("i will send now");
    while (myFile.available()) {
        a[i] = myFile.read(); 
        i++;
        }
      Udp.beginPacket(destIp, port);
     Udp.write(a);
      Udp.endPacket();
      Serial.println("Sending UDP message");
      Serial.println();
    }
    // close the file:
    myFile.close();
  } else {
   // if the file didn't open, print an error:
    Serial.println("error opening test.txt");
  }  } }
You may try:

Serial.println("Sending UDP message");  
Udp.beginPacket(destIp, port);
while (myFile.available()) {
  Udp.write(a);
}
Udp.endPacket();
Serial.println("Message sent!");


Or send the message part by part (for example 100bytes or 500bytes at a time)

Though, what makes you think that Arduino would be a platform that can rapidly send large files over network?
Potentially you are better off with an Raspberry Pi.