Load pages from SD (W5100)

[Eduort]

Hi, i want to do a webserver whit 5 pages, i used a example code and it works, i can enter to the main page then open other, but the problem is that after open pages for a few times it start to load slow or dont open the page, then start to work correctly again,this always happen andt i dont know if is problem whit the code or my arduino/ethernet shield, i would apreciate if someone can help me to know what happen, thanks.
Code:

/*--------------------------------------------------------------
  Program:      eth_websrv_SD_link

  Description:  Arduino web server that serves up a basic web
                page that links to a second page. Clicking the
                link will open the second page. The second page
                links back to the first page.
 
  Hardware:     Arduino Uno and official Arduino Ethernet
                shield. Should work with other Arduinos and
                compatible Ethernet shields.
                2Gb micro SD card formatted FAT16
               
  Software:     Developed using Arduino 1.0.3 software
                Should be compatible with Arduino 1.0 +
               
                Requires index.htm and page2.htm to be on the
                micro SD card in the Ethernet shield micro
                SD card socket.
 
  References:   - WebServer example by David A. Mellis and
                  modified by Tom Igoe
                - SD card examples by David A. Mellis and
                  Tom Igoe
                - Ethernet library documentation:
                  http://arduino.cc/en/Reference/Ethernet
                - SD Card library documentation:
                  http://arduino.cc/en/Reference/SD

  Date:         2 March 2013

  Author:       W.A. Smith, http://startingelectronics.com
--------------------------------------------------------------*/

#include <SPI.h>
#include <Ethernet.h>
#include <SD.h>

// MAC address from Ethernet shield sticker under board
byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };
IPAddress ip(10, 0, 0, 20); // IP address, may need to change depending on network
EthernetServer server(80);  // create a server at port 80

File webFile;

String HTTP_req = "";     // stores the received HTTP request

void setup()
{
    Ethernet.begin(mac, ip);  // initialize Ethernet device
    server.begin();           // start to listen for clients
    Serial.begin(9600);       // for debugging
   
    // initialize SD card
    Serial.println("Initializing SD card...");
    if (!SD.begin(4)) {
        Serial.println("ERROR - SD card initialization failed!");
        return;    // init failed
    }
    Serial.println("SUCCESS - SD card initialized.");
    // check for index.htm file
    if (!SD.exists("index.htm")) {
        Serial.println("ERROR - Can't find index.htm file!");
        return;  // can't find index file
    }
    Serial.println("SUCCESS - Found index.htm file.");
}

void loop()
{
    EthernetClient client = server.available();  // try to get client

    if (client) {  // got client?
        boolean currentLineIsBlank = true;
        while (client.connected()) {
            if (client.available()) {   // client data available to read
                char c = client.read(); // read 1 byte (character) from client
                HTTP_req += c;          // save HTTP request character
                Serial.print(c);    // print HTTP request character to serial monitor
                // last line of client request is blank and ends with \n
                // respond to client only after last line received
                if (c == '\n' && currentLineIsBlank) {
                    // send a standard http response header
                    client.println("HTTP/1.1 200 OK");
                    client.println("Content-Type: text/html");
                    client.println("Connnection: close");
                    client.println();
                    // send web page
                    if ((HTTP_req.indexOf("GET / ") > -1)
                                 || (HTTP_req.indexOf("GET /index.htm") > -1)) {
                        webFile = SD.open("index.htm");        // open web page file
                    }
                    else if (HTTP_req.indexOf("GET /page2.htm") > -1) {
                        webFile = SD.open("page2.htm");        // open web page file
                    }
                    if (webFile) {
                        while(webFile.available()) {
                            client.write(webFile.read()); // send web page to client
                        }
                        webFile.close();
                    }
                    HTTP_req = "";  // empty the string
                    break;
                }
                // every line of text received from the client ends with \r\n
                if (c == '\n') {
                    // last character on line of received text
                    // starting new line with next character read
                    currentLineIsBlank = true;
                }
                else if (c != '\r') {
                    // a text character was received from client
                    currentLineIsBlank = false;
                }
            } // end if (client.available())
        } // end while (client.connected())
        delay(1);      // give the web browser time to receive the data
        client.stop(); // close the connection
    } // end if (client)
}

[Erdin]

You have a Ethernet, SD and String class in a Arduino Uno, that uses a lot of ram.

Is it an existing example ? Can you give a link to it ?

In the sketch, every ethernet byte is echoed to the serial monitor, which is only 9600 baud. Could you try without the "Serial.print(c);" ?

[Eduort]

You have a Ethernet, SD and String class in a Arduino Uno, that uses a lot of ram.

Is it an existing example ? Can you give a link to it ?

In the sketch, every ethernet byte is echoed to the serial monitor, which is only 9600 baud. Could you try without the "Serial.print(c);" ?

Thanks for answer, im using a Arduino Mega 2560, and this is the link of the code http://startingelectronics.com/tutorials/arduino/ethernet-shield-web-server-tutorial/SD-card-web-server-links/, i will try the code whitout the serial print and edit whit the result.

[Eduort]

I tried removing the serial monitor and the problem still.

[Erdin]

I don't know what causes the slow down.
The Mega has enough ram, that should not be a problem.
Are you using the newest Arduino 1.0.4 ?
In the sketch I read 1.0.3, but you should use the newest version.
If you are using only USB power, you could try a power supply for the Mega board. Allthough a low voltage would cause other problems.

[SurferTim]

It is because of the way you are sending it. One byte per packet is very inefficient.

Code: [Select]

if (webFile) {
 while(webFile.available()) {

// Here is your holdup. You are sending one byte per packet.
// 48 bytes of header, and one byte payload.
   client.write(webFile.read()); // send web page to client
 }
 webFile.close();
}
Here is another topic that covers this, and the cure.
http://forum.arduino.cc/index.php?topic=134868.0

[Erdin]

Thanks for that.
I tried using a buffer (Arduino 1.5.2), but I still got 4kbyte per second.
Perhaps I have to try it again with that example.
zoomkat writes: "... it reduced the upload time of a 253k jpg file from 62 sec. to 15 sec.".
That is from 4kbyte per second to 16kbyte per second.

[SurferTim]

I have not tried v1.5.2 yet. Each version seems to have its own quirks. However, it seems lately we are upgrading from a lot of quirks to just a few quirks. I guess if we keep at it...

My results with v1.0.4 agree with zoomkat. About 4 times as fast.

[Erdin]

It works !
I have Arduino 1.5.2 and a Mega 2560 board with the Ethernet Shield.
I did not use the sketch by Eduort, but have my own webserver code, that started with a Adafruit example.
Data is read from the SD card and stored in a buffer of 128 byte. I write that buffer to the client.
The result is a four times higher speed. About 16 kbyte per second.