web server to read file from SD card and show its content as HTML

Using Arduino Networking, Protocols, and Devices
8

I used this as a test, and it worked good.

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

byte mac[] = { 0xDE, 0xAD, 0xBE, 0xEF, 0xFE, 0xED };

// change to your network settings
IPAddress ip( 192,168,2,2 );
IPAddress gateway( 192,168,2,1 );
IPAddress subnet( 255,255,255,0 );

EthernetServer server(80);

void setup()
{
  Serial.begin(9600);

  // disable w5100 while setting up SD
  pinMode(10,OUTPUT);
  digitalWrite(10,HIGH);

  Serial.print("Starting SD..");
  if(!SD.begin(4)) Serial.println("failed");
  else Serial.println("ok");
  
  Ethernet.begin(mac, ip, gateway, gateway, subnet);
  digitalWrite(10,HIGH);

  delay(2000);
  server.begin();
  Serial.println("Ready");
}

void loop()
{
  EthernetClient client = server.available();
  if(client) {
    boolean currentLineIsBlank = true;
    boolean currentLineIsGet = true;
    int tCount = 0;
    char tBuf[64];

    Serial.print("Client request: ");
    
    while (client.connected()) {
      while(client.available()) {
        char c = client.read();

        if(currentLineIsGet && tCount < 63)
        {
          tBuf[tCount] = c;
          tCount++;
          tBuf[tCount] = 0;          
        }

        if (c == '\n' && currentLineIsBlank) {
          Serial.println(tBuf);
          Serial.print("POST data: ");
          while(client.available()) Serial.write(client.read());
          Serial.println();

          // send a standard http response
          Serial.println("Sending response");
          client.write("HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n");

          File fh = SD.open("index.htm");

          if(fh) {
            
            byte clientBuf[64];
            int clientCount = 0;
  
            while(fh.available()) {
              clientBuf[clientCount] = fh.read();
              clientCount++;
    
              if(clientCount > 63)
              {
                Serial.println("Packet");
                client.write(clientBuf,64);
                clientCount = 0;
              }
            }
          
            if(clientCount > 0) client.write(clientBuf,clientCount);

            fh.close();
          }
          else Serial.println("file open failed");

          client.stop();
        }
        else if (c == '\n') {
          currentLineIsBlank = true;
          currentLineIsGet = false;
        } 
        else if (c != '\r') {
          currentLineIsBlank = false;
        }
      }
    }
    Serial.println("done");
  }
}

I uploaded a file to the SD card with the html in it as index.htm. Here is the contents.

<html><body>
TEST
</body></html>

Does this work for you?