Wokwi - Online ESP32, STM32, Arduino Simulator

#include <WiFi.h>
#include <WebServer.h>
#include <SPI.h>
#include <SD.h>

// Replace with your network credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

WebServer server(80);

const int chipSelect = 5;

void setup() {
  Serial.begin(115200);
  delay(1000);

  // Initialize SD card
  if (!SD.begin(chipSelect)) {
    Serial.println("SD Card initialization failed!");
    return;
  }
  Serial.println("SD Card initialized.");

  // Connect to Wi-Fi
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);
  
  int attempt = 0;
  while (WiFi.status() != WL_CONNECTED && attempt < 20) { // limit attempts to 20
    delay(500);
    Serial.print(".");
    attempt++;
  }

  if (WiFi.status() == WL_CONNECTED) {
    Serial.println("");
    Serial.println("WiFi connected.");
    Serial.print("IP address: ");
    Serial.println(WiFi.localIP());
  } else {
    Serial.println("");
    Serial.println("Failed to connect to WiFi.");
    return;
  }

  // Define server routes
  server.on("/", HTTP_GET, handleRoot);
  server.onNotFound(handleNotFound);

  server.begin();
  Serial.println("HTTP server started");
}

void loop() {
  server.handleClient();
}

void handleRoot() {
  String html = "<html><body><h1>SD Card File List</h1><ul>";

  File root = SD.open("/");
  if (!root) {
    Serial.println("Failed to open directory");
    return;
  }
  if (!root.isDirectory()) {
    Serial.println("Not a directory");
    return;
  }

  File file = root.openNextFile();
  while (file) {
    if (!file.isDirectory()) {
      html += "<li><a href='/download?file=" + String(file.name()) + "'>" + String(file.name()) + "</a></li>";
    }
    file = root.openNextFile();
  }

  html += "</ul></body></html>";
  server.send(200, "text/html", html);
}

void handleNotFound() {
  if (server.uri().startsWith("/download")) {
    handleFileDownload();
  } else {
    server.send(404, "text/plain", "Not Found");
  }
}

void handleFileDownload() {
  String filename = server.arg("file");
  if (filename.length() == 0) {
    server.send(400, "text/plain", "File name not specified");
    return;
  }

  File file = SD.open(filename);
  if (!file) {
    server.send(404, "text/plain", "File not found");
    return;
  }

  server.streamFile(file, "application/octet-stream");
  file.close();
}