ESP8266WebServer handler that serves static files from SPIFFS

handleNotFound.cpp

// this serves all URLs that can be resolved to a file on the SPIFFS filesystem
// server.onNotFound(handleNotFound);

static String getContentType(const String& path) {
  if (path.endsWith(".html"))       return "text/html";
  else if (path.endsWith(".htm"))   return "text/html";
  else if (path.endsWith(".css"))   return "text/css";
  else if (path.endsWith(".txt"))   return "text/plain";
  else if (path.endsWith(".js"))    return "application/javascript";
  else if (path.endsWith(".png"))   return "image/png";
  else if (path.endsWith(".gif"))   return "image/gif";
  else if (path.endsWith(".jpg"))   return "image/jpeg";
  else if (path.endsWith(".jpeg"))  return "image/jpeg";
  else if (path.endsWith(".ico"))   return "image/x-icon";
  else if (path.endsWith(".svg"))   return "image/svg+xml";
  else if (path.endsWith(".xml"))   return "text/xml";
  else if (path.endsWith(".pdf"))   return "application/pdf";
  else if (path.endsWith(".zip"))   return "application/zip";
  else if (path.endsWith(".gz"))    return "application/x-gzip";
  return "application/octet-stream";
}

void sendRedirect(String filename) {
  char buf[64];
  filename.toCharArray(buf, 64);
  sendRedirect(filename);
}

void sendRedirect(const char * filename) {
  server.sendHeader("Location", String(filename), true);
  server.send(302, "text/plain", "");
}

void sendStaticFile(String filename) {
  char buf[64];
  filename.toCharArray(buf, 64);
  sendStaticFile(buf);
}

void sendStaticFile(const char * filename) {
  SPIFFS.begin();
  File f = SPIFFS.open(filename, "r");
  Serial.print("Opening file ");
  Serial.print(filename);
  if (!f) {
    Serial.println("  FAILED");
    server.send(500, "text/html", "File not found");
  } else {
    Serial.println("  OK");
    String content = f.readString();
    f.close();
    server.sendHeader("Connection", "close");
    server.sendHeader("Access-Control-Allow-Origin", "*");
    server.send(200, getContentType(String(filename)), content);
  }
}

void handleNotFound() {
  SPIFFS.begin();
  if (SPIFFS.exists(server.uri())) {
    sendStaticFile(server.uri());
  }
  else {
    String message = "File Not Found\n\n";
    message += "URI: ";
    message += server.uri();
    message += "\nMethod: ";
    message += (server.method() == HTTP_GET) ? "GET" : "POST";
    message += "\nArguments: ";
    message += server.args();
    message += "\n";
    for (uint8_t i = 0; i < server.args(); i++) {
      message += " " + server.argName(i) + ": " + server.arg(i) + "\n";
    }
    server.send(404, "text/plain", message);
  }
}