feat: upgrade platform and support webdav (#1047)

## Summary
- Upgrade platform from espressif32 6.12.0 (Arduino Core 2.0.17) to
pioarduino 55.03.37 (Arduino Core 3.3.7, ESP-IDF 5.5.2)
- Add WebDAV Class 1 server (RFC 4918) - SD card can be mounted as a
network drive
- I also slightly fixed the SDK and also made a [pull request
](https://github.com/open-x4-epaper/community-sdk/pull/21)

First PR #1030 (was closed because the implementation was based on an
old version of the libraries)
Issue #439

---------

Co-authored-by: Dave Allie <dave@daveallie.com>

platformio.ini

@@ -6,7 +6,7 @@ extra_configs = platformio.local.ini
 version = 1.0.0
 
 [base]
-platform = espressif32 @ 6.12.0
+platform = https://github.com/pioarduino/platform-espressif32/releases/download/55.03.37/platform-espressif32.zip
 board = esp32-c3-devkitm-1
 framework = arduino
 monitor_speed = 115200

src/components/themes/BaseTheme.h

@@ -3,6 +3,7 @@
 #include <cstddef>
 #include <cstdint>
 #include <functional>
+#include <string>
 #include <vector>
 
 class GfxRenderer;

src/network/CrossPointWebServer.cpp

@@ -159,6 +159,12 @@ void CrossPointWebServer::begin() {
   server->onNotFound([this] { handleNotFound(); });
   LOG_DBG("WEB", "[MEM] Free heap after route setup: %d bytes", ESP.getFreeHeap());
 
+  // Collect WebDAV headers and register handler
+  const char* davHeaders[] = {"Depth", "Destination", "Overwrite", "If", "Lock-Token", "Timeout"};
+  server->collectHeaders(davHeaders, 6);
+  server->addHandler(&davHandler);
+  LOG_DBG("WEB", "WebDAV handler initialized");
+
   server->begin();
 
   // Start WebSocket server for fast binary uploads
@@ -502,7 +508,7 @@ void CrossPointWebServer::handleDownload() const {
   server->sendHeader("Content-Disposition", "attachment; filename=\"" + filename + "\"");
   server->send(200, contentType.c_str(), "");
 
-  WiFiClient client = server->client();
+  NetworkClient client = server->client();
   client.write(file);
   file.close();
 }

src/network/CrossPointWebServer.h

@@ -1,14 +1,16 @@
 #pragma once
 
 #include <HalStorage.h>
+#include <NetworkUdp.h>
 #include <WebServer.h>
 #include <WebSocketsServer.h>
-#include <WiFiUdp.h>
 
 #include <memory>
 #include <string>
 #include <vector>
 
+#include "WebDAVHandler.h"
+
 // Structure to hold file information
 struct FileInfo {
   String name;
@@ -71,11 +73,12 @@ class CrossPointWebServer {
  private:
   std::unique_ptr<WebServer> server = nullptr;
   std::unique_ptr<WebSocketsServer> wsServer = nullptr;
+  WebDAVHandler davHandler;
   bool running = false;
   bool apMode = false;  // true when running in AP mode, false for STA mode
   uint16_t port = 80;
   uint16_t wsPort = 81;  // WebSocket port
-  WiFiUDP udp;
+  NetworkUDP udp;
   bool udpActive = false;
 
   // WebSocket upload state

src/network/HttpDownloader.cpp

@@ -2,9 +2,9 @@
 
 #include <HTTPClient.h>
 #include <Logging.h>
+#include <NetworkClient.h>
+#include <NetworkClientSecure.h>
 #include <StreamString.h>
-#include <WiFiClient.h>
-#include <WiFiClientSecure.h>
 #include <base64.h>
 
 #include <cstring>
@@ -14,14 +14,14 @@
 #include "util/UrlUtils.h"
 
 bool HttpDownloader::fetchUrl(const std::string& url, Stream& outContent) {
-  // Use WiFiClientSecure for HTTPS, regular WiFiClient for HTTP
-  std::unique_ptr<WiFiClient> client;
+  // Use NetworkClientSecure for HTTPS, regular NetworkClient for HTTP
+  std::unique_ptr<NetworkClient> client;
   if (UrlUtils::isHttpsUrl(url)) {
-    auto* secureClient = new WiFiClientSecure();
+    auto* secureClient = new NetworkClientSecure();
     secureClient->setInsecure();
     client.reset(secureClient);
   } else {
-    client.reset(new WiFiClient());
+    client.reset(new NetworkClient());
   }
   HTTPClient http;
 
@@ -64,14 +64,14 @@ bool HttpDownloader::fetchUrl(const std::string& url, std::string& outContent) {
 
 HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string& url, const std::string& destPath,
                                                              ProgressCallback progress) {
-  // Use WiFiClientSecure for HTTPS, regular WiFiClient for HTTP
-  std::unique_ptr<WiFiClient> client;
+  // Use NetworkClientSecure for HTTPS, regular NetworkClient for HTTP
+  std::unique_ptr<NetworkClient> client;
   if (UrlUtils::isHttpsUrl(url)) {
-    auto* secureClient = new WiFiClientSecure();
+    auto* secureClient = new NetworkClientSecure();
     secureClient->setInsecure();
     client.reset(secureClient);
   } else {
-    client.reset(new WiFiClient());
+    client.reset(new NetworkClient());
   }
   HTTPClient http;
 
@@ -113,7 +113,7 @@ HttpDownloader::DownloadError HttpDownloader::downloadToFile(const std::string&
   }
 
   // Get the stream for chunked reading
-  WiFiClient* stream = http.getStreamPtr();
+  NetworkClient* stream = http.getStreamPtr();
   if (!stream) {
     LOG_ERR("HTTP", "Failed to get stream");
     file.close();

src/network/HttpDownloader.h

@@ -6,7 +6,7 @@
 
 /**
  * HTTP client utility for fetching content and downloading files.
- * Wraps WiFiClientSecure and HTTPClient for HTTPS requests.
+ * Wraps NetworkClientSecure and HTTPClient for HTTPS requests.
  */
 class HttpDownloader {
  public:

src/network/WebDAVHandler.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <HalStorage.h>
+#include <WebServer.h>
+
+class WebDAVHandler : public RequestHandler {
+ public:
+  // RequestHandler interface
+  bool canHandle(WebServer& server, HTTPMethod method, const String& uri) override;
+  bool canRaw(WebServer& server, const String& uri) override;
+  void raw(WebServer& server, const String& uri, HTTPRaw& raw) override;
+  bool handle(WebServer& server, HTTPMethod method, const String& uri) override;
+
+ private:
+  // PUT streaming state (raw() is called in chunks)
+  FsFile _putFile;
+  String _putPath;
+  bool _putOk = false;
+  bool _putExisted = false;
+
+  // WebDAV method handlers
+  void handleOptions(WebServer& s);
+  void handlePropfind(WebServer& s);
+  void handleGet(WebServer& s);
+  void handleHead(WebServer& s);
+  void handlePut(WebServer& s);
+  void handleDelete(WebServer& s);
+  void handleMkcol(WebServer& s);
+  void handleMove(WebServer& s);
+  void handleCopy(WebServer& s);
+  void handleLock(WebServer& s);
+  void handleUnlock(WebServer& s);
+
+  // Utilities
+  String getRequestPath(WebServer& s) const;
+  String getDestinationPath(WebServer& s) const;
+  void urlEncodePath(const String& path, String& out) const;
+  bool isProtectedPath(const String& path) const;
+  int getDepth(WebServer& s) const;
+  bool getOverwrite(WebServer& s) const;
+  void clearEpubCacheIfNeeded(const String& path) const;
+  void sendPropEntry(WebServer& s, const String& href, bool isDir, size_t size, const String& lastModified) const;
+  String getMimeType(const String& path) const;
+};