Replace custom OTA implementation in web_server_base (#9274)

Co-authored-by: Jesse Hills <3060199+jesserockz@users.noreply.github.com>

esphome/components/ota/ota_backend.h

@@ -67,7 +67,28 @@ class OTAComponent : public Component {
   }
 
  protected:
-  CallbackManager<void(ota::OTAState, float, uint8_t)> state_callback_{};
+  /** Extended callback manager with deferred call support.
+   *
+   * This adds a call_deferred() method for thread-safe execution from other tasks.
+   */
+  class StateCallbackManager : public CallbackManager<void(OTAState, float, uint8_t)> {
+   public:
+    StateCallbackManager(OTAComponent *component) : component_(component) {}
+
+    /** Call callbacks with deferral to main loop (for thread safety).
+     *
+     * This should be used by OTA implementations that run in separate tasks
+     * (like web_server OTA) to ensure callbacks execute in the main loop.
+     */
+    void call_deferred(ota::OTAState state, float progress, uint8_t error) {
+      component_->defer([this, state, progress, error]() { this->call(state, progress, error); });
+    }
+
+   private:
+    OTAComponent *component_;
+  };
+
+  StateCallbackManager state_callback_{this};
 #endif
 };
 
@@ -89,6 +110,11 @@ class OTAGlobalCallback {
 
 OTAGlobalCallback *get_global_ota_callback();
 void register_ota_platform(OTAComponent *ota_caller);
+
+// OTA implementations should use:
+// - state_callback_.call() when already in main loop (e.g., esphome OTA)
+// - state_callback_.call_deferred() when in separate task (e.g., web_server OTA)
+// This ensures proper callback execution in all contexts.
 #endif
 std::unique_ptr<ota::OTABackend> make_ota_backend();
 

esphome/components/ota/ota_backend_arduino_esp32.cpp

@@ -15,6 +15,11 @@ static const char *const TAG = "ota.arduino_esp32";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoESP32OTABackend>(); }
 
 OTAResponseTypes ArduinoESP32OTABackend::begin(size_t image_size) {
+  // Handle UPDATE_SIZE_UNKNOWN (0) which is used by web server OTA
+  // where the exact firmware size is unknown due to multipart encoding
+  if (image_size == 0) {
+    image_size = UPDATE_SIZE_UNKNOWN;
+  }
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     return OTA_RESPONSE_OK;
@@ -29,7 +34,10 @@ OTAResponseTypes ArduinoESP32OTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoESP32OTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoESP32OTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoESP32OTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -44,7 +52,9 @@ OTAResponseTypes ArduinoESP32OTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoESP32OTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  if (Update.end(!this->md5_set_)) {
     return OTA_RESPONSE_OK;
   }
 

esphome/components/ota/ota_backend_arduino_esp32.h

@@ -16,6 +16,9 @@ class ArduinoESP32OTABackend : public OTABackend {
   OTAResponseTypes end() override;
   void abort() override;
   bool supports_compression() override { return false; }
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_arduino_esp8266.cpp

@@ -17,6 +17,11 @@ static const char *const TAG = "ota.arduino_esp8266";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoESP8266OTABackend>(); }
 
 OTAResponseTypes ArduinoESP8266OTABackend::begin(size_t image_size) {
+  // Handle UPDATE_SIZE_UNKNOWN (0) by calculating available space
+  if (image_size == 0) {
+    // NOLINTNEXTLINE(readability-static-accessed-through-instance)
+    image_size = (ESP.getFreeSketchSpace() - 0x1000) & 0xFFFFF000;
+  }
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     esp8266::preferences_prevent_write(true);
@@ -38,7 +43,10 @@ OTAResponseTypes ArduinoESP8266OTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoESP8266OTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoESP8266OTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoESP8266OTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -53,13 +61,19 @@ OTAResponseTypes ArduinoESP8266OTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoESP8266OTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  bool success = Update.end(!this->md5_set_);
+
+  // On ESP8266, Update.end() might return false even with error code 0
+  // Check the actual error code to determine success
+  uint8_t error = Update.getError();
+
+  if (success || error == UPDATE_ERROR_OK) {
     return OTA_RESPONSE_OK;
   }
 
-  uint8_t error = Update.getError();
   ESP_LOGE(TAG, "End error: %d", error);
-
   return OTA_RESPONSE_ERROR_UPDATE_END;
 }
 

esphome/components/ota/ota_backend_arduino_esp8266.h

@@ -21,6 +21,9 @@ class ArduinoESP8266OTABackend : public OTABackend {
 #else
   bool supports_compression() override { return false; }
 #endif
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_arduino_libretiny.cpp

@@ -15,6 +15,11 @@ static const char *const TAG = "ota.arduino_libretiny";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoLibreTinyOTABackend>(); }
 
 OTAResponseTypes ArduinoLibreTinyOTABackend::begin(size_t image_size) {
+  // Handle UPDATE_SIZE_UNKNOWN (0) which is used by web server OTA
+  // where the exact firmware size is unknown due to multipart encoding
+  if (image_size == 0) {
+    image_size = UPDATE_SIZE_UNKNOWN;
+  }
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     return OTA_RESPONSE_OK;
@@ -29,7 +34,10 @@ OTAResponseTypes ArduinoLibreTinyOTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoLibreTinyOTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoLibreTinyOTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoLibreTinyOTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -44,7 +52,9 @@ OTAResponseTypes ArduinoLibreTinyOTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoLibreTinyOTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  if (Update.end(!this->md5_set_)) {
     return OTA_RESPONSE_OK;
   }
 

esphome/components/ota/ota_backend_arduino_libretiny.h

@@ -15,6 +15,9 @@ class ArduinoLibreTinyOTABackend : public OTABackend {
   OTAResponseTypes end() override;
   void abort() override;
   bool supports_compression() override { return false; }
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_arduino_rp2040.cpp

@@ -17,6 +17,8 @@ static const char *const TAG = "ota.arduino_rp2040";
 std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::ArduinoRP2040OTABackend>(); }
 
 OTAResponseTypes ArduinoRP2040OTABackend::begin(size_t image_size) {
+  // OTA size of 0 is not currently handled, but
+  // web_server is not supported for RP2040, so this is not an issue.
   bool ret = Update.begin(image_size, U_FLASH);
   if (ret) {
     rp2040::preferences_prevent_write(true);
@@ -38,7 +40,10 @@ OTAResponseTypes ArduinoRP2040OTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_ERROR_UNKNOWN;
 }
 
-void ArduinoRP2040OTABackend::set_update_md5(const char *md5) { Update.setMD5(md5); }
+void ArduinoRP2040OTABackend::set_update_md5(const char *md5) {
+  Update.setMD5(md5);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes ArduinoRP2040OTABackend::write(uint8_t *data, size_t len) {
   size_t written = Update.write(data, len);
@@ -53,7 +58,9 @@ OTAResponseTypes ArduinoRP2040OTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes ArduinoRP2040OTABackend::end() {
-  if (Update.end()) {
+  // Use strict validation (false) when MD5 is set, lenient validation (true) when no MD5
+  // This matches the behavior of the old web_server OTA implementation
+  if (Update.end(!this->md5_set_)) {
     return OTA_RESPONSE_OK;
   }
 

esphome/components/ota/ota_backend_arduino_rp2040.h

@@ -17,6 +17,9 @@ class ArduinoRP2040OTABackend : public OTABackend {
   OTAResponseTypes end() override;
   void abort() override;
   bool supports_compression() override { return false; }
+
+ private:
+  bool md5_set_{false};
 };
 
 }  // namespace ota

esphome/components/ota/ota_backend_esp_idf.cpp

@@ -56,7 +56,10 @@ OTAResponseTypes IDFOTABackend::begin(size_t image_size) {
   return OTA_RESPONSE_OK;
 }
 
-void IDFOTABackend::set_update_md5(const char *expected_md5) { memcpy(this->expected_bin_md5_, expected_md5, 32); }
+void IDFOTABackend::set_update_md5(const char *expected_md5) {
+  memcpy(this->expected_bin_md5_, expected_md5, 32);
+  this->md5_set_ = true;
+}
 
 OTAResponseTypes IDFOTABackend::write(uint8_t *data, size_t len) {
   esp_err_t err = esp_ota_write(this->update_handle_, data, len);
@@ -73,10 +76,12 @@ OTAResponseTypes IDFOTABackend::write(uint8_t *data, size_t len) {
 }
 
 OTAResponseTypes IDFOTABackend::end() {
-  this->md5_.calculate();
-  if (!this->md5_.equals_hex(this->expected_bin_md5_)) {
-    this->abort();
-    return OTA_RESPONSE_ERROR_MD5_MISMATCH;
+  if (this->md5_set_) {
+    this->md5_.calculate();
+    if (!this->md5_.equals_hex(this->expected_bin_md5_)) {
+      this->abort();
+      return OTA_RESPONSE_ERROR_MD5_MISMATCH;
+    }
   }
   esp_err_t err = esp_ota_end(this->update_handle_);
   this->update_handle_ = 0;

esphome/components/ota/ota_backend_esp_idf.h

@@ -24,6 +24,7 @@ class IDFOTABackend : public OTABackend {
   const esp_partition_t *partition_;
   md5::MD5Digest md5_{};
   char expected_bin_md5_[32];
+  bool md5_set_{false};
 };
 
 }  // namespace ota