Add OTA support to ESP-IDF webserver (#9264)

esphome/components/captive_portal/captive_portal.cpp

@@ -47,7 +47,9 @@ void CaptivePortal::start() {
   this->base_->init();
   if (!this->initialized_) {
     this->base_->add_handler(this);
+#ifdef USE_WEBSERVER_OTA
     this->base_->add_ota_handler();
+#endif
   }
 
 #ifdef USE_ARDUINO

esphome/components/web_server/__init__.py

@@ -40,6 +40,7 @@ CONF_SORTING_GROUP_ID = "sorting_group_id"
 CONF_SORTING_GROUPS = "sorting_groups"
 CONF_SORTING_WEIGHT = "sorting_weight"
 
+
 web_server_ns = cg.esphome_ns.namespace("web_server")
 WebServer = web_server_ns.class_("WebServer", cg.Component, cg.Controller)
 
@@ -72,12 +73,6 @@ def validate_local(config):
     return config
 
 
-def validate_ota(config):
-    if CORE.using_esp_idf and config[CONF_OTA]:
-        raise cv.Invalid("Enabling 'ota' is not supported for IDF framework yet")
-    return config
-
-
 def validate_sorting_groups(config):
     if CONF_SORTING_GROUPS in config and config[CONF_VERSION] != 3:
         raise cv.Invalid(
@@ -175,15 +170,7 @@ CONFIG_SCHEMA = cv.All(
                 web_server_base.WebServerBase
             ),
             cv.Optional(CONF_INCLUDE_INTERNAL, default=False): cv.boolean,
-            cv.SplitDefault(
-                CONF_OTA,
-                esp8266=True,
-                esp32_arduino=True,
-                esp32_idf=False,
-                bk72xx=True,
-                ln882x=True,
-                rtl87xx=True,
-            ): cv.boolean,
+            cv.Optional(CONF_OTA, default=True): cv.boolean,
             cv.Optional(CONF_LOG, default=True): cv.boolean,
             cv.Optional(CONF_LOCAL): cv.boolean,
             cv.Optional(CONF_SORTING_GROUPS): cv.ensure_list(sorting_group),
@@ -200,7 +187,6 @@ CONFIG_SCHEMA = cv.All(
     ),
     default_url,
     validate_local,
-    validate_ota,
     validate_sorting_groups,
 )
 
@@ -286,6 +272,10 @@ async def to_code(config):
         cg.add(var.set_css_url(config[CONF_CSS_URL]))
         cg.add(var.set_js_url(config[CONF_JS_URL]))
     cg.add(var.set_allow_ota(config[CONF_OTA]))
+    if config[CONF_OTA]:
+        # Define USE_WEBSERVER_OTA based only on web_server OTA config
+        # This allows web server OTA to work without loading the OTA component
+        cg.add_define("USE_WEBSERVER_OTA")
     cg.add(var.set_expose_log(config[CONF_LOG]))
     if config[CONF_ENABLE_PRIVATE_NETWORK_ACCESS]:
         cg.add_define("USE_WEBSERVER_PRIVATE_NETWORK_ACCESS")

esphome/components/web_server/web_server.cpp

@@ -299,8 +299,10 @@ void WebServer::setup() {
 #endif
   this->base_->add_handler(this);
 
+#ifdef USE_WEBSERVER_OTA
   if (this->allow_ota_)
     this->base_->add_ota_handler();
+#endif
 
   // doesn't need defer functionality - if the queue is full, the client JS knows it's alive because it's clearly
   // getting a lot of events
@@ -2030,6 +2032,10 @@ void WebServer::handleRequest(AsyncWebServerRequest *request) {
     return;
   }
 #endif
+
+  // No matching handler found - send 404
+  ESP_LOGV(TAG, "Request for unknown URL: %s", request->url().c_str());
+  request->send(404, "text/plain", "Not Found");
 }
 
 bool WebServer::isRequestHandlerTrivial() const { return false; }

esphome/components/web_server_base/web_server_base.cpp

@@ -14,11 +14,114 @@
 #endif
 #endif
 
+#if defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)
+#include <esp_ota_ops.h>
+#include <esp_task_wdt.h>
+#endif
+
 namespace esphome {
 namespace web_server_base {
 
 static const char *const TAG = "web_server_base";
 
+#if defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)
+// Minimal OTA backend implementation for web server
+// This allows OTA updates via web server without requiring the OTA component
+// TODO: In the future, this should be refactored into a common ota_base component
+// that both web_server and ota components can depend on, avoiding code duplication
+// while keeping the components independent. This would allow both ESP-IDF and Arduino
+// implementations to share the base OTA functionality without requiring the full OTA component.
+// The IDFWebServerOTABackend class is intentionally designed with the same interface
+// as OTABackend to make it easy to swap to using OTABackend when the ota component
+// is split into ota and ota_base in the future.
+class IDFWebServerOTABackend {
+ public:
+  bool begin() {
+    this->partition_ = esp_ota_get_next_update_partition(nullptr);
+    if (this->partition_ == nullptr) {
+      ESP_LOGE(TAG, "No OTA partition available");
+      return false;
+    }
+
+#if CONFIG_ESP_TASK_WDT_TIMEOUT_S < 15
+    // The following function takes longer than the default timeout of WDT due to flash erase
+#if ESP_IDF_VERSION_MAJOR >= 5
+    esp_task_wdt_config_t wdtc;
+    wdtc.idle_core_mask = 0;
+#if CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU0
+    wdtc.idle_core_mask |= (1 << 0);
+#endif
+#if CONFIG_ESP_TASK_WDT_CHECK_IDLE_TASK_CPU1
+    wdtc.idle_core_mask |= (1 << 1);
+#endif
+    wdtc.timeout_ms = 15000;
+    wdtc.trigger_panic = false;
+    esp_task_wdt_reconfigure(&wdtc);
+#else
+    esp_task_wdt_init(15, false);
+#endif
+#endif
+
+    esp_err_t err = esp_ota_begin(this->partition_, 0, &this->update_handle_);
+
+#if CONFIG_ESP_TASK_WDT_TIMEOUT_S < 15
+    // Set the WDT back to the configured timeout
+#if ESP_IDF_VERSION_MAJOR >= 5
+    wdtc.timeout_ms = CONFIG_ESP_TASK_WDT_TIMEOUT_S * 1000;
+    esp_task_wdt_reconfigure(&wdtc);
+#else
+    esp_task_wdt_init(CONFIG_ESP_TASK_WDT_TIMEOUT_S, false);
+#endif
+#endif
+
+    if (err != ESP_OK) {
+      esp_ota_abort(this->update_handle_);
+      this->update_handle_ = 0;
+      ESP_LOGE(TAG, "esp_ota_begin failed: %s", esp_err_to_name(err));
+      return false;
+    }
+    return true;
+  }
+
+  bool write(uint8_t *data, size_t len) {
+    esp_err_t err = esp_ota_write(this->update_handle_, data, len);
+    if (err != ESP_OK) {
+      ESP_LOGE(TAG, "esp_ota_write failed: %s", esp_err_to_name(err));
+      return false;
+    }
+    return true;
+  }
+
+  bool end() {
+    esp_err_t err = esp_ota_end(this->update_handle_);
+    this->update_handle_ = 0;
+    if (err != ESP_OK) {
+      ESP_LOGE(TAG, "esp_ota_end failed: %s", esp_err_to_name(err));
+      return false;
+    }
+
+    err = esp_ota_set_boot_partition(this->partition_);
+    if (err != ESP_OK) {
+      ESP_LOGE(TAG, "esp_ota_set_boot_partition failed: %s", esp_err_to_name(err));
+      return false;
+    }
+
+    return true;
+  }
+
+  void abort() {
+    if (this->update_handle_ != 0) {
+      esp_ota_abort(this->update_handle_);
+      this->update_handle_ = 0;
+    }
+  }
+
+ private:
+  esp_ota_handle_t update_handle_{0};
+  const esp_partition_t *partition_{nullptr};
+};
+#endif
+
 void WebServerBase::add_handler(AsyncWebHandler *handler) {
   // remove all handlers
 
@@ -31,6 +134,33 @@ void WebServerBase::add_handler(AsyncWebHandler *handler) {
   }
 }
 
+#ifdef USE_WEBSERVER_OTA
+void OTARequestHandler::report_ota_progress_(AsyncWebServerRequest *request) {
+  const uint32_t now = millis();
+  if (now - this->last_ota_progress_ > 1000) {
+    if (request->contentLength() != 0) {
+      float percentage = (this->ota_read_length_ * 100.0f) / request->contentLength();
+      ESP_LOGD(TAG, "OTA in progress: %0.1f%%", percentage);
+    } else {
+      ESP_LOGD(TAG, "OTA in progress: %u bytes read", this->ota_read_length_);
+    }
+    this->last_ota_progress_ = now;
+  }
+}
+
+void OTARequestHandler::schedule_ota_reboot_() {
+  ESP_LOGI(TAG, "OTA update successful!");
+  this->parent_->set_timeout(100, []() {
+    ESP_LOGI(TAG, "Performing OTA reboot now");
+    App.safe_reboot();
+  });
+}
+
+void OTARequestHandler::ota_init_(const char *filename) {
+  ESP_LOGI(TAG, "OTA Update Start: %s", filename);
+  this->ota_read_length_ = 0;
+}
+
 void report_ota_error() {
 #ifdef USE_ARDUINO
   StreamString ss;
@@ -44,8 +174,7 @@ void OTARequestHandler::handleUpload(AsyncWebServerRequest *request, const Strin
 #ifdef USE_ARDUINO
   bool success;
   if (index == 0) {
-    ESP_LOGI(TAG, "OTA Update Start: %s", filename.c_str());
-    this->ota_read_length_ = 0;
+    this->ota_init_(filename.c_str());
 #ifdef USE_ESP8266
     Update.runAsync(true);
     // NOLINTNEXTLINE(readability-static-accessed-through-instance)
@@ -72,31 +201,68 @@ void OTARequestHandler::handleUpload(AsyncWebServerRequest *request, const Strin
     return;
   }
   this->ota_read_length_ += len;
-
-  const uint32_t now = millis();
-  if (now - this->last_ota_progress_ > 1000) {
-    if (request->contentLength() != 0) {
-      float percentage = (this->ota_read_length_ * 100.0f) / request->contentLength();
-      ESP_LOGD(TAG, "OTA in progress: %0.1f%%", percentage);
-    } else {
-      ESP_LOGD(TAG, "OTA in progress: %u bytes read", this->ota_read_length_);
-    }
-    this->last_ota_progress_ = now;
-  }
+  this->report_ota_progress_(request);
 
   if (final) {
     if (Update.end(true)) {
-      ESP_LOGI(TAG, "OTA update successful!");
-      this->parent_->set_timeout(100, []() { App.safe_reboot(); });
+      this->schedule_ota_reboot_();
     } else {
       report_ota_error();
     }
   }
-#endif
+#endif  // USE_ARDUINO
+
+#ifdef USE_ESP_IDF
+  // ESP-IDF implementation
+  if (index == 0 && !this->ota_backend_) {
+    // Initialize OTA on first call
+    this->ota_init_(filename.c_str());
+    this->ota_success_ = false;
+
+    auto *backend = new IDFWebServerOTABackend();
+    if (!backend->begin()) {
+      ESP_LOGE(TAG, "OTA begin failed");
+      delete backend;
+      return;
+    }
+    this->ota_backend_ = backend;
+  }
+
+  auto *backend = static_cast<IDFWebServerOTABackend *>(this->ota_backend_);
+  if (!backend) {
+    return;
+  }
+
+  // Process data
+  if (len > 0) {
+    if (!backend->write(data, len)) {
+      ESP_LOGE(TAG, "OTA write failed");
+      backend->abort();
+      delete backend;
+      this->ota_backend_ = nullptr;
+      return;
+    }
+    this->ota_read_length_ += len;
+    this->report_ota_progress_(request);
+  }
+
+  // Finalize
+  if (final) {
+    this->ota_success_ = backend->end();
+    if (this->ota_success_) {
+      this->schedule_ota_reboot_();
+    } else {
+      ESP_LOGE(TAG, "OTA end failed");
+    }
+    delete backend;
+    this->ota_backend_ = nullptr;
+  }
+#endif  // USE_ESP_IDF
 }
+
 void OTARequestHandler::handleRequest(AsyncWebServerRequest *request) {
-#ifdef USE_ARDUINO
   AsyncWebServerResponse *response;
+#ifdef USE_ARDUINO
   if (!Update.hasError()) {
     response = request->beginResponse(200, "text/plain", "Update Successful!");
   } else {
@@ -105,16 +271,20 @@ void OTARequestHandler::handleRequest(AsyncWebServerRequest *request) {
     Update.printError(ss);
     response = request->beginResponse(200, "text/plain", ss);
   }
+#endif  // USE_ARDUINO
+#ifdef USE_ESP_IDF
+  // Send response based on the OTA result
+  response = request->beginResponse(200, "text/plain", this->ota_success_ ? "Update Successful!" : "Update Failed!");
+#endif  // USE_ESP_IDF
   response->addHeader("Connection", "close");
   request->send(response);
-#endif
 }
 
 void WebServerBase::add_ota_handler() {
-#ifdef USE_ARDUINO
   this->add_handler(new OTARequestHandler(this));  // NOLINT
-#endif
 }
+#endif
+
 float WebServerBase::get_setup_priority() const {
   // Before WiFi (captive portal)
   return setup_priority::WIFI + 2.0f;

esphome/components/web_server_base/web_server_base.h

@@ -110,13 +110,17 @@ class WebServerBase : public Component {
 
   void add_handler(AsyncWebHandler *handler);
 
+#ifdef USE_WEBSERVER_OTA
   void add_ota_handler();
+#endif
 
   void set_port(uint16_t port) { port_ = port; }
   uint16_t get_port() const { return port_; }
 
  protected:
+#ifdef USE_WEBSERVER_OTA
   friend class OTARequestHandler;
+#endif
 
   int initialized_{0};
   uint16_t port_{80};
@@ -125,6 +129,7 @@ class WebServerBase : public Component {
   internal::Credentials credentials_;
 };
 
+#ifdef USE_WEBSERVER_OTA
 class OTARequestHandler : public AsyncWebHandler {
  public:
   OTARequestHandler(WebServerBase *parent) : parent_(parent) {}
@@ -139,10 +144,21 @@ class OTARequestHandler : public AsyncWebHandler {
   bool isRequestHandlerTrivial() const override { return false; }
 
  protected:
+  void report_ota_progress_(AsyncWebServerRequest *request);
+  void schedule_ota_reboot_();
+  void ota_init_(const char *filename);
+
   uint32_t last_ota_progress_{0};
   uint32_t ota_read_length_{0};
   WebServerBase *parent_;
+
+ private:
+#ifdef USE_ESP_IDF
+  void *ota_backend_{nullptr};
+  bool ota_success_{false};
+#endif
 };
+#endif  // USE_WEBSERVER_OTA
 
 }  // namespace web_server_base
 }  // namespace esphome

esphome/components/web_server_idf/__init__.py

@@ -1,5 +1,7 @@
-from esphome.components.esp32 import add_idf_sdkconfig_option
+from esphome.components.esp32 import add_idf_component, add_idf_sdkconfig_option
 import esphome.config_validation as cv
+from esphome.const import CONF_OTA, CONF_WEB_SERVER
+from esphome.core import CORE
 
 CODEOWNERS = ["@dentra"]
 
@@ -12,3 +14,7 @@ CONFIG_SCHEMA = cv.All(
 async def to_code(config):
     # Increase the maximum supported size of headers section in HTTP request packet to be processed by the server
     add_idf_sdkconfig_option("CONFIG_HTTPD_MAX_REQ_HDR_LEN", 1024)
+    # Check if web_server component has OTA enabled
+    if CORE.config.get(CONF_WEB_SERVER, {}).get(CONF_OTA, True):
+        # Add multipart parser component for ESP-IDF OTA support
+        add_idf_component(name="zorxx/multipart-parser", ref="1.0.1")

esphome/components/web_server_idf/multipart.cpp

@@ -0,0 +1,254 @@
+#include "esphome/core/defines.h"
+#if defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)
+#include "multipart.h"
+#include "utils.h"
+#include "esphome/core/log.h"
+#include <cstring>
+#include "multipart_parser.h"
+
+namespace esphome {
+namespace web_server_idf {
+
+static const char *const TAG = "multipart";
+
+// ========== MultipartReader Implementation ==========
+
+MultipartReader::MultipartReader(const std::string &boundary) {
+  // Initialize settings with callbacks
+  memset(&settings_, 0, sizeof(settings_));
+  settings_.on_header_field = on_header_field;
+  settings_.on_header_value = on_header_value;
+  settings_.on_part_data = on_part_data;
+  settings_.on_part_data_end = on_part_data_end;
+
+  ESP_LOGV(TAG, "Initializing multipart parser with boundary: '%s' (len: %zu)", boundary.c_str(), boundary.length());
+
+  // Create parser with boundary
+  parser_ = multipart_parser_init(boundary.c_str(), &settings_);
+  if (parser_) {
+    multipart_parser_set_data(parser_, this);
+  } else {
+    ESP_LOGE(TAG, "Failed to initialize multipart parser");
+  }
+}
+
+MultipartReader::~MultipartReader() {
+  if (parser_) {
+    multipart_parser_free(parser_);
+  }
+}
+
+size_t MultipartReader::parse(const char *data, size_t len) {
+  if (!parser_) {
+    ESP_LOGE(TAG, "Parser not initialized");
+    return 0;
+  }
+
+  size_t parsed = multipart_parser_execute(parser_, data, len);
+
+  if (parsed != len) {
+    ESP_LOGW(TAG, "Parser consumed %zu of %zu bytes - possible error", parsed, len);
+  }
+
+  return parsed;
+}
+
+void MultipartReader::process_header_(const char *value, size_t length) {
+  // Process the completed header (field + value pair)
+  std::string value_str(value, length);
+
+  if (str_startswith_case_insensitive(current_header_field_, "content-disposition")) {
+    // Parse name and filename from Content-Disposition
+    current_part_.name = extract_header_param(value_str, "name");
+    current_part_.filename = extract_header_param(value_str, "filename");
+  } else if (str_startswith_case_insensitive(current_header_field_, "content-type")) {
+    current_part_.content_type = str_trim(value_str);
+  }
+
+  // Clear field for next header
+  current_header_field_.clear();
+}
+
+int MultipartReader::on_header_field(multipart_parser *parser, const char *at, size_t length) {
+  MultipartReader *reader = static_cast<MultipartReader *>(multipart_parser_get_data(parser));
+  reader->current_header_field_.assign(at, length);
+  return 0;
+}
+
+int MultipartReader::on_header_value(multipart_parser *parser, const char *at, size_t length) {
+  MultipartReader *reader = static_cast<MultipartReader *>(multipart_parser_get_data(parser));
+  reader->process_header_(at, length);
+  return 0;
+}
+
+int MultipartReader::on_part_data(multipart_parser *parser, const char *at, size_t length) {
+  MultipartReader *reader = static_cast<MultipartReader *>(multipart_parser_get_data(parser));
+  // Only process file uploads
+  if (reader->has_file() && reader->data_callback_) {
+    // IMPORTANT: The 'at' pointer points to data within the parser's input buffer.
+    // This data is only valid during this callback. The callback handler MUST
+    // process or copy the data immediately - it cannot store the pointer for
+    // later use as the buffer will be overwritten.
+    reader->data_callback_(reinterpret_cast<const uint8_t *>(at), length);
+  }
+  return 0;
+}
+
+int MultipartReader::on_part_data_end(multipart_parser *parser) {
+  MultipartReader *reader = static_cast<MultipartReader *>(multipart_parser_get_data(parser));
+  ESP_LOGV(TAG, "Part data end");
+  if (reader->part_complete_callback_) {
+    reader->part_complete_callback_();
+  }
+  // Clear part info for next part
+  reader->current_part_ = Part{};
+  return 0;
+}
+
+// ========== Utility Functions ==========
+
+// Case-insensitive string prefix check
+bool str_startswith_case_insensitive(const std::string &str, const std::string &prefix) {
+  if (str.length() < prefix.length()) {
+    return false;
+  }
+  return str_ncmp_ci(str.c_str(), prefix.c_str(), prefix.length());
+}
+
+// Extract a parameter value from a header line
+// Handles both quoted and unquoted values
+std::string extract_header_param(const std::string &header, const std::string &param) {
+  size_t search_pos = 0;
+
+  while (search_pos < header.length()) {
+    // Look for param name
+    const char *found = stristr(header.c_str() + search_pos, param.c_str());
+    if (!found) {
+      return "";
+    }
+    size_t pos = found - header.c_str();
+
+    // Check if this is a word boundary (not part of another parameter)
+    if (pos > 0 && header[pos - 1] != ' ' && header[pos - 1] != ';' && header[pos - 1] != '\t') {
+      search_pos = pos + 1;
+      continue;
+    }
+
+    // Move past param name
+    pos += param.length();
+
+    // Skip whitespace and find '='
+    while (pos < header.length() && (header[pos] == ' ' || header[pos] == '\t')) {
+      pos++;
+    }
+
+    if (pos >= header.length() || header[pos] != '=') {
+      search_pos = pos;
+      continue;
+    }
+
+    pos++;  // Skip '='
+
+    // Skip whitespace after '='
+    while (pos < header.length() && (header[pos] == ' ' || header[pos] == '\t')) {
+      pos++;
+    }
+
+    if (pos >= header.length()) {
+      return "";
+    }
+
+    // Check if value is quoted
+    if (header[pos] == '"') {
+      pos++;
+      size_t end = header.find('"', pos);
+      if (end != std::string::npos) {
+        return header.substr(pos, end - pos);
+      }
+      // Malformed - no closing quote
+      return "";
+    }
+
+    // Unquoted value - find the end (semicolon, comma, or end of string)
+    size_t end = pos;
+    while (end < header.length() && header[end] != ';' && header[end] != ',' && header[end] != ' ' &&
+           header[end] != '\t') {
+      end++;
+    }
+
+    return header.substr(pos, end - pos);
+  }
+
+  return "";
+}
+
+// Parse boundary from Content-Type header
+// Returns true if boundary found, false otherwise
+// boundary_start and boundary_len will point to the boundary value
+bool parse_multipart_boundary(const char *content_type, const char **boundary_start, size_t *boundary_len) {
+  if (!content_type) {
+    return false;
+  }
+
+  // Check for multipart/form-data (case-insensitive)
+  if (!stristr(content_type, "multipart/form-data")) {
+    return false;
+  }
+
+  // Look for boundary parameter
+  const char *b = stristr(content_type, "boundary=");
+  if (!b) {
+    return false;
+  }
+
+  const char *start = b + 9;  // Skip "boundary="
+
+  // Skip whitespace
+  while (*start == ' ' || *start == '\t') {
+    start++;
+  }
+
+  if (!*start) {
+    return false;
+  }
+
+  // Find end of boundary
+  const char *end = start;
+  if (*end == '"') {
+    // Quoted boundary
+    start++;
+    end++;
+    while (*end && *end != '"') {
+      end++;
+    }
+    *boundary_len = end - start;
+  } else {
+    // Unquoted boundary
+    while (*end && *end != ' ' && *end != ';' && *end != '\r' && *end != '\n' && *end != '\t') {
+      end++;
+    }
+    *boundary_len = end - start;
+  }
+
+  if (*boundary_len == 0) {
+    return false;
+  }
+
+  *boundary_start = start;
+
+  return true;
+}
+
+// Trim whitespace from both ends of a string
+std::string str_trim(const std::string &str) {
+  size_t start = str.find_first_not_of(" \t\r\n");
+  if (start == std::string::npos) {
+    return "";
+  }
+  size_t end = str.find_last_not_of(" \t\r\n");
+  return str.substr(start, end - start + 1);
+}
+
+}  // namespace web_server_idf
+}  // namespace esphome
+#endif  // defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)

esphome/components/web_server_idf/multipart.h

@@ -0,0 +1,86 @@
+#pragma once
+#include "esphome/core/defines.h"
+#if defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)
+
+#include <cctype>
+#include <cstring>
+#include <esp_http_server.h>
+#include <functional>
+#include <multipart_parser.h>
+#include <string>
+#include <utility>
+
+namespace esphome {
+namespace web_server_idf {
+
+// Wrapper around zorxx/multipart-parser for ESP-IDF OTA uploads
+class MultipartReader {
+ public:
+  struct Part {
+    std::string name;
+    std::string filename;
+    std::string content_type;
+  };
+
+  // IMPORTANT: The data pointer in DataCallback is only valid during the callback!
+  // The multipart parser passes pointers to its internal buffer which will be
+  // overwritten after the callback returns. Callbacks MUST process or copy the
+  // data immediately - storing the pointer for deferred processing will result
+  // in use-after-free bugs.
+  using DataCallback = std::function<void(const uint8_t *data, size_t len)>;
+  using PartCompleteCallback = std::function<void()>;
+
+  explicit MultipartReader(const std::string &boundary);
+  ~MultipartReader();
+
+  // Set callbacks for handling data
+  void set_data_callback(DataCallback callback) { data_callback_ = std::move(callback); }
+  void set_part_complete_callback(PartCompleteCallback callback) { part_complete_callback_ = std::move(callback); }
+
+  // Parse incoming data
+  size_t parse(const char *data, size_t len);
+
+  // Get current part info
+  const Part &get_current_part() const { return current_part_; }
+
+  // Check if we found a file upload
+  bool has_file() const { return !current_part_.filename.empty(); }
+
+ private:
+  static int on_header_field(multipart_parser *parser, const char *at, size_t length);
+  static int on_header_value(multipart_parser *parser, const char *at, size_t length);
+  static int on_part_data(multipart_parser *parser, const char *at, size_t length);
+  static int on_part_data_end(multipart_parser *parser);
+
+  multipart_parser *parser_{nullptr};
+  multipart_parser_settings settings_{};
+
+  Part current_part_;
+  std::string current_header_field_;
+
+  DataCallback data_callback_;
+  PartCompleteCallback part_complete_callback_;
+
+  void process_header_(const char *value, size_t length);
+};
+
+// ========== Utility Functions ==========
+
+// Case-insensitive string prefix check
+bool str_startswith_case_insensitive(const std::string &str, const std::string &prefix);
+
+// Extract a parameter value from a header line
+// Handles both quoted and unquoted values
+std::string extract_header_param(const std::string &header, const std::string &param);
+
+// Parse boundary from Content-Type header
+// Returns true if boundary found, false otherwise
+// boundary_start and boundary_len will point to the boundary value
+bool parse_multipart_boundary(const char *content_type, const char **boundary_start, size_t *boundary_len);
+
+// Trim whitespace from both ends of a string
+std::string str_trim(const std::string &str);
+
+}  // namespace web_server_idf
+}  // namespace esphome
+#endif  // defined(USE_ESP_IDF) && defined(USE_WEBSERVER_OTA)

esphome/components/web_server_idf/utils.cpp

@@ -1,5 +1,7 @@
 #ifdef USE_ESP_IDF
 #include <memory>
+#include <cstring>
+#include <cctype>
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "http_parser.h"
@@ -88,6 +90,36 @@ optional<std::string> query_key_value(const std::string &query_url, const std::s
   return {val.get()};
 }
 
+// Helper function for case-insensitive string region comparison
+bool str_ncmp_ci(const char *s1, const char *s2, size_t n) {
+  for (size_t i = 0; i < n; i++) {
+    if (!char_equals_ci(s1[i], s2[i])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+// Case-insensitive string search (like strstr but case-insensitive)
+const char *stristr(const char *haystack, const char *needle) {
+  if (!haystack) {
+    return nullptr;
+  }
+
+  size_t needle_len = strlen(needle);
+  if (needle_len == 0) {
+    return haystack;
+  }
+
+  for (const char *p = haystack; *p; p++) {
+    if (str_ncmp_ci(p, needle, needle_len)) {
+      return p;
+    }
+  }
+
+  return nullptr;
+}
+
 }  // namespace web_server_idf
 }  // namespace esphome
 #endif  // USE_ESP_IDF

esphome/components/web_server_idf/utils.h

@@ -2,6 +2,7 @@
 #ifdef USE_ESP_IDF
 
 #include <esp_http_server.h>
+#include <string>
 #include "esphome/core/helpers.h"
 
 namespace esphome {
@@ -12,6 +13,15 @@ optional<std::string> request_get_header(httpd_req_t *req, const char *name);
 optional<std::string> request_get_url_query(httpd_req_t *req);
 optional<std::string> query_key_value(const std::string &query_url, const std::string &key);
 
+// Helper function for case-insensitive character comparison
+inline bool char_equals_ci(char a, char b) { return ::tolower(a) == ::tolower(b); }
+
+// Helper function for case-insensitive string region comparison
+bool str_ncmp_ci(const char *s1, const char *s2, size_t n);
+
+// Case-insensitive string search (like strstr but case-insensitive)
+const char *stristr(const char *haystack, const char *needle);
+
 }  // namespace web_server_idf
 }  // namespace esphome
 #endif  // USE_ESP_IDF

esphome/components/web_server_idf/web_server_idf.cpp

@@ -1,16 +1,25 @@
 #ifdef USE_ESP_IDF
 
 #include <cstdarg>
+#include <memory>
+#include <cstring>
+#include <cctype>
 
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 #include "esp_tls_crypto.h"
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
 
 #include "utils.h"
-
 #include "web_server_idf.h"
 
+#ifdef USE_WEBSERVER_OTA
+#include <multipart_parser.h>
+#include "multipart.h"  // For parse_multipart_boundary and other utils
+#endif
+
 #ifdef USE_WEBSERVER
 #include "esphome/components/web_server/web_server.h"
 #include "esphome/components/web_server/list_entities.h"
@@ -72,18 +81,32 @@ void AsyncWebServer::begin() {
 esp_err_t AsyncWebServer::request_post_handler(httpd_req_t *r) {
   ESP_LOGVV(TAG, "Enter AsyncWebServer::request_post_handler. uri=%s", r->uri);
   auto content_type = request_get_header(r, "Content-Type");
-  if (content_type.has_value() && *content_type != "application/x-www-form-urlencoded") {
-    ESP_LOGW(TAG, "Only application/x-www-form-urlencoded supported for POST request");
-    // fallback to get handler to support backward compatibility
-    return AsyncWebServer::request_handler(r);
-  }
 
   if (!request_has_header(r, "Content-Length")) {
-    ESP_LOGW(TAG, "Content length is requred for post: %s", r->uri);
+    ESP_LOGW(TAG, "Content length is required for post: %s", r->uri);
     httpd_resp_send_err(r, HTTPD_411_LENGTH_REQUIRED, nullptr);
     return ESP_OK;
   }
 
+  if (content_type.has_value()) {
+    const char *content_type_char = content_type.value().c_str();
+
+    // Check most common case first
+    if (stristr(content_type_char, "application/x-www-form-urlencoded") != nullptr) {
+      // Normal form data - proceed with regular handling
+#ifdef USE_WEBSERVER_OTA
+    } else if (stristr(content_type_char, "multipart/form-data") != nullptr) {
+      auto *server = static_cast<AsyncWebServer *>(r->user_ctx);
+      return server->handle_multipart_upload_(r, content_type_char);
+#endif
+    } else {
+      ESP_LOGW(TAG, "Unsupported content type for POST: %s", content_type_char);
+      // fallback to get handler to support backward compatibility
+      return AsyncWebServer::request_handler(r);
+    }
+  }
+
+  // Handle regular form data
   if (r->content_len > HTTPD_MAX_REQ_HDR_LEN) {
     ESP_LOGW(TAG, "Request size is to big: %zu", r->content_len);
     httpd_resp_send_err(r, HTTPD_400_BAD_REQUEST, nullptr);
@@ -539,6 +562,97 @@ void AsyncEventSourceResponse::deferrable_send_state(void *source, const char *e
 }
 #endif
 
+#ifdef USE_WEBSERVER_OTA
+esp_err_t AsyncWebServer::handle_multipart_upload_(httpd_req_t *r, const char *content_type) {
+  static constexpr size_t MULTIPART_CHUNK_SIZE = 1460;       // Match Arduino AsyncWebServer buffer size
+  static constexpr size_t YIELD_INTERVAL_BYTES = 16 * 1024;  // Yield every 16KB to prevent watchdog
+
+  // Parse boundary and create reader
+  const char *boundary_start;
+  size_t boundary_len;
+  if (!parse_multipart_boundary(content_type, &boundary_start, &boundary_len)) {
+    ESP_LOGE(TAG, "Failed to parse multipart boundary");
+    httpd_resp_send_err(r, HTTPD_400_BAD_REQUEST, nullptr);
+    return ESP_FAIL;
+  }
+
+  AsyncWebServerRequest req(r);
+  AsyncWebHandler *handler = nullptr;
+  for (auto *h : this->handlers_) {
+    if (h->canHandle(&req)) {
+      handler = h;
+      break;
+    }
+  }
+
+  if (!handler) {
+    ESP_LOGW(TAG, "No handler found for OTA request");
+    httpd_resp_send_err(r, HTTPD_404_NOT_FOUND, nullptr);
+    return ESP_OK;
+  }
+
+  // Upload state
+  std::string filename;
+  size_t index = 0;
+  // Create reader on heap to reduce stack usage
+  auto reader = std::make_unique<MultipartReader>("--" + std::string(boundary_start, boundary_len));
+
+  // Configure callbacks
+  reader->set_data_callback([&](const uint8_t *data, size_t len) {
+    if (!reader->has_file() || !len)
+      return;
+
+    if (filename.empty()) {
+      filename = reader->get_current_part().filename;
+      ESP_LOGV(TAG, "Processing file: '%s'", filename.c_str());
+      handler->handleUpload(&req, filename, 0, nullptr, 0, false);  // Start
+    }
+
+    handler->handleUpload(&req, filename, index, const_cast<uint8_t *>(data), len, false);
+    index += len;
+  });
+
+  reader->set_part_complete_callback([&]() {
+    if (index > 0) {
+      handler->handleUpload(&req, filename, index, nullptr, 0, true);  // End
+      filename.clear();
+      index = 0;
+    }
+  });
+
+  // Process data
+  std::unique_ptr<char[]> buffer(new char[MULTIPART_CHUNK_SIZE]);
+  size_t bytes_since_yield = 0;
+
+  for (size_t remaining = r->content_len; remaining > 0;) {
+    int recv_len = httpd_req_recv(r, buffer.get(), std::min(remaining, MULTIPART_CHUNK_SIZE));
+
+    if (recv_len <= 0) {
+      httpd_resp_send_err(r, recv_len == HTTPD_SOCK_ERR_TIMEOUT ? HTTPD_408_REQ_TIMEOUT : HTTPD_400_BAD_REQUEST,
+                          nullptr);
+      return recv_len == HTTPD_SOCK_ERR_TIMEOUT ? ESP_ERR_TIMEOUT : ESP_FAIL;
+    }
+
+    if (reader->parse(buffer.get(), recv_len) != static_cast<size_t>(recv_len)) {
+      ESP_LOGW(TAG, "Multipart parser error");
+      httpd_resp_send_err(r, HTTPD_400_BAD_REQUEST, nullptr);
+      return ESP_FAIL;
+    }
+
+    remaining -= recv_len;
+    bytes_since_yield += recv_len;
+
+    if (bytes_since_yield > YIELD_INTERVAL_BYTES) {
+      vTaskDelay(1);
+      bytes_since_yield = 0;
+    }
+  }
+
+  handler->handleRequest(&req);
+  return ESP_OK;
+}
+#endif  // USE_WEBSERVER_OTA
+
 }  // namespace web_server_idf
 }  // namespace esphome
 

esphome/components/web_server_idf/web_server_idf.h

@@ -204,6 +204,9 @@ class AsyncWebServer {
   static esp_err_t request_handler(httpd_req_t *r);
   static esp_err_t request_post_handler(httpd_req_t *r);
   esp_err_t request_handler_(AsyncWebServerRequest *request) const;
+#ifdef USE_WEBSERVER_OTA
+  esp_err_t handle_multipart_upload_(httpd_req_t *r, const char *content_type);
+#endif
   std::vector<AsyncWebHandler *> handlers_;
   std::function<void(AsyncWebServerRequest *request)> on_not_found_{};
 };

esphome/core/defines.h

@@ -153,6 +153,7 @@
 #define USE_SPI
 #define USE_VOICE_ASSISTANT
 #define USE_WEBSERVER
+#define USE_WEBSERVER_OTA
 #define USE_WEBSERVER_PORT 80  // NOLINT
 #define USE_WEBSERVER_SORTING
 #define USE_WIFI_11KV_SUPPORT

esphome/idf_component.yml

@@ -17,3 +17,5 @@ dependencies:
     version: 2.0.11
     rules:
       - if: "target in [esp32h2, esp32p4]"
+  zorxx/multipart-parser:
+    version: 1.0.1

tests/components/web_server/test_no_ota.esp32-idf.yaml

@@ -0,0 +1,9 @@
+packages:
+  device_base: !include common.yaml
+
+# No OTA component defined for this test
+
+web_server:
+  port: 8080
+  version: 2
+  ota: false

tests/components/web_server/test_ota.esp32-idf.yaml

@@ -0,0 +1,32 @@
+# Test configuration for ESP-IDF web server with OTA enabled
+esphome:
+  name: test-web-server-ota-idf
+
+# Force ESP-IDF framework
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+packages:
+  device_base: !include common.yaml
+
+# Enable OTA for multipart upload testing
+ota:
+  - platform: esphome
+    password: "test_ota_password"
+
+# Web server with OTA enabled
+web_server:
+  port: 8080
+  version: 2
+  ota: true
+  include_internal: true
+
+# Enable debug logging for OTA
+logger:
+  level: DEBUG
+  logs:
+    web_server: VERBOSE
+    web_server_idf: VERBOSE
+

tests/components/web_server/test_ota_disabled.esp32-idf.yaml

@@ -0,0 +1,11 @@
+packages:
+  device_base: !include common.yaml
+
+# OTA is configured but web_server OTA is disabled
+ota:
+  - platform: esphome
+
+web_server:
+  port: 8080
+  version: 2
+  ota: false