[event] Store event types in flash memory

esphome/components/api/api.proto

@@ -2147,7 +2147,7 @@ message ListEntitiesEventResponse {
   EntityCategory entity_category = 7;
   string device_class = 8;
 
-  repeated string event_types = 9;
+  repeated string event_types = 9 [(container_pointer_no_template) = "FixedVector<const char *>"];
   uint32 device_id = 10 [(field_ifdef) = "USE_DEVICES"];
 }
 message EventResponse {

esphome/components/api/api_connection.cpp

@@ -1310,7 +1310,7 @@ uint16_t APIConnection::try_send_event_info(EntityBase *entity, APIConnection *c
   auto *event = static_cast<event::Event *>(entity);
   ListEntitiesEventResponse msg;
   msg.set_device_class(event->get_device_class_ref());
-  for (const auto &event_type : event->get_event_types())
+  for (const char *event_type : event->get_event_types())
     msg.event_types.push_back(event_type);
   return fill_and_encode_entity_info(event, msg, ListEntitiesEventResponse::MESSAGE_TYPE, conn, remaining_size,
                                      is_single);

esphome/components/api/api_pb2.cpp

@@ -2877,8 +2877,8 @@ void ListEntitiesEventResponse::encode(ProtoWriteBuffer buffer) const {
   buffer.encode_bool(6, this->disabled_by_default);
   buffer.encode_uint32(7, static_cast<uint32_t>(this->entity_category));
   buffer.encode_string(8, this->device_class_ref_);
-  for (auto &it : this->event_types) {
-    buffer.encode_string(9, it, true);
+  for (const char *it : *this->event_types) {
+    buffer.encode_string(9, it, strlen(it), true);
   }
 #ifdef USE_DEVICES
   buffer.encode_uint32(10, this->device_id);
@@ -2894,9 +2894,9 @@ void ListEntitiesEventResponse::calculate_size(ProtoSize &size) const {
   size.add_bool(1, this->disabled_by_default);
   size.add_uint32(1, static_cast<uint32_t>(this->entity_category));
   size.add_length(1, this->device_class_ref_.size());
-  if (!this->event_types.empty()) {
-    for (const auto &it : this->event_types) {
-      size.add_length_force(1, it.size());
+  if (!this->event_types->empty()) {
+    for (const char *it : *this->event_types) {
+      size.add_length_force(1, strlen(it));
     }
   }
 #ifdef USE_DEVICES

esphome/components/api/api_pb2.h

@@ -2788,7 +2788,7 @@ class ListEntitiesEventResponse final : public InfoResponseProtoMessage {
 #endif
   StringRef device_class_ref_{};
   void set_device_class(const StringRef &ref) { this->device_class_ref_ = ref; }
-  std::vector<std::string> event_types{};
+  const FixedVector<const char *> *event_types{};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP

esphome/components/api/api_pb2_dump.cpp

@@ -2053,7 +2053,7 @@ void ListEntitiesEventResponse::dump_to(std::string &out) const {
   dump_field(out, "disabled_by_default", this->disabled_by_default);
   dump_field(out, "entity_category", static_cast<enums::EntityCategory>(this->entity_category));
   dump_field(out, "device_class", this->device_class_ref_);
-  for (const auto &it : this->event_types) {
+  for (const auto &it : *this->event_types) {
     dump_field(out, "event_types", it, 4);
   }
 #ifdef USE_DEVICES

esphome/components/event/event.cpp

@@ -8,11 +8,11 @@ namespace event {
 static const char *const TAG = "event";
 
 void Event::trigger(const std::string &event_type) {
-  // Linear search - faster than std::set for small datasets (1-5 items typical)
-  const std::string *found = nullptr;
-  for (const auto &type : this->types_) {
-    if (type == event_type) {
-      found = &type;
+  // Linear search with strcmp - faster than std::set for small datasets (1-5 items typical)
+  const char *found = nullptr;
+  for (const char *type : this->types_) {
+    if (strcmp(type, event_type.c_str()) == 0) {
+      found = type;
       break;
     }
   }
@@ -20,8 +20,8 @@ void Event::trigger(const std::string &event_type) {
     ESP_LOGE(TAG, "'%s': invalid event type for trigger(): %s", this->get_name().c_str(), event_type.c_str());
     return;
   }
-  last_event_type = found;
-  ESP_LOGD(TAG, "'%s' Triggered event '%s'", this->get_name().c_str(), last_event_type->c_str());
+  this->last_event_type = found;
+  ESP_LOGD(TAG, "'%s' Triggered event '%s'", this->get_name().c_str(), this->last_event_type);
   this->event_callback_.call(event_type);
 }
 

esphome/components/event/event.h

@@ -1,5 +1,6 @@
 #pragma once
 
+#include <cstring>
 #include <string>
 
 #include "esphome/core/component.h"
@@ -22,16 +23,31 @@ namespace event {
 
 class Event : public EntityBase, public EntityBase_DeviceClass {
  public:
-  const std::string *last_event_type;
+  const char *last_event_type{nullptr};
 
   void trigger(const std::string &event_type);
-  void set_event_types(const std::initializer_list<std::string> &event_types) { this->types_ = event_types; }
-  const FixedVector<std::string> &get_event_types() const { return this->types_; }
+
+  /// Set the event types supported by this event (from initializer list).
+  void set_event_types(std::initializer_list<const char *> event_types) { this->types_ = event_types; }
+  /// Set the event types supported by this event (from FixedVector).
+  void set_event_types(const FixedVector<const char *> &event_types) { this->types_ = event_types; }
+  /// Set the event types supported by this event (from C array).
+  template<size_t N> void set_event_types(const char *const (&event_types)[N]) {
+    this->types_.assign(event_types, event_types + N);
+  }
+
+  // Deleted overloads to catch incorrect std::string usage at compile time with clear error messages
+  void set_event_types(std::initializer_list<std::string> event_types) = delete;
+  void set_event_types(const FixedVector<std::string> &event_types) = delete;
+
+  /// Return the event types supported by this event.
+  const FixedVector<const char *> &get_event_types() const { return this->types_; }
+
   void add_on_event_callback(std::function<void(const std::string &event_type)> &&callback);
 
  protected:
   CallbackManager<void(const std::string &event_type)> event_callback_;
-  FixedVector<std::string> types_;
+  FixedVector<const char *> types_;
 };
 
 }  // namespace event

esphome/components/mqtt/mqtt_event.cpp

@@ -38,8 +38,8 @@ void MQTTEventComponent::setup() {
 void MQTTEventComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Event '%s': ", this->event_->get_name().c_str());
   ESP_LOGCONFIG(TAG, "Event Types: ");
-  for (const auto &event_type : this->event_->get_event_types()) {
-    ESP_LOGCONFIG(TAG, "- %s", event_type.c_str());
+  for (const char *event_type : this->event_->get_event_types()) {
+    ESP_LOGCONFIG(TAG, "- %s", event_type);
   }
   LOG_MQTT_COMPONENT(true, true);
 }

esphome/components/web_server/web_server.cpp

@@ -1649,7 +1649,7 @@ std::string WebServer::event_json(event::Event *obj, const std::string &event_ty
   }
   if (start_config == DETAIL_ALL) {
     JsonArray event_types = root["event_types"].to<JsonArray>();
-    for (auto const &event_type : obj->get_event_types()) {
+    for (const char *event_type : obj->get_event_types()) {
       event_types.add(event_type);
     }
     root["device_class"] = obj->get_device_class_ref();