use stringref

esphome/components/api/api_connection.cpp

@@ -442,10 +442,8 @@ uint16_t APIConnection::try_send_fan_state(EntityBase *entity, APIConnection *co
   }
   if (traits.supports_direction())
     msg.direction = static_cast<enums::FanDirection>(fan->direction);
-  if (traits.supports_preset_modes() && fan->has_preset_mode()) {
-    auto preset = fan->get_preset_mode();
-    msg.preset_mode = StringRef(preset.data(), preset.size());
-  }
+  if (traits.supports_preset_modes() && fan->has_preset_mode())
+    msg.preset_mode = fan->get_preset_mode();
   return fill_and_encode_entity_state(fan, msg, FanStateResponse::MESSAGE_TYPE, conn, remaining_size, is_single);
 }
 uint16_t APIConnection::try_send_fan_info(EntityBase *entity, APIConnection *conn, uint32_t remaining_size,

esphome/components/fan/automation.h

@@ -223,7 +223,7 @@ class FanPresetSetTrigger : public Trigger<std::string> {
   }
 
  protected:
-  std::string_view last_preset_mode_{};
+  StringRef last_preset_mode_{};
 };
 
 }  // namespace fan

esphome/components/fan/fan.cpp

@@ -179,10 +179,10 @@ bool Fan::set_preset_mode_(const std::string &preset_mode) {
   return this->set_preset_mode_(preset_mode.data(), preset_mode.size());
 }
 
-bool Fan::set_preset_mode_(std::string_view preset_mode) {
+bool Fan::set_preset_mode_(StringRef preset_mode) {
   // Safe: find_preset_mode_ only uses the input for comparison and returns
-  // a pointer from traits, so the input string_view's lifetime doesn't matter.
-  return this->set_preset_mode_(preset_mode.data(), preset_mode.size());
+  // a pointer from traits, so the input StringRef's lifetime doesn't matter.
+  return this->set_preset_mode_(preset_mode.c_str(), preset_mode.size());
 }
 
 void Fan::clear_preset_mode_() { this->preset_mode_ = nullptr; }

esphome/components/fan/fan.h

@@ -1,12 +1,11 @@
 #pragma once
 
-#include <string_view>
-
 #include "esphome/core/entity_base.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/optional.h"
 #include "esphome/core/preferences.h"
+#include "esphome/core/string_ref.h"
 #include "fan_traits.h"
 
 namespace esphome {
@@ -131,12 +130,10 @@ class Fan : public EntityBase {
   void set_restore_mode(FanRestoreMode restore_mode) { this->restore_mode_ = restore_mode; }
 
   /// Get the current preset mode.
-  /// Returns a view of the string stored in traits, or empty view if not set.
-  /// The returned view points to string literals from codegen (static storage).
+  /// Returns a StringRef of the string stored in traits, or empty ref if not set.
+  /// The returned ref points to string literals from codegen (static storage).
   /// Traits are set once at startup and valid for the lifetime of the program.
-  std::string_view get_preset_mode() const {
-    return this->preset_mode_ != nullptr ? std::string_view(this->preset_mode_) : std::string_view();
-  }
+  StringRef get_preset_mode() const { return StringRef::from_maybe_nullptr(this->preset_mode_); }
 
   /// Check if a preset mode is currently active
   bool has_preset_mode() const { return this->preset_mode_ != nullptr; }
@@ -157,7 +154,7 @@ class Fan : public EntityBase {
   bool set_preset_mode_(const char *preset_mode, size_t len);
   bool set_preset_mode_(const char *preset_mode);
   bool set_preset_mode_(const std::string &preset_mode);
-  bool set_preset_mode_(std::string_view preset_mode);
+  bool set_preset_mode_(StringRef preset_mode);
   /// Clear the preset mode
   void clear_preset_mode_();
   /// Apply preset mode from a FanCall (handles speed-clears-preset convention)

tests/components/fan/common.yaml

@@ -10,7 +10,7 @@ fan:
     has_direction: true
     speed_count: 3
 
-# Test lambdas using get_preset_mode() which returns std::string_view
+# Test lambdas using get_preset_mode() which returns StringRef
 # These examples match the migration guide in the PR description
 binary_sensor:
   - platform: template
@@ -44,13 +44,13 @@ binary_sensor:
       std::string preset = std::string(id(test_fan).get_preset_mode());
 
       // Migration guide: Logging option 1
-      // Use .data() - works because string_view points to null-terminated string in traits
-      ESP_LOGD("test", "Preset: %s", id(test_fan).get_preset_mode().data());
+      // Use .c_str() - works because StringRef points to null-terminated string in traits
+      ESP_LOGD("test", "Preset: %s", id(test_fan).get_preset_mode().c_str());
 
       // Migration guide: Logging option 2
       // Use %.*s format (safer, no null-termination assumption)
-      auto preset_view = id(test_fan).get_preset_mode();
-      ESP_LOGD("test", "Preset: %.*s", (int)preset_view.size(), preset_view.data());
+      auto preset_ref = id(test_fan).get_preset_mode();
+      ESP_LOGD("test", "Preset: %.*s", (int)preset_ref.size(), preset_ref.c_str());
 
       // Test != comparison
       if (id(test_fan).get_preset_mode() != "Sleep") {