[web_server] Use ESPHOME_F for canHandle domain checks to reduce ESP8266 RAM (#13315)

Co-authored-by: Keith Burzinski <kbx81x@gmail.com>

esphome/components/light/light_json_schema.cpp

@@ -1,4 +1,5 @@
 #include "light_json_schema.h"
+#include "color_mode.h"
 #include "light_output.h"
 #include "esphome/core/progmem.h"
 
@@ -8,29 +9,32 @@ namespace esphome::light {
 
 // See https://www.home-assistant.io/integrations/light.mqtt/#json-schema for documentation on the schema
 
-// Get JSON string for color mode using linear search (avoids large switch jump table)
-static const char *get_color_mode_json_str(ColorMode mode) {
-  // Parallel arrays: mode values and their corresponding strings
-  // Uses less RAM than a switch jump table on sparse enum values
-  static constexpr ColorMode MODES[] = {
-      ColorMode::ON_OFF,
-      ColorMode::BRIGHTNESS,
-      ColorMode::WHITE,
-      ColorMode::COLOR_TEMPERATURE,
-      ColorMode::COLD_WARM_WHITE,
-      ColorMode::RGB,
-      ColorMode::RGB_WHITE,
-      ColorMode::RGB_COLOR_TEMPERATURE,
-      ColorMode::RGB_COLD_WARM_WHITE,
-  };
-  static constexpr const char *STRINGS[] = {
-      "onoff", "brightness", "white", "color_temp", "cwww", "rgb", "rgbw", "rgbct", "rgbww",
-  };
-  for (size_t i = 0; i < sizeof(MODES) / sizeof(MODES[0]); i++) {
-    if (MODES[i] == mode)
-      return STRINGS[i];
+// Get JSON string for color mode.
+// ColorMode enum values are sparse bitmasks (0, 1, 3, 7, 11, 19, 35, 39, 47, 51) which would
+// generate a large jump table. Converting to bit index (0-9) allows a compact switch.
+static ProgmemStr get_color_mode_json_str(ColorMode mode) {
+  switch (ColorModeBitPolicy::to_bit(mode)) {
+    case 1:
+      return ESPHOME_F("onoff");
+    case 2:
+      return ESPHOME_F("brightness");
+    case 3:
+      return ESPHOME_F("white");
+    case 4:
+      return ESPHOME_F("color_temp");
+    case 5:
+      return ESPHOME_F("cwww");
+    case 6:
+      return ESPHOME_F("rgb");
+    case 7:
+      return ESPHOME_F("rgbw");
+    case 8:
+      return ESPHOME_F("rgbct");
+    case 9:
+      return ESPHOME_F("rgbww");
+    default:
+      return nullptr;
   }
-  return nullptr;
 }
 
 void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
@@ -44,7 +48,7 @@ void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
   auto values = state.remote_values;
 
   const auto color_mode = values.get_color_mode();
-  const char *mode_str = get_color_mode_json_str(color_mode);
+  const auto *mode_str = get_color_mode_json_str(color_mode);
   if (mode_str != nullptr) {
     root[ESPHOME_F("color_mode")] = mode_str;
   }

esphome/components/opentherm/opentherm.cpp

@@ -561,8 +561,9 @@ const char *OpenTherm::message_id_to_str(MessageId id) {
 }
 
 void OpenTherm::debug_data(OpenthermData &data) {
-  ESP_LOGD(TAG, "%s %s %s %s", format_bin(data.type).c_str(), format_bin(data.id).c_str(),
-           format_bin(data.valueHB).c_str(), format_bin(data.valueLB).c_str());
+  char type_buf[9], id_buf[9], hb_buf[9], lb_buf[9];
+  ESP_LOGD(TAG, "%s %s %s %s", format_bin_to(type_buf, data.type), format_bin_to(id_buf, data.id),
+           format_bin_to(hb_buf, data.valueHB), format_bin_to(lb_buf, data.valueLB));
   ESP_LOGD(TAG, "type: %s; id: %u; HB: %u; LB: %u; uint_16: %u; float: %f",
            this->message_type_to_str((MessageType) data.type), data.id, data.valueHB, data.valueLB, data.u16(),
            data.f88());

esphome/components/web_server/list_entities.cpp

@@ -143,7 +143,7 @@ bool ListEntitiesIterator::on_water_heater(water_heater::WaterHeater *obj) {
 
 #ifdef USE_INFRARED
 bool ListEntitiesIterator::on_infrared(infrared::Infrared *obj) {
-  // Infrared web_server support not yet implemented - this stub acknowledges the entity
+  this->events_->deferrable_send_state(obj, "state_detail_all", WebServer::infrared_all_json_generator);
   return true;
 }
 #endif

esphome/components/web_server/web_server.cpp

@@ -33,6 +33,10 @@
 #include "esphome/components/water_heater/water_heater.h"
 #endif
 
+#ifdef USE_INFRARED
+#include "esphome/components/infrared/infrared.h"
+#endif
+
 #ifdef USE_WEBSERVER_LOCAL
 #if USE_WEBSERVER_VERSION == 2
 #include "server_index_v2.h"
@@ -1952,6 +1956,110 @@ std::string WebServer::water_heater_json_(water_heater::WaterHeater *obj, JsonDe
 }
 #endif
 
+#ifdef USE_INFRARED
+void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const UrlMatch &match) {
+  for (infrared::Infrared *obj : App.get_infrareds()) {
+    auto entity_match = match.match_entity(obj);
+    if (!entity_match.matched)
+      continue;
+
+    if (request->method() == HTTP_GET && entity_match.action_is_empty) {
+      auto detail = get_request_detail(request);
+      std::string data = this->infrared_json_(obj, detail);
+      request->send(200, ESPHOME_F("application/json"), data.c_str());
+      return;
+    }
+    if (!match.method_equals(ESPHOME_F("transmit"))) {
+      request->send(404);
+      return;
+    }
+
+    // Only allow transmit if the device supports it
+    if (!obj->has_transmitter()) {
+      request->send(400, ESPHOME_F("text/plain"), "Device does not support transmission");
+      return;
+    }
+
+    // Parse parameters
+    auto call = obj->make_call();
+
+    // Parse carrier frequency (optional)
+    if (request->hasParam(ESPHOME_F("carrier_frequency"))) {
+      auto value = parse_number<uint32_t>(request->getParam(ESPHOME_F("carrier_frequency"))->value().c_str());
+      if (value.has_value()) {
+        call.set_carrier_frequency(*value);
+      }
+    }
+
+    // Parse repeat count (optional, defaults to 1)
+    if (request->hasParam(ESPHOME_F("repeat_count"))) {
+      auto value = parse_number<uint32_t>(request->getParam(ESPHOME_F("repeat_count"))->value().c_str());
+      if (value.has_value()) {
+        call.set_repeat_count(*value);
+      }
+    }
+
+    // Parse base64url-encoded raw timings (required)
+    // Base64url is URL-safe: uses A-Za-z0-9-_ (no special characters needing escaping)
+    if (!request->hasParam(ESPHOME_F("data"))) {
+      request->send(400, ESPHOME_F("text/plain"), "Missing 'data' parameter");
+      return;
+    }
+
+    // .c_str() is required for Arduino framework where value() returns Arduino String instead of std::string
+    std::string encoded =
+        request->getParam(ESPHOME_F("data"))->value().c_str();  // NOLINT(readability-redundant-string-cstr)
+
+    // Validate base64url is not empty
+    if (encoded.empty()) {
+      request->send(400, ESPHOME_F("text/plain"), "Empty 'data' parameter");
+      return;
+    }
+
+#ifdef USE_ESP8266
+    // ESP8266 is single-threaded, call directly
+    call.set_raw_timings_base64url(encoded);
+    call.perform();
+#else
+    // Defer to main loop for thread safety. Move encoded string into lambda to ensure
+    // it outlives the call - set_raw_timings_base64url stores a pointer, so the string
+    // must remain valid until perform() completes.
+    this->defer([call, encoded = std::move(encoded)]() mutable {
+      call.set_raw_timings_base64url(encoded);
+      call.perform();
+    });
+#endif
+
+    request->send(200);
+    return;
+  }
+  request->send(404);
+}
+
+std::string WebServer::infrared_all_json_generator(WebServer *web_server, void *source) {
+  // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
+  return web_server->infrared_json_(static_cast<infrared::Infrared *>(source), DETAIL_ALL);
+}
+
+std::string WebServer::infrared_json_(infrared::Infrared *obj, JsonDetail start_config) {
+  json::JsonBuilder builder;
+  JsonObject root = builder.root();
+
+  set_json_icon_state_value(root, obj, "infrared", "", 0, start_config);
+
+  auto traits = obj->get_traits();
+
+  root[ESPHOME_F("supports_transmitter")] = traits.get_supports_transmitter();
+  root[ESPHOME_F("supports_receiver")] = traits.get_supports_receiver();
+
+  if (start_config == DETAIL_ALL) {
+    this->add_sorting_info_(root, obj);
+  }
+
+  return builder.serialize();
+}
+#endif
+
 #ifdef USE_EVENT
 void WebServer::on_event(event::Event *obj) {
   if (!this->include_internal_ && obj->is_internal())
@@ -2083,24 +2191,21 @@ bool WebServer::canHandle(AsyncWebServerRequest *request) const {
   const auto &url = request->url();
   const auto method = request->method();
 
-  // Static URL checks
-  static const char *const STATIC_URLS[] = {
-    "/",
+  // Static URL checks - use ESPHOME_F to keep strings in flash on ESP8266
+  if (url == ESPHOME_F("/"))
+    return true;
 #if !defined(USE_ESP32) && defined(USE_ARDUINO)
-    "/events",
+  if (url == ESPHOME_F("/events"))
+    return true;
 #endif
 #ifdef USE_WEBSERVER_CSS_INCLUDE
-    "/0.css",
+  if (url == ESPHOME_F("/0.css"))
+    return true;
 #endif
 #ifdef USE_WEBSERVER_JS_INCLUDE
-    "/0.js",
+  if (url == ESPHOME_F("/0.js"))
+    return true;
 #endif
-  };
-
-  for (const auto &static_url : STATIC_URLS) {
-    if (url == static_url)
-      return true;
-  }
 
 #ifdef USE_WEBSERVER_PRIVATE_NETWORK_ACCESS
   if (method == HTTP_OPTIONS && request->hasHeader(ESPHOME_F("Access-Control-Request-Private-Network")))
@@ -2120,90 +2225,100 @@ bool WebServer::canHandle(AsyncWebServerRequest *request) const {
   if (!is_get_or_post)
     return false;
 
-  // Use lookup tables for domain checks
-  static const char *const GET_ONLY_DOMAINS[] = {
+  // Check GET-only domains - use ESPHOME_F to keep strings in flash on ESP8266
+  if (is_get) {
 #ifdef USE_SENSOR
-      "sensor",
+    if (match.domain_equals(ESPHOME_F("sensor")))
+      return true;
 #endif
 #ifdef USE_BINARY_SENSOR
-      "binary_sensor",
+    if (match.domain_equals(ESPHOME_F("binary_sensor")))
+      return true;
 #endif
 #ifdef USE_TEXT_SENSOR
-      "text_sensor",
+    if (match.domain_equals(ESPHOME_F("text_sensor")))
+      return true;
 #endif
 #ifdef USE_EVENT
-      "event",
+    if (match.domain_equals(ESPHOME_F("event")))
+      return true;
 #endif
-  };
-
-  static const char *const GET_POST_DOMAINS[] = {
-#ifdef USE_SWITCH
-      "switch",
-#endif
-#ifdef USE_BUTTON
-      "button",
-#endif
-#ifdef USE_FAN
-      "fan",
-#endif
-#ifdef USE_LIGHT
-      "light",
-#endif
-#ifdef USE_COVER
-      "cover",
-#endif
-#ifdef USE_NUMBER
-      "number",
-#endif
-#ifdef USE_DATETIME_DATE
-      "date",
-#endif
-#ifdef USE_DATETIME_TIME
-      "time",
-#endif
-#ifdef USE_DATETIME_DATETIME
-      "datetime",
-#endif
-#ifdef USE_TEXT
-      "text",
-#endif
-#ifdef USE_SELECT
-      "select",
-#endif
-#ifdef USE_CLIMATE
-      "climate",
-#endif
-#ifdef USE_LOCK
-      "lock",
-#endif
-#ifdef USE_VALVE
-      "valve",
-#endif
-#ifdef USE_ALARM_CONTROL_PANEL
-      "alarm_control_panel",
-#endif
-#ifdef USE_UPDATE
-      "update",
-#endif
-#ifdef USE_WATER_HEATER
-      "water_heater",
-#endif
-  };
-
-  // Check GET-only domains
-  if (is_get) {
-    for (const auto &domain : GET_ONLY_DOMAINS) {
-      if (match.domain_equals(domain))
-        return true;
-    }
   }
 
   // Check GET+POST domains
   if (is_get_or_post) {
-    for (const auto &domain : GET_POST_DOMAINS) {
-      if (match.domain_equals(domain))
-        return true;
-    }
+#ifdef USE_SWITCH
+    if (match.domain_equals(ESPHOME_F("switch")))
+      return true;
+#endif
+#ifdef USE_BUTTON
+    if (match.domain_equals(ESPHOME_F("button")))
+      return true;
+#endif
+#ifdef USE_FAN
+    if (match.domain_equals(ESPHOME_F("fan")))
+      return true;
+#endif
+#ifdef USE_LIGHT
+    if (match.domain_equals(ESPHOME_F("light")))
+      return true;
+#endif
+#ifdef USE_COVER
+    if (match.domain_equals(ESPHOME_F("cover")))
+      return true;
+#endif
+#ifdef USE_NUMBER
+    if (match.domain_equals(ESPHOME_F("number")))
+      return true;
+#endif
+#ifdef USE_DATETIME_DATE
+    if (match.domain_equals(ESPHOME_F("date")))
+      return true;
+#endif
+#ifdef USE_DATETIME_TIME
+    if (match.domain_equals(ESPHOME_F("time")))
+      return true;
+#endif
+#ifdef USE_DATETIME_DATETIME
+    if (match.domain_equals(ESPHOME_F("datetime")))
+      return true;
+#endif
+#ifdef USE_TEXT
+    if (match.domain_equals(ESPHOME_F("text")))
+      return true;
+#endif
+#ifdef USE_SELECT
+    if (match.domain_equals(ESPHOME_F("select")))
+      return true;
+#endif
+#ifdef USE_CLIMATE
+    if (match.domain_equals(ESPHOME_F("climate")))
+      return true;
+#endif
+#ifdef USE_LOCK
+    if (match.domain_equals(ESPHOME_F("lock")))
+      return true;
+#endif
+#ifdef USE_VALVE
+    if (match.domain_equals(ESPHOME_F("valve")))
+      return true;
+#endif
+#ifdef USE_ALARM_CONTROL_PANEL
+    if (match.domain_equals(ESPHOME_F("alarm_control_panel")))
+      return true;
+#endif
+#ifdef USE_UPDATE
+    if (match.domain_equals(ESPHOME_F("update")))
+      return true;
+#endif
+#ifdef USE_WATER_HEATER
+    if (match.domain_equals(ESPHOME_F("water_heater")))
+      return true;
+#endif
+#ifdef USE_INFRARED
+    if (match.domain_equals(ESPHOME_F("infrared")))
+      return true;
+#endif
   }
 
   return false;
@@ -2352,6 +2467,11 @@ void WebServer::handleRequest(AsyncWebServerRequest *request) {
   else if (match.domain_equals(ESPHOME_F("water_heater"))) {
     this->handle_water_heater_request(request, match);
   }
+#endif
+#ifdef USE_INFRARED
+  else if (match.domain_equals(ESPHOME_F("infrared"))) {
+    this->handle_infrared_request(request, match);
+  }
 #endif
   else {
     // No matching handler found - send 404

esphome/components/web_server/web_server.h

@@ -460,6 +460,13 @@ class WebServer : public Controller,
   static std::string water_heater_all_json_generator(WebServer *web_server, void *source);
 #endif
 
+#ifdef USE_INFRARED
+  /// Handle an infrared request under '/infrared/<id>/transmit'.
+  void handle_infrared_request(AsyncWebServerRequest *request, const UrlMatch &match);
+
+  static std::string infrared_all_json_generator(WebServer *web_server, void *source);
+#endif
+
 #ifdef USE_EVENT
   void on_event(event::Event *obj) override;
 
@@ -662,6 +669,9 @@ class WebServer : public Controller,
 #ifdef USE_WATER_HEATER
   std::string water_heater_json_(water_heater::WaterHeater *obj, JsonDetail start_config);
 #endif
+#ifdef USE_INFRARED
+  std::string infrared_json_(infrared::Infrared *obj, JsonDetail start_config);
+#endif
 #ifdef USE_UPDATE
   std::string update_json_(update::UpdateEntity *obj, JsonDetail start_config);
 #endif

esphome/core/helpers.cpp

@@ -404,15 +404,31 @@ std::string format_hex_pretty(const std::string &data, char separator, bool show
   return format_hex_pretty_uint8(reinterpret_cast<const uint8_t *>(data.data()), data.length(), separator, show_length);
 }
 
+char *format_bin_to(char *buffer, size_t buffer_size, const uint8_t *data, size_t length) {
+  if (buffer_size == 0) {
+    return buffer;
+  }
+  // Calculate max bytes we can format: each byte needs 8 chars
+  size_t max_bytes = (buffer_size - 1) / 8;
+  if (max_bytes == 0 || length == 0) {
+    buffer[0] = '\0';
+    return buffer;
+  }
+  size_t bytes_to_format = std::min(length, max_bytes);
+
+  for (size_t byte_idx = 0; byte_idx < bytes_to_format; byte_idx++) {
+    for (size_t bit_idx = 0; bit_idx < 8; bit_idx++) {
+      buffer[byte_idx * 8 + bit_idx] = ((data[byte_idx] >> (7 - bit_idx)) & 1) + '0';
+    }
+  }
+  buffer[bytes_to_format * 8] = '\0';
+  return buffer;
+}
+
 std::string format_bin(const uint8_t *data, size_t length) {
   std::string result;
   result.resize(length * 8);
-  for (size_t byte_idx = 0; byte_idx < length; byte_idx++) {
-    for (size_t bit_idx = 0; bit_idx < 8; bit_idx++) {
-      result[byte_idx * 8 + bit_idx] = ((data[byte_idx] >> (7 - bit_idx)) & 1) + '0';
-    }
-  }
-
+  format_bin_to(&result[0], length * 8 + 1, data, length);
   return result;
 }
 

esphome/core/helpers.h

@@ -517,10 +517,6 @@ template<typename T> constexpr T convert_little_endian(T val) {
 bool str_equals_case_insensitive(const std::string &a, const std::string &b);
 /// Compare StringRefs for equality in case-insensitive manner.
 bool str_equals_case_insensitive(StringRef a, StringRef b);
-/// Compare C strings for equality in case-insensitive manner (no heap allocation).
-inline bool str_equals_case_insensitive(const char *a, const char *b) { return strcasecmp(a, b) == 0; }
-inline bool str_equals_case_insensitive(const std::string &a, const char *b) { return strcasecmp(a.c_str(), b) == 0; }
-inline bool str_equals_case_insensitive(const char *a, const std::string &b) { return strcasecmp(a, b.c_str()) == 0; }
 
 /// Check whether a string starts with a value.
 bool str_startswith(const std::string &str, const std::string &start);
@@ -1100,9 +1096,66 @@ std::string format_hex_pretty(T val, char separator = '.', bool show_length = tr
   return format_hex_pretty(reinterpret_cast<uint8_t *>(&val), sizeof(T), separator, show_length);
 }
 
+/// Calculate buffer size needed for format_bin_to: "01234567...\0" = bytes * 8 + 1
+constexpr size_t format_bin_size(size_t byte_count) { return byte_count * 8 + 1; }
+
+/** Format byte array as binary string to buffer.
+ *
+ * Each byte is formatted as 8 binary digits (MSB first).
+ * Truncates output if data exceeds buffer capacity.
+ *
+ * @param buffer Output buffer to write to.
+ * @param buffer_size Size of the output buffer.
+ * @param data Pointer to the byte array to format.
+ * @param length Number of bytes in the array.
+ * @return Pointer to buffer.
+ *
+ * Buffer size needed: length * 8 + 1 (use format_bin_size()).
+ *
+ * Example:
+ * @code
+ * char buf[9];  // format_bin_size(1)
+ * format_bin_to(buf, sizeof(buf), data, 1);  // "10101011"
+ * @endcode
+ */
+char *format_bin_to(char *buffer, size_t buffer_size, const uint8_t *data, size_t length);
+
+/// Format byte array as binary to buffer. Automatically deduces buffer size.
+template<size_t N> inline char *format_bin_to(char (&buffer)[N], const uint8_t *data, size_t length) {
+  static_assert(N >= 9, "Buffer must hold at least one binary byte (9 chars)");
+  return format_bin_to(buffer, N, data, length);
+}
+
+/** Format an unsigned integer in binary to buffer, MSB first.
+ *
+ * @tparam N Buffer size (must be >= sizeof(T) * 8 + 1).
+ * @tparam T Unsigned integer type.
+ * @param buffer Output buffer to write to.
+ * @param val The unsigned integer value to format.
+ * @return Pointer to buffer.
+ *
+ * Example:
+ * @code
+ * char buf[9];  // format_bin_size(sizeof(uint8_t))
+ * format_bin_to(buf, uint8_t{0xAA});  // "10101010"
+ * char buf16[17];  // format_bin_size(sizeof(uint16_t))
+ * format_bin_to(buf16, uint16_t{0x1234});  // "0001001000110100"
+ * @endcode
+ */
+template<size_t N, typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0>
+inline char *format_bin_to(char (&buffer)[N], T val) {
+  static_assert(N >= sizeof(T) * 8 + 1, "Buffer too small for type");
+  val = convert_big_endian(val);
+  return format_bin_to(buffer, reinterpret_cast<const uint8_t *>(&val), sizeof(T));
+}
+
 /// Format the byte array \p data of length \p len in binary.
+/// @warning Allocates heap memory. Use format_bin_to() with a stack buffer instead.
+/// Causes heap fragmentation on long-running devices.
 std::string format_bin(const uint8_t *data, size_t length);
 /// Format an unsigned integer in binary, starting with the most significant byte.
+/// @warning Allocates heap memory. Use format_bin_to() with a stack buffer instead.
+/// Causes heap fragmentation on long-running devices.
 template<typename T, enable_if_t<std::is_unsigned<T>::value, int> = 0> std::string format_bin(T val) {
   val = convert_big_endian(val);
   return format_bin(reinterpret_cast<uint8_t *>(&val), sizeof(T));

esphome/core/progmem.h

@@ -12,6 +12,8 @@
 #define ESPHOME_strncpy_P strncpy_P
 #define ESPHOME_strncat_P strncat_P
 #define ESPHOME_snprintf_P snprintf_P
+// Type for pointers to PROGMEM strings (for use with ESPHOME_F return values)
+using ProgmemStr = const __FlashStringHelper *;
 #else
 #define ESPHOME_F(string_literal) (string_literal)
 #define ESPHOME_PGM_P const char *
@@ -19,4 +21,6 @@
 #define ESPHOME_strncpy_P strncpy
 #define ESPHOME_strncat_P strncat
 #define ESPHOME_snprintf_P snprintf
+// Type for pointers to strings (no PROGMEM on non-ESP8266 platforms)
+using ProgmemStr = const char *;
 #endif

script/ci-custom.py

@@ -682,6 +682,7 @@ def lint_trailing_whitespace(fname, match):
 # Heap-allocating helpers that cause fragmentation on long-running embedded devices.
 # These return std::string and should be replaced with stack-based alternatives.
 HEAP_ALLOCATING_HELPERS = {
+    "format_bin": "format_bin_to() with a stack buffer",
     "format_hex": "format_hex_to() with a stack buffer",
     "format_hex_pretty": "format_hex_pretty_to() with a stack buffer",
     "format_mac_address_pretty": "format_mac_addr_upper() with a stack buffer",
@@ -699,6 +700,7 @@ HEAP_ALLOCATING_HELPERS = {
     # get_mac_address(?!_) ensures we don't match get_mac_address_into_buffer, etc.
     # CPP_RE_EOL captures rest of line so NOLINT comments are detected
     r"[^\w]("
+    r"format_bin(?!_)|"
     r"format_hex(?!_)|"
     r"format_hex_pretty(?!_)|"
     r"format_mac_address_pretty|"