feat: add support for build-time WiFi credentials from .env file

.gitignore

@@ -85,3 +85,6 @@ Desktop.ini
 
 # sample code
 sample-code/
+
+.env
+*.env

CMakeLists.txt

@@ -3,6 +3,40 @@
 cmake_minimum_required(VERSION 3.16)
 # target_compile_options(${COMPONENT_LIB} PRIVATE -std=c++23)
 
+# Define the path to your .env file
+set(ENV_FILE "${CMAKE_SOURCE_DIR}/.env")
+
+# Check if the .env file exists
+if(EXISTS ${ENV_FILE})
+    # Read the .env file line by line
+    file(STRINGS ${ENV_FILE} ENV_VARS)
+
+    foreach(VAR ${ENV_VARS})
+        # Use regex to extract the key and value
+        if (VAR MATCHES "([^=]+)=(.*)")
+            set(ENV{${CMAKE_MATCH_1}} ${CMAKE_MATCH_2})
+            message(STATUS "Loaded environment variable from .env: ${CMAKE_MATCH_1}")
+        endif()
+    endforeach()
+else()
+    message(STATUS ".env file not found at ${ENV_FILE}")
+endif()
+
+# If build-time WiFi environment variables were loaded above, expose them
+# as compile-time definitions so C++ can use them.
+if(DEFINED ENV{WIFI_SSID})
+    add_compile_definitions(BUILD_WIFI_SSID="$ENV{WIFI_SSID}")
+    message(STATUS "Added BUILD_WIFI_SSID compile definition")
+else()
+    message(STATUS "WIFI_SSID not defined; skipping BUILD_WIFI_SSID compile definition")
+endif()
+if(DEFINED ENV{WIFI_PASSWORD})
+    add_compile_definitions(BUILD_WIFI_PASSWORD="$ENV{WIFI_PASSWORD}")
+    message(STATUS "Added BUILD_WIFI_PASSWORD compile definition")
+else()
+    message(STATUS "WIFI_PASSWORD not defined; skipping BUILD_WIFI_PASSWORD compile definition")
+endif()
+
 include($ENV{IDF_PATH}/tools/cmake/project.cmake)
 # "Trim" the build. Include the minimal set of components, main, and anything it depends on.
 idf_build_set_property(MINIMAL_BUILD ON)

main/network/wifi_handler.cpp

@@ -120,6 +120,19 @@ esp_err_t WifiHandler::init() {
   std::string password;
   this->get_wifi_credentials(ssid, password);
 
+  // If KV storage didn't provide credentials, allow build-time injected values
+  // via compile-time defines BUILD_WIFI_SSID and BUILD_WIFI_PASSWORD.
+#if defined(BUILD_WIFI_SSID) and defined(BUILD_WIFI_PASSWORD)
+  if (ssid.empty()) {
+    ssid = std::string(BUILD_WIFI_SSID);
+    ESP_LOGI(TAG, "Using build-time injected WiFi SSID");
+  }
+  if (password.empty()) {
+    password = std::string(BUILD_WIFI_PASSWORD);
+    ESP_LOGI(TAG, "Using build-time injected WiFi password");
+  }
+#endif
+
   if (!ssid.empty() && !password.empty()) {
     ESP_LOGI(TAG, "Found stored WiFi credentials, connecting to SSID: %s", ssid.c_str());
     err = this->connect(ssid, password);