refactor(minion): store string constants in flash memory

3 files changed, 71 insertions, 36 deletions

diff --git a/minion/src/gymnasiearbete.cpp b/minion/src/gymnasiearbete.cpp
index 5c4f725..41be0ea 100644
--- a/minion/src/gymnasiearbete.cpp
+++ b/minion/src/gymnasiearbete.cpp
@@ -7,6 +7,7 @@
 
 #include <Arduino.h>
 #include <SoftwareSerial.h>
+#include <avr/pgmspace.h>
 #include <string.h>
 
 constexpr auto HTTP_PORT = 80U;
@@ -43,8 +44,8 @@ void setup()
 
 	auto wifi_module_connected = wifi_module.test();
 
-	Serial.print("Wifi module connected: ");
-	Serial.println(wifi_module_connected ? "Yes" : "No");
+	Serial.print(F("Wifi module connected: "));
+	Serial.println(wifi_module_connected ? F("Yes") : F("No"));
 
 	if (!wifi_module_connected)
 	{
@@ -59,8 +60,8 @@ void setup()
 		wifi_module.connect_to_wifi(WIFI_SSID, WIFI_PASSWORD);
 
 	Serial.print(
-		wifi_connect_success ? "Connected to wifi network '"
-							 : "Failed to connect to wifi network '"
+		wifi_connect_success ? F("Connected to wifi network '")
+							 : F("Failed to connect to wifi network '")
 	);
 	Serial.print(WIFI_SSID);
 	Serial.println("'");
@@ -76,7 +77,7 @@ void setup()
 
 	char local_ip[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";
 
-	Serial.print("IP address: ");
+	Serial.print(F("IP address: "));
 	Serial.println(wifi_module.get_local_ip(local_ip));
 
 	wifi_module.set_multiple_connections_enabled(true);
@@ -102,16 +103,16 @@ void loop()
 		return;
 	}
 
-	Serial.print("Connection ID: ");
+	Serial.print(F("Connection ID: "));
 	Serial.println(connection.id());
 
-	Serial.print("Request method: ");
+	Serial.print(F("Request method: "));
 	Serial.println(http_request_method_strs[static_cast<size_t>(request.method())]);
 
-	Serial.print("Request HTTP version: ");
+	Serial.print(F("Request HTTP version: "));
 	Serial.println(request.http_version());
 
-	Serial.print("Request path: ");
+	Serial.print(F("Request path: "));
 	Serial.println(request.path());
 
 	const auto temperature_sensor_status = temperature_sensor.read_temperature();
@@ -124,7 +125,7 @@ void loop()
 
 	if (temperature_sensor_status != TemperatureSensorStatus::OK)
 	{
-		Serial.print("Error: ");
+		Serial.print(F("Error: "));
 		Serial.println(static_cast<int>(temperature_sensor_status));
 
 		wifi_module.send_response(
@@ -161,7 +162,7 @@ void loop()
 
 	if (!send_response_ok)
 	{
-		Serial.println("Failed to send response");
+		Serial.println(F("Failed to send response"));
 		wifi_module.close_connection(connection);
 		return;
 	}
diff --git a/minion/src/wifi_module.cpp b/minion/src/wifi_module.cpp
index 6c989f9..5174168 100644
--- a/minion/src/wifi_module.cpp
+++ b/minion/src/wifi_module.cpp
@@ -23,21 +23,27 @@ auto WiFiModule::get_available() noexcept -> int
 
 void WiFiModule::reset() noexcept
 {
-	_send_serial("AT+RST");
+	const auto send_success = _send_serial("AT+RST");
+
+	if (!send_success)
+	{
+		Serial.println(F("Failed to send command to reset wifi module"));
+		return;
+	}
 
 	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";
 
 	const auto response_status = _read(2000U, response);
 
 	Serial.println(
-		response_status == WiFiModuleResponseStatus::OK ? "Reset wifi module"
-														: "Failed to reset wifi module"
+		response_status == WiFiModuleResponseStatus::OK ? F("Reset wifi module")
+														: F("Failed to reset wifi module")
 	);
 }
 
 auto WiFiModule::connect_to_wifi(const char *ssid, const char *password) noexcept -> bool
 {
-	const char cmd[] = "AT+CWJAP";
+	const auto cmd = "AT+CWJAP_CUR";
 
 	auto command_length =
 		WIFI_CONNECT_COMMAND_BASE_LENGTH + strlen(cmd) + strlen(ssid) + strlen(password);
@@ -46,7 +52,9 @@ auto WiFiModule::connect_to_wifi(const char *ssid, const char *password) noexcep
 
 	if (command == nullptr)
 	{
-		Serial.println("Memory allocation failed for creating wifi connection command");
+		Serial.println(
+			F("Heap memory allocation failed for creating a wifi connection command")
+		);
 		return false;
 	}
 
@@ -56,7 +64,8 @@ auto WiFiModule::connect_to_wifi(const char *ssid, const char *password) noexcep
 
 	if (!send_success)
 	{
-		Serial.println("Failed to send connection command");
+		Serial.println(F("Failed to send wifi connect command"));
+		free(command);
 		return false;
 	}
 
@@ -64,7 +73,7 @@ auto WiFiModule::connect_to_wifi(const char *ssid, const char *password) noexcep
 
 	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";
 
-	const auto response_status = _read(20000U, response);
+	const auto response_status = _read(40000U, response);
 
 	return response_status == WiFiModuleResponseStatus::OK;
 }
@@ -77,6 +86,11 @@ void WiFiModule::set_wifi_mode(WifiMode wifi_mode) noexcept
 
 	auto *command = util::malloc<char>(command_length);
 
+	if (command == nullptr)
+	{
+		return;
+	}
+
 	snprintf(command, command_length, "%s=%u", cmd, static_cast<int>(wifi_mode));
 
 	_send_serial(command);
@@ -96,6 +110,11 @@ void WiFiModule::set_multiple_connections_enabled(bool is_enabled) noexcept
 
 	auto *command = util::malloc<char>(command_length);
 
+	if (command == nullptr)
+	{
+		return;
+	}
+
 	snprintf(command, command_length, "%s=%u", cmd, is_enabled ? 1U : 0U);
 
 	_send_serial(command);
@@ -115,6 +134,11 @@ void WiFiModule::set_echo_enabled(bool is_enabled) noexcept
 
 	auto *command = util::malloc<char>(command_length);
 
+	if (command == nullptr)
+	{
+		return;
+	}
+
 	snprintf(command, command_length, "%s%u", cmd, is_enabled ? 1U : 0U);
 
 	_send_serial(command);
@@ -126,10 +150,11 @@ void WiFiModule::set_echo_enabled(bool is_enabled) noexcept
 	const auto response_status = _read(1500U, response);
 
 	Serial.print(
-		response_status == WiFiModuleResponseStatus::OK ? "Turned " : "Failed to turn "
+		response_status == WiFiModuleResponseStatus::OK ? F("Turned ")
+														: F("Failed to turn ")
 	);
-	Serial.print(is_enabled ? "on" : "off");
-	Serial.println(" AT commands echo");
+	Serial.print(is_enabled ? F("on") : F("off"));
+	Serial.println(F(" AT commands echo"));
 }
 
 void WiFiModule::create_tcp_server(size_t port) noexcept
@@ -140,6 +165,11 @@ void WiFiModule::create_tcp_server(size_t port) noexcept
 
 	auto *command = util::malloc<char>(command_length);
 
+	if (command == nullptr)
+	{
+		return;
+	}
+
 	snprintf(command, command_length, "%s=1,%u", cmd, port);
 
 	_send_serial(command);
@@ -162,7 +192,7 @@ auto WiFiModule::test() noexcept -> bool
 
 	char response[MAX_NETWORK_MODULE_RESPONSE_LENGTH] = "";
 
-	const auto response_status = _read(5000U, response);
+	const auto response_status = _read(8000U, response);
 
 	if (response_status == WiFiModuleResponseStatus::TIMEOUT)
 	{
@@ -174,9 +204,7 @@ auto WiFiModule::test() noexcept -> bool
 
 auto WiFiModule::get_local_ip(char *local_ip_out) noexcept -> const char *
 {
-	const auto *command = "AT+CIFSR";
-
-	const auto send_success = _send_serial(command);
+	const auto send_success = _send_serial("AT+CIFSR");
 
 	if (!send_success)
 	{
@@ -300,7 +328,9 @@ auto WiFiModule::close_connection(NetworkConnection &connection) noexcept -> boo
 
 	if (command == nullptr)
 	{
-		Serial.println("Memory allocation failed for creating close connection command");
+		Serial.println(
+			F("Heap memory allocation failed for creating close connection command")
+		);
 		return false;
 	}
 
@@ -316,14 +346,15 @@ auto WiFiModule::close_connection(NetworkConnection &connection) noexcept -> boo
 
 	if (response_status != WiFiModuleResponseStatus::OK)
 	{
-		Serial.print("Failed to close connection to ");
+		Serial.print(F("Failed to close connection to "));
 		Serial.println(connection.id());
+		Serial.println(response);
 		return false;
 	}
 
 	connection.set_is_closed(true);
 
-	Serial.print("Closed connection to ");
+	Serial.print(F("Closed connection to "));
 	Serial.println(connection.id());
 
 	return true;
@@ -346,7 +377,7 @@ auto WiFiModule::send_response(
 		tot_headers_lengths += strlen(headers[index]) + 2U;
 	}
 
-	const auto data_length = strlen(RESPONSE_HTTP_VERSION) + 1 +
+	const auto data_length = strlen_P(RESPONSE_HTTP_VERSION) + 1 +
 							 RESPONSE_STATUS_CODE_LENGTH + 4 + strlen(body) +
 							 tot_headers_lengths;
 
@@ -356,7 +387,9 @@ auto WiFiModule::send_response(
 
 	if (command == nullptr)
 	{
-		Serial.println("Memory allocation failed for creating send response command");
+		Serial.println(
+			F("Heap memory allocation failed for creating send response command")
+		);
 		return false;
 	}
 
@@ -370,19 +403,19 @@ auto WiFiModule::send_response(
 
 	_read(TIMEOUT_MEDIUM, response);
 
-	_serial.print(RESPONSE_HTTP_VERSION);
-	_serial.print(" ");
+	_serial.print(reinterpret_cast<const __FlashStringHelper *>(RESPONSE_HTTP_VERSION));
+	_serial.print(F(" "));
 	_serial.print(status_code);
-	_serial.print("\r\n");
+	_serial.print(F("\r\n"));
 
 	// Print headers
 	for (size_t index = 0U; index < headers_cnt; index++)
 	{
 		_serial.print(headers[index]);
-		_serial.print("\r\n");
+		_serial.print(F("\r\n"));
 	}
 
-	_serial.print("\r\n");
+	_serial.print(F("\r\n"));
 	_serial.print(body);
 
 	strcpy(response, "");
diff --git a/minion/src/wifi_module.hpp b/minion/src/wifi_module.hpp
index 963a1de..9bc2c20 100644
--- a/minion/src/wifi_module.hpp
+++ b/minion/src/wifi_module.hpp
@@ -4,6 +4,7 @@
 #include "network_connection.hpp"
 
 #include <SoftwareSerial.h>
+#include <avr/pgmspace.h>
 #include <stddef.h>
 #include <stdint.h>
 
@@ -25,7 +26,7 @@ constexpr auto TIMEOUT_SHORT = 1500U;
 constexpr auto TIMEOUT_MEDIUM = 4000U;
 constexpr auto TIMEOUT_LONG = 10000U;
 
-constexpr auto RESPONSE_HTTP_VERSION = "HTTP/1.1";
+const char RESPONSE_HTTP_VERSION[] PROGMEM = { "HTTP/1.1" };
 constexpr auto RESPONSE_STATUS_CODE_LENGTH = 3U;
 
 constexpr auto NUMBER_BASE = 10U;