feat: Enhance HttpHandler to manage response data dynamically and improve memory handling

main/network/http_handler.cpp

@@ -2,16 +2,46 @@
 #include "esp_http_client.h"
 #include "esp_log.h"
 #include "string.h"
+#include <cstring>
+
+esp_err_t http_event_handler(esp_http_client_event_t *evt) {
+  HttpHandler* handler = static_cast<HttpHandler*>(evt->user_data);
+  
+  switch (evt->event_id) {
+    case HTTP_EVENT_ON_DATA:
+      if (handler && evt->data_len > 0) {
+        char* new_buffer = new char[handler->response_size + evt->data_len + 1];
+        if (handler->response_buffer && handler->response_size > 0) {
+          memcpy(new_buffer, handler->response_buffer, handler->response_size);
+          delete[] handler->response_buffer;
+        }
+        memcpy(new_buffer + handler->response_size, evt->data, evt->data_len);
+        handler->response_size += evt->data_len;
+        new_buffer[handler->response_size] = '\0';
+        handler->response_buffer = new_buffer;
+      }
+      break;
+    default:
+      break;
+  }
+  return ESP_OK;
+}
 
 HttpHandler::HttpHandler(const esp_http_client_config_t&& config, WifiHandler* wifiHandler)
-  : wifiHandler(wifiHandler) {
-  this->client = esp_http_client_init(&config);
+  : wifiHandler(wifiHandler), response_buffer(nullptr), response_size(0) {
+  esp_http_client_config_t modified_config = config;
+  modified_config.event_handler = http_event_handler;
+  modified_config.user_data = this;
+  this->client = esp_http_client_init(&modified_config);
 }
 
 HttpHandler::~HttpHandler() {
   if (this->client) {
     esp_http_client_cleanup(this->client);
   }
+  if (response_buffer) {
+    delete[] response_buffer;
+  }
 }
 
 esp_err_t HttpHandler::set_method(esp_http_client_method_t method) {
@@ -34,18 +64,13 @@ void HttpHandler::get_body(
   char*& buffer,
   int& total_len
 ) {
-  total_len = esp_http_client_get_content_length(this->client);
-  buffer = new char[total_len + 1]; // +1 for null-terminator
-  if (buffer) {
-    int read_len = esp_http_client_read(this->client, buffer, total_len);
-    if (read_len >= 0) {
-      buffer[read_len] = '\0'; // null-terminate
-    } else {
-      delete[] buffer;
-      buffer = nullptr;
-      total_len = 0;
-    }
+  total_len = response_size;
+  if (response_buffer && response_size > 0) {
+    buffer = new char[response_size + 1];
+    memcpy(buffer, response_buffer, response_size);
+    buffer[response_size] = '\0';
   } else {
+    buffer = nullptr;
     total_len = 0;
   }
 }

main/network/http_handler.h

@@ -41,6 +41,7 @@ public:
 
   // only NetworkHandler can create HttpHandler instances
   friend class NetworkHandler;
+  friend esp_err_t http_event_handler(esp_http_client_event_t *evt);
   // disable copy constructor and assignment operator
   HttpHandler(const HttpHandler&) = delete;
   HttpHandler& operator=(const HttpHandler&) = delete;
@@ -52,4 +53,6 @@ private:
   esp_http_client_handle_t client;
   // backreference to WifiHandler to ensure WiFi is connected, DO NOT DELETE
   WifiHandler* wifiHandler;
+  char* response_buffer;
+  size_t response_size;
 };