feat(esp_http_client): Add API to support set event handler

components/esp_http_client/esp_http_client.c

@@ -560,6 +560,15 @@ esp_err_t esp_http_client_set_user_data(esp_http_client_handle_t client, void *d
     return ESP_OK;
 }
 
+esp_err_t esp_http_client_set_event_handler(esp_http_client_handle_t client, http_event_handle_cb event_handler)
+{
+    if (client == NULL) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    client->event_handler = event_handler;
+    return ESP_OK;
+}
+
 static esp_err_t _set_config(esp_http_client_handle_t client, const esp_http_client_config_t *config)
 {
     esp_err_t ret = ESP_OK;

components/esp_http_client/include/esp_http_client.h

@@ -571,6 +571,18 @@ esp_err_t esp_http_client_get_user_data(esp_http_client_handle_t client, void **
  */
 esp_err_t esp_http_client_set_user_data(esp_http_client_handle_t client, void *data);
 
+/**
+ * @brief      Set the event handler for the client
+ *
+ * @param[in]  client  The esp_http_client handle
+ * @param[in]  event_handler     The event handler
+ *
+ * @return
+ *     - ESP_OK
+ *     - ESP_ERR_INVALID_ARG
+ */
+esp_err_t esp_http_client_set_event_handler(esp_http_client_handle_t client, http_event_handle_cb event_handler);
+
 /**
  * @brief      Get HTTP client session errno
  *

docs/en/api-reference/protocols/esp_http_client.rst

@@ -198,6 +198,8 @@ ESP HTTP Client supports event handling by triggering an event handler correspon
 
 To enable event handling, you just need to set a callback function using the :cpp:member:`esp_http_client_config_t::event_handler` member.
 
+Also you can set a callback function after the client is initialized using the :cpp:func:`esp_http_client_set_event_handler` function.
+
 ESP HTTP Client Diagnostic Information
 --------------------------------------
 

docs/zh_CN/api-reference/protocols/esp_http_client.rst

@@ -198,6 +198,8 @@ ESP HTTP 客户端支持事件处理，发生相关事件时会触发相应的
 
 通过 :cpp:member:`esp_http_client_config_t::event_handler` 设置回调函数即可启用事件处理功能。
 
+也可以在客户端初始化后使用 :cpp:func:`esp_http_client_set_event_handler` 函数设置回调函数。
+
 ESP HTTP 客户端诊断信息
 --------------------------