ESP32 Forum

Posted: **Fri Dec 25, 2020 8:23 am**

Here is my case :

Wifi NVS FLash is enabled. I am using esp_wifi_get_config to find out whether wifi configuration is saved in NVS. My code is :

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wifi_config_t conf;
 ret = esp_wifi_get_config(ESP_IF_WIFI_STA, &conf);
if (ret == ESP_OK)
    {

  ESP_LOGI(TAG, "Wifi configuration already stored in flash partition called NVS");
ESP_LOGI(TAG, "%s" ,conf.sta.ssid);
ESP_LOGI(TAG, "%s" ,conf.sta.password);
    }
else
    {

ESP_LOGI(TAG, "Wifi configuration not found in flash partition called NVS.");    
    configure_wifi();
    }

It worked as expected. Then I erased and then initialized my nvs using nvs_flash_erase(); nvs_flash_init(); before the above written code. Now my output is

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I (697) Wifi station: Wifi configuration already stored in flash partition called NVS

I (707) Wifi station:

I (707) Wifi station:

Expected output is:

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Wifi configuration not found in flash partition called NVS

Is my approach right? If not, then what is the correct way to check Wifi nvs data before configuring wifi?

Posted: **Sat Nov 27, 2021 11:07 pm**

This reply may be almost a year late, but I just happened to have this same question and figured others may benefit from an answer.

Your solution is looking at the error returned by esp_wifi_get_config(), however this will return ESP_OK even when the NVS has been erased (as indicated by your code not working as you expected). In fact, if you look at the function description in esp_wifi.h, an error will only be returned if the WiFi has not been initialized, or you gave a bad parameter:

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/**
  * @brief     Get configuration of specified interface
  *
  * @param     interface  interface
  * @param[out]  conf  station or soft-AP configuration
  *
  * @return
  *    - ESP_OK: succeed
  *    - ESP_ERR_WIFI_NOT_INIT: WiFi is not initialized by esp_wifi_init
  *    - ESP_ERR_INVALID_ARG: invalid argument
  *    - ESP_ERR_WIFI_IF: invalid interface
  */

My solution is to look at the length of the SSID with

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size_t ssidLen = strlen((char*)conf.sta.ssid);

If it has a length of 0, then you know nothing is stored there. There may be another better solution, but this has worked well in my testing.

Posted: **Wed Aug 21, 2024 6:42 pm**

One could also check for WIFI_INIT_CONFIG_MAGIC - that seems to be its purpose:

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if (cfg.magic == WIFI_INIT_CONFIG_MAGIC) {
    // cfg is valid.
}

Posted: **Mon Aug 26, 2024 12:50 pm**

One could also check for WIFI_INIT_CONFIG_MAGIC - that seems to be its purpose

Where did you find the magic member for struct wifi_config_t?
I cannot find it in the latest stable (5.3):

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typedef union {
    wifi_ap_config_t  ap;  /**< configuration of AP */
    wifi_sta_config_t sta; /**< configuration of STA */
    wifi_nan_config_t nan; /**< configuration of NAN */
} wifi_config_t;

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