Problems to use FTP with Zephyr

[Felipe Dantas]

Hi,

I´m tryng to developer an application with nrf9161dk and i need create and upload a txt file with FTP. I´m in trouble to create the file with  <zephyr/fs/fs.h> and  <zephyr/sys/fdtable.h>. I receive a lot of errors of compiler. I also dont have idea of how use FTP in zephyr for nrf cause don´t exist any lib or example of ftp client lib or ftp api. Thanks! 

[Hakon]

Hello,

I receive a lot of errors of compiler.

please show a screenshot or something from the compile errors.

I also dont have idea of how use FTP in zephyr for nrf cause don´t exist any lib or example of ftp client lib or ftp api.

How about this one? https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/libraries/networking/ftp_client.html

[Felipe Dantas]

Hello,

I forgot about this open topic. I'm back to post the solution. When I opened this topic I was a beginner in Zephyr. After some trial and errors, I solved this issue with the code below:

static K_SEM_DEFINE(ftp_sem, 0, 1);

char ftp_svr[80];
char ftp_path[80];
char ftp_user[50];
char ftp_pass[50];
uint16_t ftp_port = 21;	 
char remote_path[128] = "/"; 
char ftp_string_to_send[300] = "File Content Here"; 

void ftp_ctrl_callback(const uint8_t *msg, uint16_t len)
{
	LOG_INF("%s", msg);
	/* Release semaphore when receiving answer from server */
	k_sem_give(&ftp_sem);
}

void ftp_data_callback(const uint8_t *msg, uint16_t len)
{
	LOG_INF("%s", msg);
}

static void ftp_send_data(void)
{
	char file_name[100];

	int err = snprintf(ftp_string_to_send, sizeof(ftp_string_to_send) - 1, "File Content Here");

	// Deactivate psm and edrx to don´t interfere with the FTP transmission (optional)
	lte_lc_psm_req(false);
	lte_lc_edrx_req(false);

	// Initialize FTP Client
	int ret = ftp_init(ftp_ctrl_callback, ftp_data_callback);
	if (ret)
	{
		LOG_ERR("FTP Client initialization failed: %d\n", ret);
		return;
	}

	// Conect to FTP server
	ret = ftp_open(ftp_svr, ftp_port, -1);
	if (ret < 0)
	{
		LOG_ERR("Failed to open an FTP connection: %d\n", ret);
		ftp_close();
		return;
	}

	// Wait server response
	k_sem_take(&ftp_sem, K_FOREVER);

	// Login on FTP server
	ret = ftp_login(ftp_user, ftp_pass);
	if (ret < 0)
	{
		LOG_ERR("Login to FTP server failed: %d\n", ret);
		ftp_close();
		return;
	}

	// Wait server response
	k_sem_take(&ftp_sem, K_FOREVER);

	// Get server status
	ret = ftp_status();
	if (ret < 0)
	{
		LOG_ERR("Requesting server status failed: %d\n", ret);
		ftp_close();
		return;
	}

	// Wait server response
	k_sem_take(&ftp_sem, K_FOREVER);

	// Config remote Path
	if (strlen(remote_path) > 0)
	{
		LOG_INF("Changing remote directory to: %s\n", remote_path);
		ret = ftp_cwd(remote_path);
		if (ret < 0)
		{
			LOG_ERR("Failed to change remote directory: %d\n", ret);
			ftp_close();
			return;
		}

		// Wait server response
		k_sem_take(&ftp_sem, K_FOREVER);
	}

	// Define transfer mode (ASCII ou BINARY)
	LOG_INF("Setting transfer type to ASCII...\n");
	ret = ftp_type(FTP_TYPE_ASCII);
	if (ret < 0)
	{
		LOG_ERR("Failed to set transfer type: %d\n", ret);
		ftp_close();
		return;
	}

	// Wait server response
	k_sem_take(&ftp_sem, K_FOREVER);

	// FILE UPLOAD
	LOG_INF("Uploading file to FTP server...\n");

	ret = ftp_put(file_name, (const uint8_t *)ftp_string_to_send, strlen(ftp_string_to_send), FTP_PUT_NORMAL);
	if (ret < 0)
	{
		LOG_ERR("FTP file upload failed: %d\n", ret);
		ftp_close();
		return;
	}
	else
	{
		LOG_INF("File uploaded successfully.\n");
	}

	// Wait server response
	k_sem_take(&ftp_sem, K_FOREVER);

	// Close FTP connection
	ret = ftp_close();
	if (ret < 0)
	{
		LOG_ERR("Disconnecting from server failed: %d\n", ret);
	}

	// Wait server response
	k_sem_take(&ftp_sem, K_FOREVER);

	LOG_INF("Disconnected from FTP server.\n");

	// Activate PSM e eDRX 
	lte_lc_psm_req(true);
	lte_lc_edrx_req(true);
}

What I and many developers need sometimes is just an example. It would be nice to have this in the FTP documentation.

Best regards,

Felipe Dantas