httpd_resp_send_chunk() to send JSON data issue (IDFGH-14548)

[pavel808]

I have a HTTP server running on an ESP32-S3 device. I can receive the POST requests via CURL fine, but I am having issues sending back a JSON response string as below. test_json_data. CURL just sits there blocked and nothing gets received. What exactly am I doing wrong here ? Thanks. This is the curl command from the client :

curl -X POST --data "volume_up" edge-server.local:83/sendCommand -v

It causes the below my_post_handler function to get invoked, but problems getting simple JSON data back to the client.

static esp_err_t my_post_handler(httpd_req_t *req)
{
   ESP_LOGI(TAG, "my_post_handler");

    char buf[60];
    int ret = 0;
	int remaining = req->content_len;

    esp_err_t err = ESP_OK;

    httpd_resp_set_type(req, "application/json");
    httpd_resp_set_hdr(req, "Connection", "keep-alive");
    httpd_resp_set_status(req, HTTPD_200);

    while (remaining > 0)
    {
        /* Read the data for the request */
        if ((ret = httpd_req_recv(req, buf,
                        MIN(remaining, sizeof(buf)))) <= 0)
        {
            if (ret == HTTPD_SOCK_ERR_TIMEOUT)
            {
                /* Retry receiving if timeout occurred */
                continue;
            }

            err = ESP_FAIL;
        }

        if (err == ESP_OK)
        {
        	
		remaining -= ret;

		/* Log data received */
		ESP_LOGI(TAG, "=========== RECEIVED DATA ==========");
		ESP_LOGI(TAG, "%.*s", ret, buf);
		ESP_LOGI(TAG, "====================================");

		char delimiter = '/';
		std::string tmp = "";

		std::string fullcmd(buf, buf + req->content_len);
		ESP_LOGI(TAG, "fullcmd : %s ", fullcmd.c_str());
		std::vector<std::string> parts;

		std::istringstream iss(fullcmd);
		while(std::getline(iss, tmp, delimiter))
		{
			ESP_LOGI(TAG, "PART : %s", tmp.c_str());
			parts.push_back(tmp);
		}

		if (parts.size() >=  3)
		{
			err = process_data(parts);

			if (err != ESP_OK)
			{
				ESP_LOGE(TAG, "ERROR! Unable to process data");
				err = ESP_FAIL;
			}
		}
		else
		{
			err = ESP_FAIL;
		}
        }
    }

    if (err != ESP_OK)
    {
    	httpd_resp_set_status(req, HTTPD_500);
    }

    memset(buf, 0, sizeof(buf));
    const char *test_json_data = "{\"channel\":\"A\",\"value\":\"X\"}";
    strncpy(buf, test_json_data, sizeof(buf));

    httpd_resp_send_chunk(req, buf, ret);

    return err;
}

[chegewara]

You need this at the end
httpd_resp_send_chunk(req, NULL, 0);

[hrushikesh430]

Hi @pavel808, Could you please send your sdkconfig and patch file. So that It will help me to reproduce the issue easily. Even some of the functions like process_data(), send me the file where they are defined.

[hrushikesh430]

Hello @pavel808, Closing this issue due to response delay. Please feel free to reopen the issue for further query. Thank you.