How to upload a file to a server via UDP? Help needed.

Hi,

I have started playing around with the module. I have written a program that correctly connects to my home router, from where it connects to the server via WLAN.
However, I have a conundrum... How do I upload a file to the server?

At the moment I send the command and I get the answer:
"425 No data connection".
Which is logical, as I only have one port open.

Greetings.

Kronosss wrote:

I started playing around with the WiFi module.

.
Which one specifically?

Kronosss wrote:

I wrote the program

.
Although a snippet of 'problematic' code would be appreciated.

I work on the cheapest one I could find in the shop.

The problematic code isn't there yet, after all, as I wrote I don't know how to do it.
I currently log in to the ftp server with AT commands via port 21:
AT+CWMODE=1
AT+CIPMUX=0
AT+CIPMODE=1
AT+CWJAP=...

Kronosss wrote:

But how to create a second connection at the same time for a port

AT+CIPSEND: " This command can only be used in transparent transmission mode which requires single connection "
Try with AT+CIPSENDEX. Also, if you have set "AT+CIPMUX=0" then it is "single connection mode"

Documentation: https://www.espressif.com/sites/default/files...entation/4a-esp8266_at_instruction_set_en.pdf

OK, but how do you mount the second port (data connection) in "AT+CIPMUX=1"?
And how to switch between these ports?

Kronosss wrote:

And how to switch between these ports?

.
By "link ID" in AT+CIPSENDEX.

Something is not working for me. I am entering the commands:
AT+CWMODE=1
AT+CIPMUX=1
AT+CWJAP=logging into the router
AT+CIPSTART=...
I then try to mount the second port and a message appears:
ERROR
2,CLOSED

How should the second port for data be started?

If you want to send data from the ESP to the server in non-blocking mode, you should use the command AT+CIPSENDBUF . You specify the size of this data and then enter it. The data goes into a buffer from which it will be progressively sent - you can continuously check the status of the sending of this data with the command AT+CIPBUFSTATUS . During this time you can also execute other AT commands, including triggering the sending of other data.

Unlike AT+CIPSENDBUF, the command AT+CIPSENDEX is a blocking function. You will not be able to execute other commands until the send is complete.

For multiple TCP connections ( AT+CIPMUX=1 ), use a different syntax for the AT+CIPSTART command:
.
where link ID is the identifier of the link in question and can then be used in AT+CIPSEND, AT+CIPSENDEX or AT+CIPSENDBUF commands

All of the above is described in detail in the documentation I provided a link to in post #4. In addition, I am attaching the document "ESP8266 AT Command Examples", where it is explained how to create Single and Multiple connections for TCP and UDP.