FTP Timeout and FTP protocol question

[Hepcat]

I'm unable to open an FTP connection in LabVIEW, I can in a browser.  I drilled down and found TCP Read xTP Reply.vi  is the issue.

It's using ^[0-9][0-9][0-9] [^\r\n]*\r\n as the pattern on a match pattern.

My FTP's reply is:

220-FTP Server
220-*** Files stored here are not backed up ***
220-*** Please move any important files to  ***
220 *** alternate storage.            ***

The dash is the problem.  I'm trying to find out if the dash is actually violating the FTP protocol on replys so I can tell IT they messed up!  😛  I mean, ask them nicely to change it.  Or if the VI should be modified because there mite not always be a space.

[davidraj]

Hey , 

I'm not really sure what your question is with regards to LabVIEW. 

It seems you are talking about FTP protocol with references to syntax and using a hyphen? "-"?

In the following link, it talks about using a hyphen in the reply of FTP protocol:

https://www.w3.org/Protocols/rfc959/4_FileTransfer.html

Specifically,

"

the format for multi-line replies is that the first line
         will begin with the exact required reply code, followed
         immediately by a Hyphen, "-" (also known as Minus), followed by
         text.  The last line will begin with the same code, followed
         immediately by Space <SP>, optionally some text, and the Telnet
         end-of-line code.

            For example:
                                123-First line
                                Second line
                                  234 A line beginning with numbers
                                123 The last line"

 Let me know if this addresses the issue you were having. 

[Hepcat]

LabVIEW won't open an FTP site that replies with multiple lines then.  The pattern anchors the 3 digit reply code to the start of the string and there is no space.

[davidraj]

Hey, 

To get a better idea of what you're working with. Are you using the FTP functions built into LabVIEW? 

FTP VIs

https://www.ni.com/docs/en-US/bundle/labview-api-ref/page/menus/categories/data-communication/protoc...

Also would you be able to make a snippit of your code so that I could determine what the issue is? 

Use VI Snippet to Store and Share Reusable Code Sections

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000x2PkCAI&l=en-US

[Hepcat]

Built in FTP VI's.  It is getting stuck in the FTP open.

[davidraj]

I have a couple ideas about that.

Firstly, your syntax should probably look something like the following: 

Also, I suggest testing your VI with constants to make sure that your syntax is correct. Try finding a simple example that works and then building on that. 

[Hepcat]

You have a reset from somewhere in front, but the only input that matters is the IP.  The IP is right because I'm getting a reply.  I never get out of the FTP open.  I'm pretty sure if you aim your VI at any FTP server with a multi-line response it will fail.

[PezDeSpencer]

How are you getting a reply back if you hang in the FTP open?

Have you tested this reading back a single line? Is that working exactly as expected?

What does a "fail" mean for multi-line responses?

It appears that the standard FTP protocol uses "-" (minus) when doing multi-line responses, so I'm still a bit confused on what behavior you are seeing. 

Spencer R | NI

[Hepcat]

I have now also put a filezilla FTP server up locally.  I can open it in my browser. (ftp://192.168.44.53/)

My code also opens that FTP site and gets a directory list, as designed.

When I change the IP to point at the company FTP that responds with multiple lines it gets error 56

Open the FTP Open Session.vi

Drill down to: FTP Get Command Reply.vi -> TCP Read xTP Reply.vi (Snippet attached)

You can see a match pattern with ^[0-9][0-9][0-9] [^\r\n]*\r\n   It's looking at a shift register with the reply string.  I probed it:

220-FTP Server
220-*** Files stored here are not backed up ***
220-*** Please move any important files to  ***
220 *** alternate storage.            ***

As I said in the first post, that pattern will NEVER find the reply because it must be ###<SPACE> and a multi line replies ###<DASH> and it's anchored to the start of the offset 0.

Also attached a match pattern wired up to show it.

[Adam_S]

Hi,

Is it possible to receive the multiple line response and convert it to a single line so that FTP Open will not hang?