Format of the data returned by the FTP LIST command?

list ftp command format

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Solution 1

The standard doesn't define format of the directory listing sent/received using LIST command. Most servers use Unix listing format (don't know if it's defined in any document, but it's rather simple to generate and parse), some use DOS/Windows format. Other formats (over 400 as far as I know) are used worldwide, but the Unix one has become a standard de-facto.

Now there's important thing to implement: MLST and LMSD extension commands, defined in RFC 3659. They define a way to produce and obtain machine-readable listing, which is very welcome in any modern FTP server.

Solution 2

This is what the RFC has to say:

The data transfer is over the data connection in type ASCII or type EBCDIC. (The user must ensure that the TYPE is appropriately ASCII or EBCDIC). Since the information on a file may vary widely from system to system, this information may be hard to use automatically in a program, but may be quite useful to a human user.

So, the result is not expected to be automatically parsed.

Solution 3

The RFC is poor there, but there are some nice links:

https://files.stairways.com/other/ftp-list-specs-info.txt

http://cr.yp.to/ftp/list/binls.html

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Nathan Osman

Email: [email protected] By profession, I am a software developer and I work with C++, Python, and (more recently) Go. Here are some of my recent projects: - Hectane - lightweight SMTP server written in Go - NitroShare - a cross-platform network file transfer utility - REST Easy - Firefox add-on for analyzing HTTP responses

Updated on May 14, 2022

Comments

Nathan Osman almost 2 years

I'm in the middle of writing an FTP server but I'm a little confused about what format to send the file list in.

Using 2 terminals and an FTP client, I was able to run through a simple FTP exchange. However, I wasn't really sure what format to send the file lists in.

Is there some accepted format? What columns should I use?
- skaffman over 13 years
  
  I don't believe this is anything resembling a standard. Different servers give different outputs, they're supposed to be human-readable rather than machine-readable.
- Eugene Mayevski 'Callback over 13 years
  
  @George They try to guess the output format and parse it. Some clients recognize hundreds of formats.
Nathan Osman over 13 years

Then how do graphical FTP clients enumerate files?
Oded over 13 years

@George Edison - they probably have a list of commonly used formats and parse those.
Oded over 13 years

@George Edison - See the answer from @Eugene Mayevsky, these are apparently done through extensions to the FTP standard.
Nyerguds over 10 years

@NathanOsman - I looked into the code of FileZilla on Sourceforge, and... it's not pretty, heh. Trial and error of about a dozen different formats.