FTP is not a better fit other than by sounding like it is. It barely has a reliable way to list directories whereas hypertext can actually structurally represent a tree.
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.
It works by convention and people writing piles of hairy code to over the years to make it behave. FTP is a really ancient protocol with many problems beside that. Much like short people, it got no reason to live.
FTP may have its quirks but I'd argue that nobody can say that it's simpler/easier to parse HTML than to parse FTP payloads.
In any case, can't this be solved to configure the server to conform to the most standard/clean/mainstream conventions? We are writing a server after all in this case, not a client.
I'm not convinced that FTP's shortcomings can't be easily worked around in this case; but I understand that you are trying to say that the ancient FTP protocol should die. Maybe you are right. And maybe there are very good reasons for that.
And then I'd say we need a modern file transfer protocol. HTML over HTTP still isn't optimal for this task at least some of the time, for some people. And I, with my limited knowledge, still believe that FTP can't be worse than HTML over HTTP for the task in question, even if not better.
In my limited understanding, the only parameters that can change is the separator and the number of columns. How hard can it be to establish a straightforward convention? Or why are we being judged so hard, despite the fact that we are advocating to use the protocol in a consistent, straightforward way; just because some people apparently made very bad technical decisions in the past?
In the web you can build a universe if you want. The API surface of it is gigantic compared to FTP. I like to use the simplest technology I can for the purpose at hand. And if the servers I use are outputting straightforward payloads, I don't have to care about what stupid things people did in the past.
I realized that I'm making the mistake of thinking that all we can serve over HTTP is HTML+Javascript+CSS. But anybody can easily serve structured JSON over HTTP, or any other clear format, like you pointed out:
> and in a modern system you'd just honor a .json (or Accept header) that would give you the result as a trivially parsed array
HTTP is not tightly coupled to HTML+Javascript+CSS. I guess I acted a bit defensive on this one because I hate the usual bloat that the web brings and suffered much from it.
Anyway.
Your approach would be to serve JSON over HTTP then, I guess. Would you have any other recommendations to for this apart from JSON over HTTP? Are there other simple and viable alternatives?
There are actually standards documents you can read that specify how to parse html. (Mind boggling length and complexity, aside.) But there's nothing that tells you how to interpret an ftp list response.
I also browsed a few of the FTP mirrors for OpenBSD and took note of how they formatted their response, and tried to make my format match what I observed to be the most common response. It's worked with all the clients I've tried so far: ncftp on mac, ftp on openbsd, Firefox, mac's ftp-finder integration, and Filezilla.
So while there is admittedly ambiguity in FTP servers on the whole, I think my server in particular should work OK. Keeping an open mind though if you know about a problem I haven't foreseen.
But the client parsing code is mostly strsep() and cross your fingers and hope to die. It's not terribly robust.
Like if you were writing a program, you would not prefer parsing the output of ls to running stat yourself.