How to know file names into a directory with processing.js or p5.js?

ecce_robot

Hello everyone.

I'm working on a simple project with an industrial controller.
It uses some physical sensors to measure some physical values (voltage, current, etc.) and creates a log file (.csv) every hour, keeping the older files into its memory. Then I can go via ftp:// xxx.xxx.xxx.xxx into its memory and get those files.

What I would like to do is to put a web page on it, and show a plot of the csv recorded values.
I tried both using processing.js and p5.js, and, if I know the name of the file, it works (I've never made a web page before! :) ).

But, if I don't know the files names, I don't know how to open a file whose name is unknown (obviously).

Any idea how to know files names into a folder?
(the web page is in the same directory of the csv files, so I don't need to use absolute url path).
What I usually use with "standard" Processing doesn't work in this situation.
I just need to have a String variable that contains the name of the unknown file (or an array, if many files).

The file have this format: controller-name_YYYY_MM_DD_hh_mm.csv (and I can't change this :( )

Thanks to everyone

GoToLoop

• AFAIK, a browser program (frontend) can't get the list of files within a directory. :(
• You're gonna need a server program for it. L-)
• However, my backend knowledge is almost nil. X_X
• Processing (Java Mode) is based on Java. And we can write servers in Java. Just look up for it.

ecce_robot

thanks for your answer :)

but I think there could be some "trick", to let me find out those file names.

I've already tried two ways:
1. I've put a button, that pressed, let me select a file. It works locally on my PC, but when I put the web page on the ftp server it doesn't work anymore.
2. I've used exceptions: I try to load a file using a String variable that changes thanks to a cycle. For example, I try to load files from controller-name_YYYY_MM_DD_hh__00.csv to controller-name_YYYY_MM_DD_hh__59.csv. If one of these 60 file exists, I show the plot. Again, It works locally on my PC, but when I put the web page on the ftp server it doesn't work anymore.

What do you mean with "we can write servers in Java"?
I can't install anything on the server, it's an industrial controller, a PLC, not a PC :(

Any suggestion?

GoToLoop

Sorry. I dunno the effects of an FTP server.
What I meant by a server in Java is having a program that creates and serves an HTML file.
The server has access to any file. While scripts run in a browser can't scan for files.
But as I've mentioned before, that's as far as I know about the subject. ~:>

kfrajer

What OS runs on the PLC? The unit is the the server so people connect to it, is that right? Can you provide the model and mark of the unit?

Kf

ecce_robot

The device is an industrial controller (not common CPU, OS, etc.)
A program is running, and at the same time, it works as ftp server, and let you browse into its memory.
I can put any kind of file inside the memory/ftp server.
But nothing can be executed or installed on it.
It's a memory storage that can be reached via ftp. Nothing else.
This is why I have to use javascript, 'cause in this way, what I get from the web page is list of commands that the client have to execute. Any client. But not the server.
Right?
In fact, it works when, using loadStrings, I put as argument a String variable who contains the name of the file that I want to load.
But, is there an FTP library (or something else) that let me know which files are contained in a folder of an fpt server?

Any trick? [-O<

jeremydouglass

@ecce_robot

I think there could be some "trick", to let me find out those file names.

There are a lot of StackOverflow answers that say "you can't do this."

However, if you are looking for a client-side javascript library that speaks FTP and that is the only solution you can use, perhaps this will work? Untested.

https://github.com/sergi/jsftp

As an alternative approach I would suggest that you create a separate sync job (e.g. a cron job) that periodically (hourly) syncs the complete contents of the ftp server to a directory on the same webserver as your p5.js script. Then load your directory listing in Javascript as normal.

ecce_robot

thank you so much for your help but (if I understood correctly) this library is for NodeJS.
So it doesn't work in my situation.
I'll update this discussion when i'll find a solution.

Thanks a lot again!