Using loadStrings() to load a text file from a relative URL in a Procesing applet

romwell

Using loadStrings() to load a text file from a relative URL in a Procesing applet

in Integration and Hardware • 1 year ago

I am writing a Processing sketch that will run as an applet.

How do I use the loadStrings() method to load a file from an URL relative to the applet folder (i.e. a file "example.txt" contained in the applet folder)?

Note that loadStrings("example.txt") will only work to read the file from the sketch folder when run locally/as a standalone application. When the applet is run, the "example.txt" will refer to a file somewhere on the local machine, not on the server. Additionally, loadStrings cannot take a Java URL class (and, besides, I want to avoid using classes not present in Processing spec so that I could have a project that works in ProcessingJS as well).

Thanks!

Replies(5)

amnon.owed

Re: Using loadStrings() to load a text file from a relative URL in a Procesing applet

1 year ago

LoadStrings() can take an URL as input, see the reference.

PhiLho

Re: Using loadStrings() to load a text file from a relative URL in a Procesing applet

1 year ago

When you export a sketch to an applet, the files in the data folder are included in the jar file and loadStrings() is still able to load them.

romwell

Re: Using loadStrings() to load a text file from a relative URL in a Procesing applet

1 year ago

Thanks, PhilHo! This is the solution I am using right now, but it has the disadvantage that the files cannot be easily edit after deployment, since they are packaged in a jar.

Here is another solution that works, but uses the Java URL class to convert a relative URL to absolute:

  String path = "";
  try{
    URL url = getCodeBase();
    path = url.toString();
  }
  catch (Exception E){
    println("Probably you are not running this as an applet.");
  }
  loadStrings(path+"example.txt");

Is there a way to to the same with Processing classes (to ease porting to Processing JS in the future)?

PhiLho

Re: Using loadStrings() to load a text file from a relative URL in a Procesing applet

1 year ago

" it has the disadvantage that the files cannot be easily edit after deployment, since they are packaged in a jar."
Not so much.
It is easy to export again, and otherwise, if I open a jar in 7-Zip, and ask it to edit the file, it opens it in the editor I have set and upon saving, it asks me if it must update the file.

romwell

Re: Using loadStrings() to load a text file from a relative URL in a Procesing applet

1 year ago

PhiLho, it's easy to re-export/edit for me as a developer, but it's a hassle for the final user. I am writing a small 3D model viewer to read OOGL (ModelView) files that is going to run as an applet, and I can't expect the users to have Processing installed to re-export or have them repackage every time they want to show a file on the web (just like you don't have to package .doc documents into .cab files of MS Word if you need to open them).

In the final usage, the data files are going to be in some directory on the server (either the applet's directory, or something nearby), and the filename is probably going to be passed to the applet as a parameter from the HTML page the applet is displayed on.

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