Unable to retrieve image when image name is code generated

[jiemin]

URL of experiment:

Pavlovia

Description of the problem:
I am programming a Dot Probe Task, using JS code to randomize the image file name for my image stimulus components “positiveimage” and “negaltimage” . Yet, I keep encountering the same error (see screenshot).

I don’t think there’s a problem with the image file being uploaded, as the programme ran perfectly when I input the file name “images/test_p2.jpeg” directly instead of the variable that is set every repeat. Yet, the error message said that I couldn’t retrieve the value images/test_p2.jpeg when I use my JS randomization code.

Hence, I suspect it could be an issue of the JS code producing a string e.g. “images/test_p2.jpeg” instead of a file path images/test_p2.jpeg.

In case you’re wondering why I don’t just use a conditions Excel file for the image names, it’s because I’m randomizing multiple variables of this experiment – image file, image stimulus position (left/right), probe position (left/right), probe symbol (up/down arrow) – and i won’t be fully counterbalancing all conditions, so I can’t list out all the trials in conditions file. I only input the conditions that I am fully counterbalancing in the conditions file.

Note: this topic title is similar to this, but their solution isn’t relevant for me: Image doesn't appear on Pavlovia when image name is code-generated

[wakecarter]

You need to either attach all the possible images via Experiment Resources / Online or use code to attach the ones you need.

Downloading and checking resources on the fly

URL of experiment: spelling [PsychoPy] Description of the problem: I’m writing a spelling test where I want to download each word within the experiment. Since I’m now using 2021.2.3, I need to use psychoJS._serverManager.prepareResources() instead of psychoJS.downloadResources(); The following code seems to be working in principle (for the conditions file). psychoJS._serverManager.prepareResources([{name: conditionsFile,path: conditionsFile}]); If I put if(conditionsFile.exists()){ conti…

[jiemin]

Hi, thanks for the quick reply. The resources seem to be uploaded to the Pavlovia server already though. My programme runs perfectly when I type the file path “images/test_p2.jpeg” directly instead of the variable $positive[snapshot.thisN]

Is it necessary to add this code for downloading resources? If so, which portion of the code from here should I add?

[wakecarter]

Uploaded to the server is different from made available to the experiment during the run.

The code to do this is:

psychoJS.serverManager.prepareResources([
        {
          'name': fileName,
          'path': folderName+'/'+fileName,
          'download': true
        }
    ]);

You can create a list of these dictionaries (using append/push) and give them to prepareResources in a single step.

[jiemin]

@wakecarter

psychoJS.serverManager.prepareResources([
        {
          'name': fileName,
          'path': folderName+'/'+fileName,
          'download': true
        }
    ]);

Hi @wakecarter sorry I’m pretty new to Javascript and Pavlovia. Could you help me with my code?

If the participant ID is “test”, and I want to make available these 24 files:
“images/test_p1.jpeg”, …, “images/test_p8.jpeg”,
“images/test_n1.jpeg”, …, “images/test_n8.jpeg”,
“images/a1.jpeg”, …, “images/a8.jpeg”,

How should I write the code for the “each frame” tab? I’ve written a draft below but it doesn’t work, hope you can help me with it:

// fetch the selection - this could be the participant ID
selection = expInfo['participant'];//'cute_sloth';
    
// info on the folder name where the resources are stored and the extension
ext = '.jpeg';
directory = 'images/';
    
selectedResource = selection + ext;
psychoJS.serverManager.prepareResources([
        {
          'name': selectedResource,
          'path': directory + selectedResource,
          'download': true
        }
]);

for (var i = 1; i <= 8; i++) {
    psychoJS.serverManager.prepareResources.push('images/' + selection +'_p'+ i + '.jpeg'); //  e.g. 'images/test_p1.jpeg' 
    psychoJS.serverManager.prepareResources.push('images/' + selection +'_n'+ i + '.jpeg'); //  e.g. 'images/test_n1.jpeg' 
    psychoJS.serverManager.prepareResources.push('images/a' + i + '.jpeg'); // e.g. 'images/a1.jpeg' 
}

[wakecarter]

Begin Experiment

// fetch the selection - this could be the participant ID
selection = expInfo['participant'];//'cute_sloth';
    
// info on the folder name where the resources are stored and the extension
ext = '.jpeg';
directory = 'images/';
    
selectedResources = [];

for (var i = 1; i <= 8; i++) {
    selectedResources.push({name: selection +'_p'+ i + '.jpeg', path: 'images/' + selection +'_p'+ i + '.jpeg'}); //  e.g. 'images/test_p1.jpeg' 
    selectedResources.push({name: selection +'_p'+ i + '.jpeg', path: 'images/' + selection +'_n'+ i + '.jpeg'}); //  e.g. 'images/test_n1.jpeg' 
    selectedResources.push({name: 'a'+ i + '.jpeg', path: 'images/a'+ i + '.jpeg'}); //  e.g. 'images/a1.jpeg' 
}

psychoJS.serverManager.prepareResources(selectedResources);

I wouldn’t worry about the each frame test yet. The resources should download while the participant is reading the instructions.

[jiemin]

Sorry for the delay in reply. Thanks so much for your help! I used the more manual method of adding my image resources via the Experiment Settings > Online instead, and it worked

I referred to this Keep getting unknown resource errors - #9 by Becca