Read from SQL during task

[steffejr]

Hello all,
I would like to have a jsPsych task read from a MySQL database and I cannot figure out how to do it. Within my jsPsych code I would like to return data from MySQL that I can use within jsPsych. I have been able to read from the database and write the data via console.log() but not to get data as a variable.

Can anyone help please? Thank you.

[becky-gilbert]

Hi @steffejr, if you're able to read from the database and write the data to the console, then you should be most of the way there! Can you share a bit of (simplified) code so that we can see where/how you're reading the data in, and give you some tips for how to turn that data into a variable that jsPsych can use?

Without having seen exactly what you're doing, one approach that comes to mind would be to initialize a global variable to hold the data, and then use the call-function plugin to access the MySQL data and save the result to this variable. You'll want to set the async parameter to true (example here) in order to force jsPsych to wait for the data transfer to finish before moving on with the experiment.

Another tip is to use dynamic parameters and event-related callback functions to access and manipulate the global variable that contains your database data, since it will be undefined when the page first loads.

Here's a sketch of the general approach:

var mysql_data;

var get_data = {
    type: 'call-function',
    async: true,
    func: function(done) {
        // get data from database here and store in mysql_data variable
        mysql_data = result;
        done(); // call the callback function to end the call-function trial once the data transfer has finished
    }
}

var trial = {
    // other parameters ...
    stimulus: function() {
        return mysql_data.stimulus[0];
    }
}

Would something like this work?