Redirecting to external site, then back to complete survey

Question

Hi all,

I'm afraid I need some help as I'm very new to PHP. I will try to describe my issue clearly.

What I need: Halfway through the survey, participants will be redirected to a behavioural task on Pavlovia, parsing their prolific ID as 'participant' and the interview ID as 'token'. I need this token to later continue this interview; if I understood the information on the following link correctly: https://www.soscisurvey.de/help/doku.php/en:create:functions:redirect

What I tried: In my redirect link, the reference is always passed on (this would be 'r' in the link on pavlovia. It's the id token that is problematic and I tried a few different ways. The current version is that I attempt to get 'i' from the sosci URL bar with readget() by using a PHP function on an otherwise blank page in the 'compose questionnaire' area, see: https://www.soscisurvey.de/help/doku.php/en:create:functions:readget#readget.

What happens with this version is that the url after redirecting to pavlovia says: https://run.pavlovia.org/S4HRI/mlj_a2b/html/?participant=333333&token=%id%. In other words, it passes $id as a literal STRING instead of replacing it with the unique letter-number combination.

If, instead of 'i' I use casenumber or casetoken (https://www.soscisurvey.de/help/doku.php/en:create:functions:casetoken) in the link, it does pass as a number without having to use readget(), but this number does not work as a continue token when Pavlovia redirects back to the questionnaire at the end of the task (SoSci will show an error to the participant saying that the token is invalid).

Specifically:
- What is the token I need to be able to continue the survey directly after coming back from an external site?
- And if it is indeed the '&i=xxxxx' part of the url, how do I parse it?

TL;DR - The address bar of my survey has a php variable i. I need to grab this i and pass it on to Pavlovia.

Answer 1

Please try this redirect:

redirect('https://run.pavlovia.org/S4HRI/mlj_a2b/html/?participant=333333&token=%caseToken%');

The placeholder %caseToken% is predefined, and you need no workaround with readGET() or anything else. You would also be able to access the token via caseToken(), if necessary.

If you need to send another ID (prolific ID) to Pavlovia, and you have stored that token in XY01_01 (fie example), then your redirect would look like this:

redirect('https://run.pavlovia.org/S4HRI/mlj_a2b/html/?token=%caseToken%&participant='.value('XY01_01'));

Please note that the dot (.) is the operator to connect strings in PHP.

Comments

That worked, thank you!