If JATOS runs locally it's usually not necessary to change the defaults. On a server, you may want to set up the IP and port, or use a different database, change the path of the study assets root folder, or add some password restrictions.
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Restart JATOS after making any changes to the configuration (loader.sh restart)

IP / domain and port

By default JATOS uses the address and port 9000. There are two ways to configure the host name or IP address and the port:

  1. In loader.sh change the values of ‘address’ and ‘port’ according to your IP address or domain name and port.

  2. Via command-line arguments -Dhttp.address and -Dhttp.port, e.g. with the following command you’d start JATOS with IP and port 80

    loader.sh start -Dhttp.address= -Dhttp.port=80

URL base path (JATOS >= v3.3.1)

JATOS can be configured to use an base path. E.g we have the host “www.example.org” and let JATOS run under “mybasepath” so that JATOS’ URL all start with “www.example.org/mybasepath/”. This can be achieved in two ways:

  1. Via the command-line argument -DJATOS_URL_BASE_PATH, e.g.

    loader.sh start -DJATOS_URL_BASE_PATH="/mybasepath/"
  2. Via conf/production.conf: change play.http.context

    play.http.context = "/mybasepath/"

The path always has to start and end with a “/”. And keep in mind that if you add a base path to JATOS’ URL you have to adjust all absolute paths to the study assets (in HTML and JavaScript files) too - or use relative paths.

Study assets root path

By default the study assets root folder (where all your study’s HTML, JavaScript files etc. are stored) is located within JATOS installation’s folder in study_assets_root. There are three ways to change this path:

  1. Via the command-line argument -DJATOS_STUDY_ASSETS_ROOT_PATH, e.g.

    loader.sh start -DJATOS_STUDY_ASSETS_ROOT_PATH="/path/to/my/assets/root/folder"
  2. Via conf/production.conf: change jatos.studyAssetsRootPath

  3. Via the environment variable JATOS_STUDY_ASSETS_ROOT_PATH, e.g. the following export adds it to the env variables:

    export JATOS_STUDY_ASSETS_ROOT_PATH="/path/to/my/assets/root/folder"

External Database

By default JATOS uses an embedded H2 database and no further setup is necessary but it can be easily configured to work with a MySQL database.

Possible scenarios why one would use an external database are

  • the expected traffic is rather high and many users will run studies with many participants and the studies will store a lot of data in the database
  • to be able to do a regular database backup
  • higher trust in the reliability of a MySQL database (although we never had problems with H2)

One could install the external database on the same server as JATOS is running or on an extra server depending on ones need.

Appart from giving JATOS access to the external database it is not necessary to set it up any further, e.g. to create any tables inside database - JATOS is doing this automatically.

You can confirm that JATOS is accessing the correct database by looking in the logs. One of the lines after JATOS starts should look like this (with your JDBC URL).

19:03:42.000 [info] - p.a.d.DefaultDBApi - Database [default] connected at jdbc:mysql://localhost/jatos?characterEncoding=UTF-8

JATOS requires MySQL >= 5.5 or H2 >= 1.4.192 (prior versions might work - I just never tested)

Note: If you want to use a MySQL database consider using the utf8mb4 Character Set with 4-Byte UTF-8 Unicode Encoding. Only this character set contains the whole unicode and you won’t run into issues like this one.

There are three ways to set up JATOS to work with an external database:

  1. Via command-line arguments:
    • -DJATOS_DB_URL - specifies the JDBC URL to the database
    • -DJATOS_DB_USERNAME and -DJATOS_DB_PASSWORD - set username and password
    • -DJATOS_DB_DRIVER - can be either org.h2.Driver or com.mysql.jdbc.Driver
    • -DJATOS_JPA - can be either h2PersistenceUnit or mysqlPersistenceUnit

    E.g. to connect to a MySQL database running on and a table named ‘jatos’ use:

    loader.sh start -DJATOS_DB_URL='jdbc:mysql://' -DJATOS_DB_USERNAME=sa -DJATOS_DB_PASSWORD=sa -DJATOS_JPA=mysqlPersistenceUnit -DJATOS_DB_DRIVER=com.mysql.jdbc.Driver
  2. Via conf/production.conf (description analog to 1.)

  3. Via environment variables (description analog to 1.)

    E.g. to set all database environment variables for a MySQL database and table called ‘jatos’ you could use a command (change the values):

    export JATOS_DB_URL='jdbc:mysql://localhost/jatos?characterEncoding=UTF-8' JATOS_DB_USERNAME='jatosuser' JATOS_DB_PASSWORD='mypassword' JATOS_DB_DRIVER=com.mysql.jdbc.Driver JATOS_JPA=mysqlPersistenceUnit

Password restrictions

By default JATOS’ keeps it simple and relies on the users to choose save passwords: it just enforces a length of at least 7 characters. But this can be changed in the conf/production.conf with the following two properties.

  • jatos.user.password.length - Set with an positive integer (default is 7)
  • jatos.user.password.strength - Set to 0, 1, 2, or 3 (default is 0)
    • 0: No restrictions on characters
    • 1: At least one Latin letter and one number
    • 2: At least one Latin letter, one number and one special character (#?!@$%^&*-)
    • 3: At least one uppercase Latin letter, one lowercase Latin letter, one number and one special character (#?!@$%^&*-)

Other configuration in production.conf

Additional to the database and the study assets root path some other properties can be configured in the conf/production.conf.

  • jatos.userSession.timeout - time in minutes a user stays logged in (default is 1440 = 1 day)
  • jatos.userSession.inactivity - defines the time in minutes a user is automatically logged out after inactivity (default is 60)
  • jatos.userSession.validation - (since JATOS >= 3.1.10) - toggles user session validation: set to false to switch it off (default is true) - WARNING: Turning off the user session validation reduces JATOS security! Sometimes this is necessary, e.g. if your users have a extremely dynamic IP address.
  • play.http.session.secure - secure session cookie: set true to restrict user access to HTTPS (default is false)

Apart from those all configuration properties possible in the Play Framework are possible in JATOS production.conf too.