Voters

Voters are used in Magnolia whenever configuration values are not assigned at startup but instead depend on rules. For example the Cache module has to determine if a requested resource may be cached or not. The rules to determine values should be configurable. The rules are user-defined using voters which evaluate established criteria by determining true or false of each rule. Voters are currently used for:

  • Filter configuration: uses voters to determine whether a filter should be executed or bypassed.

  • Cache configuration: uses voters to determine whether a file should be cached or not.

The basic concept of voters uses Voter classes which calculate an int vote value, where positive (1, 2, 3, …) results are treated as yes or true'' and (0, -1, -2, …) results are treated as ``no or false. If you have a set of voters, then the result of a voting is the largest absolute result. If there are two voters with the same absolute result, then the one with the higher positive value will be taken.

Examples
Vote results VoterSet result

-3, 0, 2

-3

-3, 0, 3

3

-3, 0, 4

4

For most of the real world voters only boolean results make sense. These boolean voters return 1'' for a true'' and 0 for a false result.

Voter examples

Voter Parameters Description

AuthenticatedVoter

none

Boolean Checks if the current user is authenticated.

ExtensionVoter

yes

  • allow: comma separated lists of allowed extensions.

  • deny: comma separated lists of denied extensions.

Boolean

  • Returns false if the extension is not a valid mimetype (as configured in config:/server/MIMEMapping).

  • Returns false if the allow list exists, but the extension is not in the allow list.

  • Returns false if the deny list exists and the extension is in the deny list.

  • Returns true in any other cases.
For more information see the voters package.
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