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Version: 2.4.2

Custom Predicate Judge

Introduction#

  • This paper describes how to customize the extension of org.apache.shenyu.plugin.base.condition.judge.PredicateJudge.
  • The conditional predicate is the bridge between data and rules in the selector and serves to filter out requests that match the conditions.
  • There are already seven conditional predicates including match, =, regex, contains, TimeBefore, TimeAfter, exclude.
  • Please refer to judge module, add your own conditional predicates, or submit pr to the official website if you have a good common plugin.

Extension#

  • Create a new project and introduce the following dependencies:
<dependencies>    <dependency>        <groupId>org.apache.shenyu</groupId>        <artifactId>shenyu-plugin-base</artifactId>        <version>${project.version}</version>    </dependency></dependencies>
  • Create a new class CustomPredicateJudge, implements org.apache.shenyu.plugin.base.condition.judge.PredicateJudge, add annotation org.apache.shenyu.spi.Join.
/** * custom predicate judge. */@Joinpublic class CustomPredicateJudge implements PredicateJudge {
    @Override    public Boolean judge(final ConditionData conditionData, final String realData) {        // Custom Predicate Judge    }}
  • In the project's META-INF/services directory, create org.apache.shenyu.plugin.base.condition.judge.PredicateJudge file, add key-value as following:
script
${spi name} = ${custom class path}

${spi name} represents the name of spi and ${custom class path} represents the fully qualified name of the class. Such as:

script
custom=xxx.xxx.xxx.CustomPredicateJudge

  • Package the project and copy it to the lib or ext-lib directory of the gateway (bootstrap-bin).

  • In the Apache ShenYu gateway management system --> BasicConfig --> Dictionary, find the dictionary code as OPERATOR, add a new piece of data, pay attention to the dictionary name: ${spi name}.

DictionaryType: operator;

DictionaryCode: OPERATOR;

DictionaryName: ${spi name}, input your custom spi name;

DictionaryValue: When used, the value of the drop-down box, do not repeat with the existing;

DictionaryDescribe: desc your custom match strategy;

Sort: to sort;

Status: open or close.

  • When adding selectors or rules, you can use custom predicate judge:

Example#

  • Add GroovyPredicateJudge and SpELPredicateJudge extension.
/** * Groovy predicate judge. */@Joinpublic class GroovyPredicateJudge implements PredicateJudge {        @Override    public Boolean judge(final ConditionData conditionData, final String realData) {        return (Boolean) Eval.me(conditionData.getParamName(), realData, conditionData.getParamValue());    }}
/** * SpEL predicate judge. */@Joinpublic class SpELPredicateJudge implements PredicateJudge {        private static final ExpressionParser EXPRESSION_PARSER = new SpelExpressionParser();        @Override    public Boolean judge(final ConditionData conditionData, final String realData) {        Expression expression = EXPRESSION_PARSER.parseExpression(conditionData.getParamValue().replace('#' + conditionData.getParamName(), realData));        return expression.getValue(Boolean.class);    }}
  • Update org.apache.shenyu.plugin.base.condition.judge.PredicateJudge:
script
Groovy=xxx.xxx.xxx.GroovyPredicateJudgeSpEL=xxx.xxx.xxx.SpELPredicateJudge