Bean Validation with JAX-RS (rest-easy): parameter name not recognized

user_2108919 0
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I'm using JAX-RS resources with Bean Validation and integration between these two works as expected.

However, the default error messages generated in case of a validation error report parameter names as arg0, like so

[PARAMETER]
[login.arg0.password]
[password is required]
[]

Corresponding method definition:

@POST //and other JAX-RS annotations
public Response login(
        @NotNull
        @Valid
        LoginBody loginBody) {

   [...]

protected static class LoginBody {

    @NotNull(message =  EMAIL_REQUIRED)
    public String email;

    @NotNull(message = PASSWORD_REQUIRED)
    public String password;
}

While I'm generally fine with this message pattern, what actually is annyoing, is the fact that the original parameter name is not recognized, i. e. I'd rather like to see

login.loginBody.password instead of arg0.

Is there an easy way to fix this, e. g. somehow provide an explicit name for that parameter?

I'm using WildFly Swarm 2017.6.0. From what I found out this means I have resteasy + resteasy-validator + hibernate-validator

Thanks.

wildfly-swarm bean-validation resteasy jax-rs
4 Answers

There is a very simple solution: you can set your own error message in the constraint definition as follows

@NotNull(message = "password is required")

If you want a more generic solution based on the JAX-RS parameter annotations you can implement your own simple ParameterNamProvider and register it in validation.xml as follows. This has the advantage of not having to change the jboss module structure. I also didn't have to change any compiler flags...

public class AnnotatedParameterNameProvider implements ParameterNameProvider {
  @Override
  public List<String> getParameterNames(Constructor<?> constructor) {
    return lookupParameterNames(constructor.getParameterAnnotations());
  }

  @Override
  public List<String> getParameterNames(Method method) {
    return lookupParameterNames(method.getParameterAnnotations());
  }

  private List<String> lookupParameterNames(Annotation[][] annotations) {
    final List<String> names = new ArrayList<>();
    if (annotations != null) {
      for (Annotation[] annotation : annotations) {
        String annotationValue = null;
        for (Annotation ann : annotation) {
          annotationValue = getAnnotationValue(ann);
          if (annotationValue != null) {
            break;
          }
        }

        // if no matching annotation, must be the request body
        if (annotationValue == null) {
          annotationValue = "requestBody";
        }
        names.add(annotationValue);
      }
    }

    return names;
  }

  private static String getAnnotationValue(Annotation annotation) {
    if (annotation instanceof HeaderParam) {
      return ((HeaderParam) annotation).value();
    } else if (annotation instanceof PathParam) {
      return ((PathParam) annotation).value();
    } else if (annotation instanceof QueryParam) {
      return ((QueryParam) annotation).value();
    }
    return null;
  }
}

In validation.xml:

    <validation-config xmlns="http://jboss.org/xml/ns/javax/validation/configuration"
                   xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                   xsi:schemaLocation="http://jboss.org/xml/ns/javax/validation/configuration validation-configuration-1.1.xsd"
                   version="1.1">
  <parameter-name-provider>com.yourcompany.providers.AnnotatedParameterNameProvider</parameter-name-provider>
</validation-config>

Note that you can also customize how the error message is formatted by implementing your own MessageInterpolator and registering it in the validation.xml

user_9099080

Updated version of @thomas-darimont for Hibernate Validator 6.X.

Variant#1 - with build in Java 8 (using -parameters compile parameter)

  1. Specify dependencies (gradle example):
// Define explicit hibernate validator 6.x
implementation('org.hibernate.validator:hibernate-validator:6.0.13.Final')
implementation('org.jboss.resteasy:resteasy-validator-provider-11:3.6.2.Final') {
    // Exclude transitive hibernate validator 5.x
    exclude group: 'org.hibernate', module: 'hibernate-validator'
}
  1. Specify validator(s):
@GET
@Path("user/{userId}")
public Response getUser(@Size(min = 2) @PathParam("userId") String userId) {
    return null;
}

Note: org.hibernate.validator.internal.engine.DefaultParameterNameProvider will return parameter names obtained from the Java reflection API.

Variant #2 - use ParaNamer library. (xml configuration) In case you don't want to be dependant on compilation flag.

  1. Specify dependencies (gradle example):
// Define explicit hibernate validator 6.x
implementation('org.hibernate.validator:hibernate-validator:6.0.13.Final')
implementation('org.jboss.resteasy:resteasy-validator-provider-11:3.6.2.Final') {
    // Exclude transitive hibernate validator 5.x
    exclude group: 'org.hibernate', module: 'hibernate-validator'
}
// ParaNamer library
implementation('com.thoughtworks.paranamer:paranamer:2.8')
  1. Specify validator(s):
@GET
@Path("user/{userId}")
public Response getUser(@Size(min = 2) @PathParam("userId") String userId) {
    return null;
}
  1. Put <project_dir>/src/main/resources/META-INF/validation.xml
<?xml version="1.0" encoding="UTF-8"?>
<validation-config
        xmlns="http://xmlns.jcp.org/xml/ns/validation/configuration"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/validation/configuration
            http://xmlns.jcp.org/xml/ns/validation/configuration/validation-configuration-2.0.xsd"
        version="2.0">
    <parameter-name-provider>org.hibernate.validator.parameternameprovider.ParanamerParameterNameProvider</parameter-name-provider>
</validation-config>

Note: Since Hibernate Validator 6.x org.hibernate.validator.parameternameprovider.ReflectionParameterNameProvider is deprecated, use org.hibernate.validator.parameternameprovider.ParanamerParameterNameProvider instead.

Question: Can I configure this with Java-code style only? Unfortunately, no. (See details here).

user_9635070
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