TemplateValidator.java

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 * Licensed under the Apache License, Version 2.0 (the "License");
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package io.wcm.devops.conga.tooling.maven.plugin.validation;

import java.nio.charset.StandardCharsets;

import org.apache.commons.lang3.StringUtils;
import org.apache.maven.plugin.MojoFailureException;

import com.github.jknack.handlebars.Handlebars;

import io.wcm.devops.conga.generator.handlebars.HandlebarsManager;
import io.wcm.devops.conga.generator.plugins.handlebars.escaping.NoneEscapingStrategy;
import io.wcm.devops.conga.resource.Resource;
import io.wcm.devops.conga.resource.ResourceCollection;
import io.wcm.devops.conga.tooling.maven.plugin.util.PathUtil;

/**
 * Validates Handlebars templates by compiling it.
 */
public final class TemplateValidator implements DefinitionValidator<Void> {

  private static final String FILE_EXTENSION = "hbs";

  private final ResourceCollection templateDir;
  private final HandlebarsManager handlebarsManager;

  /**
   * @param templateDir Template directory
   * @param handlebarsManager Handlebars Manager
   */
  public TemplateValidator(ResourceCollection templateDir, HandlebarsManager handlebarsManager) {
    this.templateDir = templateDir;
    this.handlebarsManager = handlebarsManager;
  }

  @Override
  @SuppressWarnings({
      "PMD.PreserveStackTrace",
      "java:S1075" // uses / by intention
  })
  public Void validate(Resource resource, String pathForLog) throws MojoFailureException {
    if (StringUtils.equalsIgnoreCase(resource.getFileExtension(), FILE_EXTENSION)) {
      String templatePath = StringUtils.substringAfter(PathUtil.unifySlashes(resource.getCanonicalPath()),
          PathUtil.unifySlashes(templateDir.getCanonicalPath()) + "/");
      Handlebars handlebars = handlebarsManager.get(NoneEscapingStrategy.NAME, StandardCharsets.UTF_8.name());
      try {
        handlebars.compile(templatePath);
      }
      /*CHECKSTYLE:OFF*/ catch (Exception ex) { /*CHECKSTYLE:ON*/
        throw new MojoFailureException("Template " + pathForLog + " is invalid:\n" + ex.getMessage());
      }
    }
    return null;
  }

}