heron/tools/apiserver/src/java/com/twitter/heron/apiserver/resources/Forms.java

//  Copyright 2017 Twitter. All rights reserved.
//
//  Licensed under the Apache License, Version 2.0 (the "License");
//  you may not use this file except in compliance with the License.
//  You may obtain a copy of the License at
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
package com.twitter.heron.apiserver.resources;

import java.io.File;
import java.io.IOException;
import java.io.InputStream;
import java.nio.file.Path;
import java.nio.file.Paths;

import javax.ws.rs.core.MultivaluedMap;

import org.glassfish.jersey.media.multipart.FormDataBodyPart;
import org.glassfish.jersey.media.multipart.FormDataMultiPart;

import com.twitter.heron.apiserver.utils.FileHelper;

final class Forms {

  static String getString(FormDataMultiPart form, String key) {
    return getValueAs(form, key, String.class);
  }

  static String getString(FormDataMultiPart form, String key, String defaultValue) {
    return form.getFields().containsKey(key) ? getValueAs(form, key, String.class) : defaultValue;
  }

  static String getFirstOrDefault(MultivaluedMap<String, String> params, String key,
        String defaultValue) {
    return params.containsKey(key) ? params.getFirst(key) : defaultValue;
  }

  static File uploadFile(FormDataBodyPart part, String directory) throws IOException {
    try (InputStream in = part.getValueAs(InputStream.class)) {
      Path path = Paths.get(directory, part.getFormDataContentDisposition().getFileName());
      FileHelper.copy(in, path);
      return path.toFile();
    }
  }

  private static <T> T getValueAs(FormDataMultiPart form, String key, Class<T> type) {
    return form.getField(key).getValueAs(type);
  }

  private Forms() {
  }
}