D-Net

package eu.dnetlib.efg.workflows.nodes.thumbnail;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.io.InputStream;

import java.nio.file.FileSystems;

import java.nio.file.Files;

import java.nio.file.Path;

import java.nio.file.StandardCopyOption;

import java.util.UUID;

import org.apache.tika.Tika;

import org.im4java.core.ConvertCmd;

import org.im4java.core.IMOperation;

/**

 * Created by sandro on 4/8/16.

 */

public class ThumbnailGenerator {

	private Path baseDirPath;

	private String dirName;

	public ThumbnailGenerator() throws IOException {

		dirName = UUID.randomUUID().toString();

		baseDirPath = Files.createTempDirectory(dirName);

	}

	public static boolean deleteRecursive(File path) throws FileNotFoundException {

		if (!path.exists()) throw new FileNotFoundException(path.getAbsolutePath());

		boolean ret = true;

		if (path.isDirectory()) {

			for (File f : path.listFiles()) {

				ret = ret && deleteRecursive(f);

			}

		}

		return ret && path.delete();

	}

	public InputStream convert(final InputStream input, int width, int height, final String name, boolean deleteBeforeConver) {

		try {

			destroyFolder();

			baseDirPath = Files.createTempDirectory(dirName);

			final Path tempFile = baseDirPath.resolve(name + "_orig");

			Files.copy(input, tempFile, StandardCopyOption.REPLACE_EXISTING);

			final String inputType = guessMimeType(tempFile.toAbsolutePath().toString());

			String inputPath = tempFile.toAbsolutePath().toString();

			if (inputType != null && inputType.contains("pdf")) {

				inputPath += "[0]";

			}

			ConvertCmd cmd = new ConvertCmd();

			IMOperation op = new IMOperation();

			op.addImage(inputPath);

			op.define(String.format("jpeg:size=%dx%d", width * 2, height * 2));

			op.thumbnail(width, height);

			op.unsharp(0.5);

			op.background("transparent");

			op.gravity("center");

			op.extent(width, height);

			op.colors(256);

			op.addImage(tempFile.toAbsolutePath().toString().replace("orig", "conv.png"));

			cmd.run(op);

			final Path path = FileSystems.getDefault().getPath(tempFile.toAbsolutePath().toString().replace("orig", "conv.png"));

			return Files.newInputStream(path);

		} catch (Throwable e) {

			System.out.println("Error on convert file" + e.toString());

			return null;

		}

	}

	private String guessMimeType(final String inputPath) throws IOException {

		Tika tika = new Tika();

		return tika.detect(new File(inputPath));

	}

	public boolean destroyFolder() throws FileNotFoundException {

		return deleteRecursive(baseDirPath.toFile());

	}

}