Stirling-PDF/src/main/java/stirling/software/SPDF/utils/PDFToFile.java

package stirling.software.SPDF.utils;

import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.StandardCopyOption;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import org.apache.commons.io.FileUtils;
import org.apache.commons.io.IOUtils;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.web.multipart.MultipartFile;

public class PDFToFile {
    public ResponseEntity<byte[]> processPdfToOfficeFormat(MultipartFile inputFile, String outputFormat, String libreOfficeFilter) throws IOException, InterruptedException {

        if (!"application/pdf".equals(inputFile.getContentType())) {
            return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
        }

        // Get the original PDF file name without the extension
        String originalPdfFileName = inputFile.getOriginalFilename();
        String pdfBaseName = originalPdfFileName.substring(0, originalPdfFileName.lastIndexOf('.'));

        // Validate output format
        List<String> allowedFormats = Arrays.asList("doc", "docx", "odt", "ppt", "pptx", "odp", "rtf", "html", "xml", "txt:Text");
        if (!allowedFormats.contains(outputFormat)) {
            return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
        }

        Path tempInputFile = null;
        Path tempOutputDir = null;
        byte[] fileBytes;
        // Prepare response
        HttpHeaders headers = new HttpHeaders();

        try {
            // Save the uploaded file to a temporary location
            tempInputFile = Files.createTempFile("input_", ".pdf");
            Files.copy(inputFile.getInputStream(), tempInputFile, StandardCopyOption.REPLACE_EXISTING);

            // Prepare the output directory
            tempOutputDir = Files.createTempDirectory("output_");

            // Run the LibreOffice command
            List<String> command = new ArrayList<>(
                    Arrays.asList("soffice", "--infilter=" + libreOfficeFilter, "--convert-to", outputFormat, "--outdir", tempOutputDir.toString(), tempInputFile.toString()));
            int returnCode = ProcessExecutor.getInstance(ProcessExecutor.Processes.LIBRE_OFFICE).runCommandWithOutputHandling(command);

            // Get output files
            List<File> outputFiles = Arrays.asList(tempOutputDir.toFile().listFiles());

            if (outputFiles.size() == 1) {
                // Return single output file
                File outputFile = outputFiles.get(0);
                headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
                if (outputFormat.equals("txt:Text")) {
                    outputFormat = "txt";
                }
                headers.setContentDispositionFormData("attachment", pdfBaseName + "." + outputFormat);
                fileBytes = FileUtils.readFileToByteArray(outputFile);
            } else {
                // Return output files in a ZIP archive
                headers.setContentType(MediaType.APPLICATION_OCTET_STREAM);
                headers.setContentDispositionFormData("attachment", pdfBaseName + "To" + outputFormat + ".zip");
                ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
                ZipOutputStream zipOutputStream = new ZipOutputStream(byteArrayOutputStream);

                for (File outputFile : outputFiles) {
                    ZipEntry entry = new ZipEntry(outputFile.getName());
                    zipOutputStream.putNextEntry(entry);
                    FileInputStream fis = new FileInputStream(outputFile);
                    IOUtils.copy(fis, zipOutputStream);
                    fis.close();
                    zipOutputStream.closeEntry();
                }

                zipOutputStream.close();
                fileBytes = byteArrayOutputStream.toByteArray();
            }

        } finally {
            // Clean up the temporary files
            if (tempInputFile != null)
                Files.delete(tempInputFile);
            if (tempOutputDir != null)
                FileUtils.deleteDirectory(tempOutputDir.toFile());
        }
        return new ResponseEntity<>(fileBytes, headers, HttpStatus.OK);
    }
}