ufal/be-22-54-download-preview-item (#444)

* lock/download-preview-temp

* Changed preview limit

* Temp commit - some refactoring done

* Removed unwanted changes.

* Refactoring

* Added some doc

* Test passed

* Fixed tests

* Fixed checkstyle errors

* Updated endpoints and fixed tests

dspace-api/src/main/java/org/dspace/util/FileInfo.java

@@ -0,0 +1,40 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.util;
+
+import java.util.Hashtable;
+/**
+ * This class is used to store the information about a file or a directory
+ *
+ * @author longtv
+ */
+public class FileInfo {
+
+    public String name;
+    public String content;
+    public String size;
+    public boolean isDirectory;
+
+    public Hashtable<String, FileInfo> sub = null;
+
+    public FileInfo(String name) {
+        this.name = name;
+        sub = new Hashtable<String, FileInfo>();
+        isDirectory = true;
+    }
+    public FileInfo(String content, boolean isDirectory) {
+        this.content = content;
+        this.isDirectory = isDirectory;
+    }
+
+    public FileInfo(String name, String size) {
+        this.name = name;
+        this.size = size;
+        isDirectory = false;
+    }
+}

dspace-api/src/main/java/org/dspace/util/FileTreeViewGenerator.java

@@ -0,0 +1,85 @@
+/**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.util;
+
+import java.io.IOException;
+import java.io.StringReader;
+import java.util.ArrayList;
+import java.util.List;
+import javax.xml.parsers.DocumentBuilder;
+import javax.xml.parsers.DocumentBuilderFactory;
+import javax.xml.parsers.ParserConfigurationException;
+
+import org.w3c.dom.Document;
+import org.w3c.dom.Element;
+import org.w3c.dom.Node;
+import org.w3c.dom.NodeList;
+import org.xml.sax.InputSource;
+import org.xml.sax.SAXException;
+/**
+ * Generate a tree view of the file in a bitstream
+ *
+ * @author longtv
+ */
+public class FileTreeViewGenerator {
+    private FileTreeViewGenerator () {
+    }
+
+    public static List<FileInfo> parse(String data) throws ParserConfigurationException, IOException, SAXException {
+        DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+        DocumentBuilder builder = factory.newDocumentBuilder();
+        Document document = builder.parse(new InputSource(new StringReader(data)));
+        Element rootElement = document.getDocumentElement();
+        NodeList nl = rootElement.getChildNodes();
+        FileInfo root = new FileInfo("root");
+        Node n = nl.item(0);
+        do {
+            String fileInfo = n.getFirstChild().getTextContent();
+            String f[] = fileInfo.split("\\|");
+            String fileName = "";
+            String path = f[0];
+            long size = Long.parseLong(f[1]);
+            if (!path.endsWith("/")) {
+                fileName = path.substring(path.lastIndexOf('/') + 1);
+                if (path.lastIndexOf('/') != -1) {
+                    path = path.substring(0, path.lastIndexOf('/'));
+                } else {
+                    path = "";
+                }
+            }
+            FileInfo current = root;
+            for (String p : path.split("/")) {
+                if (current.sub.containsKey(p)) {
+                    current = current.sub.get(p);
+                } else {
+                    FileInfo temp = new FileInfo(p);
+                    current.sub.put(p, temp);
+                    current = temp;
+                }
+            }
+            if (!fileName.isEmpty()) {
+                FileInfo temp = new FileInfo(fileName, humanReadableFileSize(size));
+                current.sub.put(fileName, temp);
+            }
+        } while ((n = n.getNextSibling()) != null);
+        return new ArrayList<>(root.sub.values());
+    }
+    public static String humanReadableFileSize(long bytes) {
+        int thresh = 1024;
+        if (Math.abs(bytes) < thresh) {
+            return bytes + " B";
+        }
+        String units[] = {"kB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"};
+        int u = -1;
+        do {
+            bytes /= thresh;
+            ++u;
+        } while (Math.abs(bytes) >= thresh && u < units.length - 1);
+        return bytes + " " + units[u];
+    }
+}

dspace-server-webapp/src/main/java/org/dspace/app/rest/MetadataBitstreamController.java

@@ -0,0 +1,245 @@
+ /**
+ * The contents of this file are subject to the license and copyright
+ * detailed in the LICENSE and NOTICE files at the root of the source
+ * tree and available online at
+ *
+ * http://www.dspace.org/license/
+ */
+package org.dspace.app.rest;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.sql.SQLException;
+import java.util.List;
+import java.util.Objects;
+import java.util.zip.Deflater;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import org.apache.commons.collections4.CollectionUtils;
+import org.apache.commons.compress.archivers.zip.ZipArchiveEntry;
+import org.apache.commons.compress.archivers.zip.ZipArchiveOutputStream;
+import org.apache.commons.compress.utils.IOUtils;
+import org.apache.commons.lang3.StringUtils;
+import org.apache.logging.log4j.Logger;
+import org.dspace.app.rest.exception.DSpaceBadRequestException;
+import org.dspace.app.rest.exception.UnprocessableEntityException;
+import org.dspace.app.rest.model.BitstreamRest;
+import org.dspace.app.rest.utils.ContextUtil;
+import org.dspace.authorize.AuthorizeException;
+import org.dspace.authorize.MissingLicenseAgreementException;
+import org.dspace.authorize.service.AuthorizeService;
+import org.dspace.content.Bitstream;
+import org.dspace.content.BitstreamFormat;
+import org.dspace.content.Bundle;
+import org.dspace.content.DSpaceObject;
+import org.dspace.content.Item;
+import org.dspace.content.service.BitstreamService;
+import org.dspace.core.Constants;
+import org.dspace.core.Context;
+import org.dspace.handle.service.HandleService;
+import org.dspace.services.ConfigurationService;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.core.io.InputStreamResource;
+import org.springframework.core.io.Resource;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+import org.springframework.web.bind.annotation.RestController;
+
+/**
+ * This CLARIN Controller download a single file or a ZIP file from the Item's bitstream.
+ */
+@RestController
+@RequestMapping("/api/" + BitstreamRest.CATEGORY + "/" + BitstreamRest.PLURAL_NAME)
+public class MetadataBitstreamController {
+
+    private static Logger log = org.apache.logging.log4j.LogManager.getLogger(MetadataBitstreamController.class);
+
+    @Autowired
+    private BitstreamService bitstreamService;
+
+    @Autowired
+    private HandleService handleService;
+    @Autowired
+    private AuthorizeService authorizeService;
+    @Autowired
+    private ConfigurationService configurationService;
+
+
+    @GetMapping("/handle/{id}/{subId}/{fileName}")
+    public ResponseEntity<Resource> downloadSingleFile(@PathVariable("id") String id,
+                                                       @PathVariable("subId") String subId,
+                                                       @PathVariable("fileName") String fileName,
+                                                       HttpServletRequest request, HttpServletResponse response)
+            throws IOException {
+        String handleID = id + "/" + subId;
+        if (StringUtils.isBlank(id) || StringUtils.isBlank(subId)) {
+            log.error("Handle cannot be null! PathVariable `id` or `subId` is null.");
+            throw new DSpaceBadRequestException("Handle cannot be null!");
+        }
+
+        Context context = ContextUtil.obtainContext(request);
+        if (Objects.isNull(context)) {
+            log.error("Cannot obtain the context from the request.");
+            throw new RuntimeException("Cannot obtain the context from the request.");
+        }
+
+        DSpaceObject dso = null;
+        try {
+            dso = handleService.resolveToObject(context, handleID);
+        } catch (Exception e) {
+            log.error("Cannot resolve handle: " + handleID);
+            throw new RuntimeException("Cannot resolve handle: " + handleID);
+        }
+
+
+        if (Objects.isNull(dso)) {
+            log.error("DSO is null");
+            return null;
+        }
+
+        if (!(dso instanceof Item)) {
+            log.error("DSO is not instance of Item");
+            return null;
+        }
+
+        Item item = (Item) dso;
+        List<Bundle> bundles = item.getBundles();
+        // Find bitstream and start downloading.
+        for (Bundle bundle: bundles) {
+            for (Bitstream bitstream: bundle.getBitstreams()) {
+                // Authorize the action - it will send response redirect if something gets wrong.
+                authorizeBitstreamAction(context, bitstream, response);
+
+                String btName = bitstream.getName();
+                if (!(btName.equalsIgnoreCase(fileName))) {
+                    continue;
+                }
+                try {
+                    BitstreamFormat bitstreamFormat = bitstream.getFormat(context);
+                    // Check if the bitstream has some extensions e.g., `.txt, .jpg,..`
+                    checkBitstreamExtensions(bitstreamFormat);
+
+                    // Get content of the bitstream
+                    InputStream inputStream = bitstreamService.retrieve(context, bitstream);
+                    InputStreamResource resource = new InputStreamResource(inputStream);
+                    HttpHeaders header = new HttpHeaders();
+                    header.add(HttpHeaders.CONTENT_DISPOSITION,
+                            "attachment; filename=" + fileName);
+                    header.add("Cache-Control", "no-cache, no-store, must-revalidate");
+                    header.add("Pragma", "no-cache");
+                    header.add("Expires", "0");
+                    return ResponseEntity.ok()
+                            .headers(header)
+                            .contentLength(inputStream.available())
+                            .contentType(MediaType.APPLICATION_OCTET_STREAM)
+                            .body(resource);
+                } catch (Exception e) {
+                    throw new RuntimeException(e);
+                }
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Download all Item's bitstreams as single ZIP file.
+     */
+    @GetMapping("/allzip")
+    public void downloadFileZip(@RequestParam("handleId") String handleId,
+                                HttpServletResponse response,
+                                HttpServletRequest request) throws IOException, SQLException, AuthorizeException {
+        if (StringUtils.isBlank(handleId)) {
+            log.error("Handle cannot be null!");
+            throw new DSpaceBadRequestException("Handle cannot be null!");
+        }
+        Context context = ContextUtil.obtainContext(request);
+        if (Objects.isNull(context)) {
+            log.error("Cannot obtain the context from the request.");
+            throw new RuntimeException("Cannot obtain the context from the request.");
+        }
+
+        DSpaceObject dso = null;
+        String name = "";
+        try {
+            dso = handleService.resolveToObject(context, handleId);
+        } catch (Exception e) {
+            log.error("Cannot resolve handle: " + handleId);
+            throw new RuntimeException("Cannot resolve handle: " + handleId);
+        }
+
+        if (Objects.isNull(dso)) {
+            log.error("DSO is null");
+            throw new UnprocessableEntityException("Retrieved DSO is null, handle: " + handleId);
+        }
+
+        if (!(dso instanceof Item)) {
+            log.info("DSO is not instance of Item");
+        }
+
+        Item item = (Item) dso;
+        name = item.getName() + ".zip";
+        response.setHeader(HttpHeaders.CONTENT_DISPOSITION, String.format("attachment;filename=\"%s\"", name));
+        response.setContentType("application/zip");
+        List<Bundle> bundles = item.getBundles("ORIGINAL");
+
+        ZipArchiveOutputStream zip = new ZipArchiveOutputStream(response.getOutputStream());
+        zip.setCreateUnicodeExtraFields(ZipArchiveOutputStream.UnicodeExtraFieldPolicy.ALWAYS);
+        zip.setLevel(Deflater.NO_COMPRESSION);
+        for (Bundle original : bundles) {
+            List<Bitstream> bss = original.getBitstreams();
+            for (Bitstream bitstream : bss) {
+                authorizeBitstreamAction(context, bitstream, response);
+
+                String filename = bitstream.getName();
+                ZipArchiveEntry ze = new ZipArchiveEntry(filename);
+                zip.putArchiveEntry(ze);
+                InputStream is = bitstreamService.retrieve(context, bitstream);
+                IOUtils.copy(is, zip);
+                zip.closeArchiveEntry();
+                is.close();
+            }
+        }
+        zip.close();
+        response.getOutputStream().flush();
+    }
+
+    /**
+     * Could the user download that bitstream?
+     * @param context DSpace context object
+     * @param bitstream Bitstream to download
+     * @param response for possibility to redirect
+     */
+    private void authorizeBitstreamAction(Context context, Bitstream bitstream, HttpServletResponse response)
+            throws IOException {
+
+        String uiURL = configurationService.getProperty("dspace.ui.url");
+        if (StringUtils.isBlank(uiURL)) {
+            log.error("Configuration property `dspace.ui.url` cannot be empty or null!");
+            throw new RuntimeException("Configuration property `dspace.ui.url` cannot be empty or null!");
+        }
+        try {
+            authorizeService.authorizeAction(context, bitstream, Constants.READ);
+        } catch (MissingLicenseAgreementException e) {
+            response.sendRedirect(uiURL + "/bitstream/" + bitstream.getID() + "/download");
+        } catch (AuthorizeException | SQLException e) {
+            response.sendRedirect(uiURL + "/login");
+        }
+    }
+
+    /**
+     * Check if the bitstream has file extension.
+     */
+    private void checkBitstreamExtensions(BitstreamFormat bitstreamFormat) {
+        if ( Objects.isNull(bitstreamFormat) ||  CollectionUtils.isEmpty(bitstreamFormat.getExtensions())) {
+            log.error("Bitstream Extensions cannot be empty for downloading/previewing bitstreams.");
+            throw new RuntimeException("Bitstream Extensions cannot be empty for downloading/previewing bitstreams.");
+        }
+    }
+}