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DSpace core data model and service APIs.
/**
* 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.core;
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.math.BigInteger;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.net.URL;
import java.net.UnknownHostException;
import java.nio.charset.StandardCharsets;
import java.rmi.dgc.VMID;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Collections;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.Random;
import java.util.StringTokenizer;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import com.coverity.security.Escape;
import org.apache.commons.lang3.StringUtils;
import org.apache.commons.text.StringSubstitutor;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.dspace.services.ConfigurationService;
import org.dspace.services.factory.DSpaceServicesFactory;
/**
* Utility functions for DSpace.
*
* @author Peter Breton
*/
public final class Utils {
/**
* log4j logger
*/
private static final Logger log = LogManager.getLogger(Utils.class);
private static final Pattern DURATION_PATTERN = Pattern
.compile("(\\d+)([smhdwy])");
private static final long MS_IN_SECOND = 1000L;
private static final long MS_IN_MINUTE = 60000L;
private static final long MS_IN_HOUR = 3600000L;
private static final long MS_IN_DAY = 86400000L;
private static final long MS_IN_WEEK = 604800000L;
private static final long MS_IN_YEAR = 31536000000L;
private static int counter = 0;
private static final Random random = new Random();
private static final VMID vmid = new VMID();
// for parseISO8601Date
private static final SimpleDateFormat parseFmt[] = {
// first try at parsing, has milliseconds (note General time zone)
new SimpleDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ss.SSSz"),
// second try at parsing, no milliseconds (note General time zone)
new SimpleDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ssz"),
// finally, try without any timezone (defaults to current TZ)
new SimpleDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ss.SSS"),
new SimpleDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ss")
};
// for formatISO8601Date
// output canonical format (note RFC22 time zone, easier to hack)
private static final SimpleDateFormat outFmtSecond
= new SimpleDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ssZ");
// output format with millsecond precision
private static final SimpleDateFormat outFmtMillisec
= new SimpleDateFormat("yyyy'-'MM'-'dd'T'HH':'mm':'ss.SSSZ");
private static final Calendar outCal = GregorianCalendar.getInstance();
/**
* Private constructor
*/
private Utils() { }
/**
* Return an MD5 checksum for data in hex format.
*
* @param data The data to checksum.
* @return MD5 checksum for the data in hex format.
*/
public static String getMD5(String data) {
return getMD5(data.getBytes(StandardCharsets.UTF_8));
}
/**
* Return an MD5 checksum for data in hex format.
*
* @param data The data to checksum.
* @return MD5 checksum for the data in hex format.
*/
public static String getMD5(byte[] data) {
return toHex(getMD5Bytes(data));
}
/**
* Return an MD5 checksum for data as a byte array.
*
* @param data The data to checksum.
* @return MD5 checksum for the data as a byte array.
*/
public static byte[] getMD5Bytes(byte[] data) {
try {
MessageDigest digest = MessageDigest.getInstance("MD5");
return digest.digest(data);
} catch (NoSuchAlgorithmException nsae) {
// ignore
}
// Should never happen
return null;
}
/**
* Return a hex representation of the byte array
*
* @param data The data to transform.
* @return A hex representation of the data.
*/
public static String toHex(byte[] data) {
if ((data == null) || (data.length == 0)) {
return null;
}
StringBuilder result = new StringBuilder();
// This is far from the most efficient way to do things...
for (int i = 0; i < data.length; i++) {
int low = (int) (data[i] & 0x0F);
int high = (int) (data[i] & 0xF0);
result.append(Integer.toHexString(high).substring(0, 1));
result.append(Integer.toHexString(low));
}
return result.toString();
}
/**
* Generate a unique key. The key is a long (length 38 to 40) sequence of
* digits.
*
* @return A unique key as a long sequence of base-10 digits.
*/
public static String generateKey() {
return new BigInteger(generateBytesKey()).abs().toString();
}
/**
* Generate a unique key. The key is a 32-character long sequence of hex
* digits.
*
* @return A unique key as a long sequence of hex digits.
*/
public static String generateHexKey() {
return toHex(generateBytesKey());
}
/**
* Generate a unique key as a byte array.
*
* @return A unique key as a byte array.
*/
public static synchronized byte[] generateBytesKey() {
byte[] junk = new byte[16];
random.nextBytes(junk);
String input = new StringBuilder()
.append(vmid)
.append(new java.util.Date())
.append(Arrays.toString(junk))
.append(counter++)
.toString();
return getMD5Bytes(input.getBytes(StandardCharsets.UTF_8));
}
// The following two methods are taken from the Jakarta IOUtil class.
/**
* Copy stream-data from source to destination. This method does not buffer,
* flush or close the streams, as to do so would require making non-portable
* assumptions about the streams' origin and further use. If you wish to
* perform a buffered copy, use {@link #bufferedCopy}.
*
* @param input The InputStream to obtain data from.
* @param output The OutputStream to copy data to.
* @throws IOException if IO error
*/
public static void copy(final InputStream input, final OutputStream output)
throws IOException {
final int BUFFER_SIZE = 1024 * 4;
final byte[] buffer = new byte[BUFFER_SIZE];
while (true) {
final int count = input.read(buffer, 0, BUFFER_SIZE);
if (-1 == count) {
break;
}
// write out those same bytes
output.write(buffer, 0, count);
}
// needed to flush cache
// output.flush();
}
/**
* Copy stream-data from source to destination, with buffering. This is
* equivalent to passing {@link #copy}a
* java.io.BufferedInputStream and
* java.io.BufferedOutputStream to {@link #copy}, and
* flushing the output stream afterwards. The streams are not closed after
* the copy.
*
* @param source The InputStream to obtain data from.
* @param destination The OutputStream to copy data to.
* @throws IOException if IO error
*/
public static void bufferedCopy(final InputStream source,
final OutputStream destination) throws IOException {
final BufferedInputStream input = new BufferedInputStream(source);
final BufferedOutputStream output = new BufferedOutputStream(
destination);
copy(input, output);
output.flush();
}
/**
* Replace characters that could be interpreted as HTML codes with symbolic
* references (entities). This function should be called before displaying
* any metadata fields that could contain the characters {@code "<", ">", "&", "'"},
* and double quotation marks. This will effectively disable HTML links
* in metadata.
*
* @param value the metadata value to be scrubbed for display
* @return the passed-in string, with html special characters replaced with
* entities.
*/
public static String addEntities(String value) {
return Escape.html(value);
}
/**
* Utility method to parse durations defined as {@code \d+[smhdwy]} (seconds,
* minutes, hours, days, weeks, years)
*
* @param duration specified duration
* @return number of milliseconds equivalent to duration.
* @throws ParseException if the duration is of incorrect format
*/
public static long parseDuration(String duration) throws ParseException {
Matcher m = DURATION_PATTERN.matcher(duration.trim());
if (!m.matches()) {
throw new ParseException("'" + duration
+ "' is not a valid duration definition", 0);
}
String units = m.group(2);
long multiplier = MS_IN_SECOND;
if ("s".equals(units)) {
multiplier = MS_IN_SECOND;
} else if ("m".equals(units)) {
multiplier = MS_IN_MINUTE;
} else if ("h".equals(units)) {
multiplier = MS_IN_HOUR;
} else if ("d".equals(units)) {
multiplier = MS_IN_DAY;
} else if ("w".equals(units)) {
multiplier = MS_IN_WEEK;
} else if ("y".equals(units)) {
multiplier = MS_IN_YEAR;
} else {
throw new ParseException(units
+ " is not a valid time unit (must be 'y', "
+ "'w', 'd', 'h', 'm' or 's')", duration.indexOf(units));
}
long qint = Long.parseLong(m.group(1));
return qint * multiplier;
}
/**
* Translates timestamp from an ISO 8601-standard format, which
* is commonly used in XML and RDF documents.
* This method is synchronized because it depends on a non-reentrant
* static DateFormat (more efficient than creating a new one each call).
*
* @param s the input string
* @return Date object, or null if there is a problem translating.
*/
public static synchronized Date parseISO8601Date(String s) {
// attempt to normalize the timezone to something we can parse;
// SimpleDateFormat can't handle "Z"
char tzSign = s.charAt(s.length() - 6);
if (s.endsWith("Z")) {
s = s.substring(0, s.length() - 1) + "GMT+00:00";
} else if (tzSign == '-' || tzSign == '+') {
// check for trailing timezone
s = s.substring(0, s.length() - 6) + "GMT" + s.substring(s.length() - 6);
}
// try to parse without milliseconds
ParseException lastError = null;
for (int i = 0; i < parseFmt.length; ++i) {
try {
return parseFmt[i].parse(s);
} catch (ParseException e) {
lastError = e;
}
}
if (lastError != null) {
log.error("Error parsing date:", lastError);
}
return null;
}
/**
* Convert a Date to String in the ISO 8601 standard format.
* The RFC822 timezone is almost right, still need to insert ":".
* This method is synchronized because it depends on a non-reentrant
* static DateFormat (more efficient than creating a new one each call).
*
* @param d the input Date
* @return String containing formatted date.
*/
public static synchronized String formatISO8601Date(Date d) {
String result;
outCal.setTime(d);
if (outCal.get(Calendar.MILLISECOND) == 0) {
result = outFmtSecond.format(d);
} else {
result = outFmtMillisec.format(d);
}
int rl = result.length();
return result.substring(0, rl - 2) + ":" + result.substring(rl - 2);
}
public static java.util.Collection emptyIfNull(java.util.Collection collection) {
return collection == null ? Collections.emptyList() : collection;
}
/**
* Utility method to extract schema, element, qualifier from the metadata field key
* Keep in mind that this method try to auto discover the common separator used in DSpace ("_" or ".")
*
* Return an array of token with size 3 which contains:
* schema = tokens[0];
* element = tokens[1];
* qualifier = tokens[2]; //it can be empty string
*
* @param metadata (the field in the form dc.title or dc_title)
* @return array of tokens
*/
public static String[] tokenize(String metadata) {
String separator = metadata.contains("_") ? "_" : ".";
StringTokenizer dcf = new StringTokenizer(metadata, separator);
String[] tokens = {"", "", ""};
int i = 0;
while (dcf.hasMoreTokens()) {
tokens[i] = dcf.nextToken().trim();
i++;
}
// Tokens contains:
// schema = tokens[0];
// element = tokens[1];
// qualifier = tokens[2];
return tokens;
}
/**
* Make the metadata field key using the separator.
*
* @param schema
* @param element
* @param qualifier
* @param separator (DSpace common separator are "_" or ".")
* @return metadata field key
*/
public static String standardize(String schema, String element, String qualifier, String separator) {
if (StringUtils.isBlank(qualifier)) {
return schema + separator + element;
} else {
return schema + separator + element + separator + qualifier;
}
}
/**
* Retrieve the baseurl from a given URL string
* @param urlString URL string
* @return baseurl (without any context path) or null (if URL was invalid)
*/
public static String getBaseUrl(String urlString) {
try {
URL url = new URL(urlString);
String baseUrl = url.getProtocol() + "://" + url.getHost();
if (url.getPort() != -1) {
baseUrl += (":" + url.getPort());
}
return baseUrl;
} catch (MalformedURLException e) {
return null;
}
}
/**
* Retrieve the hostname from a given URI string
* @param uriString URI string
* @return hostname (without any www.) or null (if URI was invalid)
*/
public static String getHostName(String uriString) {
try {
URI uri = new URI(uriString);
String hostname = uri.getHost();
// remove the "www." from hostname, if it exists
if (hostname != null) {
return hostname.startsWith("www.") ? hostname.substring(4) : hostname;
}
return hostname;
} catch (URISyntaxException e) {
return null;
}
}
/**
* Retrieve the IP address(es) of a given URI string.
*
* At this time, DSpace only supports IPv4, so this method will only return IPv4 addresses.
* @param uriString URI string
* @return IP address(es) in a String array (or null if not found)
*/
public static String[] getIPAddresses(String uriString) {
String[] ipAddresses = null;
// First, get the hostname
String hostname = getHostName(uriString);
if (StringUtils.isNotEmpty(hostname)) {
try {
// Then, get the list of all IPs for that hostname
InetAddress[] inetAddresses = InetAddress.getAllByName(hostname);
// Convert array of InetAddress objects to array of IP address Strings
ipAddresses = Arrays.stream(inetAddresses)
// Filter our array to ONLY include IPv4 addresses
.filter((address) -> address instanceof Inet4Address)
// Call getHostAddress() on each to get the IPv4 address as a string
.map((address) -> ((Inet4Address) address).getHostAddress())
.toArray(String[]::new);
} catch (UnknownHostException ex) {
return null;
}
}
return ipAddresses;
}
/**
* Replaces configuration placeholders within a String with the corresponding value
* from DSpace's Configuration Service.
*
* For example, given a String like "My DSpace is installed at ${dspace.dir}", this
* method will replace "${dspace.dir}" with the configured value of that property.
* @param string source string
* @return string with any placeholders replaced with configured values.
*/
public static String interpolateConfigsInString(String string) {
ConfigurationService config = DSpaceServicesFactory.getInstance().getConfigurationService();
return StringSubstitutor.replace(string, config.getProperties());
}
}
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