/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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 edu.gatech.oad.rocket.findmythings.util.validation;
import java.io.Serializable;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.Set;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/**
* <p><b>URL Validation</b> routines.</p>
* Behavior of validation is modified by passing in options:
* <li>ALLOW_2_SLASHES - [FALSE] Allows double '/' characters in the path
* component.</li>
* <li>NO_FRAGMENT- [FALSE] By default fragments are allowed, if this option is
* included then fragments are flagged as illegal.</li>
* <li>ALLOW_ALL_SCHEMES - [FALSE] By default only http, https, and ftp are
* considered valid schemes. Enabling this option will let any scheme pass validation.</li>
*
* <p>Originally based in on php script by Debbie Dyer, validation.php v1.2b, Date: 03/07/02,
* http://javascript.internet.com. However, this validation now bears little resemblance
* to the php original.</p>
* <pre>
* Example of usage:
* Construct a UrlValidator with valid schemes of "http", and "https".
*
* String[] schemes = {"http","https"}.
* UrlValidator urlValidator = new UrlValidator(schemes);
* if (urlValidator.isValid("ftp://foo.bar.com/")) {
* System.out.println("url is valid");
* } else {
* System.out.println("url is invalid");
* }
*
* prints "url is invalid"
* If instead the default constructor is used.
*
* UrlValidator urlValidator = new UrlValidator();
* if (urlValidator.isValid("ftp://foo.bar.com/")) {
* System.out.println("url is valid");
* } else {
* System.out.println("url is invalid");
* }
*
* prints out "url is valid"
* </pre>
*
* @see
* <a href="http://www.ietf.org/rfc/rfc2396.txt">
* Uniform Resource Identifiers (URI): Generic Syntax
* </a>
*
* @version $Revision: 1227719 $ $Date: 2012-01-05 12:45:51 -0500 (Thu, 05 Jan 2012) $
* @since Validator 1.4
*/
@SuppressWarnings({"RedundantIfStatement", "BooleanMethodIsAlwaysInverted"})
public class UrlValidator implements Serializable {
private static final long serialVersionUID = 7557161713937335013L;
/**
* Allows all validly formatted schemes to pass validation instead of
* supplying a set of valid schemes.
*/
public static final long ALLOW_ALL_SCHEMES = 1 << 0;
/**
* Allow two slashes in the path component of the URL.
*/
public static final long ALLOW_2_SLASHES = 1 << 1;
/**
* Enabling this options disallows any URL fragments.
*/
public static final long NO_FRAGMENTS = 1 << 2;
/**
* Allow local URLs, such as http://localhost/ or http://machine/ .
* This enables a broad-brush check, for complex local machine name
* validation requirements you should create your validator with
* a {@link RegexValidator} instead ({@link #UrlValidator(RegexValidator, long)})
*/
public static final long ALLOW_LOCAL_URLS = 1 << 3;
// Drop numeric, and "+-." for now
private static final String AUTHORITY_CHARS_REGEX = "\\p{Alnum}\\-\\.";
/**
* This expression derived/taken from the BNF for URI (RFC2396).
*/
private static final String URL_REGEX =
"^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?";
// 12 3 4 5 6 7 8 9
private static final Pattern URL_PATTERN = Pattern.compile(URL_REGEX);
/**
* Schema/Protocol (ie. http:, ftp:, file:, etc).
*/
private static final int PARSE_URL_SCHEME = 2;
/**
* Includes hostname/ip and port number.
*/
private static final int PARSE_URL_AUTHORITY = 4;
private static final int PARSE_URL_PATH = 5;
private static final int PARSE_URL_QUERY = 7;
private static final int PARSE_URL_FRAGMENT = 9;
/**
* Protocol (ie. http:, ftp:,https:).
*/
private static final String SCHEME_REGEX = "^\\p{Alpha}[\\p{Alnum}\\+\\-\\.]*";
private static final Pattern SCHEME_PATTERN = Pattern.compile(SCHEME_REGEX);
private static final String AUTHORITY_REGEX =
"^([" + AUTHORITY_CHARS_REGEX + "]*)(:\\d*)?(.*)?";
// 1 2 3 4
private static final Pattern AUTHORITY_PATTERN = Pattern.compile(AUTHORITY_REGEX);
private static final int PARSE_AUTHORITY_HOST_IP = 1;
private static final int PARSE_AUTHORITY_PORT = 2;
/**
* Should always be empty.
*/
private static final int PARSE_AUTHORITY_EXTRA = 3;
private static final String PATH_REGEX = "^(/[-\\w:@&?=+,.!/~*'%$_;\\(\\)]*)?$";
private static final Pattern PATH_PATTERN = Pattern.compile(PATH_REGEX);
private static final String QUERY_REGEX = "^(.*)$";
private static final Pattern QUERY_PATTERN = Pattern.compile(QUERY_REGEX);
private static final String LEGAL_ASCII_REGEX = "^\\p{ASCII}+$";
private static final Pattern ASCII_PATTERN = Pattern.compile(LEGAL_ASCII_REGEX);
private static final String PORT_REGEX = "^:(\\d{1,5})$";
private static final Pattern PORT_PATTERN = Pattern.compile(PORT_REGEX);
/**
* Holds the set of current validation options.
*/
private final long options;
/**
* The set of schemes that are allowed to be in a URL.
*/
private final Set<String> allowedSchemes;
/**
* Regular expressions used to manually validate authorities if IANA
* domain name validation isn't desired.
*/
private final RegexValidator authorityValidator;
/**
* If no schemes are provided, default to this set.
*/
private static final String[] DEFAULT_SCHEMES = {"http", "https", "ftp"};
/**
* Singleton instance of this class with default schemes and options.
*/
private static final UrlValidator DEFAULT_URL_VALIDATOR = new UrlValidator();
/**
* Returns the singleton instance of this class with default schemes and options.
* @return singleton instance with default schemes and options
*/
public static UrlValidator getInstance() {
return DEFAULT_URL_VALIDATOR;
}
/**
* Create a UrlValidator with default properties.
*/
public UrlValidator() {
this(null);
}
/**
* Behavior of validation is modified by passing in several strings options:
* @param schemes Pass in one or more url schemes to consider valid, passing in
* a null will default to "http,https,ftp" being valid.
* If a non-null schemes is specified then all valid schemes must
* be specified. Setting the ALLOW_ALL_SCHEMES option will
* ignore the contents of schemes.
*/
public UrlValidator(String[] schemes) {
this(schemes, 0L);
}
/**
* Initialize a UrlValidator with the given validation options.
* @param options The options should be set using the public constants declared in
* this class. To set multiple options you simply add them together. For example,
* ALLOW_2_SLASHES + NO_FRAGMENTS enables both of those options.
*/
public UrlValidator(long options) {
this(null, null, options);
}
/**
* Behavior of validation is modified by passing in options:
* @param schemes The set of valid schemes.
* @param options The options should be set using the public constants declared in
* this class. To set multiple options you simply add them together. For example,
* ALLOW_2_SLASHES + NO_FRAGMENTS enables both of those options.
*/
public UrlValidator(String[] schemes, long options) {
this(schemes, null, options);
}
/**
* Initialize a UrlValidator with the given validation options.
* @param authorityValidator Regular expression validator used to validate the authority part
* @param options Validation options. Set using the public constants of this class.
* To set multiple options, simply add them together:
* <p><code>ALLOW_2_SLASHES + NO_FRAGMENTS</code></p>
* enables both of those options.
*/
public UrlValidator(RegexValidator authorityValidator, long options) {
this(null, authorityValidator, options);
}
/**
* Customizable constructor. Validation behavior is modifed by passing in options.
* @param schemes the set of valid schemes
* @param authorityValidator Regular expression validator used to validate the authority part
* @param options Validation options. Set using the public constants of this class.
* To set multiple options, simply add them together:
* <p><code>ALLOW_2_SLASHES + NO_FRAGMENTS</code></p>
* enables both of those options.
*/
public UrlValidator(String[] schemes, RegexValidator authorityValidator, long options) {
this.options = options;
if (isOn(ALLOW_ALL_SCHEMES)) {
this.allowedSchemes = Collections.emptySet();
} else {
if (schemes == null) {
schemes = DEFAULT_SCHEMES;
}
this.allowedSchemes = new HashSet<String>();
this.allowedSchemes.addAll(Arrays.asList(schemes));
}
this.authorityValidator = authorityValidator;
}
/**
* <p>Checks if a field has a valid url address.</p>
*
* @param value The value validation is being performed on. A <code>null</code>
* value is considered invalid.
* @return true if the url is valid.
*/
public boolean isValid(String value) {
if (value == null) {
return false;
}
if (!ASCII_PATTERN.matcher(value).matches()) {
return false;
}
// Check the whole url address structure
Matcher urlMatcher = URL_PATTERN.matcher(value);
if (!urlMatcher.matches()) {
return false;
}
String scheme = urlMatcher.group(PARSE_URL_SCHEME);
if (!isValidScheme(scheme)) {
return false;
}
String authority = urlMatcher.group(PARSE_URL_AUTHORITY);
if ("file".equals(scheme) && "".equals(authority)) {
// Special case - file: allows an empty authority
} else {
// Validate the authority
if (!isValidAuthority(authority)) {
return false;
}
}
if (!isValidPath(urlMatcher.group(PARSE_URL_PATH))) {
return false;
}
if (!isValidQuery(urlMatcher.group(PARSE_URL_QUERY))) {
return false;
}
if (!isValidFragment(urlMatcher.group(PARSE_URL_FRAGMENT))) {
return false;
}
return true;
}
/**
* Validate scheme. If schemes[] was initialized to a non null,
* then only those scheme's are allowed. Note this is slightly different
* than for the constructor.
* @param scheme The scheme to validate. A <code>null</code> value is considered
* invalid.
* @return true if valid.
*/
protected boolean isValidScheme(String scheme) {
if (scheme == null) {
return false;
}
if (!SCHEME_PATTERN.matcher(scheme).matches()) {
return false;
}
if (isOff(ALLOW_ALL_SCHEMES)) {
if (!this.allowedSchemes.contains(scheme)) {
return false;
}
}
return true;
}
/**
* Returns true if the authority is properly formatted. An authority is the combination
* of hostname and port. A <code>null</code> authority value is considered invalid.
* @param authority Authority value to validate.
* @return true if authority (hostname and port) is valid.
*/
protected boolean isValidAuthority(String authority) {
if (authority == null) {
return false;
}
// check manual authority validation if specified
if (authorityValidator != null) {
if (authorityValidator.isValid(authority)) {
return true;
}
}
Matcher authorityMatcher = AUTHORITY_PATTERN.matcher(authority);
if (!authorityMatcher.matches()) {
return false;
}
String hostLocation = authorityMatcher.group(PARSE_AUTHORITY_HOST_IP);
// check if authority is hostname or IP address:
// try a hostname first since that's much more likely
DomainValidator domainValidator = DomainValidator.getInstance(isOn(ALLOW_LOCAL_URLS));
if (!domainValidator.isValid(hostLocation)) {
// try an IP address
InetAddressValidator inetAddressValidator =
InetAddressValidator.getInstance();
if (!inetAddressValidator.isValid(hostLocation)) {
// isn't either one, so the URL is invalid
return false;
}
}
String port = authorityMatcher.group(PARSE_AUTHORITY_PORT);
if (port != null) {
if (!PORT_PATTERN.matcher(port).matches()) {
return false;
}
}
String extra = authorityMatcher.group(PARSE_AUTHORITY_EXTRA);
if (extra != null && extra.trim().length() > 0){
return false;
}
return true;
}
/**
* Returns true if the path is valid. A <code>null</code> value is considered invalid.
* @param path Path value to validate.
* @return true if path is valid.
*/
protected boolean isValidPath(String path) {
if (path == null) {
return false;
}
if (!PATH_PATTERN.matcher(path).matches()) {
return false;
}
int slash2Count = countToken("//", path);
if (isOff(ALLOW_2_SLASHES) && (slash2Count > 0)) {
return false;
}
int slashCount = countToken("/", path);
int dot2Count = countToken("..", path);
if (dot2Count > 0) {
if ((slashCount - slash2Count - 1) <= dot2Count) {
return false;
}
}
return true;
}
/**
* Returns true if the query is null or it's a properly formatted query string.
* @param query Query value to validate.
* @return true if query is valid.
*/
protected boolean isValidQuery(String query) {
return query == null || QUERY_PATTERN.matcher(query).matches();
}
/**
* Returns true if the given fragment is null or fragments are allowed.
* @param fragment Fragment value to validate.
* @return true if fragment is valid.
*/
protected boolean isValidFragment(String fragment) {
return fragment == null || isOff(NO_FRAGMENTS);
}
/**
* Returns the number of times the token appears in the target.
* @param token Token value to be counted.
* @param target Target value to count tokens in.
* @return the number of tokens.
*/
protected int countToken(String token, String target) {
int tokenIndex = 0;
int count = 0;
while (tokenIndex != -1) {
tokenIndex = target.indexOf(token, tokenIndex);
if (tokenIndex > -1) {
tokenIndex++;
count++;
}
}
return count;
}
/**
* Tests whether the given flag is on. If the flag is not a power of 2
* (ie. 3) this tests whether the combination of flags is on.
*
* @param flag Flag value to check.
*
* @return whether the specified flag value is on.
*/
private boolean isOn(long flag) {
return (this.options & flag) > 0;
}
/**
* Tests whether the given flag is off. If the flag is not a power of 2
* (ie. 3) this tests whether the combination of flags is off.
*
* @param flag Flag value to check.
*
* @return whether the specified flag value is off.
*/
private boolean isOff(long flag) {
return (this.options & flag) == 0;
}
}