Java tutorial
/* * 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 org.apache.commons.validator.routines; 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: 595020 $ $Date: 2007-11-14 19:36:45 +0000 (Qua, 14 Nov 2007) $ * @since Validator 1.4 */ public class UrlValidator implements Serializable { /** * 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; // 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 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, 0); } /** * 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.EMPTY_SET; } else { if (schemes == null) { schemes = DEFAULT_SCHEMES; } this.allowedSchemes = new HashSet(); 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; } if (!isValidScheme(urlMatcher.group(PARSE_URL_SCHEME))) { return false; } if (!isValidAuthority(urlMatcher.group(PARSE_URL_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(); 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) { if (query == null) { return true; } return 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) { if (fragment == null) { return true; } return 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; } }