com.google.common.net.HostSpecifier Maven / Gradle / Ivy
/*
* Copyright (C) 2009 The Guava Authors
*
* Licensed 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 com.google.common.net;
import com.google.common.annotations.Beta;
import com.google.common.base.Preconditions;
import java.net.InetAddress;
import java.text.ParseException;
import javax.annotation.Nullable;
/**
* A syntactically valid host specifier, suitable for use in a URI.
* This may be either a numeric IP address in IPv4 or IPv6 notation, or a
* domain name.
*
* Because this class is intended to represent host specifiers which can
* reasonably be used in a URI, the domain name case is further restricted to
* include only those domain names which end in a recognized public suffix; see
* {@link InternetDomainName#isPublicSuffix()} for details.
*
*
Note that no network lookups are performed by any {@code HostSpecifier}
* methods. No attempt is made to verify that a provided specifier corresponds
* to a real or accessible host. Only syntactic and pattern-based checks are
* performed.
*
*
If you know that a given string represents a numeric IP address, use
* {@link InetAddresses} to obtain and manipulate a
* {@link java.net.InetAddress} instance from it rather than using this class.
* Similarly, if you know that a given string represents a domain name, use
* {@link InternetDomainName} rather than this class.
*
* @author Craig Berry
* @since 5.0
*/
@Beta
public final class HostSpecifier {
private final String canonicalForm;
private HostSpecifier(String canonicalForm) {
this.canonicalForm = canonicalForm;
}
/**
* Returns a {@code HostSpecifier} built from the provided {@code specifier},
* which is already known to be valid. If the {@code specifier} might be
* invalid, use {@link #from(String)} instead.
*
*
The specifier must be in one of these formats:
*
* - A domain name, like {@code google.com}
*
- A IPv4 address string, like {@code 127.0.0.1}
*
- An IPv6 address string with or without brackets, like
* {@code [2001:db8::1]} or {@code 2001:db8::1}
*
*
* @throws IllegalArgumentException if the specifier is not valid.
*/
public static HostSpecifier fromValid(String specifier) {
// Verify that no port was specified, and strip optional brackets from
// IPv6 literals.
final HostAndPort parsedHost = HostAndPort.fromString(specifier);
Preconditions.checkArgument(!parsedHost.hasPort());
final String host = parsedHost.getHostText();
// Try to interpret the specifier as an IP address. Note we build
// the address rather than using the .is* methods because we want to
// use InetAddresses.toUriString to convert the result to a string in
// canonical form.
InetAddress addr = null;
try {
addr = InetAddresses.forString(host);
} catch (IllegalArgumentException e) {
// It is not an IPv4 or IPv6 literal
}
if (addr != null) {
return new HostSpecifier(InetAddresses.toUriString(addr));
}
// It is not any kind of IP address; must be a domain name or invalid.
// TODO(user): different versions of this for different factories?
final InternetDomainName domain = InternetDomainName.from(host);
if (domain.hasPublicSuffix()) {
return new HostSpecifier(domain.name());
}
throw new IllegalArgumentException(
"Domain name does not have a recognized public suffix: " + host);
}
/**
* Attempts to return a {@code HostSpecifier} for the given string, throwing
* an exception if parsing fails. Always use this method in preference to
* {@link #fromValid(String)} for a specifier that is not already known to be
* valid.
*
* @throws ParseException if the specifier is not valid.
*/
public static HostSpecifier from(String specifier)
throws ParseException {
try {
return fromValid(specifier);
} catch (IllegalArgumentException e) {
// Since the IAE can originate at several different points inside
// fromValid(), we implement this method in terms of that one rather
// than the reverse.
ParseException parseException =
new ParseException("Invalid host specifier: " + specifier, 0);
parseException.initCause(e);
throw parseException;
}
}
/**
* Determines whether {@code specifier} represents a valid
* {@link HostSpecifier} as described in the documentation for
* {@link #fromValid(String)}.
*/
public static boolean isValid(String specifier) {
try {
fromValid(specifier);
return true;
} catch (IllegalArgumentException e) {
return false;
}
}
@Override
public boolean equals(@Nullable Object other) {
if (this == other) {
return true;
}
if (other instanceof HostSpecifier) {
final HostSpecifier that = (HostSpecifier) other;
return this.canonicalForm.equals(that.canonicalForm);
}
return false;
}
@Override
public int hashCode() {
return canonicalForm.hashCode();
}
/**
* Returns a string representation of the host specifier suitable for
* inclusion in a URI. If the host specifier is a domain name, the
* string will be normalized to all lower case. If the specifier was
* an IPv6 address without brackets, brackets are added so that the
* result will be usable in the host part of a URI.
*/
@Override
public String toString() {
return canonicalForm;
}
}