org.springframework.web.reactive.function.client.ExchangeFilterFunctions Maven / Gradle / Ivy
/*
* Copyright 2002-2018 the original author or 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 org.springframework.web.reactive.function.client;
import java.nio.charset.CharsetEncoder;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.Map;
import java.util.Optional;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.Predicate;
import reactor.core.publisher.Mono;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.util.Assert;
/**
* Implementations of {@link ExchangeFilterFunction} that provide various useful request filter
* operations, such as basic authentication, error handling, etc.
*
* @author Rob Winch
* @author Arjen Poutsma
* @since 5.0
*/
public abstract class ExchangeFilterFunctions {
/**
* Name of the {@link ClientRequest} attribute that contains the
* {@link Credentials}, as used by {@link #basicAuthentication()}.
*/
public static final String BASIC_AUTHENTICATION_CREDENTIALS_ATTRIBUTE =
ExchangeFilterFunctions.class.getName() + ".basicAuthenticationCredentials";
/**
* Return a filter that adds an Authorization header for HTTP Basic Authentication, based on
* the given username and password.
* Note that Basic Authentication only supports characters in the
* {@link StandardCharsets#ISO_8859_1 ISO-8859-1} character set.
* @param username the username to use
* @param password the password to use
* @return the {@link ExchangeFilterFunction} that adds the Authorization header
* @throws IllegalArgumentException if either {@code username} or {@code password} contain
* characters that cannot be encoded to ISO-8859-1
*/
public static ExchangeFilterFunction basicAuthentication(String username, String password) {
Assert.notNull(username, "'username' must not be null");
Assert.notNull(password, "'password' must not be null");
checkIllegalCharacters(username, password);
return basicAuthenticationInternal(r -> Optional.of(new Credentials(username, password)));
}
/**
* Return a filter that adds an Authorization header for HTTP Basic Authentication, based on
* the {@link Credentials} provided in the
* {@linkplain ClientRequest#attributes() request attributes}. If the attribute is not found,
* no authorization header is added.
*
Note that Basic Authentication only supports characters in the
* {@link StandardCharsets#ISO_8859_1 ISO-8859-1} character set.
* @return the {@link ExchangeFilterFunction} that adds the Authorization header
* @see #BASIC_AUTHENTICATION_CREDENTIALS_ATTRIBUTE
* @see Credentials#basicAuthenticationCredentials(String, String)
*/
public static ExchangeFilterFunction basicAuthentication() {
return basicAuthenticationInternal(
request -> request.attribute(BASIC_AUTHENTICATION_CREDENTIALS_ATTRIBUTE).map(o -> (Credentials)o));
}
private static ExchangeFilterFunction basicAuthenticationInternal(
Function> credentialsFunction) {
return ExchangeFilterFunction.ofRequestProcessor(
clientRequest -> credentialsFunction.apply(clientRequest).map(
credentials -> {
ClientRequest authorizedRequest = ClientRequest.from(clientRequest)
.headers(headers -> headers.set(HttpHeaders.AUTHORIZATION,
authorization(credentials)))
.build();
return Mono.just(authorizedRequest);
})
.orElse(Mono.just(clientRequest)));
}
private static String authorization(Credentials credentials) {
String credentialsString = credentials.username + ":" + credentials.password;
byte[] credentialBytes = credentialsString.getBytes(StandardCharsets.ISO_8859_1);
byte[] encodedBytes = Base64.getEncoder().encode(credentialBytes);
String encodedCredentials = new String(encodedBytes, StandardCharsets.ISO_8859_1);
return "Basic " + encodedCredentials;
}
/*
* Basic authentication only supports ISO 8859-1, see
* https://stackoverflow.com/questions/702629/utf-8-characters-mangled-in-http-basic-auth-username#703341
*/
private static void checkIllegalCharacters(String username, String password) {
CharsetEncoder encoder = StandardCharsets.ISO_8859_1.newEncoder();
if (!encoder.canEncode(username) || !encoder.canEncode(password)) {
throw new IllegalArgumentException(
"Username or password contains characters that cannot be encoded to ISO-8859-1");
}
}
/**
* Return a filter that returns a given {@link Throwable} as response if the given
* {@link HttpStatus} predicate matches.
* @param statusPredicate the predicate that should match the
* {@linkplain ClientResponse#statusCode() response status}
* @param exceptionFunction the function that returns the exception
* @return the {@link ExchangeFilterFunction} that returns the given exception if the predicate
* matches
*/
public static ExchangeFilterFunction statusError(Predicate statusPredicate,
Function exceptionFunction) {
Assert.notNull(statusPredicate, "Predicate must not be null");
Assert.notNull(exceptionFunction, "Function must not be null");
return ExchangeFilterFunction.ofResponseProcessor(
clientResponse -> {
if (statusPredicate.test(clientResponse.statusCode())) {
return Mono.error(exceptionFunction.apply(clientResponse));
}
else {
return Mono.just(clientResponse);
}
}
);
}
/**
* Represents a combination of username and password, as used by {@link #basicAuthentication()}.
* @see #basicAuthenticationCredentials(String, String)
*/
public static final class Credentials {
private final String username;
private final String password;
/**
* Create a new {@code Credentials} instance with the given username and password.
* @param username the username
* @param password the password
*/
public Credentials(String username, String password) {
Assert.notNull(username, "'username' must not be null");
Assert.notNull(password, "'password' must not be null");
this.username = username;
this.password = password;
}
/**
* Return a consumer that stores the given username and password in the
* {@linkplain ClientRequest.Builder#attributes(java.util.function.Consumer) request
* attributes} as a {@code Credentials} object.
* @param username the username
* @param password the password
* @return a consumer that adds the given credentials to the attribute map
* @see ClientRequest.Builder#attributes(java.util.function.Consumer)
* @see #BASIC_AUTHENTICATION_CREDENTIALS_ATTRIBUTE
*/
public static Consumer> basicAuthenticationCredentials(String username, String password) {
Credentials credentials = new Credentials(username, password);
checkIllegalCharacters(username, password);
return attributes -> attributes.put(BASIC_AUTHENTICATION_CREDENTIALS_ATTRIBUTE, credentials);
}
@Override
public boolean equals(Object o) {
if (this == o) {
return true;
}
if (o instanceof Credentials) {
Credentials other = (Credentials) o;
return this.username.equals(other.username) &&
this.password.equals(other.password);
}
return false;
}
@Override
public int hashCode() {
return 31 * this.username.hashCode() + this.password.hashCode();
}
}
}