BasicAuthenticationInterceptor with HttpHeaders.setBasicAuth alignment

Issue: SPR-17326

spring-web/src/main/java/org/springframework/http/HttpHeaders.java

@@ -711,13 +711,14 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 	/**
 	 * Set the value of the {@linkplain #AUTHORIZATION Authorization} header to
 	 * Basic Authentication based on the given username and password.
-	 * <p>Note that Basic Authentication only supports characters in the
+	 * <p>Note that this method only supports characters in the
 	 * {@link StandardCharsets#ISO_8859_1 ISO-8859-1} character set.
 	 * @param username the username
 	 * @param password the password
 	 * @throws IllegalArgumentException if either {@code user} or
-	 * {@code password} contain characters that cannot be encoded to ISO-8859-1.
+	 * {@code password} contain characters that cannot be encoded to ISO-8859-1
 	 * @since 5.1
+	 * @see #setBasicAuth(String, String, Charset)
 	 * @see <a href="https://tools.ietf.org/html/rfc7617">RFC 7617</a>
 	 */
 	public void setBasicAuth(String username, String password) {
@@ -730,9 +731,9 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 	 * @param username the username
 	 * @param password the password
 	 * @param charset the charset to use to convert the credentials into an octet
-	 * sequence. Defaults to {@linkplain StandardCharsets#ISO_8859_1 ISO-8859-1}
-	 * @throws IllegalArgumentException if either {@code user} or
-	 * {@code password} contain characters that cannot be encoded to ISO-8859-1.
+	 * sequence. Defaults to {@linkplain StandardCharsets#ISO_8859_1 ISO-8859-1}.
+	 * @throws IllegalArgumentException if {@code username} or {@code password}
+	 * contains characters that cannot be encoded to the given charset
 	 * @since 5.1
 	 * @see <a href="https://tools.ietf.org/html/rfc7617">RFC 7617</a>
 	 */
@@ -746,8 +747,7 @@ public class HttpHeaders implements MultiValueMap<String, String>, Serializable
 		CharsetEncoder encoder = charset.newEncoder();
 		if (!encoder.canEncode(username) || !encoder.canEncode(password)) {
 			throw new IllegalArgumentException(
-					"Username or password contains characters that cannot be encoded to " +
-			charset.displayName());
+					"Username or password contains characters that cannot be encoded to " + charset.displayName());
 		}
 
 		String credentialsString = username + ":" + password;

spring-web/src/main/java/org/springframework/http/client/support/BasicAuthenticationInterceptor.java

@@ -0,0 +1,87 @@
+/*
+ * 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.http.client.support;
+
+import java.io.IOException;
+import java.nio.charset.Charset;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpRequest;
+import org.springframework.http.client.ClientHttpRequestExecution;
+import org.springframework.http.client.ClientHttpRequestInterceptor;
+import org.springframework.http.client.ClientHttpResponse;
+import org.springframework.lang.Nullable;
+import org.springframework.util.Assert;
+
+/**
+ * {@link ClientHttpRequestInterceptor} to apply a given HTTP Basic Authentication
+ * username/password pair, unless a custom Authorization header has been set before.
+ *
+ * @author Juergen Hoeller
+ * @since 5.1.1
+ * @see HttpHeaders#setBasicAuth
+ * @see HttpHeaders#AUTHORIZATION
+ */
+public class BasicAuthenticationInterceptor implements ClientHttpRequestInterceptor {
+
+	private final String username;
+
+	private final String password;
+
+	@Nullable
+	private final Charset charset;
+
+
+	/**
+	 * Create a new interceptor which adds Basic Authentication for the
+	 * given username and password.
+	 * @param username the username to use
+	 * @param password the password to use
+	 * @see HttpHeaders#setBasicAuth(String, String)
+	 */
+	public BasicAuthenticationInterceptor(String username, String password) {
+		this(username, password, null);
+	}
+
+	/**
+	 * Create a new interceptor which adds Basic Authentication for the
+	 * given username and password, encoded using the specified charset.
+	 * @param username the username to use
+	 * @param password the password to use
+	 * @param charset the charset to use
+	 * @see HttpHeaders#setBasicAuth(String, String, Charset)
+	 */
+	public BasicAuthenticationInterceptor(String username, String password, @Nullable Charset charset) {
+		Assert.doesNotContain(username, ":", "Username must not contain a colon");
+		this.username = username;
+		this.password = password;
+		this.charset = charset;
+	}
+
+
+	@Override
+	public ClientHttpResponse intercept(
+			HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
+
+		HttpHeaders headers = request.getHeaders();
+		if (!headers.containsKey(HttpHeaders.AUTHORIZATION)) {
+			headers.setBasicAuth(this.username, this.password, this.charset);
+		}
+		return execution.execute(request, body);
+	}
+
+}

spring-web/src/main/java/org/springframework/http/client/support/BasicAuthorizationInterceptor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2017 the original author or authors.
+ * 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.
@@ -32,7 +32,11 @@ import org.springframework.util.Base64Utils;
  *
  * @author Phillip Webb
  * @since 4.3.1
+ * @deprecated as of 5.1.1, in favor of {@link BasicAuthenticationInterceptor}
+ * which reuses {@link org.springframework.http.HttpHeaders#setBasicAuth},
+ * sharing its default charset ISO-8859-1 instead of UTF-8 as used here
  */
+@Deprecated
 public class BasicAuthorizationInterceptor implements ClientHttpRequestInterceptor {
 
 	private final String username;
@@ -54,8 +58,8 @@ public class BasicAuthorizationInterceptor implements ClientHttpRequestIntercept
 
 
 	@Override
-	public ClientHttpResponse intercept(HttpRequest request, byte[] body,
-			ClientHttpRequestExecution execution) throws IOException {
+	public ClientHttpResponse intercept(
+			HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException {
 
 		String token = Base64Utils.encodeToString(
 				(this.username + ":" + this.password).getBytes(StandardCharsets.UTF_8));