Add UnknownContentTypeException

Closes gh-24964

spring-web/src/main/java/org/springframework/web/client/HttpMessageConverterExtractor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2019 the original author or authors.
+ * Copyright 2002-2020 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.
@@ -31,6 +31,7 @@
 import org.springframework.http.converter.HttpMessageNotReadableException;
 import org.springframework.lang.Nullable;
 import org.springframework.util.Assert;
+import org.springframework.util.FileCopyUtils;
 
 /**
  * Response extractor that uses the given {@linkplain HttpMessageConverter entity converters}
@@ -120,17 +121,17 @@ public T extractData(ClientHttpResponse response) throws IOException {
 					this.responseType + "] and content type [" + contentType + "]", ex);
 		}
 
-		throw new RestClientException("Could not extract response: no suitable HttpMessageConverter found " +
-				"for response type [" + this.responseType + "] and content type [" + contentType + "]");
+		throw new UnknownContentTypeException(this.responseType, contentType,
+				response.getRawStatusCode(), response.getStatusText(), response.getHeaders(),
+				getResponseBody(response));
 	}
 
 	/**
 	 * Determine the Content-Type of the response based on the "Content-Type"
 	 * header or otherwise default to {@link MediaType#APPLICATION_OCTET_STREAM}.
 	 * @param response the response
-	 * @return the MediaType, possibly {@code null}.
+	 * @return the MediaType, or "application/octet-stream"
 	 */
-	@Nullable
 	protected MediaType getContentType(ClientHttpResponse response) {
 		MediaType contentType = response.getHeaders().getContentType();
 		if (contentType == null) {
@@ -142,4 +143,13 @@ protected MediaType getContentType(ClientHttpResponse response) {
 		return contentType;
 	}
 
+	private static byte[] getResponseBody(ClientHttpResponse response) {
+		try {
+			return FileCopyUtils.copyToByteArray(response.getBody());
+		}
+		catch (IOException ex) {
+			// ignore
+		}
+		return new byte[0];
+	}
 }

spring-web/src/main/java/org/springframework/web/client/UnknownContentTypeException.java

@@ -0,0 +1,128 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ *      https://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.client;
+
+import java.lang.reflect.Type;
+import java.nio.charset.StandardCharsets;
+
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.MediaType;
+import org.springframework.lang.Nullable;
+
+/**
+ * Raised when no suitable
+ * {@link org.springframework.http.converter.HttpMessageConverter} could be
+ * found to extract the response.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.2.7
+ */
+public class UnknownContentTypeException extends RestClientException {
+
+	private static final long serialVersionUID = 2759516676367274084L;
+
+
+	private final Type targetType;
+
+	private final MediaType contentType;
+
+	private final int rawStatusCode;
+
+	private final String statusText;
+
+	private final byte[] responseBody;
+
+	private final HttpHeaders responseHeaders;
+
+
+	/**
+	 * Construct a new instance of with the given response data.
+	 * @param targetType the expected target type
+	 * @param contentType the content type of the response
+	 * @param statusCode the raw status code value
+	 * @param statusText the status text
+	 * @param responseHeaders the response headers (may be {@code null})
+	 * @param responseBody the response body content (may be {@code null})
+	 */
+	public UnknownContentTypeException(Type targetType, MediaType contentType,
+			int statusCode, String statusText, HttpHeaders responseHeaders, byte[] responseBody) {
+
+		super("Could not extract response: no suitable HttpMessageConverter found " +
+				"for response type [" + targetType + "] and content type [" + contentType + "]");
+
+		this.targetType = targetType;
+		this.contentType = contentType;
+		this.rawStatusCode = statusCode;
+		this.statusText = statusText;
+		this.responseHeaders = responseHeaders;
+		this.responseBody = responseBody;
+	}
+
+
+	/**
+	 * Return the target type expected for the response.
+	 */
+	public Type getTargetType() {
+		return this.targetType;
+	}
+
+	/**
+	 * Return the content type of the response, or "application/octet-stream".
+	 */
+	public MediaType getContentType() {
+		return this.contentType;
+	}
+
+	/**
+	 * Return the raw HTTP status code value.
+	 */
+	public int getRawStatusCode() {
+		return this.rawStatusCode;
+	}
+
+	/**
+	 * Return the HTTP status text.
+	 */
+	public String getStatusText() {
+		return this.statusText;
+	}
+
+	/**
+	 * Return the HTTP response headers.
+	 */
+	@Nullable
+	public HttpHeaders getResponseHeaders() {
+		return this.responseHeaders;
+	}
+
+	/**
+	 * Return the response body as a byte array.
+	 */
+	public byte[] getResponseBody() {
+		return this.responseBody;
+	}
+
+	/**
+	 * Return the response body converted to String using the charset from the
+	 * response "Content-Type" or {@code "UTF-8"} otherwise.
+	 */
+	public String getResponseBodyAsString() {
+		return new String(this.responseBody, this.contentType.getCharset() != null ?
+				this.contentType.getCharset() : StandardCharsets.UTF_8);
+	}
+
+}