Updates B2WebApiHttpClientImpl to return subtypes of B2Exception (#179)

Return a subtype of B2Exception on errors when the response body does not conform to B2ErrorStructure. 
Returning a B2Exception subtype enables the B2Retryer to retry exceptions that may succeed on retry.

Author: nschile

CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## [Unreleased] - TBD
+### Added
+* Return a subtype of `B2Exception` on errors when the response body does not conform to `B2ErrorStructure`. 
+  Returning a `B2Exception` subtype enables the `B2Retryer` to retry exceptions that may succeed on retry.
+
 ## [6.1.0] - 2022-09-19
 ### Added
 * Added support for Java 8's `-parameters` option so constructor parameters do not need to be reiterated in `B2Json.constructor#params`

httpclient/src/main/java/com/backblaze/b2/client/webApiHttpClient/B2WebApiHttpClientImpl.java

@@ -284,11 +284,11 @@ private B2Exception extractExceptionFromErrorResponse(CloseableHttpResponse resp
         try {
             B2ErrorStructure err = B2Json.get().fromJson(responseText, B2ErrorStructure.class);
             return B2Exception.create(err.code, err.status, getRetryAfterSecondsOrNull(response), err.message);
-        }
-        catch (Throwable t) {
+        } catch (Throwable t) {
             // we can't parse the response as a B2 JSON error structure.
-            // so use the default.
-            return new B2Exception("unknown", statusCode, getRetryAfterSecondsOrNull(response), responseText);
+            // so use the "unknown" as the code
+            return B2Exception.create("unknown", statusCode, getRetryAfterSecondsOrNull(response), responseText);
+
         }
     }
 

httpclient/src/test/java/com/backblaze/b2/client/webApiHttpClient/B2WebApiHttpClientImplTest.java

@@ -8,6 +8,7 @@
 import com.backblaze.b2.client.contentSources.B2Headers;
 import com.backblaze.b2.client.contentSources.B2HeadersImpl;
 import com.backblaze.b2.client.exceptions.B2Exception;
+import com.backblaze.b2.client.exceptions.B2InternalErrorException;
 import com.backblaze.b2.client.structures.B2ErrorStructure;
 import com.backblaze.b2.client.webApiClients.B2WebApiClient;
 import com.backblaze.b2.json.B2Json;
@@ -73,10 +74,11 @@ public class B2WebApiHttpClientImplTest {
             RESPONSE_HEADERS
     );
 
+    private static final String ERROR_MESSAGE = "something went wrong";
     private static final B2ErrorStructure INTERNAL_ERROR_STRUCTURE = new B2ErrorStructure(
             HttpStatus.SC_INTERNAL_SERVER_ERROR,
             "bad",
-            "something went wrong");
+            ERROR_MESSAGE);
 
 
     private static final SimpleHttpRequestHandler.Response JSON_ERROR_RESPONSE = createResponse(
@@ -85,6 +87,12 @@ public class B2WebApiHttpClientImplTest {
             B2Json.toJsonOrThrowRuntime(INTERNAL_ERROR_STRUCTURE).getBytes()
     );
 
+    private static final SimpleHttpRequestHandler.Response TEXT_ERROR_RESPONSE = createResponse(
+            HttpStatus.SC_INTERNAL_SERVER_ERROR,
+            ContentType.TEXT_PLAIN.toString(),
+            ERROR_MESSAGE.getBytes()
+    );
+
     @Test
     public void testGetContent() throws B2Exception {
         // large content with enableContentCompression set to true
@@ -93,11 +101,14 @@ public void testGetContent() throws B2Exception {
         // compressed large content with false enableContentCompression
         doTestGetContent(REQUEST_HEADERS, COMPRESSED_LARGE_CONTENT_RESPONSE, RESPONSE_HEADERS);
 
-        // error case
-        doTestGetContentWithException(REQUEST_HEADERS, JSON_ERROR_RESPONSE, RESPONSE_HEADERS);
+        // error case with JSON response
+        doTestGetContentWithJsonException(REQUEST_HEADERS, JSON_ERROR_RESPONSE, RESPONSE_HEADERS);
+
+        // error case with text/plain response
+        doTestGetContentWithTextException(REQUEST_HEADERS, TEXT_ERROR_RESPONSE);
     }
 
-    private void doTestGetContentWithException(Map<String, String> requestHeaders, SimpleHttpRequestHandler.Response expectedResponse, Map<String, String> responseHeaders) {
+    private void doTestGetContentWithJsonException(Map<String, String> requestHeaders, SimpleHttpRequestHandler.Response expectedResponse, Map<String, String> responseHeaders) {
         final B2HeadersImpl.Builder requestHeaderBuilder = B2HeadersImpl.builder();
         requestHeaders.forEach(requestHeaderBuilder::set);
         requestHandler.setNextResponse(expectedResponse);
@@ -114,6 +125,24 @@ private void doTestGetContentWithException(Map<String, String> requestHeaders, S
         }
     }
 
+    private void doTestGetContentWithTextException(Map<String, String> requestHeaders, SimpleHttpRequestHandler.Response expectedResponse) {
+        final B2HeadersImpl.Builder requestHeaderBuilder = B2HeadersImpl.builder();
+        requestHeaders.forEach(requestHeaderBuilder::set);
+        requestHandler.setNextResponse(expectedResponse);
+
+        final B2ContentMemoryWriter sink = B2ContentMemoryWriter.build();
+
+        // call getContent and verify the returned exception response data
+        try {
+            b2WebApiClient.getContent(url, requestHeaderBuilder.build(), sink);
+        } catch (B2Exception b2Exception) {
+            assertEquals(B2InternalErrorException.class, b2Exception.getClass());
+            assertEquals(HttpStatus.SC_INTERNAL_SERVER_ERROR, b2Exception.getStatus());
+            assertEquals("unknown", b2Exception.getCode());
+            assertEquals(ERROR_MESSAGE, b2Exception.getMessage());
+        }
+    }
+
     private void doTestGetContent(Map<String, String> requestHeaders, SimpleHttpRequestHandler.Response expectedResponse, Map<String, String> responseHeaders) throws B2Exception {
         final B2HeadersImpl.Builder requestHeaderBuilder = B2HeadersImpl.builder();
         requestHeaders.forEach(requestHeaderBuilder::set);