Fix #1512: Plugin doesn't abort building an image in case Podman is u…

src/main/java/io/fabric8/maven/docker/access/hc/HcChunkedResponseHandlerWrapper.java

@@ -1,11 +1,14 @@
 package io.fabric8.maven.docker.access.hc;
 
+import com.google.gson.JsonIOException;
+import com.google.gson.JsonParser;
+import com.google.gson.JsonSyntaxException;
+import com.google.gson.stream.JsonReader;
 import io.fabric8.maven.docker.access.chunked.EntityStreamReaderUtil;
 import org.apache.http.HttpResponse;
 import org.apache.http.client.ResponseHandler;
 
-import java.io.IOException;
-import java.io.InputStream;
+import java.io.*;
 import java.util.stream.Stream;
 
 public class HcChunkedResponseHandlerWrapper implements ResponseHandler<Object> {
@@ -18,15 +21,64 @@ public class HcChunkedResponseHandlerWrapper implements ResponseHandler<Object>
     @Override
     public Object handleResponse(HttpResponse response) throws IOException {
         try (InputStream stream = response.getEntity().getContent()) {
-            // Parse text as json
-            if (isJson(response)) {
-                EntityStreamReaderUtil.processJsonStream(handler, stream);
+            ByteArrayOutputStream baos = getMultipleReadbleOutputStream(stream);
+            InputStream is = new ByteArrayInputStream(baos.toByteArray());
+            // In the previous version of this file the following if() was as follows. The methode isJson() checks
+            // by header (not by body):
+            //      if(isJson(response)) {
+            //          EntityStreamReaderUtil.processJsonStream(handler, stream);
+            //      }
+            //
+            // In case the Podman daemon is used, the POST /build response is JSON and the HTTP status code is 200
+            // as expected, but there is no header "Content-Type = application/json" nor "Content-Type" at all. Seen in
+            // Podman 3.4.2. But the docker-maven-plugin relies on that JSON-body. In BuildJsonResponseHandler.process():
+            //      if (json.has("error")) {
+            //          ...
+            //          throw new DockerAccessException();
+            //      ...
+            //
+            // If no error is detected, the Maven-build goes on despite there was a problem building the
+            // image!
+            // The following if() first checks for the application/json Content-Type. If no Content-Type is set,
+            // it tries to detect if the body is JSON. If so, the handler is called.
+            if(isJsonCheckedByHeader(response) || (isMissingContentType(response) && isJsonCheckedByBody(is))){
+                is = new ByteArrayInputStream(baos.toByteArray());
+                EntityStreamReaderUtil.processJsonStream(handler, is);
             }
         }
         return null;
     }
 
-    private static boolean isJson(HttpResponse response) {
+    private ByteArrayOutputStream getMultipleReadbleOutputStream(InputStream is) throws IOException {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        byte[] buffer = new byte[1024];
+        int len;
+        while ((len = is.read(buffer)) > -1 ) {
+            baos.write(buffer, 0, len);
+        }
+        baos.flush();
+        return baos;
+    }
+
+    private static boolean isJsonCheckedByBody(InputStream is){
+        try {
+            JsonReader json = new JsonReader(new InputStreamReader(is));
+            JsonParser parser = new JsonParser();
+            parser.parse(json);
+            // No exception until here: Content is JSON.
+        } catch (JsonIOException | JsonSyntaxException e){
+            // No JSON.
+            return false;
+        }
+        return true;
+    }
+
+    private static boolean isMissingContentType(HttpResponse response){
+        return Stream.of(response.getAllHeaders())
+                .noneMatch(h -> h.getName().equalsIgnoreCase("Content-Type"));
+    }
+
+    private static boolean isJsonCheckedByHeader(HttpResponse response) {
         return Stream.of(response.getAllHeaders())
                 .filter(h -> h.getName().equalsIgnoreCase("Content-Type"))
                 .anyMatch(h -> h.getValue().toLowerCase().startsWith("application/json"));

src/test/java/io/fabric8/maven/docker/access/hc/HcChunkedResponseHandlerWrapperTest.java

@@ -16,6 +16,7 @@
 import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.nio.charset.StandardCharsets;
+import java.io.InputStream;
 
 @SuppressWarnings("unused")
 @ExtendWith(MockitoExtension.class)
@@ -56,7 +57,9 @@ void handleResponseWithTextPlainResponse() throws IOException {
     void handleResponseWithNoContentType() throws IOException {
         givenResponseHeaders();
         hcChunkedResponseHandlerWrapper.handleResponse(response);
-        verifyProcessJsonStream(0);
+        // timesCalled is 1 here because without "Content-Type" handleResponse() tries to parse the body to
+        // detect if it is JSON or not. See HcChunkedResponseHandlerWrapper.handleResponse() for more details.
+        verifyProcessJsonStream(1);
     }
 
     private void givenResponseHeaders(Header... headers) throws IOException {