[MNG-6975] Wagon-HTTP, set content-type when determinable from file extension

wagon-providers/pom.xml

@@ -78,4 +78,20 @@ under the License.
       <scope>test</scope>
     </dependency>
   </dependencies>
+
+  <profiles>
+    <profile>
+      <id>jdk11</id>
+      <activation>
+        <jdk>[1.11,)</jdk>
+      </activation>
+      <dependencies>
+        <dependency>
+          <groupId>com.sun.activation</groupId>
+          <artifactId>javax.activation</artifactId>
+          <version>1.2.0</version>
+        </dependency>
+      </dependencies>
+    </profile>
+  </profiles>
 </project>

wagon-providers/wagon-http-shared/src/main/java/org/apache/maven/wagon/shared/http/AbstractHttpClientWagon.java

@@ -82,6 +82,7 @@
 import org.apache.maven.wagon.resource.Resource;
 import org.codehaus.plexus.util.StringUtils;
 
+import javax.activation.MimetypesFileTypeMap;
 import javax.net.ssl.HttpsURLConnection;
 import javax.net.ssl.SSLContext;
 import java.io.Closeable;
@@ -119,6 +120,8 @@
 public abstract class AbstractHttpClientWagon
     extends StreamWagon
 {
+    private static final MimetypesFileTypeMap FILE_TYPE_MAP = new MimetypesFileTypeMap();
+
     final class WagonHttpEntity
         extends AbstractHttpEntity
     {
@@ -142,6 +145,19 @@ private WagonHttpEntity( final InputStream stream, final Resource resource, fina
             {
                 this.source = source;
                 this.repeatable = true;
+                // if the content-type has not been set then
+                // if the option flag is TRUE and the content type is determinable from the file extension
+                // then set it from the file extension
+                if ( getContentType() == null )
+                {
+                    final String mimeType = SET_CONTENT_TYPE_FROM_FILE_EXTENSION
+                            ? FILE_TYPE_MAP.getContentType( source )
+                            : null;
+                    if ( mimeType != null && !mimeType.isEmpty() )
+                    {
+                        setContentType( mimeType );
+                    }
+                }
             }
             else
             {
@@ -152,6 +168,7 @@ private WagonHttpEntity( final InputStream stream, final Resource resource, fina
             this.length = resource == null ? -1 : resource.getContentLength();
 
             this.wagon = wagon;
+
         }
 
         public Resource getResource()
@@ -279,6 +296,13 @@ public boolean isStreaming()
     private static final boolean SSL_ALLOW_ALL =
         Boolean.valueOf( System.getProperty( "maven.wagon.http.ssl.allowall", "false" ) );
 
+    /**
+     * If enabled, then the content-type HTTP header will be set using the file extension to determine the type,
+     * <b>disabled by default</b>
+     * This flag is only effective when uploading from a File, not directly from a Stream.
+     */
+    private static final boolean SET_CONTENT_TYPE_FROM_FILE_EXTENSION =
+            Boolean.valueOf( System.getProperty( "maven.wagon.http.file.autocontenttype", "false" ) );
 
     /**
      * Maximum concurrent connections per distinct route.