added rest webservice method to fetch a single commit

scm-webapp/src/main/java/sonia/scm/api/rest/resources/RepositoryResource.java

@@ -91,6 +91,7 @@ import javax.ws.rs.core.GenericEntity;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Request;
 import javax.ws.rs.core.Response;
+import javax.ws.rs.core.Response.Status;
 import javax.ws.rs.core.StreamingOutput;
 import javax.ws.rs.core.UriInfo;
 
@@ -409,7 +410,6 @@ public class RepositoryResource
    *   <li>500 internal server error</li>
    * </ul>
    *
-   * @param request the current request
    * @param type the type of the repository
    * @param name the name of the repository
    *
@@ -438,6 +438,73 @@ public class RepositoryResource
     return response;
   }
 
+  /**
+   * Returns the {@link Changeset} from the given repository
+   * with the specified revision.<br />
+   * <br />
+   * Status codes:
+   * <ul>
+   *   <li>200 get successful</li>
+   *   <li>400 bad request, the changeset feature is not
+   *       supported by this type of repositories.</li>
+   *   <li>404 not found, if the repository or
+   *       the revision could not be found</li>
+   *   <li>500 internal server error</li>
+   * </ul>
+   *
+   * @param id the id of the repository
+   * @param revision the revision of the changeset
+   *
+   * @return a {@link Changeset} from the given repository
+   *
+   * @throws IOException
+   * @throws RepositoryException
+   */
+  @GET
+  @Path("{id}/changeset/{revision}")
+  public Response getChangeset(@PathParam("id") String id,
+                               @PathParam("revision") String revision)
+          throws IOException, RepositoryException
+  {
+    Response response = null;
+
+    if (Util.isNotEmpty(id) && Util.isNotEmpty(revision))
+    {
+      try
+      {
+        Changeset changeset = changesetViewerUtil.getChangeset(id, revision);
+
+        if (changeset != null)
+        {
+          response = Response.ok(changeset).build();
+        }
+        else
+        {
+          response = Response.status(Status.NOT_FOUND).build();
+        }
+      }
+      catch (RepositoryNotFoundException ex)
+      {
+        response = Response.status(Response.Status.NOT_FOUND).build();
+      }
+      catch (NotSupportedFeatuerException ex)
+      {
+        response = Response.status(Response.Status.BAD_REQUEST).build();
+      }
+    }
+    else
+    {
+      if (logger.isWarnEnabled())
+      {
+        logger.warn("id or revision is empty");
+      }
+
+      response = Response.status(Status.BAD_REQUEST).build();
+    }
+
+    return response;
+  }
+
   /**
    * Returns a list of {@link Changeset} for the given repository.<br />
    * <br />