Correctly return HAL resources in from/to links

frontend/app/components/api/api-v3/hal-resource-types/hal-resource-types.config.ts

@@ -36,6 +36,7 @@ function halResourceTypesConfig(halResourceTypes:HalResourceTypesService) {
       attrTypes: {
         parent: 'WorkPackage',
         children: 'WorkPackage',
+        relations: 'Relation',
       }
     },
     Activity: {
@@ -47,6 +48,13 @@ function halResourceTypesConfig(halResourceTypes:HalResourceTypesService) {
     'Activity::Revision': {
       user: 'User'
     },
+    Relation: {
+      className: 'RelationResource',
+      attrTypes: {
+        from: 'WorkPackage',
+        to: 'WorkPackage'
+      }
+    },
     Error: 'ErrorResource',
     User: 'UserResource',
     Collection: 'CollectionResource'

frontend/app/components/api/api-v3/hal-resources/relation-resource.service.ts

@@ -0,0 +1,53 @@
+//-- copyright
+// OpenProject is a project management system.
+// Copyright (C) 2012-2015 the OpenProject Foundation (OPF)
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License version 3.
+//
+// OpenProject is a fork of ChiliProject, which is a fork of Redmine. The copyright follows:
+// Copyright (C) 2006-2013 Jean-Philippe Lang
+// Copyright (C) 2010-2013 the ChiliProject Team
+//
+// This program is free software; you can redistribute it and/or
+// modify it under the terms of the GNU General Public License
+// as published by the Free Software Foundation; either version 2
+// of the License, or (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program; if not, write to the Free Software
+// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+//
+// See doc/COPYRIGHT.rdoc for more details.
+//++
+
+import {HalResource} from './hal-resource.service';
+import {opApiModule} from "../../../../angular-modules";
+import {WorkPackageResource} from './work-package-resource.service';
+
+export class RelationResource extends HalResource {
+
+  // Properties
+  public id:number;
+  public description:string|null;
+  public name:string;
+  public type:string;
+
+  // Links
+  public to:WorkPackageResource;
+  public from:WorkPackageResource;
+  public updateImmediately:HalResource;
+  public delete:HalResource;
+
+}
+
+function relationResource() {
+  return RelationResource;
+}
+
+opApiModule.factory('RelationResource', relationResource);

frontend/app/components/wp-relations/wp-relation-row/wp-relation-row.template.html

@@ -4,13 +4,13 @@
     <div class="grid-block hierarchy-item">
 
         <div class="grid-content medium-3 collapse" aria-hidden="true">
-            {{ $ctrl.relationType }}
+            {{ $ctrl.relation.type }}
         </div>
 
         <div class="grid-content medium-5 collapse" wp-single-relation
              ng-if="$ctrl.relatedWorkPackage">
             <a href="{{ singleRelationCtrl.workPackagePath($ctrl.relatedWorkPackage.id) }}"
-               aria-label="{{ $ctrl.relationType + ' ' + singleRelationCtrl.getFullIdentifier($ctrl.relatedWorkPackage, true) }}">
+               aria-label="{{ $ctrl.relation.type + ' ' + singleRelationCtrl.getFullIdentifier($ctrl.relatedWorkPackage, true) }}">
                 {{ singleRelationCtrl.getFullIdentifier($ctrl.relatedWorkPackage, true) }}
             </a>
         </div>
@@ -23,7 +23,7 @@
 
         <div class="grid-content medium-1 collapse wp-relations-controls-section">
             <accessible-by-keyboard ng-show="$ctrl.showRelationControls"
-                                    ng-if="$ctrl.relation.remove"
+                                    ng-if="$ctrl.relation.delete"
                                     execute="$ctrl.removeRelation($ctrl.relation)"
                                     aria-hidden="false"
                                     class="-shown-in-accessibility-mode">

frontend/app/components/wp-relations/wp-relations.service.ts

@@ -36,13 +36,17 @@ export class WorkPackageRelationsService {
               protected wpCacheService:WorkPackageCacheService,
               protected wpNotificationsService:WorkPackageNotificationService,
               protected I18n:op.I18n,
+              protected PathHelper,
               protected NotificationsService) {
   }
 
   public addCommonRelation(workPackage, relationType, relatedWpId) {
     const params = {
-      to_id: relatedWpId,
-      relation_type: relationType
+      _links: {
+        from: { href: workPackage.href },
+        to: { href: this.PathHelper.apiV3WorkPackagePath(relatedWpId) }
+      },
+      type: relationType
     };
 
     return workPackage.addRelation(params);
@@ -61,7 +65,7 @@ export class WorkPackageRelationsService {
   }
 
   public removeCommonRelation(relation) {
-    return relation.remove();
+    return relation.delete();
   }
 
   public getTranslatedRelationTitle(relationTypeName:string) {

lib/api/v3/relations/relation_representer.rb

@@ -156,11 +156,19 @@ module API
         end
 
         def from
-          represented.from
+          represent_work_package(represented.from)
         end
 
         def to
-          represented.to
+          represent_work_package(represented.to)
+        end
+
+        def represent_work_package(wp)
+          ::API::V3::WorkPackages::WorkPackageRepresenter.create(
+            wp,
+            current_user: current_user,
+            embed_links: false
+          )
         end
       end
     end