add bulk deletion functionality to frontend

frontend/js/apicalls.js

@@ -273,6 +273,7 @@ async function setDatasetView() {
     $('#modifyDatasetButtonGroup').hide();
     $('#filterForm').hide();
     $('#pagingBar').hide();
+    $('#deleteButtonDiv').hide();
     if (window.sessionStorage.auth_token) {
         $('#modifyDatasetButtonGroup').show();
     }
@@ -450,11 +451,13 @@ async function showListingOrSingleDataset() {
             $('#addNewDatasetForm').show();
             $('#filterForm').show();
             $('#pagingBar').show();
+            $('#deleteButtonDiv').show();
         }
         listDatasets(getType(), getFilterSearch(), getFilterName(), getFilterUrl(), getFilterKeys(), getPage());
     } else if (getId() == "new") {
         $('#datasetListTable').hide();
         $('#pagingBar').hide();
+        $('#deleteButtonDiv').hide();
         $('#storageTypeChooser').hide();
         $('#datasetViewTable').show();
         $('#filterForm').hide();
@@ -538,6 +541,16 @@ function deleteMultipleDatasets(oids, datatype) {
     disableMetadataButtons();
 }
 
+function deleteMultipleButtonPressed() {
+    // collect list of oids
+    oids = collectDeleteOIDs();
+    datatype = getType()
+    // query if user is sure to delete X datasets
+    if (confirm("Delete " + oids.length +  " elements of the type " + datatype + "?")) {
+        deleteMultipleDatasets(oids, datatype);
+    }
+}
+
 function editButtonPressed() {
     // make all inputfields editable, enable save button, disable edit button
     enableButtons(true, false, true);

frontend/templates/storage_content.html.jinja

@@ -101,6 +101,10 @@
         </table>
       </div>
 
+      <div id ="deleteButtonDiv">
+        <button type="button" class="btn btn-danger" onclick="deleteMultipleButtonPressed()">Delete Selected Datasets</button>
+      </div>
+
       <div class="btn-group" role="group" id="modifyDatasetButtonGroup">
         <button type="button" class="btn btn-success" disabled id="button-save" onclick="saveButtonPressed()">Save</button>
         <button type="button" class="btn btn-primary" id="button-edit" onclick="editButtonPressed()">Edit</button>