Add workaround for "share grid link" on insecure sites

tailbone/templates/grids/buefy.mako

@@ -315,6 +315,12 @@
       </template>
 
     </b-table>
+
+    ## dummy input field needed for sharing links on *insecure* sites
+    % if request.scheme == 'http':
+        <b-input v-model="shareLink" ref="shareLink" v-show="shareLink"></b-input>
+    % endif
+
   </div>
 </script>
 
@@ -349,6 +355,11 @@
       filters: ${json.dumps(filters_data if grid.filterable else None)|n},
       filtersSequence: ${json.dumps(filters_sequence if grid.filterable else None)|n},
       selectedFilter: null,
+
+      ## dummy input value needed for sharing links on *insecure* sites
+      % if request.scheme == 'http':
+      shareLink: null,
+      % endif
   }
 
   let ${grid.component_studly} = {
@@ -382,7 +393,27 @@
       methods: {
 
           copyDirectLink() {
+
+              if (navigator.clipboard) {
+                  // this is the way forward, but requires HTTPS
                   navigator.clipboard.writeText(this.directLink)
+
+              } else {
+                  // use deprecated 'copy' command, but this just
+                  // tells the browser to copy currently-selected
+                  // text..which means we first must "add" some text
+                  // to screen, and auto-select that, before copying
+                  // to clipboard
+                  this.shareLink = this.directLink
+                  this.$nextTick(() => {
+                      let input = this.$refs.shareLink.$el.firstChild
+                      input.select()
+                      document.execCommand('copy')
+                      // re-hide the dummy input
+                      this.shareLink = null
+                  })
+              }
+
               this.$buefy.toast.open({
                   message: "Link was copied to clipboard",
                   type: 'is-info',