query_suggestions: unsupported keywords

* Adds a message for when unsupported keywords are used.

* Addresses inspirehep/inspire-next#817 .

Signed-off-by: Panos Paparrigopoulos <panos.paparrigopoulos@cern.ch>

invenio_search/query_suggestions.py

@@ -21,21 +21,27 @@
 
 from blinker import Namespace
 
-from flask import flash
+from flask import Markup, flash
 
 _signals = Namespace()
 
+unsupported_keyword = _signals.signal('unsupported_keyword')
 malformed_query = _signals.signal('malformed_query')
 extra_keywords = _signals.signal('extra_keywords')
 
 
+@unsupported_keyword.connect
+def unsupported_keyword_message(sender, keyword, *args, **kwargs):
+    flash(Markup(str('<b>' + keyword +
+                     "</b> keyword is currently unsupported.")), "query_suggestion")
+
+
 @malformed_query.connect
 def malformed_query_message(sender):
-    flash("Malformed Query", "query_suggestion")
-    pass
+    flash("Malformed Query. The results may contain unintended results.",
+          "query_suggestion")
 
 
 @extra_keywords.connect
 def extra_keywords_message(sender):
     flash("Extra-keyword Query", "query_suggestion")
-    pass

invenio_search/walkers/elasticsearch.py

@@ -30,7 +30,8 @@
 )
 from invenio_query_parser.visitor import make_visitor
 
-from invenio_search.query_suggestions import extra_keywords
+from invenio_search.query_suggestions import extra_keywords, unsupported_keyword
+
 
 class ElasticSearchDSL(object):
 
@@ -80,6 +81,11 @@ def visit(self, node, op):
 
     @visitor(KeywordOp)
     def visit(self, node, left, right):
+        if str(left) == 'refersto' or str(left) == 'citedby':
+            unsupported_keyword.send(keyword=left)
+            return {
+                "match_all": {}
+            }
         if callable(right):
             keyword = self.map_keyword_to_fields(
                 left, getattr(right, '__search_mode__', 'a')