refactored parsing node strings to MacrogenesisInfo

graphviewer/graphviewer.py

@@ -3,7 +3,6 @@
 
 from flask import Flask, render_template, request, Response
 from markupsafe import Markup
-from werkzeug.contrib.cache import SimpleCache
 
 from macrogen import MacrogenesisInfo, write_dot
 from macrogen.graphutils import remove_edges, simplify_timeline
@@ -17,23 +16,12 @@ class NoNodes(ValueError):
     pass
 
 
-def parse_nodes(node_str):
-    nodes = []
-    if node_str:
-        for node_spec in node_str.split(','):
-            try:
-                nodes.append(info.node(node_spec.strip()))
-            except KeyError:
-                ...  # flash("Knoten »%s« nicht gefunden", node_spec.strip())
-    return nodes
-
-
 def prepare_agraph():
     node_str = request.args.get('nodes')
-    nodes = parse_nodes(node_str)
+    nodes = info.nodes(node_str)
     context = request.args.get('context', False)
     abs_dates = request.args.get('abs_dates', False)
-    extra = parse_nodes(request.args.get('extra', ''))
+    extra = info.nodes(request.args.get('extra', ''))
     induced_edges = request.args.get('induced_edges', False)
     ignored_edges = request.args.get('ignored_edges', False)
     direct_assertions = request.args.get('assertions', False)

src/macrogen/graph.py

@@ -357,6 +357,33 @@ def first(iterable):
         except StopIteration:
             raise KeyError("No node matching {!r} in the base graph.".format(spec))
 
+    def nodes(self, node_str: str, check: bool = False) -> List[Node]:
+        """
+        Find nodes for a comma-separated list of node strings.
+
+        Args:
+            node_str:
+            check: if true, raise exception when a node has not been found
+
+        See also:
+            MacrogenesisInfo.node
+
+        Returns:
+
+        """
+        nodes = []
+        if node_str:
+            for node_spec in node_str.split(','):
+                try:
+                    stripped = node_spec.strip()
+                    nodes.append(self.node(stripped))
+                except KeyError:
+                    if check:
+                        raise
+                    else:
+                        logger.warning('Requested node %s not found in the graph', stripped)
+        return nodes
+
     def add_path(self, graph: nx.MultiDiGraph, source: Node, target: Node, weight='iweight', method='dijkstra',
                  must_exist=False, edges_from: Optional[nx.MultiDiGraph] = None):
         """