GraphViewer: Error reporting

graphviewer/graphviewer.py

@@ -2,7 +2,7 @@
 import subprocess
 
 import networkx as nx
-from flask import Flask, render_template, request, Response
+from flask import Flask, render_template, request, Response, flash
 from markupsafe import Markup
 from networkx import DiGraph
 
@@ -11,6 +11,14 @@
 
 app = Flask(__name__)
 
+try:
+    from gv_config import SECRET_KEY
+    app.secret_key = SECRET_KEY
+except ImportError:
+    app.logger.error('No secret key config -- using unsafe default')
+    app.secret_key = b'not-really-a-secret-key'
+
+
 info = MacrogenesisInfo('target/macrogenesis/macrogen-info.zip')  # FIXME evil
 
 
@@ -20,10 +28,14 @@ class NoNodes(ValueError):
 
 def prepare_agraph():
     node_str = request.args.get('nodes')
-    nodes = info.nodes(node_str)
+    nodes, errors = info.nodes(node_str, report_errors=True)
+    if errors:
+        flash('Die folgenden zentralen Knoten wurden nicht gefunden: ' + ', '.join(errors), 'warning')
     context = request.args.get('context', False)
     abs_dates = request.args.get('abs_dates', False)
-    extra = info.nodes(request.args.get('extra', ''))
+    extra, errors = info.nodes(request.args.get('extra', ''), report_errors=True)
+    if errors:
+        flash('Die folgenden Pfadziele wurden nicht gefunden: ' + ', '.join(errors), 'warning')
     induced_edges = request.args.get('induced_edges', False)
     ignored_edges = request.args.get('ignored_edges', False)
     direct_assertions = request.args.get('assertions', False)
@@ -45,7 +57,7 @@ def prepare_agraph():
                 reduction = nx.transitive_reduction(g)
                 g = g.edge_subgraph([(u, v, k) for u, v, k, _ in expand_edges(g, reduction.edges)])
             else:
-                g.add_node('Cannot produce DAG!?')  # FIXME improve error reporting
+                flash('Cannot produce DAG – subgraph is not acyclic!?', 'error')
         g = simplify_timeline(g)
         g.add_nodes_from(nodes)
         agraph = write_dot(g, target=None, highlight=nodes, edge_labels=not no_edge_labels)
@@ -68,7 +80,8 @@ def render_form():
         output = subprocess.check_output(['dot', '-T', 'svg'], input=codecs.encode(agraph.to_string()), timeout=30)
         svg = Markup(codecs.decode(output))
     except NoNodes:
-        svg = 'Bitte Knoten und Optionen im Formular angeben.'
+        flash(Markup('<strong>Keine Knoten im Graphen.</strong> Bitte mindestens einen Knoten im Feld <em>Zentrale Knoten</em> eingeben.'), 'danger')
+        svg = ''
     return render_template('form.html', svg=svg, query=codecs.decode(request.query_string), **_normalize_args(request.args))
 
 

graphviewer/templates/faustedition.html

@@ -42,6 +42,21 @@
         </nav>
     </header>
     <main>
+        {% block errors %}
+            {% with messages = get_flashed_messages(with_categories=true) %}
+                {% if messages %}
+                    <div class="error-container center pure-g-r">
+                        {% for category, message in messages %}
+                            <div class="pure-u-1 pure-alert pure-alert-{{ category }}">
+                                <i class="fa fa-cancel pure-pull-right closebtn"
+                                   onclick="this.parentElement.parentElement.removeChild(this.parentElement);"></i>
+                                {{ message }}
+                            </div>
+                        {% endfor %}
+                    </div>
+                {% endif %}
+            {% endwith %}
+        {% endblock %}
         {% block content %}
         {% endblock %}
     </main>

graphviewer/templates/form.html

@@ -12,7 +12,7 @@ <h3>Zentrale Knoten</h3>
     <p><input type="text" name="nodes" id="nodes" value="{{ nodes }}" style="width: 100%;" placeholder="2 V H.13"></p>
     <p><input type="checkbox" name="context" id="context" {% if context %}checked{% endif %}> <label for="context">Nachbarknoten</label></p>
     <p><input type="checkbox" name="assertions" id="assertions" {% if assertions %}checked{% endif %} <label for="assertions">unmittelbare Aussagen über Kernknoten</label> </p>
-    <p><input type="submit"></p></section>
+    <p><input type="submit" class="pure-button pure-button-primary" value="Teilgraph zeichnen"></p></section>
     </section>
     <section class="pure-u-1-3">
     <h3>Zusätzliche Pfade</h3>

src/macrogen/graph.py

@@ -366,32 +366,41 @@ def first(iterable):
             else:
                 return default
 
-    def nodes(self, node_str: str, check: bool = False) -> List[Node]:
+    def nodes(self, node_str: str, check: bool = False, report_errors: bool = False) -> Union[List[Node], Tuple[List[Node], List[str]]]:
         """
         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
+            report_errors: if True, return an additional list of strings that couldn’t be resolved
 
         See also:
             MacrogenesisInfo.node
 
         Returns:
+            unless report_errors, a list of Nodes (i.e. each item is either a Reference or a date).
+            Otherwise, a pair: first a list of Nodes, then a list of strings which could not be resolved; both possibly empty.
 
         """
-        nodes = []
+        nodes: List[Node] = []
+        errors: List[str] = []
         if node_str:
             for node_spec in node_str.split(','):
                 try:
                     stripped = node_spec.strip()
                     nodes.append(self.node(stripped))
                 except KeyError:
+                    if report_errors:
+                        errors.append(node_spec)
                     if check:
                         raise
                     else:
                         logger.warning('Requested node %s not found in the graph', stripped)
-        return nodes
+        if report_errors:
+            return nodes, errors
+        else:
+            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):