From ab5a4a6b6caae8f7738ad50a8c7fdfb9bea33a0b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sybren=20A=2E=20St=C3=BCvel?= <sybren@stuvel.eu>
Date: Tue, 6 Sep 2016 14:22:43 +0200
Subject: [PATCH] Custom error pages.

These make a distinction between API requests on /api/ (which will return
a JSON response) and other requests (which will return HTML).

Fixes T49212
---
 pillar/__init__.py           | 34 +++++++++++++++++++++++++++++++++-
 pillar/api/nodes/__init__.py |  2 ++
 2 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/pillar/__init__.py b/pillar/__init__.py
index 77c46173..c37a63ba 100644
--- a/pillar/__init__.py
+++ b/pillar/__init__.py
@@ -10,10 +10,11 @@ import jinja2
 import os
 import os.path
 from eve import Eve
+from flask import render_template, request
+from flask.templating import TemplateNotFound
 
 from pillar.api import custom_field_validation
 from pillar.api.utils import authentication
-from pillar.api.utils import gravatar
 from pillar.web.utils import pretty_date
 from pillar.web.nodes.routes import url_for_node
 
@@ -277,6 +278,37 @@ class PillarServer(Eve):
 
         self.finish_startup()
 
+    def register_error_handlers(self):
+        super(PillarServer, self).register_error_handlers()
+
+        for code in (403, 404, 500):
+            self.register_error_handler(code, self.pillar_error_handler)
+
+    def pillar_error_handler(self, error_ob):
+
+        if request.full_path.startswith('/%s/' % self.config['URL_PREFIX']):
+            from pillar.api.utils import jsonify
+            # This is an API request, so respond in JSON.
+            return jsonify({
+                '_status': 'ERR',
+                '_code': error_ob.code,
+                '_message': error_ob.description,
+            }, status=error_ob.code)
+
+        # See whether we should return an embedded page or a regular one.
+        if request.is_xhr:
+            fname = 'errors/%i_embed.html' % error_ob.code
+        else:
+            fname = 'errors/%i.html' % error_ob.code
+
+        # Also handle the case where we didn't create a template for this error.
+        try:
+            return render_template(fname), error_ob.code
+        except TemplateNotFound:
+            self.log.warning('Error template %s for code %i not found',
+                             fname, error_ob.code)
+            return render_template('errors/500.html'), error_ob.code
+
     def finish_startup(self):
         self.log.info('Using MongoDB database %r', self.config['MONGO_DBNAME'])
 
diff --git a/pillar/api/nodes/__init__.py b/pillar/api/nodes/__init__.py
index 07ba746e..6acdaece 100644
--- a/pillar/api/nodes/__init__.py
+++ b/pillar/api/nodes/__init__.py
@@ -34,6 +34,8 @@ def share_node(node_id):
                                    'node_type': 1,
                                    'short_code': 1
                                })
+    if not node:
+        raise wz_exceptions.NotFound('Node %s does not exist.' % node_id)
 
     check_permissions('nodes', node, request.method)