support opening the browser via pserve.open_url config setting

pyramid/scripts/pserve.py

@@ -146,11 +146,11 @@ def pserve_file_config(self, filename, global_conf=None):
 
         config = self.ConfigParser(defaults=defaults)
         config.optionxform = str
-        config.read(filename)
         try:
+            config.read(filename)
             items = dict(config.items('pserve'))
-        except configparser.NoSectionError:
-            items = {}
+        except (IOError, configparser.NoSectionError):
+            return
 
         watch_files = aslist(items.get('watch_files', ''), flatten=False)
 
@@ -163,10 +163,31 @@ def pserve_file_config(self, filename, global_conf=None):
                 file = os.path.join(here, file)
             self.watch_files.add(os.path.abspath(file))
 
+        # attempt to determine the url of the server
         open_url = items.get('open_url')
         if open_url:
             self.open_url = open_url
 
+    def _guess_server_url(self, filename, server_name,
+                          global_conf=None):  # pragma: no cover
+        server_name = server_name or 'main'
+        here = os.path.abspath(os.path.dirname(filename))
+        defaults = {}
+        if global_conf:
+            defaults.update(global_conf)
+        defaults['here'] = here
+
+        config = self.ConfigParser(defaults=defaults)
+        config.optionxform = str
+        try:
+            config.read(filename)
+            items = dict(config.items('server:' + server_name))
+        except (IOError, configparser.NoSectionError):
+            return
+
+        if 'port' in items:
+            return 'http://127.0.0.1:{port}'.format(**items)
+
     def run(self):  # pragma: no cover
         if not self.args.config_uri:
             self.out('You must give a config file')
@@ -194,6 +215,12 @@ def run(self):  # pragma: no cover
         if self.args.browser and not hupper.is_active():
             self.pserve_file_config(config_path, global_conf=vars)
             url = self.open_url
+
+            # do not guess the url if the server is sourced from a different
+            # location than the config_path
+            if not url and server_spec == app_spec:
+                url = self._guess_server_url(config_path, server_name, vars)
+
             if not url:
                 self.out('WARNING: could not determine the server\'s url to '
                          'open the browser. To fix this set the "open_url" '

pyramid/tests/test_scripts/test_pserve.py

@@ -80,6 +80,32 @@ def test_config_file_finds_watch_files(self):
             os.path.abspath(os.path.join(here, '*.py')),
         ]))
 
+    def test_config_file_finds_open_url(self):
+        inst = self._makeOne('development.ini')
+        self.config_factory.items = [(
+            'open_url', 'http://127.0.0.1:8080/',
+        )]
+        inst.pserve_file_config('/base/path.ini', global_conf={'a': '1'})
+        self.assertEqual(self.config_factory.defaults, {
+            'a': '1',
+            'here': os.path.abspath('/base'),
+        })
+        self.assertEqual(inst.open_url, 'http://127.0.0.1:8080/')
+
+    def test__guess_server_url(self):
+        inst = self._makeOne('development.ini')
+        self.config_factory.items = [(
+            'port', '8080',
+        )]
+        url = inst._guess_server_url(
+            '/base/path.ini', 'main', global_conf={'a': '1'})
+        self.assertEqual(self.config_factory.defaults, {
+            'a': '1',
+            'here': os.path.abspath('/base'),
+        })
+        self.assertEqual(self.config_factory.parser.section, 'server:main')
+        self.assertEqual(url, 'http://127.0.0.1:8080')
+
     def test_reload_call_hupper_with_correct_args(self):
         from pyramid.scripts import pserve