pyflake and pylint cleanups.

src/daemon.py

@@ -1,3 +1,7 @@
+"""
+Provide daemon capabilities via the Daemon class.
+"""
+
 import logging
 import os
 import sys
@@ -8,10 +12,13 @@ import atexit
 
 
 class DaemonError(Exception):
+    """
+    Default error for Daemon class.
+    """
     pass
 
 
-class Daemon:  # pragma: no cover
+class Daemon(object):  # pragma: no cover
     """
     Daemonize the current process (detach it from the console).
     """
@@ -27,17 +34,24 @@ class Daemon:  # pragma: no cover
             self.log_file = log_file
         self.foreground = foreground
 
+        log_fmt = '%(asctime)s:%(name)s:%(levelname)s:%(message)s'
         logging.basicConfig(level=log_level,
-                            format='%(asctime)s:%(name)s:%(levelname)s:%(message)s',
+                            format=log_fmt,
                             filename=self.log_file,
                             filemode='a')
         self.log = logging.getLogger('DAEMON')
-        self.shutdown_cb = None
+        self.shutdown_callback = None
 
-    def register_shutdown_cb(self, cb):
-        self.shutdown_cb = cb
+    def register_shutdown_callback(self, callback):
+        """
+        Register a callback to be executed when the daemon is stopped.
+        """
+        self.shutdown_callback = callback
 
     def start(self):
+        """
+        Start the daemon. Raises a DaemonError if it's already running.
+        """
         self.log.info("Starting")
         if self.is_running():
             self.log.error('Already running')
@@ -46,6 +60,10 @@ class Daemon:  # pragma: no cover
             self._fork()
 
     def stop(self):
+        """
+        Stop the daemon. Raises a DaemonError if the daemon is ot running,
+        which is determined by examaning the PID file.
+        """
         if not self.is_running():
             raise DaemonError("Not running")
 
@@ -101,6 +119,11 @@ class Daemon:  # pragma: no cover
         return True
 
     def _fork(self):
+        """
+        Fork the current process daemon-style. Forks twice, closes file
+        descriptors, etc. A signal handler is also registered to be called if
+        the daemon received a SIGTERM signal.
+        """
         # Fork a child and end the parent (detach from parent)
         pid = os.fork()
         if pid > 0:
@@ -114,9 +137,9 @@ class Daemon:  # pragma: no cover
         pid = os.fork()
         if pid > 0:
             self.log.info("PID = {0}".format(pid))
-            f = file(self.pid_file, 'w')
-            f.write(str(pid))
-            f.close()
+            pidfile = file(self.pid_file, 'w')
+            pidfile.write(str(pid))
+            pidfile.close()
             sys.exit(0)  # End parent
 
         atexit.register(self._cleanup)
@@ -124,9 +147,9 @@ class Daemon:  # pragma: no cover
 
         # Close STDIN, STDOUT and STDERR so we don't tie up the controlling
         # terminal
-        for fd in (0, 1, 2):
+        for fdescriptor in (0, 1, 2):
             try:
-                os.close(fd)
+                os.close(fdescriptor)
             except OSError:
                 pass
 
@@ -139,7 +162,10 @@ class Daemon:  # pragma: no cover
         return pid
 
     def _cleanup(self, sig=None):
+        """
+        Remvoe pid files and call registered shutodnw callbacks.
+        """
         self.log.info("Received signal {0}".format(sig))
         if os.path.exists(self.pid_file):
             os.unlink(self.pid_file)
-        self.shutdown_cb()
+        self.shutdown_callback()

src/formconfig.py

@@ -1,3 +1,9 @@
+"""
+FormConfig is the in-memory representation of a form configuration JSON file.
+It holds information (title, users, the form definitions) on the form
+configuration being served by this instance of ScriptForm.
+"""
+
 import logging
 import stat
 import os
@@ -5,16 +11,20 @@ import subprocess
 
 
 class FormConfigError(Exception):
+    """
+    Default error for FormConfig errors
+    """
     pass
 
 
-class FormConfig:
+class FormConfig(object):
     """
     FormConfig is the in-memory representation of a form configuration JSON
     file. It holds information (title, users, the form definitions) on the
     form configuration being served by this instance of ScriptForm.
     """
-    def __init__(self, title, forms, users=None, static_dir=None, custom_css=None):
+    def __init__(self, title, forms, users=None, static_dir=None,
+                 custom_css=None):
         self.title = title
         self.users = {}
         if users is not None:
@@ -27,7 +37,8 @@ class FormConfig:
         # Validate scripts
         for form_def in self.forms:
             if not stat.S_IXUSR & os.stat(form_def.script)[stat.ST_MODE]:
-                raise FormConfigError("{0} is not executable".format(form_def.script))
+                msg = "{0} is not executable".format(form_def.script)
+                raise FormConfigError(msg)
 
     def get_form_def(self, form_name):
         """
@@ -70,29 +81,33 @@ class FormConfig:
 
         # Validate params
         if form.output == 'raw' and (stdout is None or stderr is None):
-            raise ValueError('stdout and stderr cannot be None if script output is \'raw\'')
+            msg = 'stdout and stderr cannot be none if script output ' \
+                  'is \'raw\''
+            raise ValueError(msg)
 
         # Pass form values to the script through the environment as strings.
         env = os.environ.copy()
-        for k, v in form_values.items():
-            env[k] = str(v)
+        for key, value in form_values.items():
+            env[key] = str(value)
 
         # If the form output type is 'raw', we directly stream the output to
         # the browser. Otherwise we store it for later displaying.
         if form.output == 'raw':
-            p = subprocess.Popen(form.script, shell=True,
-                                 stdout=stdout,
-                                 stderr=stderr,
-                                 env=env)
-            stdout, stderr = p.communicate(input)
-            return p.returncode
+            proc = subprocess.Popen(form.script, shell=True,
+                                    stdout=stdout,
+                                    stderr=stderr,
+                                    env=env)
+            stdout, stderr = proc.communicate(input)
+            return proc.returncode
         else:
-            p = subprocess.Popen(form.script, shell=True, stdin=subprocess.PIPE,
-                                 stdout=subprocess.PIPE, stderr=subprocess.PIPE,
-                                 env=env)
-            stdout, stderr = p.communicate()
+            proc = subprocess.Popen(form.script, shell=True,
+                                    stdin=subprocess.PIPE,
+                                    stdout=subprocess.PIPE,
+                                    stderr=subprocess.PIPE,
+                                    env=env)
+            stdout, stderr = proc.communicate()
             return {
                 'stdout': stdout,
                 'stderr': stderr,
-                'exitcode': p.returncode
+                'exitcode': proc.returncode
             }

src/formdefinition.py

@@ -1,12 +1,18 @@
+"""
+FormDefinition holds information about a single form and provides methods for
+validation of the form values.
+"""
+
 import os
 import datetime
 
 
 class ValidationError(Exception):
+    """Default exception for Validation errors"""
     pass
 
 
-class FormDefinition:
+class FormDefinition(object):
     """
     FormDefinition holds information about a single form and provides methods
     for validation of the form values.
@@ -25,6 +31,9 @@ class FormDefinition:
         self.allowed_users = allowed_users
 
     def get_field_def(self, field_name):
+        """
+        Return the field definition for `field_name`.
+        """
         for field in self.fields:
             if field['name'] == field_name:
                 return field
@@ -40,9 +49,11 @@ class FormDefinition:
 
         # First make sure all required fields are there
         for field in self.fields:
-            if 'required' in field and \
-               field['required'] is True and \
-               (field['name'] not in form_values or form_values[field['name']] == ''):
+            field_required = ('required' in field and
+                              field['required'] is True)
+            field_missing = (field['name'] not in form_values or
+                             form_values[field['name']] == '')
+            if field_required and field_missing:
                 errors.setdefault(field['name'], []).append(
                     "This field is required"
                 )
@@ -51,14 +62,15 @@ class FormDefinition:
         for field in self.fields:
             field_name = field['name']
             if field_name in errors:
-                # Skip fields that are required but missing, since they can't be validated
+                # Skip fields that are required but missing, since they can't
+                # be validated
                 continue
             try:
-                v = self._field_validate(field_name, form_values)
-                if v is not None:
-                    values[field_name] = v
-            except ValidationError, e:
-                errors.setdefault(field_name, []).append(str(e))
+                value = self._field_validate(field_name, form_values)
+                if value is not None:
+                    values[field_name] = value
+            except ValidationError, err:
+                errors.setdefault(field_name, []).append(str(err))
 
         return (errors, values)
 
@@ -75,6 +87,9 @@ class FormDefinition:
         return validate_cb(field_def, form_values)
 
     def validate_string(self, field_def, form_values):
+        """
+        Validate a form field of type 'string'.
+        """
         value = form_values[field_def['name']]
         maxlen = field_def.get('maxlen', None)
         minlen = field_def.get('minlen', None)
@@ -87,6 +102,9 @@ class FormDefinition:
         return value
 
     def validate_integer(self, field_def, form_values):
+        """
+        Validate a form field of type 'integer'.
+        """
         value = form_values[field_def['name']]
         maxval = field_def.get('max', None)
         minval = field_def.get('min', None)
@@ -104,6 +122,9 @@ class FormDefinition:
         return int(value)
 
     def validate_float(self, field_def, form_values):
+        """
+        Validate a form field of type 'float'.
+        """
         value = form_values[field_def['name']]
         maxval = field_def.get('max', None)
         minval = field_def.get('min', None)
@@ -121,6 +142,9 @@ class FormDefinition:
         return float(value)
 
     def validate_date(self, field_def, form_values):
+        """
+        Validate a form field of type 'date'.
+        """
         value = form_values[field_def['name']]
         maxval = field_def.get('max', None)
         minval = field_def.get('min', None)
@@ -140,6 +164,9 @@ class FormDefinition:
         return value
 
     def validate_radio(self, field_def, form_values):
+        """
+        Validate a form field of type 'radio'.
+        """
         value = form_values[field_def['name']]
         if not value in [o[0] for o in field_def['options']]:
             raise ValidationError(
@@ -147,6 +174,9 @@ class FormDefinition:
         return value
 
     def validate_select(self, field_def, form_values):
+        """
+        Validate a form field of type 'select'.
+        """
         value = form_values[field_def['name']]
         if not value in [o[0] for o in field_def['options']]:
             raise ValidationError(
@@ -154,6 +184,9 @@ class FormDefinition:
         return value
 
     def validate_checkbox(self, field_def, form_values):
+        """
+        Validate a form field of type 'checkbox'.
+        """
         value = form_values.get(field_def['name'], 'off')
         if not value in ['on', 'off']:
             raise ValidationError(
@@ -161,6 +194,9 @@ class FormDefinition:
         return value
 
     def validate_text(self, field_def, form_values):
+        """
+        Validate a form field of type 'text'.
+        """
         value = form_values[field_def['name']]
         minlen = field_def.get('minlen', None)
         maxlen = field_def.get('maxlen', None)
@@ -174,6 +210,9 @@ class FormDefinition:
         return value
 
     def validate_password(self, field_def, form_values):
+        """
+        Validate a form field of type 'password'.
+        """
         value = form_values[field_def['name']]
         minlen = field_def.get('minlen', None)
 
@@ -183,6 +222,9 @@ class FormDefinition:
         return value
 
     def validate_file(self, field_def, form_values):
+        """
+        Validate a form field of type 'file'.
+        """
         value = form_values[field_def['name']]
         field_name = field_def['name']
         upload_fname = form_values[u'{0}__name'.format(field_name)]
@@ -190,6 +232,7 @@ class FormDefinition:
         extensions = field_def.get('extensions', None)
 
         if extensions is not None and upload_fname_ext not in extensions:
-            raise ValidationError("Only file types allowed: {0}".format(u','.join(extensions)))
+            msg = "Only file types allowed: {0}".format(u','.join(extensions))
+            raise ValidationError(msg)
 
         return value

src/formrender.py

@@ -1,37 +1,74 @@
-html_field = u'''
+"""
+FormRender takes care of the rendering of forms to HTML.
+"""
+
+HTML_FIELD = u'''
   <li class="{classes}">
     <p class="form-field-title">{title}</p>
-    <p class="form-field-input">{h_input} <span class="error">{errors}</span></p>
+    <p class="form-field-input">
+      {h_input}
+      <span class="error">{errors}</span>
+    </p>
   </li>
 '''
 
-html_field_checkbox = u'''
+HTML_FIELD_CHECKBOX = u'''
   <li class="checkbox {classes}">
-    <p class="form-field-input">{h_input} <p class="form-field-title">{title}</p><span class="error">{errors}</span></p>
+    <p class="form-field-input">
+      {h_input}
+      <p class="form-field-title">{title}</p>
+      <span class="error">{errors}</span>
+    </p>
   </li>
 '''
 
 
-class FormRender():
+class FormRender(object):
+    """
+    FormRender takes care of the rendering of forms to HTML.
+    """
     field_tpl = {
-        "string": u'<input {required} type="text" name="{name}" value="{value}" size="{size}" class="{classes}" style="{style}" />',
-        "number": u'<input {required} type="number" min="{minval}" max="{maxval}" name="{name}" value="{value}" class="{classes}" style="{style}" />',
-        "integer": u'<input {required} type="number" min="{minval}" max="{maxval}" name="{name}" value="{value}" class="{classes}" style="{style}" />',
-        "float": u'<input {required} type="number" min="{minval}" max="{maxval}" step="any" name="{name}" value="{value}" class="{classes}" style="{style}" />',
-        "date": u'<input {required} type="date" name="{name}" value="{value}" class="{classes}" style="{style}" />',
-        "file": u'<input {required} type="file" name="{name}" class="{classes}" style="{style}" />',
-        "password": u'<input {required} type="password" min="{minval}" name="{name}" value="{value}" class="{classes}" style="{style}" />',
-        "text": u'<textarea {required} name="{name}" rows="{rows}" cols="{cols}" style="{style}" class="{classes}">{value}</textarea>',
-        "radio_option": u'<input {checked} type="radio" name="{name}" value="{value}" class="{classes} style="{style}"">{label}<br/>',
-        "select_option": u'<option value="{value}" style="{style}" {selected}>{label}</option>',
-        "select": u'<select name="{name}" class="{classes}" style="{style}">{select_elems}</select>',
-        "checkbox": u'<input {checked} type="checkbox" name="{name}" value="on" class="{classes} style="{style}"" />',
+        "string": u'<input {required} type="text" name="{name}" '
+                  u'value="{value}" size="{size}" '
+                  u'class="{classes}" style="{style}" />',
+        "number": u'<input {required} type="number" min="{minval}" '
+                  u'max="{maxval}" name="{name}" value="{value}" '
+                  u'class="{classes}" style="{style}" />',
+        "integer": u'<input {required} type="number" min="{minval}" '
+                   u'max="{maxval}" name="{name}" value="{value}" '
+                   u'class="{classes}" style="{style}" />',
+        "float": u'<input {required} type="number" min="{minval}" '
+                 u'max="{maxval}" step="any" name="{name}" '
+                 u'value="{value}" class="{classes}" style="{style}" />',
+        "date": u'<input {required} type="date" name="{name}" value="{value}" '
+                u'class="{classes}" style="{style}" />',
+        "file": u'<input {required} type="file" name="{name}" '
+                u'class="{classes}" style="{style}" />',
+        "password": u'<input {required} type="password" min="{minval}" '
+                    u'name="{name}" value="{value}" class="{classes}" '
+                    u'style="{style}" />',
+        "text": u'<textarea {required} name="{name}" rows="{rows}" '
+                u'cols="{cols}" style="{style}" '
+                u'class="{classes}">{value}</textarea>',
+        "radio_option": u'<input {checked} type="radio" name="{name}" '
+                        u'value="{value}" class="{classes} '
+                        u'style="{style}"">{label}<br/>',
+        "select_option": u'<option value="{value}" style="{style}" '
+                         u'{selected}>{label}</option>',
+        "select": u'<select name="{name}" class="{classes}" '
+                  u'style="{style}">{select_elems}</select>',
+        "checkbox": u'<input {checked} type="checkbox" name="{name}" '
+                    u'value="on" class="{classes} style="{style}"" />',
     }
 
     def __init__(self, form_def):
         self.form_def = form_def
 
     def cast_params(self, params):
+        """
+        Casts values in `params` dictionary to the correct types and values for
+        use in the form rendering.
+        """
         new_params = params.copy()
 
         if 'required' in new_params:
@@ -52,60 +89,105 @@ class FormRender():
         return new_params
 
     def r_field(self, field_type, **kwargs):
+        """
+        Render a generic field to HTML.
+        """
         params = self.cast_params(kwargs)
         method_name = 'r_field_{0}'.format(field_type)
         method = getattr(self, method_name, None)
         return method(**params)
 
-    def r_field_string(self, name, value, size=50, required=False, classes=None, style=""):
+    def r_field_string(self, name, value, size=50, required=False,
+                       classes=None, style=""):
+        """
+        Render a string field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['string']
-        return tpl.format(name=name, value=value, size=size, required=required, classes=classes, style=style)
-
-    def r_field_number(self, name, value, minval=None, maxval=None, required=False, classes=None, style=""):
+        return tpl.format(name=name, value=value, size=size, required=required,
+                          classes=classes, style=style)
+
+    def r_field_number(self, name, value, minval=None, maxval=None,
+                       required=False, classes=None, style=""):
+        """
+        Render a number field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['number']
-        return tpl.format(name=name, value=value, minval=minval, maxval=maxval, required=required, classes=classes, style=style)
-
-    def r_field_integer(self, name, value, minval=None, maxval=None, required=False, classes=None, style=""):
+        return tpl.format(name=name, value=value, minval=minval, maxval=maxval,
+                          required=required, classes=classes, style=style)
+
+    def r_field_integer(self, name, value, minval=None, maxval=None,
+                        required=False, classes=None, style=""):
+        """
+        Render a integer field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['integer']
-        return tpl.format(name=name, value=value, minval=minval, maxval=maxval, required=required, classes=classes, style=style)
-
-    def r_field_float(self, name, value, minval=None, maxval=None, required=False, classes=None, style=""):
+        return tpl.format(name=name, value=value, minval=minval, maxval=maxval,
+                          required=required, classes=classes, style=style)
+
+    def r_field_float(self, name, value, minval=None, maxval=None,
+                      required=False, classes=None, style=""):
+        """
+        Render a float field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['integer']
-        return tpl.format(name=name, value=value, minval=minval, maxval=maxval, required=required, classes=classes, style=style)
-
-    def r_field_date(self, name, value, required=False, classes=None, style=""):
+        return tpl.format(name=name, value=value, minval=minval, maxval=maxval,
+                          required=required, classes=classes, style=style)
+
+    def r_field_date(self, name, value, required=False, classes=None,
+                     style=""):
+        """
+        Render a date field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['date']
-        return tpl.format(name=name, value=value, required=required, classes=classes, style=style)
+        return tpl.format(name=name, value=value, required=required,
+                          classes=classes, style=style)
 
     def r_field_file(self, name, required=False, classes=None, style=""):
+        """
+        Render a file field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['file']
-        return tpl.format(name=name, required=required, classes=classes, style=style)
-
-    def r_field_password(self, name, value, minval=None, required=False, classes=None, style=""):
+        return tpl.format(name=name, required=required, classes=classes,
+                          style=style)
+
+    def r_field_password(self, name, value, minval=None, required=False,
+                         classes=None, style=""):
+        """
+        Render a password field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['password']
-        return tpl.format(name=name, value=value, minval=minval, required=required, classes=classes, style=style)
-
-    def r_field_text(self, name, value, rows=4, cols=80, required=False, classes=None, style=""):
+        return tpl.format(name=name, value=value, minval=minval,
+                          required=required, classes=classes, style=style)
+
+    def r_field_text(self, name, value, rows=4, cols=80, required=False,
+                     classes=None, style=""):
+        """
+        Render a text field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['text']
-        return tpl.format(name=name, value=value, rows=rows, cols=cols, required=required, classes=classes, style=style)
+        return tpl.format(name=name, value=value, rows=rows, cols=cols,
+                          required=required, classes=classes, style=style)
 
     def r_field_radio(self, name, value, options, classes=None, style=""):
+        """
+        Render a radio field to HTML.
+        """
         if classes is None:
             classes = []
         tpl_option = self.field_tpl['radio_option']
@@ -114,16 +196,25 @@ class FormRender():
             checked = ''
             if o_value == value:
                 checked = 'checked'
-            radio_elems.append(tpl_option.format(name=name, value=value, checked=checked, label=o_label, classes=classes, style=style))
+            radio_elems.append(tpl_option.format(name=name, value=value,
+                               checked=checked, label=o_label, classes=classes,
+                               style=style))
         return u''.join(radio_elems)
 
     def r_field_checkbox(self, name, checked, classes='', style=""):
+        """
+        Render a checkbox field to HTML.
+        """
         if classes is None:
             classes = []
         tpl = self.field_tpl['checkbox']
-        return tpl.format(name=name, checked=checked, classes=classes, style=style)
+        return tpl.format(name=name, checked=checked, classes=classes,
+                          style=style)
 
     def r_field_select(self, name, value, options, classes=None, style=""):
+        """
+        Render a select field to HTML.
+        """
         if classes is None:
             classes = []
         tpl_option = self.field_tpl['select_option']
@@ -132,16 +223,22 @@ class FormRender():
             selected = ''
             if o_value == value:
                 selected = 'selected'
-            select_elems.append(tpl_option.format(value=o_value, selected=selected, label=o_label, style=style))
+            select_elems.append(tpl_option.format(value=o_value,
+                                selected=selected, label=o_label,
+                                style=style))
 
         tpl = self.field_tpl['select']
-        return tpl.format(name=name, select_elems=''.join(select_elems), classes=classes, style=style)
+        return tpl.format(name=name, select_elems=''.join(select_elems),
+                          classes=classes, style=style)
 
     def r_form_line(self, field_type, title, h_input, classes, errors):
+        """
+        Render a line (label + input) to HTML.
+        """
         if field_type == 'checkbox':
-            html = html_field_checkbox
+            html = HTML_FIELD_CHECKBOX
         else:
-            html = html_field
+            html = HTML_FIELD
 
         return (html.format(classes=' '.join(classes),
                             title=title,

src/scriptform.py

@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 # -*- coding: utf-8 -*-
-
+#
 # Scriptform roughly works like this:
 #
 # 1. Instantiate a ScriptForm class. This takes care of loading the form config
@@ -18,9 +18,9 @@
 # 5. Depending on the request, a method is called on ScriptFormWebApp. These
 #    methods render HTML to as a response.
 # 6. If a form is submitted, its fields are validated and the script callback
-#    is called. Depending on the output type, the output of the script is either
-#    captured and displayed as HTML to the user or directly streamed to the
-#    browser.
+#    is called. Depending on the output type, the output of the script is
+#    either captured and displayed as HTML to the user or directly streamed to
+#    the browser.
 # 7. GOTO 4.
 # 8. Upon receiving an OS signal (kill, etc) the daemon calls the shutdown
 #    callback.
@@ -28,6 +28,10 @@
 #    until the next request) to stop the server.
 # 10. The program exits.
 
+"""
+Main ScriptForm program
+"""
+
 import sys
 import optparse
 import os
@@ -43,10 +47,13 @@ from webapp import ThreadedHTTPServer, ScriptFormWebApp
 
 
 class ScriptFormError(Exception):
+    """
+    Default exception thrown by ScriptForm errors.
+    """
     pass
 
 
-class ScriptForm:
+class ScriptForm(object):
     """
     'Main' class that orchestrates parsing the Form configurations and running
     the webserver.
@@ -60,7 +67,8 @@ class ScriptForm:
         self.running = False
         self.httpd = None
 
-        self.get_form_config()  # Init form config so it can raise errors about problems.
+        # Init form config so it can raise errors about kproblems.
+        self.get_form_config()
 
     def get_form_config(self):
         """
@@ -122,7 +130,8 @@ class ScriptForm:
         is called or something like SystemExit is raised in a handler.
         """
         ScriptFormWebApp.scriptform = self
-        self.httpd = ThreadedHTTPServer((listen_addr, listen_port), ScriptFormWebApp)
+        self.httpd = ThreadedHTTPServer((listen_addr, listen_port),
+                                        ScriptFormWebApp)
         self.httpd.daemon_threads = True
         self.log.info("Listening on {0}:{1}".format(listen_addr, listen_port))
         self.running = True
@@ -136,10 +145,14 @@ class ScriptForm:
         """
         self.log.info("Attempting server shutdown")
 
-        def t_shutdown(sf):
-            sf.log.info(self.websrv)
-            sf.httpd.socket.close()  # Undocumented requirement to shut the server
-            sf.httpd.shutdown()
+        def t_shutdown(scriptform_instance):
+            """
+            Callback for when the server is shutdown.
+            """
+            scriptform_instance.log.info(self.websrv)
+            # Undocumented feature to shutdow the server.
+            scriptform_instance.httpd.socket.close()
+            scriptform_instance.httpd.shutdown()
 
         # We need to spawn a new thread in which the server is shut down,
         # because doing it from the main thread blocks, since the server is
@@ -148,6 +161,9 @@ class ScriptForm:
 
 
 def main():  # pragma: no cover
+    """
+    main method
+    """
     usage = [
         sys.argv[0] + " [option] (--start|--stop) <form_definition.json>",
         "       " + sys.argv[0] + " --generate-pw",
@@ -205,15 +221,16 @@ def main():  # pragma: no cover
         log = logging.getLogger('MAIN')
         try:
             if options.action_start:
-                sf = ScriptForm(args[0], cache=not options.reload)
-                daemon.register_shutdown_cb(sf.shutdown)
+                cache = not options.reload
+                scriptform_instance = ScriptForm(args[0], cache=cache)
+                daemon.register_shutdown_callback(scriptform_instance.shutdown)
                 daemon.start()
-                sf.run(listen_port=options.port)
+                scriptform_instance.run(listen_port=options.port)
             elif options.action_stop:
                 daemon.stop()
                 sys.exit(0)
-        except Exception, e:
-            log.exception(e)
+        except Exception, err:
+            log.exception(err)
             raise
 
 if __name__ == "__main__":  # pragma: no cover

src/webapp.py

@@ -1,3 +1,8 @@
+"""
+The webapp part of Scriptform, which takes care of serving requests and
+handling them.
+"""
+
 from SocketServer import ThreadingMixIn
 import BaseHTTPServer
 from BaseHTTPServer import BaseHTTPRequestHandler
@@ -12,7 +17,7 @@ import hashlib
 from formrender import FormRender
 
 
-html_header = u'''<html>
+HTML_HEADER = u'''<html>
 <head>
   <meta charset="UTF-8">
   <style>
@@ -49,7 +54,8 @@ html_header = u'''<html>
     div.form li.hidden {{ display: none; }}
     div.form p.form-field-title {{ margin-bottom: 0px; }}
     div.form p.form-field-input {{ margin-top: 0px; }}
-    div.form li.checkbox p.form-field-input {{ float: left; margin-right: 8px; }}
+    div.form li.checkbox p.form-field-input {{ float: left;
+                                               margin-right: 8px; }}
     select,
     textarea,
     input[type=text],
@@ -82,14 +88,18 @@ html_header = u'''<html>
   <div class="page">
 '''
 
-html_footer = u'''
-  <div class="about">Powered by <a href="https://github.com/fboender/scriptform">Scriptform</a> v%%VERSION%%</div>
+HTML_FOOTER = u'''
+    <div class="about">
+      Powered by
+      <a href="https://github.com/fboender/scriptform">Scriptform</a>
+      v%%VERSION%%
+    </div>
   </div>
 </body>
 </html>
 '''
 
-html_list = u''''
+HTML_LIST = u''''
 {header}
 <div class="list">
   {form_list}
@@ -97,18 +107,23 @@ html_list = u''''
 {footer}
 '''
 
-html_form = u'''
+HTML_FORM = u'''
 {header}
 <div class="form">
   <h2 class="form-title">{title}</h2>
   <p class="form-description">{description}</p>
-  <form id="{name}" action="submit" method="post" enctype="multipart/form-data">
+  <form id="{name}" action="submit" method="post"
+   enctype="multipart/form-data">
     <input type="hidden" name="form_name" value="{name}" />
     <ul>
         {fields}
         <li class="submit">
           <input type="submit" class="btn btn-act" value="{submit_title}" />
-          <a href="."><button type="button" class="btn btn-lnk" value="Back">Back to the list</button></a>
+          <a href=".">
+            <button type="button" class="btn btn-lnk" value="Back">
+              Back to the list
+            </button>
+          </a>
         </li>
     </ul>
   </form>
@@ -116,7 +131,17 @@ html_form = u'''
 {footer}
 '''
 
-html_submit_response = u'''
+HTML_FORM_LIST = u'''
+  <li>
+    <h2 class="form-title">{title}</h2>
+    <p class="form-description">{description}</p>
+    <a class="form-link btn btn-act" href="./form?form_name={name}">
+      {title}
+    </a>
+  </li>
+'''
+
+HTML_SUBMIT_RESPONSE = u'''
 {header}
 <div class="result">
   <h2 class="result-title">{title}</h2>
@@ -136,6 +161,10 @@ html_submit_response = u'''
 
 
 class HTTPError(Exception):
+    """
+    HTTPError may be thrown by routes to indicate HTTP errors such as 404, 301,
+    etc. They are caught by the 'framework' and sent to the client's browser.
+    """
     def __init__(self, status_code, msg, headers=None):
         if headers is None:
             headers = {}
@@ -146,6 +175,9 @@ class HTTPError(Exception):
 
 
 class ThreadedHTTPServer(ThreadingMixIn, BaseHTTPServer.HTTPServer):
+    """
+    Base class for multithreaded HTTP servers.
+    """
     pass
 
 
@@ -163,9 +195,15 @@ class WebAppHandler(BaseHTTPRequestHandler):
         self.scriptform.log.info(fmt.format(self.address_string(), args))
 
     def do_GET(self):
+        """
+        Handle a GET request.
+        """
         self._call(*self._parse(self.path))
 
     def do_POST(self):
+        """
+        Handle a POST request.
+        """
         form_values = cgi.FieldStorage(
             fp=self.rfile,
             headers=self.headers,
@@ -173,12 +211,15 @@ class WebAppHandler(BaseHTTPRequestHandler):
         self._call(self.path.strip('/'), params={'form_values': form_values})
 
     def _parse(self, reqinfo):
+        """
+        Parse information from a request.
+        """
         url_comp = urlparse.urlsplit(reqinfo)
         path = url_comp.path
-        qs = urlparse.parse_qs(url_comp.query)
+        query_vars = urlparse.parse_qs(url_comp.query)
         # Only return the first value of each query var. E.g. for
         # "?foo=1&foo=2" return '1'.
-        var_values = dict([(k, v[0]) for k, v in qs.items()])
+        var_values = dict([(k, v[0]) for k, v in query_vars.items()])
         return (path.strip('/'), var_values)
 
     def _call(self, path, params):
@@ -206,21 +247,21 @@ class WebAppHandler(BaseHTTPRequestHandler):
             else:
                 raise HTTPError(404, "Not found")
             method_cb(**params)
-        except HTTPError, e:
+        except HTTPError, err:
             # HTTP erors are generally thrown by the webapp on purpose. Send
             # error to the browser.
-            if e.status_code not in (401, ):
-                self.scriptform.log.exception(e)
-            self.send_response(e.status_code)
-            for header_k, header_v in e.headers.items():
+            if err.status_code not in (401, ):
+                self.scriptform.log.exception(err)
+            self.send_response(err.status_code)
+            for header_k, header_v in err.headers.items():
                 self.send_header(header_k, header_v)
             self.end_headers()
-            self.wfile.write("Error {}: {}".format(e.status_code,
-                                                   e.msg))
+            self.wfile.write("Error {}: {}".format(err.status_code,
+                                                   err.msg))
             self.wfile.flush()
             return False
-        except Exception, e:
-            self.scriptform.log.exception(e)
+        except Exception, err:
+            self.scriptform.log.exception(err)
             self.send_error(500, "Internal server error")
             raise
 
@@ -236,7 +277,8 @@ class ScriptFormWebApp(WebAppHandler):
         """
         form_config = self.scriptform.get_form_config()
 
-        visible_forms = form_config.get_visible_forms(getattr(self, 'username', None))
+        username = getattr(self, 'username', None)
+        visible_forms = form_config.get_visible_forms(username)
         if len(visible_forms) == 1:
             first_form = visible_forms[0]
             return self.h_form(first_form.name)
@@ -282,24 +324,20 @@ class ScriptFormWebApp(WebAppHandler):
 
         form_config = self.scriptform.get_form_config()
         h_form_list = []
-        for form_def in form_config.get_visible_forms(getattr(self, 'username', None)):
-            h_form_list.append(u'''
-              <li>
-                <h2 class="form-title">{title}</h2>
-                <p class="form-description">{description}</p>
-                <a class="form-link btn btn-act" href="./form?form_name={name}">
-                  {title}
-                </a>
-              </li>
-            '''.format(title=form_def.title,
-                       description=form_def.description,
-                       name=form_def.name)
+        username = getattr(self, 'username', None)
+        for form_def in form_config.get_visible_forms(username):
+            h_form_list.append(
+                HTML_FORM_LIST.format(
+                    title=form_def.title,
+                    description=form_def.description,
+                    name=form_def.name
+                )
             )
 
-        output = html_list.format(
-            header=html_header.format(title=form_config.title,
+        output = HTML_LIST.format(
+            header=HTML_HEADER.format(title=form_config.title,
                                       custom_css=form_config.custom_css),
-            footer=html_footer,
+            footer=HTML_FOOTER,
             form_list=u''.join(h_form_list)
         )
         self.send_response(200)
@@ -317,9 +355,12 @@ class ScriptFormWebApp(WebAppHandler):
             return
 
         form_config = self.scriptform.get_form_config()
-        fr = FormRender(None)
+        fr_inst = FormRender(None)
 
         def render_field(field, errors):
+            """
+            Render a HTML field.
+            """
             params = {
                 'name': field['name'],
                 'classes': [],
@@ -336,7 +377,7 @@ class ScriptFormWebApp(WebAppHandler):
             if field['type'] not in ('radio', 'checkbox', 'select'):
                 params['required'] = field.get('required', False)
 
-            if field['type'] in ('string'):
+            if field['type'] == 'string':
                 params['size'] = field.get('size', '')
 
             if field['type'] in ('number', 'integer', 'float', 'password'):
@@ -345,7 +386,7 @@ class ScriptFormWebApp(WebAppHandler):
             if field['type'] in ('number', 'integer', 'float'):
                 params['maxval'] = field.get("max", '')
 
-            if field['type'] in ('text'):
+            if field['type'] == 'text':
                 params['rows'] = field.get("rows", '')
                 params['cols'] = field.get("cols", '')
 
@@ -359,13 +400,14 @@ class ScriptFormWebApp(WebAppHandler):
 
             if field['type'] == 'checkbox':
                 params['checked'] = False
-                if field['name'] in form_values and form_values[field['name']] == 'on':
+                if field['name'] in form_values and \
+                   form_values[field['name']] == 'on':
                     params['checked'] = True
 
-            h_input = fr.r_field(field['type'], **params)
+            h_input = fr_inst.r_field(field['type'], **params)
 
-            return fr.r_form_line(field['type'], field['title'],
-                                  h_input, params['classes'], errors)
+            return fr_inst.r_form_line(field['type'], field['title'],
+                                       h_input, params['classes'], errors)
 
         # Make sure the user is allowed to access this form.
         form_def = form_config.get_form_def(form_name)
@@ -380,15 +422,18 @@ class ScriptFormWebApp(WebAppHandler):
                 html_errors += u'<li class="error">{0}</li>'.format(error)
             html_errors += u'</ul>'
 
-        output = html_form.format(
-            header=html_header.format(title=form_config.title,
+        output = HTML_FORM.format(
+            header=HTML_HEADER.format(title=form_config.title,
                                       custom_css=form_config.custom_css),
-            footer=html_footer,
+            footer=HTML_FOOTER,
             title=form_def.title,
             description=form_def.description,
             errors=html_errors,
             name=form_def.name,
-            fields=u''.join([render_field(f, errors.get(f['name'], [])) for f in form_def.fields]),
+            fields=u''.join(
+                [render_field(f, errors.get(f['name'], []))
+                 for f in form_def.fields]
+            ),
             submit_title=form_def.submit_title
         )
         self.send_response(200)
@@ -427,18 +472,18 @@ class ScriptFormWebApp(WebAppHandler):
                 # something was actually uploaded
                 if field.filename == '':
                     continue
-                tmpfile = tempfile.mktemp(prefix="scriptform_")
-                f = file(tmpfile, 'w')
+                tmp_fname = tempfile.mktemp(prefix="scriptform_")
+                tmp_file = file(tmp_fname, 'w')
                 while True:
                     buf = field.file.read(1024 * 16)
                     if not buf:
                         break
-                    f.write(buf)
-                f.close()
+                    tmp_file.write(buf)
+                tmp_file.close()
                 field.file.close()
 
-                tmp_files.append(tmpfile)  # For later cleanup
-                values[field_name] = tmpfile
+                tmp_files.append(tmp_fname)  # For later cleanup
+                values[field_name] = tmp_fname
                 values['{0}__name'.format(field_name)] = field.filename
             else:
                 # Field is a normal form field. Store its value.
@@ -455,28 +500,35 @@ class ScriptFormWebApp(WebAppHandler):
 
             # Log the callback and its parameters for auditing purposes.
             log = logging.getLogger('CALLBACK_AUDIT')
+            cwd = os.path.realpath(os.curdir)
+            username = getattr(self.request, 'username', 'None')
             log.info("Calling script: {0}".format(form_def.script))
-            log.info("Current working dir: {0}".format(os.path.realpath(os.curdir)))
-            log.info("User: {0}".format(getattr(self.request, 'username', 'None')))
+            log.info("Current working dir: {0}".format(cwd))
+            log.info("User: {0}".format(username))
             log.info("Variables: {0}".format(dict(form_values.items())))
 
-            result = form_config.callback(form_name, form_values, self.wfile, self.wfile)
+            result = form_config.callback(form_name, form_values, self.wfile,
+                                          self.wfile)
             if form_def.output != 'raw':
                 # Ignore everything if we're doing raw output, since it's the
                 # scripts responsibility.
                 if result['exitcode'] != 0:
-                    msg = u'<span class="error">{0}</span>'.format(cgi.escape(result['stderr'].decode('utf8')))
+                    stderr = cgi.escape(result['stderr'].decode('utf8'))
+                    msg = u'<span class="error">{0}</span>'.format(stderr)
                 else:
                     if form_def.output == 'escaped':
-                        msg = u'<pre>{0}</pre>'.format(cgi.escape(result['stdout'].decode('utf8')))
+                        stdout = cgi.escape(result['stdout'].decode('utf8'))
+                        msg = u'<pre>{0}</pre>'.format(stdout)
                     else:
                         # Non-escaped output (html, usually)
                         msg = result['stdout'].decode('utf8')
 
-                output = html_submit_response.format(
-                    header=html_header.format(title=form_config.title,
-                                              custom_css=form_config.custom_css),
-                    footer=html_footer,
+                output = HTML_SUBMIT_RESPONSE.format(
+                    header=HTML_HEADER.format(
+                        title=form_config.title,
+                        custom_css=form_config.custom_css
+                    ),
+                    footer=HTML_FOOTER,
                     title=form_def.title,
                     form_name=form_def.name,
                     msg=msg,
@@ -512,7 +564,7 @@ class ScriptFormWebApp(WebAppHandler):
         if not os.path.exists(path):
             raise HTTPError(404, "Not found")
 
-        f = file(path, 'r')
+        static_file = file(path, 'r')
         self.send_response(200)
         self.end_headers()
-        self.wfile.write(f.read())
+        self.wfile.write(static_file.read())