implement basic error handling and validation for forms

owrx/controllers/settings/__init__.py

@@ -1,6 +1,7 @@
 from owrx.config import Config
 from owrx.controllers.admin import AuthorizationMixin
 from owrx.controllers.template import WebpageController
+from owrx.form.error import FormError
 from abc import ABCMeta, abstractmethod
 from urllib.parse import parse_qs
 
@@ -10,16 +11,16 @@ class Section(object):
         self.title = title
         self.inputs = inputs
 
-    def render_input(self, input, data):
-        return input.render(data)
+    def render_input(self, input, data, errors):
+        return input.render(data, errors)
 
-    def render_inputs(self, data):
-        return "".join([self.render_input(i, data) for i in self.inputs])
+    def render_inputs(self, data, errors):
+        return "".join([self.render_input(i, data, errors) for i in self.inputs])
 
     def classes(self):
         return ["col-12", "settings-section"]
 
-    def render(self, data):
+    def render(self, data, errors):
         return """
             <div class="{classes}">
                 <h3 class="settings-header">
@@ -28,11 +29,20 @@ class Section(object):
                 {inputs}
             </div>
         """.format(
-            classes=" ".join(self.classes()), title=self.title, inputs=self.render_inputs(data)
+            classes=" ".join(self.classes()), title=self.title, inputs=self.render_inputs(data, errors)
         )
 
     def parse(self, data):
-        return {k: v for i in self.inputs for k, v in i.parse(data).items()}
+        parsed_data = {}
+        errors = []
+        for i in self.inputs:
+            try:
+                parsed_data.update(i.parse(data))
+            except FormError as e:
+                errors.append(e)
+            except Exception as e:
+                errors.append(FormError(i.id, "{}: {}".format(type(e).__name__, e)))
+        return parsed_data, errors
 
 
 class SettingsController(AuthorizationMixin, WebpageController):
@@ -41,6 +51,10 @@ class SettingsController(AuthorizationMixin, WebpageController):
 
 
 class SettingsFormController(AuthorizationMixin, WebpageController, metaclass=ABCMeta):
+    def __init__(self, handler, request, options):
+        super().__init__(handler, request, options)
+        self.errors = {}
+
     @abstractmethod
     def getSections(self):
         pass
@@ -52,8 +66,11 @@ class SettingsFormController(AuthorizationMixin, WebpageController, metaclass=AB
     def getData(self):
         return Config.get()
 
+    def getErrors(self):
+        return self.errors
+
     def render_sections(self):
-        sections = "".join(section.render(self.getData()) for section in self.getSections())
+        sections = "".join(section.render(self.getData(), self.getErrors()) for section in self.getSections())
         buttons = self.render_buttons()
         return """
             <form class="settings-body" method="POST">
@@ -84,15 +101,34 @@ class SettingsFormController(AuthorizationMixin, WebpageController, metaclass=AB
 
     def parseFormData(self):
         data = parse_qs(self.get_body().decode("utf-8"), keep_blank_values=True)
-        return {k: v for i in self.getSections() for k, v in i.parse(data).items()}
+        result = {}
+        errors = []
+        for section in self.getSections():
+            section_data, section_errors = section.parse(data)
+            result.update(section_data)
+            errors += section_errors
+        return result, errors
 
     def getSuccessfulRedirect(self):
         return self.request.path
 
+    def _mergeErrors(self, errors):
+        result = {}
+        for e in errors:
+            if e.getKey() not in result:
+                result[e.getKey()] = []
+            result[e.getKey()].append(e.getMessage())
+        return result
+
     def processFormData(self):
-        self.processData(self.parseFormData())
-        self.store()
-        self.send_redirect(self.getSuccessfulRedirect())
+        data, errors = self.parseFormData()
+        if errors:
+            self.errors = self._mergeErrors(errors)
+            self.indexAction()
+        else:
+            self.processData(data)
+            self.store()
+            self.send_redirect(self.getSuccessfulRedirect())
 
     def processData(self, data):
         config = self.getData()