Limit attachments to specified file types

README.md

@@ -15,6 +15,7 @@ assignment application for Django, designed to be dropped into an existing site
 * Mobile-friendly (work in progress)
 * Separate view for My Tasks (across lists)
 * Batch-import tasks via CSV
+* Multiple file attachments per task (see settings)
 * Integrated mail tracking (unify a task list with an email box)
 
 
@@ -39,6 +40,8 @@ Identical list names can exist in different groups, but not in the same group.
 
 Emails are generated to the assigned-to person when new tasks are created.
 
+File attachments of a few types are allowed on tasks by default. See settings to disable or to limit filetypes.
+
 Comment threads can be added to tasks. Each participant in a thread receives email when new comments are added.
 
 django-todo is auth-only. You must set up a login system and at least one group before deploying.
@@ -101,7 +104,7 @@ Add links to your site's navigation system:
 <a href="{% url 'todo:mine' %}">My Tasks</a>
 ```
 
-django-todo makes use of the Django `messages` system. Make sure you have something like [this](https://docs.djangoproject.com/en/2.0/ref/contrib/messages/#displaying-messages) (link) in your `base.html`.
+django-todo makes use of the Django `messages` system. Make sure you have something like [this](https://docs.djangoproject.com/en/2.1/ref/contrib/messages/#displaying-messages) (link) in your `base.html`.
 
 Log in and access `/todo`!
 
@@ -136,6 +139,11 @@ TODO_DEFAULT_LIST_SLUG = 'tickets'
 # Defaults to "/"
 TODO_PUBLIC_SUBMIT_REDIRECT = 'dashboard'
 
+# Enable or disable file attachments on Tasks
+# Optionally limit list of allowed filetypes
+TODO_ALLOW_FILE_ATTACHMENTS = True
+TODO_ALLOWED_FILE_ATTACHMENTS = [".jpg", ".gif", ".csv", ".pdf", ".zip"]
+
 # additionnal classes the comment body should hold
 # adding "text-monospace" makes comment monospace
 TODO_COMMENT_CLASSES = []

todo/templates/todo/task_detail.html

@@ -124,7 +124,7 @@
     <div class="card-body pb-0">
       {% if task.attachment_set.count %}
         <div class="table-responsive">
-          <table class="table mb-0">
+          <table class="table mb-3">
             <thead>
               <tr>
                 <th>File</th>
@@ -147,7 +147,7 @@
         </div>
       {% endif %}
 
-      <form method="POST" action="#" enctype="multipart/form-data">
+      <form method="POST" action="" enctype="multipart/form-data" style="width:50%;">
         {% csrf_token %}
         <div class="input-group mb-3">
           <div class="custom-file">

todo/views/task_detail.py

@@ -1,4 +1,5 @@
 import datetime
+import os
 
 import bleach
 from django import forms
@@ -117,15 +118,26 @@ def task_detail(request, task_id: int) -> HttpResponse:
 
     # Handle uploaded files
     if request.FILES.get("attachment_file_input"):
+        file = request.FILES.get("attachment_file_input")
+
+        # Validate inbound file extension against allowed filetypes
+        # FIXME: Move defaults to centralized module
+        allowed_extensions = (
+            settings.TODO_ALLOWED_FILE_ATTACHMENTS
+            if hasattr(settings, "TODO_ALLOWED_FILE_ATTACHMENTS")
+            else [".jpg", ".gif", ".csv", ".pdf", ".zip"]
+        )
+        name, extension = os.path.splitext(file.name)
+        if extension not in allowed_extensions:
+            messages.error(request, f"This site does not allow upload of {extension} files.")
+            return redirect("todo:task_detail", task_id=task.id)
+
         Attachment.objects.create(
-            task=task,
-            added_by=request.user,
-            timestamp=datetime.datetime.now(),
-            file=request.FILES.get("attachment_file_input"),
+            task=task, added_by=request.user, timestamp=datetime.datetime.now(), file=file
         )
         return redirect("todo:task_detail", task_id=task.id)
 
-    # For the context: Settings for file attachments defaults to True
+    # Settings for file attachments defaults to True
     # FIXME: Move settings defaults to a central location?
     attachments_enabled = True
     if (