Add uniqueness of slug and uid and messages

litl/forms.py

@@ -4,6 +4,7 @@
 # Forms for litl. The main form is for creating the link.
 
 from django import forms
+from django.core.exceptions import ValidationError
 from crispy_forms.helper import FormHelper
 from crispy_forms.layout import Submit
 from .models import Slug

litl/templates/base.html

@@ -23,6 +23,17 @@ Code</a>
         <div class="col-sm-1">
         </div>
         <div class="col-sm-10">
+            {% if messages %}
+            <div class="mt-5 mb-5">
+            {% for message in messages %}
+                {% if message.tags == "error" %}
+                <div class="alert alert-danger">{{ message }}</div>
+                {% else %}
+                <div class="alert alert-info">{{ message }}</div>
+                {% endif %}
+            {% endfor %}
+            </div>
+            {% endif %}
             <div class="pt-5">
             {% block content %}
             {% endblock %}

litl/views.py

@@ -4,7 +4,9 @@
 # Views for litl.
 
 from django.shortcuts import render
-from django.http import HttpResponseRedirect
+from django import forms
+from django.http import HttpResponseRedirect, HttpResponsePermanentRedirect
+from django.contrib import messages
 
 from .settings import TEMPLATES, RANDOM_SLUG_LEN, UID_LEN
 from .models import Slug
@@ -23,25 +25,31 @@ def index(request):
 def AddSlug(request):
     """Display the form for creating a new slug.
     """
-    if request.method == 'POST':
-        form = SlugAddForm(request.POST)
-        if form.is_valid():
-            slug = form.save(commit=False)
+    form = SlugAddForm(request.POST or None)
+    if request.method == 'POST' and form.is_valid():
+        # Add slug if needed
+        if form.cleaned_data['slug'] == '':
+            rand_slug = ''.join(random.choice(ensemble) for _ in range(RANDOM_SLUG_LEN))
+            while Slug.object.filter(slug = rand_slug).exists():
+                rand_string = ''.join(random.choice(ensemble) for _ in range(RANDOM_SLUG_LEN))
+            form.cleaned_data['slug'] = rand_string
+        else:
+            # If slug added by the user, check uniqueness
+            if Slug.objects.filter(slug=form.cleaned_data['slug']).exists():
+                messages.error(request,"This slug is already in use.")
+                return render(request,'add_slug.html',{'form':form})
 
-            if slug.slug == '':
-                while slug.slug=='':
-                    rand_string = ''.join(random.choice(ensemble) for _ in range(RANDOM_SLUG_LEN))
-                    if not Slug.objects.filter(slug=rand_string).exists():
-                        slug.slug =  rand_string
-            while slug.uid == None:
-                rand_uid = ''.join(random.choice(ensemble) for _ in range(UID_LEN))
-                if not Slug.objects.filter(uid = rand_uid).exists():
-                    slug.uid = rand_uid
+        # Generate uid
+        rand_uid = ''.join(random.choice(ensemble) for _ in range(UID_LEN))
+        while  Slug.objects.filter(uid = rand_uid).exists():
+            rand_uid = ''.join(random.choice(ensemble) for _ in range(UID_LEN))
         
-            slug.save()
-            return HttpResponseRedirect('display/{}'.format(slug.slug))
-    else:
-        form = SlugAddForm()
+        slug = form.save(commit=False)
+        slug.uid = rand_uid
+        slug.save()
+        return HttpResponseRedirect('display/{}'.format(slug.slug))
+    
+    # First call, return empty form
     return render(request,'add_slug.html',{'form':form})
 
 def display(request, slug_got):
@@ -58,5 +66,5 @@ def redirect(request,slug_got):
         context = {'slug':slug_got,'request': request}
         return render(request,'unknown.html',context)
     else:
-        return HttpResponseRedirect(slug.get().destination)
+        return HttpResponsePermanentRedirect(slug.get().destination)