fix #49 avoid infinite links with a configuration limit

schedule/conf/settings.py

@@ -44,3 +44,5 @@ def get_events(request, calendar):
 
 # URL to redirect to to after an occurrence is canceled
 OCCURRENCE_CANCEL_REDIRECT = get_config('OCCURRENCE_CANCEL_REDIRECT', None)
+
+SCHEDULER_PREVNEXT_LIMIT_SECONDS = get_config('SCHEDULER_PREVNEXT_LIMIT_SECONDS', 62208000)  # two years

schedule/templates/schedule/_prevnext.html

@@ -1,11 +1,6 @@
 {% load scheduletags staticfiles %}
-<div class="prevnext">
-    <a href="{% prev_url target slug period %}">
-      <img align="top" border="0" src="{% static "schedule/img/left_mod.png" %}"/>
-    </a> 
-    &nbsp; <b>{{period_name}}</b> &nbsp; 
-    <a href="{% next_url target slug period %}">
-      <img align="top" border="0" src="{% static "schedule/img/right_mod.png" %}"/>
-    </a>
+<div class="row row-centered">
+    {% prev_url target calendar period %}
+    &nbsp; <b>{{period_name}}</b> &nbsp;
+    {% next_url target calendar period %}
 </div>
-

schedule/templates/schedule/calendar_day.html

@@ -16,8 +16,8 @@
   </a>
 </div>
 <div class="tablewrapper">
-    <div class="calendarname">{{ calendar.name }}</div>
-    {% prevnext "day_calendar" calendar.slug periods.day "l, F d, Y" %}
+    <h1>{{ calendar.name }}</h1>
+    {% prevnext "day_calendar" calendar periods.day "l, F d, Y" %}
     <div class="now">
       <a href="{% url "day_calendar" calendar.slug %}">
         {% trans "Today" %}

schedule/templates/schedule/calendar_month.html

@@ -5,7 +5,7 @@
 {% include "schedule/_dialogs.html" %}
 <div class="tablewrapper">
   <div class="calendarname">{{ calendar.name }}</div>
-  {% prevnext "month_calendar" calendar.slug periods.month "F Y"%}
+  {% prevnext "month_calendar" calendar periods.month "F Y"%}
   <div class="now">
     <a href="{% url "month_calendar" calendar.slug %}">
       {% trans "This month" %}

schedule/templates/schedule/calendar_tri_month.html

@@ -3,7 +3,7 @@
 {% block body %}
 <div class="tablewrapper">
   <div class="calendarname">{{ calendar.name }}</div>
-  {% prevnext "tri_month_calendar" calendar.slug periods.month "F Y"%}
+  {% prevnext "tri_month_calendar" calendar periods.month "F Y"%}
   <div class="now">
     <a href="{% url "tri_month_calendar" calendar.slug %}">
       {% trans "This month" %}

schedule/templates/schedule/calendar_week.html

@@ -16,7 +16,7 @@
 
 <div class="tablewrapper">
     <div class="calendarname">{{ calendar.name }}</div>
-    {% prevnext "week_calendar" calendar.slug periods.week "\W\e\ek W, M Y" %}
+    {% prevnext "week_calendar" calendar periods.week "\W\e\ek W, M Y" %}
     <div class="now">
       <a href="{% url "week_calendar" calendar.slug %}">
         {% trans "This week" %}

schedule/templates/schedule/calendar_year.html

@@ -3,7 +3,7 @@
 {% block body %}
 <div class="tablewrapper">
     <div class="calendarname">{{ calendar.name }}</div>
-    {% prevnext "year_calendar" calendar.slug periods.year "Y" %}
+    {% prevnext "year_calendar" calendar periods.year "Y" %}
     <table align="center">
     <tr>
     {% for month in periods.year.get_months %}

schedule/templatetags/scheduletags.py

@@ -7,7 +7,9 @@
 from django.utils.dateformat import format
 from django.utils.html import conditional_escape
 from django.utils.safestring import mark_safe
-from schedule.conf.settings import CHECK_EVENT_PERM_FUNC, CHECK_CALENDAR_PERM_FUNC
+from django.utils import timezone
+
+from schedule.conf.settings import CHECK_EVENT_PERM_FUNC, CHECK_CALENDAR_PERM_FUNC, SCHEDULER_PREVNEXT_LIMIT_SECONDS
 from schedule.models import Calendar
 from schedule.periods import weekday_names, weekday_abbrs
 
@@ -196,25 +198,38 @@ def querystring_for_date(date, num=6, autoescape=None):
 
 
 @register.simple_tag
-def prev_url(target, slug, period):
-    return '%s%s' % (
+def prev_url(target, calendar, period):
+    now = timezone.now()
+    delta = now - period.prev().start
+    slug = calendar.slug
+    if delta.total_seconds() > SCHEDULER_PREVNEXT_LIMIT_SECONDS:
+        return ''
+
+    return '<a href="%s%s"><span class="glyphicon glyphicon-circle-arrow-left" /></a>' % (
         reverse(target, kwargs=dict(calendar_slug=slug)),
         querystring_for_date(period.prev().start, autoescape=True))
 
 
 @register.simple_tag
-def next_url(target, slug, period):
-    return '%s%s' % (
+def next_url(target, calendar, period):
+    now = timezone.now()
+    slug = calendar.slug
+
+    delta = period.next().start - now
+    if delta.total_seconds() > SCHEDULER_PREVNEXT_LIMIT_SECONDS:
+        return ''
+
+    return '<a href="%s%s"><span class="glyphicon glyphicon-circle-arrow-right" /></a>' % (
         reverse(target, kwargs=dict(calendar_slug=slug)),
-        querystring_for_date(next(period).start, autoescape=True))
+        querystring_for_date(period.next().start, autoescape=True))
 
 
 @register.inclusion_tag("schedule/_prevnext.html")
-def prevnext(target, slug, period, fmt=None):
+def prevnext(target, calendar, period, fmt=None):
     if fmt is None:
         fmt = settings.DATE_FORMAT
     context = {
-        'slug': slug,
+        'calendar': calendar,
         'period': period,
         'period_name': format(period.start, fmt),
         'target': target,