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[wolnelektury.git] / src / wolnelektury / utils.py

diff --git a/src/wolnelektury/utils.py b/src/wolnelektury/utils.py
index e8aa7fb..2ce231b 100644 (file)
--- a/src/wolnelektury/utils.py
+++ b/src/wolnelektury/utils.py
@@ -2,8 +2,16 @@
 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
 #
+import json
 import os
+from functools import wraps
+
 import pytz
+from inspect import getargspec
+
+from django.http import HttpResponse
+from django.template import RequestContext
+from django.template.loader import render_to_string
 from django.utils import timezone
 from django.conf import settings
 
@@ -23,3 +31,78 @@ def utc_for_js(dt):
 def makedirs(path):
     if not os.path.isdir(path):
         os.makedirs(path)
+
+
+def stringify_keys(dictionary):
+    return dict((keyword.encode('ascii'), value)
+                for keyword, value in dictionary.iteritems())
+
+
+def json_encode(obj, sort_keys=True, ensure_ascii=False):
+    return json.dumps(obj, sort_keys=sort_keys, ensure_ascii=ensure_ascii)
+
+
+def json_decode(obj):
+    return json.loads(obj)
+
+
+def json_decode_fallback(value):
+    try:
+        return json_decode(value)
+    except ValueError:
+        return value
+
+
+class AjaxError(Exception):
+    pass
+
+
+def ajax(login_required=False, method=None, template=None, permission_required=None):
+    def decorator(fun):
+        @wraps(fun)
+        def ajax_view(request):
+            kwargs = {}
+            request_params = None
+            if method == 'post':
+                request_params = request.POST
+            elif method == 'get':
+                request_params = request.GET
+            fun_params, xx, fun_kwargs, defaults = getargspec(fun)
+            if defaults:
+                required_params = fun_params[1:-len(defaults)]
+            else:
+                required_params = fun_params[1:]
+            missing_params = set(required_params) - set(request_params)
+            if missing_params:
+                res = {
+                    'result': 'missing params',
+                    'missing': ', '.join(missing_params),
+                }
+            else:
+                if request_params:
+                    request_params = dict(
+                        (key, json_decode_fallback(value))
+                        for key, value in request_params.iteritems()
+                        if fun_kwargs or key in fun_params)
+                    kwargs.update(stringify_keys(request_params))
+                res = None
+                if login_required and not request.user.is_authenticated():
+                    res = {'result': 'logout'}
+                if (permission_required and
+                        not request.user.has_perm(permission_required)):
+                    res = {'result': 'access denied'}
+            if not res:
+                try:
+                    res = fun(request, **kwargs)
+                    if res and template:
+                        res = {'html': render_to_string(template, res, RequestContext(request))}
+                except AjaxError as e:
+                    res = {'result': e.args[0]}
+            if 'result' not in res:
+                res['result'] = 'ok'
+            return HttpResponse(json_encode(res), content_type='application/json; charset=utf-8',
+                                status=200 if res['result'] == 'ok' else 400)
+
+        return ajax_view
+
+    return decorator