source: djangobb/djangobb_forum/util.py @ 223:8630bac391e6

from datetime import datetime
import os.path
import random
import re
from HTMLParser import HTMLParser

from django.shortcuts import render_to_response
from django.template import RequestContext
from django.http import HttpResponse, Http404
from django.utils.functional import Promise
from django.utils.translation import force_unicode, check_for_language
from django.utils.simplejson import JSONEncoder
from django import forms
from django.template.defaultfilters import urlize as django_urlize
from django.core.paginator import Paginator, EmptyPage, InvalidPage
from django.conf import settings

from djangobb_forum import settings as forum_settings


#compile smiles regexp
_SMILES = [(re.compile(smile_re), path) for smile_re, path in forum_settings.SMILES]


def render_to(template):
    """
    Decorator for Django views that sends returned dict to render_to_response function.

    Template name can be decorator parameter or TEMPLATE item in returned dictionary.
    RequestContext always added as context instance.
    If view doesn't return dict then decorator simply returns output.

    Parameters:
     - template: template name to use

    Examples:
    # 1. Template name in decorator parameters

    @render_to('template.html')
    def foo(request):
        bar = Bar.object.all()  
        return {'bar': bar}

    # equals to 
    def foo(request):
        bar = Bar.object.all()  
        return render_to_response('template.html', 
                                  {'bar': bar}, 
                                  context_instance=RequestContext(request))

    # 2. Template name as TEMPLATE item value in return dictionary

    @render_to()
    def foo(request, category):
        template_name = '%s.html' % category
        return {'bar': bar, 'TEMPLATE': template_name}
    
    #equals to
    def foo(request, category):
        template_name = '%s.html' % category
        return render_to_response(template_name, 
                                  {'bar': bar}, 
                                  context_instance=RequestContext(request))
    """

    def renderer(function):
        def wrapper(request, *args, **kwargs):
            output = function(request, *args, **kwargs)
            if not isinstance(output, dict):
                return output
            tmpl = output.pop('TEMPLATE', template)
            return render_to_response(tmpl, output, context_instance=RequestContext(request))
        return wrapper
    return renderer


def absolute_url(path):
    return 'http://%s%s' % (forum_settings.HOST, path)


def paged(paged_list_name, per_page):
    """
    Parse page from GET data and pass it to view. Split the
    query set returned from view.
    """

    def decorator(func):
        def wrapper(request, *args, **kwargs):
            result = func(request, *args, **kwargs)
            if not isinstance(result, dict) or 'paged_qs' not in result:
                return result
            try:
                page = int(request.GET.get('page', 1))
            except ValueError:
                page = 1

            real_per_page = per_page

            #if per_page_var:
                #try:
                    #value = int(request.GET[per_page_var])
                #except (ValueError, KeyError):
                    #pass
                #else:
                    #if value > 0:
                        #real_per_page = value

            from django.core.paginator import Paginator
            paginator = Paginator(result['paged_qs'], real_per_page)
            try:
                result[paged_list_name] = paginator.page(page).object_list
            except (InvalidPage, EmptyPage):
                raise Http404
            result['page'] = page
            result['page_list'] = range(1, paginator.num_pages + 1)
            result['pages'] = paginator.num_pages
            result['per_page'] = real_per_page
            result['request'] = request
            return result
        return wrapper

    return decorator


def ajax(func):
    """
    Checks request.method is POST. Return error in JSON in other case.

    If view returned dict, returns JsonResponse with this dict as content.
    """
    def wrapper(request, *args, **kwargs):
        if request.method == 'POST':
            try:
                response = func(request, *args, **kwargs)
            except Exception, ex:
                response = {'error': traceback.format_exc()}
        else:
            response = {'error': {'type': 403, 'message': 'Accepts only POST request'}}
        if isinstance(response, dict):
            return JsonResponse(response)
        else:
            return response
    return wrapper


class LazyJSONEncoder(JSONEncoder):
    """
    This fing need to save django from crashing.
    """

    def default(self, o):
        if isinstance(o, Promise):
            return force_unicode(o)
        else:
            return super(LazyJSONEncoder, self).default(o)


class JsonResponse(HttpResponse):
    """
    HttpResponse subclass that serialize data into JSON format.
    """

    def __init__(self, data, mimetype='application/json'):
        json_data = LazyJSONEncoder().encode(data)
        super(JsonResponse, self).__init__(
            content=json_data, mimetype=mimetype)

        
def build_form(Form, _request, GET=False, *args, **kwargs):
    """
    Shorcut for building the form instance of given form class
    """

    if not GET and 'POST' == _request.method:
        form = Form(_request.POST, _request.FILES, *args, **kwargs)
    elif GET and 'GET' == _request.method:
        form = Form(_request.GET, _request.FILES, *args, **kwargs)
    else:
        form = Form(*args, **kwargs)
    return form

class ExcludeTagsHTMLParser(HTMLParser):
        """
        Class for html parsing with excluding specified tags.
        """

        def __init__(self, func, tags=('a', 'code')):
            HTMLParser.__init__(self)
            self.func = func
            self.is_ignored = False
            self.tags = tags
            self.html = []

        def handle_starttag(self, tag, attrs):
            self.html.append('<%s%s>' % (tag, self.__html_attrs(attrs)))
            if tag in self.tags:
                self.is_ignored = True

        def handle_data(self, data):
            if not self.is_ignored:
                data = self.func(data)
            self.html.append(data)

        def handle_startendtag(self, tag, attrs):
            self.html.append('<%s%s/>' % (tag, self.__html_attrs(attrs))) 

        def handle_endtag(self, tag):
            self.is_ignored = False
            self.html.append('</%s>' % (tag))

        def handle_entityref(self, name):
            self.html.append('&%s;' % name)

        def handle_charref(self, name):
            self.html.append('&#%s;' % name)

        def __html_attrs(self, attrs):
            _attrs = ''
            if attrs:
                _attrs = ' %s' % (' '.join([('%s="%s"' % (k,v)) for k,v in attrs]))
            return _attrs

        def feed(self, data):
            HTMLParser.feed(self, data)
            self.html = ''.join(self.html)

def urlize(data):
    """
    Urlize plain text links in the HTML contents.
   
    Do not urlize content of A and CODE tags.
    """

    parser = ExcludeTagsHTMLParser(django_urlize)
    parser.feed(data)
    urlized_html = parser.html
    parser.close()
    return urlized_html

def _smile_replacer(data):
    for smile, path in _SMILES:
        data = smile.sub(path, data)
    return data

def smiles(data):
    """
    Replace text smiles.
    """

    parser = ExcludeTagsHTMLParser(_smile_replacer)
    parser.feed(data)
    smiled_html = parser.html
    parser.close()
    return smiled_html

def paginate(items, request, per_page, total_count=None):
    try:
        page_number = int(request.GET.get('page', 1))
    except ValueError:
        page_number = 1

    paginator = Paginator(items, per_page)
    pages = paginator.num_pages
    try:
        paged_list_name = paginator.page(page_number).object_list
    except (InvalidPage, EmptyPage):
        raise Http404
    return pages, paginator, paged_list_name 

def set_language(request, language):
    """
    Change the language of session of authenticated user.
    """

    if language and check_for_language(language):
        if hasattr(request, 'session'):
            request.session['django_language'] = language
        else:
            response.set_cookie(settings.LANGUAGE_COOKIE_NAME, language)