Response Object

response.py

from django.core import serializers
import simplejson
from django import dispatch
from django.core.serializers.json import DateTimeAwareJSONEncoder
from django.http import HttpResponse
from django.db import models
import utils
from xml.dom import minidom
from django.conf import settings

JSON_INDENT = 4 if settings.DEBUG else 0

XMLSerializer = serializers.get_serializer("xml")
JSONSerializer = serializers.get_serializer('json')

message_sent = dispatch.Signal(providing_args=['message'])

class ResponseObject():
    """
    A generic response object for generating and returning api responses
    """
    def __init__(self, request=None):
        self._errors = []
        self._request = request
        self._messages = []
        self.success = True
        self._data = {}
        self._status = 200
        self.doc = None
        self.headers = {}
        
        if self._request:
            message_sent.connect(self.message_callback, sender=None, dispatch_uid='response_receiver')
    
    def set_headers(self, headers):
        for k, v in headers.items():
            self.headers[k] = v
    
    
    def addErrors(self, errors, status=400):
        
        self.success = False
        
        if status:
            self._status = status
            
        if isinstance(errors, basestring):
            #just a single error
            self._errors.append(errors)
            return
        
        elif isinstance(errors, list):
            # a list of errors
            for error in errors:
                self._errors.append(error)
            return
        raise TypeError("Argument 'errors' must be of type 'string' or 'list'")
    
    
    def message_callback(self, signal, sender, **kwargs):
        message = kwargs.get('message', '')
        if self._request.user.id == sender.id:
            self.addMessages(message)
        
    
    def addMessages(self, messages):
        if isinstance(messages, basestring):
            #just a single message
            self._messages.append(messages)
            return
        
        elif isinstance(messages, (list, tuple)):
            # a list of errors
            for message in messages:
                self._messages.append(message)
            return
        self._messages.append(messages)

    
    def set(self, **kwargs):
        self._data.update(kwargs)
    
    def __setitem__(self, key, value):
        self._data[key] = value
    
    def __getitem__(self, key):
        return self._data[key]
        
    def get(self, key):
        return self._data[key]
    
    def setStatus(self, status):
        assert isinstance(status, int)
        self._status = status
    
    
    def send(self, messages=None, errors=None, status=None):
        
        if errors:
            self.addErrors(errors)
        
        if status:
            self.setStatus(status)
        
        if messages:
            self.addMessages(messages)
        
        responseDict = {}
        responseDict['data'] = self._data
        responseDict['errors'] = self._errors
        responseDict['success'] = self.success
        responseDict['data']['messages'] = self._messages
        if self.doc:
            responseDict['doc'] = self.doc
        
        return HttpResponse(responseDict, status=self._status)