Source Code for Module hm.app.lib.json_utils

  1  from django.contrib.contenttypes.models import ContentType 
  2  from django.utils import simplejson 
  3  #from django.core import serializers 
  4  from django.core.serializers.json import DjangoJSONEncoder 
  5  from django.db import models 
  6   
  7   
  8  ###########     
  9  ## UTILS ## 
 10  ########### 
 11   
 12 -def get_item(item_id, item_type): 
 13      if isinstance(item_type, (int, long)): 
 14          item_type = ContentType.objects.get(id=item_type) 
 15      if isinstance(item_type, ContentType): 
 16          item_type = item_type.model_class() 
 17      return item_type.objects.get(id=item_id) 
 18   
 19 -def get_type(item): 
 20      if isinstance(item, (int, long)): 
 21          return ContentType.objects.get(id=item); 
 22      else: 
 23          return ContentType.objects.get_for_model(item) 
 24   
 25   
 26 -def get_params(dict, *args, **kwargs): 
 27      """ 
 28      @summary: Tries to extract parameters from the provided dict for each keyword. 
 29      If a parameter isn't found, the keyword's value is returned. 
 30      """ 
 31      ret = [] 
 32      for k in args: 
 33          if isinstance(k, (tuple, list)): 
 34              if k[0] in dict: ret.append(dict[k]) 
 35              else: ret.append(k[1]) 
 36          else: 
 37              ret.append(dict[k]) 
 38      return ret 
 39   
 40   
 41 -def default_fields(obj): 
 42      if isinstance(obj, models.Model): 
 43          return [f.attname for f in obj._meta.fields] 
 44      return [] 
 45       
 46 -def get_field(obj, path): 
 47      if not isinstance(path, (list, tuple)): 
 48          path = [path] 
 49       
 50      ret = obj 
 51      for p in path: 
 52          if isinstance(ret, models.Model): 
 53              if isinstance(p, str): 
 54                  ret = getattr(ret, p) 
 55              else: 
 56                  raise RuntimeError("Invalid path: %s" % (".".join(path),)) 
 57               
 58          elif isinstance(ret, models.query.QuerySet): 
 59              if isinstance(p, (int, long)): 
 60                  ret = ret[p] 
 61              #elif isinstance(p, (slice)): 
 62              #    ret = list(ret.__iter__(field)) 
 63              else: 
 64                  raise RuntimeError("Invalid path: %s" % (".".join(path),)) 
 65               
 66          elif isinstance(ret, dict): 
 67              try: 
 68                  ret = ret[p] 
 69              except: 
 70                  raise RuntimeError("%s %s %s" % (ret, ret.__class__, str(path))) 
 71               
 72          else: 
 73              raise RuntimeError("Invalid path: %s" % (".".join(path),)) 
 74           
 75      #if isinstance(ret, models.Model): 
 76      #    ret = dict([(f.attname, f.value_from_object(ret)) for f in ret._meta.fields]) 
 77      #elif not isinstance(ret, (int, long, str, unicode, dict, list)): 
 78      #    raise RuntimeError("Path leads to non-json object! %s => <%s> %s" % (".".join(path), ret.__class__, ret)) 
 79   
 80      return ret 
 81   
 82 -def get_data(obj, fields=None): 
 83      """ 
 84      @summary: 
 85      Given an object and a structured list of fields, returns a dict, list, int, or str. 
 86      """ 
 87      if fields is None: 
 88          return obj 
 89      elif not isinstance(fields, (tuple, list)): 
 90          return get_field(obj, fields) 
 91      else: 
 92          if len(fields) == 0 or fields[0] == '*': 
 93              fields = default_fields(obj) + fields[1:] 
 94          fields = list(fields) 
 95       
 96      #handle double-array, which denotes an iterable object 
 97      if len(fields) == 1 and isinstance(fields[0], list): 
 98          return [get_data(o, fields[0]) for o in obj] 
 99       
100      ret = {} 
101      for f in fields: 
102          if not f: #guarantees not empty string or list 
103              continue 
104          elif isinstance(f, str): 
105              ret[f] = get_field(obj, f) 
106          elif isinstance(f, list) and isinstance(f[0], str): 
107              name = f[0] 
108              path = subfields = None 
109               
110              if isinstance(f[1], str): path = f[1].split(".")  
111              else: path = [name] 
112              if isinstance(f[-1], list): subfields = f[-1] 
113              else: subfields = None 
114               
115              if subfields is None: 
116                  ret[name] = get_field(obj, path) 
117              else: 
118                  ret[name] = get_data(get_field(obj, path), subfields) 
119          else: 
120              raise RuntimeError("Invalid field: %s" % str(f)) 
121      return ret 
122       
123 -def get_json(obj, fields=None): 
124      return simplejson.dumps(get_data(obj, fields), cls=DjangoJSONEncoder) 
125   
126 -def to_json(obj): 
127      return simplejson.dumps(obj, cls=DjangoJSONEncoder) 
128   
129   
130   
131  from django.http import Http404, HttpResponseRedirect, HttpResponse 
132  from structures import StructureDefinition, DjangoStructureDefinition 
133   
134 -def JSON_API(definition): 
135      return DjangoStructureDefinition(definition) 
136   
137 -def make_json_api(definition): 
138      return DjangoStructureDefinition(definition) 
139   
140 -def json_api(definition): 
141      if isinstance(definition, StructureDefinition): 
142          struct = definition 
143      else: 
144          struct = DjangoStructureDefinition(definition) 
145       
146      def decorator(func): 
147          def inner(*args, **kwargs): 
148              response = func(*args, **kwargs) 
149              if isinstance(response, (Http404, HttpResponseRedirect, HttpResponse)): 
150                  return response 
151              else: 
152                  data = struct.render(response) 
153                  json = to_json(data) 
154                  return HttpResponse(json, mimetype="text/javascript") 
155          inner.__name__ = func.__name__ 
156          inner.__doc__  = func.__doc__ 
157          inner.__dict__.update(func.__dict__) 
158          return inner 
159       
160      return decorator 
161   
162   
163 -def json_response(data): 
164      if not isinstance(data, (str, unicode)): 
165          data = to_json(data) 
166      return HttpResponse(data, mimetype="text/javascript") 
167