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# jsonrpc.py

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#   original code: http://trac.pyworks.org/pyjamas/wiki/DjangoWithPyJamas

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#   also from: http://www.pimentech.fr/technologies/outils

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import datetime

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from django.core.serializers import serialize

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# JSONRPCService and jsonremote are used in combination to drastically

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# simplify the provision of JSONRPC services.  use as follows:

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#

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# jsonservice = JSONRPCService()

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#

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# @jsonremote(jsonservice)

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# def test(request, echo_param):

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#     return "echoing the param back: %s" % echo_param

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#

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# dump jsonservice into urlpatterns:

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#  (r'^service1/$', 'djangoapp.views.jsonservice'),

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class JSONRPCService(JSONRPCServiceBase):

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    def __call__(self, request, extra=None):

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        return self.process(request.raw_post_data)

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def jsonremote(service):

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    """Make JSONRPCService a decorator so that you can write :

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    from jsonrpc import JSONRPCService

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    chatservice = JSONRPCService()

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    @jsonremote(chatservice)

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    def login(request, user_name):

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        (...)

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    """

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    def remotify(func):

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        if isinstance(service, JSONRPCService):

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            service.add_method(func.__name__, func)

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        else:

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            emsg = 'Service "%s" not found' % str(service.__name__)

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            raise NotImplementedError(emsg)

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        return func

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    return remotify

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# FormProcessor provides a mechanism for turning Django Forms into JSONRPC

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# Services.  If you have an existing Django app which makes prevalent

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# use of Django Forms it will save you rewriting the app.

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# use as follows.  in djangoapp/views.py :

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#

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# class SimpleForm(forms.Form):

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#     testfield = forms.CharField(max_length=100)

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#

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# class SimpleForm2(forms.Form):

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#     testfield = forms.CharField(max_length=20)

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#

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# processor = FormProcessor({'processsimpleform': SimpleForm,

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#                            'processsimpleform2': SimpleForm2})

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#

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# this will result in a JSONRPC service being created with two

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# RPC functions.  dump "processor" into urlpatterns to make it

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# part of the app:

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#  (r'^formsservice/$', 'djangoapp.views.processor'),

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def builderrors(form):

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    d = {}

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    for error in form.errors.keys():

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        if error not in d:

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            d[error] = []

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        for errorval in form.errors[error]:

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            d[error].append(unicode(errorval))

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    return d

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# contains the list of arguments in each field

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field_names = {

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 'CharField': ['max_length', 'min_length'],

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 'IntegerField': ['max_value', 'min_value'],

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 'FloatField': ['max_value', 'min_value'],

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 'DecimalField': ['max_value', 'min_value', 'max_digits', 'decimal_places'],

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 'DateField': ['input_formats'],

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 'DateTimeField': ['input_formats'],

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 'TimeField': ['input_formats'],

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 'RegexField': ['max_length', 'min_length'],  # sadly we can't get the expr

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 'EmailField': ['max_length', 'min_length'],

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 'URLField': ['max_length', 'min_length', 'verify_exists', 'user_agent'],

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 'ChoiceField': ['choices'],

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 'FilePathField': ['path', 'match', 'recursive', 'choices'],

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 'IPAddressField': ['max_length', 'min_length'],

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 }

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def describe_field_errors(field):

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    res = {}

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    field_type = field.__class__.__name__

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    msgs = {}

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    for n, m in field.error_messages.items():

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        msgs[n] = unicode(m)

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    res['error_messages'] = msgs

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    if field_type in ['ComboField', 'MultiValueField', 'SplitDateTimeField']:

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        res['fields'] = map(describe_field, field.fields)

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    return res

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def describe_fields_errors(fields, field_names):

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    res = {}

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    if not field_names:

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        field_names = fields.keys()

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    for name in field_names:

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        field = fields[name]

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        res[name] = describe_field_errors(field)

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    return res

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def describe_field(field):

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    res = {}

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    field_type = field.__class__.__name__

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    for fname in (field_names.get(field_type, []) +

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                  ['help_text', 'label', 'initial', 'required']):

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        res[fname] = getattr(field, fname)

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    if field_type in ['ComboField', 'MultiValueField', 'SplitDateTimeField']:

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        res['fields'] = map(describe_field, field.fields)

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    return res

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def describe_fields(fields, field_names):

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    res = {}

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    if not field_names:

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        field_names = fields.keys()

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    for name in field_names:

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        field = fields[name]

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        res[name] = describe_field(field)

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    return res

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class FormProcessor(JSONRPCService):

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    def __init__(self, forms, _formcls=None):

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        if _formcls is None:

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            JSONRPCService.__init__(self)

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            for k in forms.keys():

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                s = FormProcessor({}, forms[k])

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                self.add_method(k, s.__process)

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        else:

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            JSONRPCService.__init__(self, forms)

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            self.formcls = _formcls

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    def __process(self, request, params, command=None):

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        f = self.formcls(params)

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        if command is None:  # just validate

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            if not f.is_valid():

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                return {'success': False, 'errors': builderrors(f)}

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            return {'success': True}

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        elif 'describe_errors' in command:

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            field_names = command['describe_errors']

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            return describe_fields_errors(f.fields, field_names)

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        elif 'describe' in command:

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            field_names = command['describe']

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            return describe_fields(f.fields, field_names)

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        elif 'save' in command:

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            if not f.is_valid():

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                return {'success': False, 'errors': builderrors(f)}

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            instance = f.save()  # XXX: if you want more, over-ride save.

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            return {'success': True, 'instance': json_convert(instance)}

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        elif 'html' in command:

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            return {'success': True, 'html': f.as_table()}

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        return "unrecognised command"

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# The following is incredibly convenient for saving vast amounts of

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# coding, avoiding doing silly things like this:

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#     jsonresult = {'field1': djangoobject.field1,

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#                   'field2': djangoobject.date.strftime('%Y.%M'),

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#                    ..... }

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#

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# The date/time flatten function is there because JSONRPC doesn't

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# support date/time objects or formats, so conversion to a string

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# is the most logical choice.  pyjamas, being python, can easily

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# be used to parse the string result at the other end.

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#

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# use as follows:

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#

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# jsonservice = JSONRPCService()

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#

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# @jsonremote(jsonservice)

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# def list_some_model(request, start=0, count=10):

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#     l = SomeDjangoModelClass.objects.filter()

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#     res = json_convert(l[start:end])

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#

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# @jsonremote(jsonservice)

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# def list_another_model(request, start=0, count=10):

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#     l = AnotherDjangoModelClass.objects.filter()

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#     res = json_convert(l[start:end])

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#

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# dump jsonservice into urlpatterns to make the two RPC functions,

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# list_some_model and list_another_model part of the django app:

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#  (r'^service1/$', 'djangoapp.views.jsonservice'),

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def dict_datetimeflatten(item):

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    d = {}

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    for k, v in item.items():

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        k = str(k)

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        if isinstance(v, datetime.date):

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            d[k] = str(v)

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        elif isinstance(v, dict):

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            d[k] = dict_datetimeflatten(v)

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        else:

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            d[k] = v

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    return d

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def json_convert(l, fields=None):

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    res = []

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    for item in serialize('python', l, fields=fields):

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        res.append(dict_datetimeflatten(item))

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    return res