validation.py

import json
import datetime
import pytz
import re
import ckan.lib.helpers as h
import ckanext.scheming.helpers as sh

from ckantoolkit import get_validator, UnknownValidator, missing, Invalid, _

from ckanext.scheming.errors import SchemingException

OneOf = get_validator('OneOf')
ignore_missing = get_validator('ignore_missing')
not_empty = get_validator('not_empty')

def scheming_validator(fn):
    """
    Decorate a validator that needs to have the scheming fields
    passed with this function. When generating navl validator lists
    the function decorated will be called passing the field
    and complete schema to produce the actual validator for each field.
    """
    fn.is_a_scheming_validator = True
    return fn


@scheming_validator
def scheming_choices(field, schema):
    """
    Require that one of the field choices values is passed.
    """
    if 'choices' in field:
        return OneOf([c['value'] for c in field['choices']])

    def validator(value):
        if value is missing or not value:
            return value
        choices = sh.scheming_field_choices(field)
        for c in choices:
            if value == c['value']:
                return value
        raise Invalid(_('unexpected choice "%s"') % value)

    return validator


@scheming_validator
def scheming_required(field, schema):
    """
    not_empty if field['required'] else ignore_missing
    """
    if field.get('required'):
        return not_empty
    return ignore_missing


@scheming_validator
def scheming_multiple_choice(field, schema):
    """
    Accept zero or more values from a list of choices and convert
    to a json list for storage:

    1. a list of strings, eg.:

       ["choice-a", "choice-b"]

    2. a single string for single item selection in form submissions:

       "choice-a"
    """
    static_choice_values = None
    if 'choices' in field:
        static_choice_order = [c['value'] for c in field['choices']]
        static_choice_values = set(static_choice_order)

    def validator(key, data, errors, context):
        # if there was an error before calling our validator
        # don't bother with our validation
        if errors[key]:
            return

        value = data[key]
        if value is not missing:
            if isinstance(value, basestring):
                value = [value]
            elif not isinstance(value, list):
                errors[key].append(_('expecting list of strings'))
                return
        else:
            value = []

        choice_values = static_choice_values
        if not choice_values:
            choice_order = [c['value'] for c in sh.scheming_field_choices(field)]
            choice_values = set(choice_order)

        selected = set()
        for element in value:
            if element in choice_values:
                selected.add(element)
                continue
            errors[key].append(_('unexpected choice "%s"') % element)

        if not errors[key]:
            data[key] = json.dumps([v for v in
                (static_choice_order if static_choice_values else choice_order)
                if v in selected])

            if field.get('required') and not selected:
                errors[key].append(_('Select at least one'))

    return validator


def validate_date_inputs(field, key, data, extras, errors, context):
    date_error = _('Date format incorrect')
    time_error = _('Time format incorrect')

    date = None

    def get_input(suffix):
        inpt = key[0] + '_' + suffix
        new_key = (inpt,) + tuple(x for x in key if x != key[0])
        value = extras.get(inpt)
        data[new_key] = value
        errors[new_key] = []

        if value:
            del extras[inpt]

        if field.get('required'):
            not_empty(new_key, data, errors, context)

        return (new_key, value)

    date_key, value = get_input('date')
    value_full = ''

    if value:
        try:
            value_full = value
            date = h.date_str_to_datetime(value)
        except (TypeError, ValueError), e:
            errors[date_key].append(date_error)

    time_key, value = get_input('time')
    if value:
        if not value_full:
            errors[date_key].append(
                _('Date is required when a time is provided'))
        else:
            try:
                value_full += ' ' + value
                date = h.date_str_to_datetime(value_full)
            except (TypeError, ValueError), e:
                errors[time_key].append(time_error)

    tz_key, value = get_input('tz')
    if value:
        if value not in pytz.all_timezones:
            errors[tz_key].append('Invalid timezone')
        else:
            if isinstance(date, datetime.datetime):
                date = pytz.timezone(value).localize(date)

    return date


@scheming_validator
def scheming_isodatetime(field, schema):
    def validator(key, data, errors, context):
        value = data[key]
        date = None

        if value:
            if isinstance(value, datetime.datetime):
                return value
            else:
                try:
                    date = h.date_str_to_datetime(value)
                except (TypeError, ValueError), e:
                    raise Invalid(_('Date format incorrect'))
        else:
            extras = data.get(('__extras',))
            if not extras or (key[0] + '_date' not in extras and
                              key[0] + '_time' not in extras):
                if field.get('required'):
                    not_empty(key, data, errors, context)
            else:
                date = validate_date_inputs(
                    field, key, data, extras, errors, context)

        data[key] = date

    return validator


@scheming_validator
def scheming_isodatetime_tz(field, schema):
    def validator(key, data, errors, context):
        value = data[key]
        date = None

        if value:
            if isinstance(value, datetime.datetime):
                date = sh.scheming_datetime_to_UTC(value)
            else:
                try:
                    date = sh.date_tz_str_to_datetime(value)
                except (TypeError, ValueError), e:
                    raise Invalid(_('Date format incorrect'))
        else:
            extras = data.get(('__extras',))
            if not extras or (key[0] + '_date' not in extras and
                              key[0] + '_time' not in extras):
                if field.get('required'):
                    not_empty(key, data, errors, context)
            else:
                date = validate_date_inputs(
                    field, key, data, extras, errors, context)
                if isinstance(date, datetime.datetime):
                    date = sh.scheming_datetime_to_UTC(date)

        data[key] = date

    return validator


def scheming_valid_json_object(value, context):
    """Store a JSON object as a serialized JSON string

    It accepts two types of inputs:
        1. A valid serialized JSON string (it must be an object or a list)
        2. An object that can be serialized to JSON

    """
    if not value:
        return
    elif isinstance(value, basestring):
        try:
            loaded = json.loads(value)

            if not isinstance(loaded, dict):
                raise Invalid(
                    _('Unsupported value for JSON field: {}').format(value)
                )

            return value
        except (ValueError, TypeError) as e:
            raise Invalid(_('Invalid JSON string: {}').format(e))

    elif isinstance(value, dict):
        try:
            return json.dumps(value)
        except (ValueError, TypeError) as e:
            raise Invalid(_('Invalid JSON object: {}').format(e))
    else:
        raise Invalid(
            _('Unsupported type for JSON field: {}').format(type(value))
        )

    return value


def scheming_load_json(value, context):
    if isinstance(value, basestring):
        try:
            return json.loads(value)
        except ValueError:
            return value
    return value


def scheming_multiple_choice_output(value):
    """
    return stored json as a proper list
    """
    if isinstance(value, list):
        return value
    try:
        return json.loads(value)
    except ValueError:
        return [value]


def validators_from_string(s, field, schema):
    """
    convert a schema validators string to a list of validators

    e.g. "if_empty_same_as(name) unicode" becomes:
    [if_empty_same_as("name"), unicode]
    """
    out = []
    parts = s.split()
    for p in parts:
        if '(' in p and p[-1] == ')':
            name, args = p.split('(', 1)
            args = args[:-1].split(',')  # trim trailing ')', break up
            v = get_validator_or_converter(name)(*args)
        else:
            v = get_validator_or_converter(p)
        if getattr(v, 'is_a_scheming_validator', False):
            v = v(field, schema)
        out.append(v)
    return out


def get_validator_or_converter(name):
    """
    Get a validator or converter by name
    """
    if name == 'unicode':
        return unicode
    try:
        v = get_validator(name)
        return v
    except UnknownValidator:
        pass
    raise SchemingException('validator/converter not found: %r' % name)