lodel2_mirror/lodel/validator/validator.py

#-*- coding: utf-8 -*-

import sys
import os.path
import re
import socket
import inspect
import copy

from lodel.context import LodelContext
LodelContext.expose_modules(globals(), {
    'lodel.mlnamedobject.mlnamedobject': ['MlNamedObject'],
    'lodel.exceptions': ['LodelException', 'LodelExceptions',
                         'LodelFatalError', 'FieldValidationError']})

# @package lodel.settings.validator Lodel2 settings validators/cast module
#
# Validator are registered in the Validator class.
# @note to get a list of registered default validators just run
# <pre>$ python scripts/settings_validator.py</pre>

# @brief Exception class that should be raised when a validation fails


class ValidationError(Exception):
    pass

# @brief Handles settings validators
#
# Class instance are callable objects that takes a value argument (the value to validate). It raises
# a ValidationError if validation fails, else it returns a properly
# casted value.
#@todo implement an IP validator and use it in multisite confspec


class Validator(MlNamedObject):

    _validators = dict()
    _description = dict()

    # @brief Instanciate a validator
    #@param name str : validator name
    #@param none_is_valid bool : if True None will be validated
    #@param **kwargs : more arguement for the validator
    def __init__(self, name, none_is_valid=False, display_name=None, help_text=None, **kwargs):
        if name is not None and name not in self._validators:
            raise LodelFatalError("No validator named '%s'" % name)
        self.__none_is_valid = none_is_valid
        self.__name = name
        self._opt_args = kwargs
        if display_name is None:
            display_name = name
        super().__init__(display_name, help_text)

    # @brief Call the validator
    # @param value *
    # @return properly casted value
    # @throw ValidationError
    def __call__(self, value):
        if value is None:
            if self.__none_is_valid:
                return None
            else:
                raise ValidationError('None is not a valid value')
        if self.__none_is_valid and value is None:
            return None
        try:
            ret = self._validators[self.__name](value, **self._opt_args)
            return ret
        except Exception as exp:
            raise ValidationError(exp)

    # @brief Register a new validator
    # @param name str : validator name
    # @param callback callable : the function that will validate a value
    # @param description str
    @classmethod
    def register_validator(cls, name, callback, description=None):
        if name in cls._validators:
            raise NameError("A validator named '%s' allready exists" % name)
        # Broken test for callable
        if not inspect.isfunction(callback) and not inspect.ismethod(callback) and not hasattr(callback, '__call__'):
            raise TypeError("Callable expected but got %s" % type(callback))
        cls._validators[name] = callback
        cls._description[name] = description

    # @brief Get the validator list associated with description
    @classmethod
    def validators_list(cls):
        return copy.copy(cls._description)

    # @brief Create and register a list validator
    # @param elt_validator callable : The validator that will be used for validate each elt value
    # @param validator_name str
    # @param description None | str
    # @param separator str : The element separator
    # @return A Validator instance
    @classmethod
    def create_list_validator(cls, validator_name, elt_validator, description=None, separator=','):
        def list_validator(value):
            res = list()
            if value is None:
                return res
            errors = list()
            for elt in value.split(separator):
                elt = elt_validator(elt)
                if len(elt) > 0:
                    res.append(elt)
            return res
        description = "Convert value to an array" if description is None else description
        cls.register_validator(validator_name, list_validator, description)
        return cls(validator_name)

    # @brief Create and register a list validator which reads an array and returns a string
    # @param elt_validator callable : The validator that will be used for validate each elt value
    # @param validator_name str
    # @param description None | str
    # @param separator str : The element separator
    # @return A Validator instance
    @classmethod
    def create_write_list_validator(cls, validator_name, elt_validator, description=None, separator=','):
        def write_list_validator(value):
            res = ''
            for elt in value:
                res += elt_validator(elt) + ','
            return res[:len(res) - 1]
        description = "Convert value to a string" if description is None else description
        cls.register_validator(validator_name, write_list_validator, description)
        return cls(validator_name)

    # @brief Create and register a regular expression validator
    # @param pattern str : regex pattern
    # @param validator_name str : The validator name
    # @param description str : Validator description
    # @return a Validator instance
    @classmethod
    def create_re_validator(cls, pattern, validator_name, description=None):
        def re_validator(value):
            if not re.match(pattern, value):
                raise ValidationError(
                    "The value '%s' doesn't match the following pattern '%s'"
                    % pattern)
            return value
        # registering the validator
        cls.register_validator(validator_name, re_validator,
                               ("Match value to '%s'" % pattern)
                               if description is None else description)
        return cls(validator_name)

    #  @return a list of registered validators
    @classmethod
    def validators_list_str(cls):
        result = ''
        for name in sorted(cls._validators.keys()):
            result += "\t%016s" % name
            if name in cls._description and cls._description[name] is not None:
                result += ": %s" % cls._description[name]
            result += "\n"
        return result

# @brief Integer value validator callback


def int_val(value):
    return int(value)

# @brief Output file validator callback
# @return A file object (if filename is '-' return sys.stderr)


def file_err_output(value):
    if not isinstance(value, str):
        raise ValidationError("A string was expected but got '%s' " % value)
    if value == '-':
        return None
    return value

# @brief Boolean value validator callback


def boolean_val(value):
    if isinstance(value, bool):
        return value
    if value.strip().lower() == 'true' or value.strip() == '1':
        value = True
    elif value.strip().lower() == 'false' or value.strip() == '0':
        value = False
    else:
        raise ValidationError("A boolean was expected but got '%s' " % value)
    return bool(value)

# @brief Validate a directory path


def directory_val(value):
    res = Validator('strip')(value)
    if not os.path.isdir(res):
        raise ValidationError("Following path don't exists or is not a directory : '%s'" % res)
    return res

# @brief Validate a loglevel value


def loglevel_val(value):
    valids = ['DEBUG', 'INFO', 'WARNING', 'SECURITY', 'ERROR', 'CRITICAL']
    if value.upper() not in valids:
        raise ValidationError(
            "The value '%s' is not a valid loglevel" % value)
    return value.upper()

# @brief Validate a path


def path_val(value):
    if value is None or not os.path.exists(value):
        raise ValidationError(
            "path '%s' doesn't exists" % value)
    return value

# @brief Validate None


def none_val(value):
    if value is None:
        return None
    raise ValidationError("This settings cannot be set in configuration file")

# @brief Validate a string


def str_val(value):
    try:
        return str(value)
    except Exception as exp:
        raise ValidationError("Can't to convert value to string: " + str(exp))

# @brief Validate using a regex


def regex_val(value, pattern):
    if re.match(pattern, value) is None:
        raise ValidationError("The value '%s' is not validated by : \
r\"%s\"" % (value, pattern))
    return value

# @brief Validate a hostname (ipv4 or ipv6)


def host_val(value):
    if value == 'localhost':
        return value
    ok = False
    try:
        socket.inet_aton(value)
        return value
    except (TypeError, OSError):
        pass
    try:
        socket.inet_pton(socket.AF_INET6, value)
        return value
    except (TypeError, OSError):
        pass
    try:
        socket.getaddrinfo(value, 80)
        return value
    except (TypeError, socket.gaierror):
        msg = "The value '%s' is not a valid host"
        raise ValidationError(msg % value)


def custom_list_validator(value, validator_name, validator_kwargs=None):
    validator_kwargs = dict() if validator_kwargs is None else validator_kwargs
    validator = Validator(validator_name, **validator_kwargs)
    for item in value.split():
        validator(item)
    return value.split()

#
#   Default validators registration
#

Validator.register_validator('custom_list', custom_list_validator,
                             'A list validator that takes a "validator_name" as argument')

Validator.register_validator('dummy', lambda value: value, 'Validate anything')

Validator.register_validator('none', none_val, 'Validate None')

Validator.register_validator('string', str_val, 'Validate string values')

Validator.register_validator('strip', str.strip, 'String trim')

Validator.register_validator('int', int_val, 'Integer value validator')

Validator.register_validator('bool', boolean_val, 'Boolean value validator')

Validator.register_validator('errfile', file_err_output,
                             'Error output file validator (return stderr if filename is "-")')

Validator.register_validator('directory', directory_val,
                             'Directory path validator')

Validator.register_validator('loglevel', loglevel_val, 'Loglevel validator')

Validator.register_validator('path', path_val, 'path validator')

Validator.register_validator('host', host_val, 'host validator')

Validator.register_validator('regex', regex_val,
                             'RegEx name validator (take re as argument)')

Validator.create_list_validator('list', Validator('strip'), description="Simple list validator. Validate a list of values separated by ','",
                                separator=',')

Validator.create_list_validator(
    'directory_list',
    Validator('directory'),
    description="Validator for a list of directory path separated with ','",
    separator=',')

Validator.create_write_list_validator(
    'write_list',
    Validator('directory'),
    description="Validator for an array of values \
        which will be set in a string, separated by ','",
    separator=',')

Validator.create_re_validator(
    r'^https?://[^\./]+.[^\./]+/?.*$',
    'http_url',
    'Url validator')

# @brief Validator for Editorial model component
#
# Designed to validate a conf that indicate a class.field in an EM
#@todo modified the hardcoded dyncode import (it's a warning)


def emfield_val(value):
    LodelContext.expose_modules(globals(),
                                {'lodel.plugin.hooks': ['LodelHook']})
    spl = value.split('.')
    if len(spl) != 2:
        msg = "Expected a value in the form CLASSNAME.FIELDNAME but got : %s"
        raise ValidationError(msg % value)
    value = tuple(spl)
    # Late validation hook

    @LodelHook('lodel2_dyncode_bootstraped')
    def emfield_conf_check(hookname, caller, payload):
        import leapi_dyncode as dyncode  # <-- dirty & quick
        classnames = {cls.__name__.lower(): cls for cls in dyncode.dynclasses}
        if value[0].lower() not in classnames:
            msg = "Following dynamic class do not exists in current EM : %s"
            raise ValidationError(msg % value[0])
        ccls = classnames[value[0].lower()]
        if value[1].lower() not in ccls.fieldnames(True):
            msg = "Following field not found in class %s : %s"
            raise ValidationError(msg % value)
    return value

# @brief Validator for plugin name & optionnaly type
#
# Able to check that the value is a plugin and if it is of a specific type


def plugin_validator(value, ptype=None):
    if value:
        LodelContext.expose_modules(globals(), {
            'lodel.plugin.hooks': ['LodelHook']})
        value = copy.copy(value)

        @LodelHook('lodel2_dyncode_bootstraped')
        def plugin_type_checker(hookname, caller, payload):
            LodelContext.expose_modules(globals(), {
                'lodel.plugin.plugins': ['Plugin'],
                'lodel.plugin.exceptions': ['PluginError']})
            if value is None:
                return
            try:
                plugin = Plugin.get(value)
            except PluginError:
                msg = "No plugin named %s found"
                msg %= value
                raise ValidationError(msg)
            if plugin._type_conf_name.lower() != ptype.lower():
                msg = "A plugin of type '%s' was expected but found a plugin \
    named  '%s' that is a '%s' plugin"
                msg %= (ptype, value, plugin._type_conf_name)
                raise ValidationError(msg)
        return value
    return None


Validator.register_validator(
    'plugin',
    plugin_validator,
    'plugin name & type validator')

Validator.register_validator(
    'emfield',
    emfield_val,
    'EmField name validator')

#
#   Lodel 2 configuration specification
#

# @brief Append a piece of confspec
#@note orig is modified during the process
#@param orig dict : the confspec to update
#@param section str : section name
#@param key str
#@param validator Validator : the validator to use to check this configuration key's value
#@param default
#@return new confspec


def confspec_append(orig, section, key, validator, default):
    if section not in orig:
        orig[section] = dict()
    if key not in orig[section]:
        orig[section][key] = (default, validator)
    return orig

# @brief Global specifications for lodel2 settings
LODEL2_CONF_SPECS = {
    'lodel2': {
        'debug': (True, Validator('bool')),
        'sitename': ('noname', Validator('strip')),
        'runtest': (False, Validator('bool')),
    },
    'lodel2.logging.*': {
        'level': ('ERROR', Validator('loglevel')),
        'context': (False, Validator('bool')),
        'filename': ("-", Validator('errfile', none_is_valid=False)),
        'backupcount': (5, Validator('int', none_is_valid=False)),
        'maxbytes': (1024 * 10, Validator('int', none_is_valid=False)),
    },
    'lodel2.editorialmodel': {
        'emfile': ('em.pickle', Validator('strip')),
        'emtranslator': ('picklefile', Validator('strip')),
        'dyncode': ('leapi_dyncode.py', Validator('strip')),
        'groups': ('', Validator('list')),
        'editormode': (False, Validator('bool')),
    },
    'lodel2.datasources.*': {
        'read_only': (False, Validator('bool')),
        'identifier': (None, Validator('string')),
    },
    'lodel2.auth': {
        'login_classfield': ('user.login', Validator('emfield')),
        'pass_classfield': ('user.password', Validator('emfield')),
    },
}