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The Validator object is used to check that supplied values conform to a specification.
The value can be supplied as a string - e.g. from a config file. In this case the check will also convert the value to the required type. This allows you to add validation as a transparent layer to access data stored as strings. The validation checks that the data is correct and converts it to the expected type.
Some standard checks are provided for basic data types. Additional checks are easy to write. They can be provided when the Validator is instantiated or added afterwards.
The standard functions work with the following basic data types :
plus lists of these datatypes
Adding additional checks is done through coding simple functions.
The full set of standard checks are :
Takes optional 'min' and 'max' arguments :
integer() integer(3, 9) # any value from 3 to 9 integer(min=0) # any positive value integer(max=9)
Has the same parameters as the integer check.
true, on, yes, 1
false, off, no, 0
Any other value raises an error.
by a dotted-quad string, i.e. '1.2.3.4'.
Takes optional keyword args 'min' and 'max' to specify min and max lengths of the string.
Takes optional keyword args 'min', and 'max' to specify min and max sizes of the list.
Takes the same arguments as list.
Takes the same arguments as list.
Takes the same arguments as list.
Takes the same arguments as list.
Takes the same arguments as list.
specific positions. List size must match the number of arguments.
Each position can be one of : 'integer', 'float', 'ip_addr', 'string', 'boolean'
So to specify a list with two strings followed by two integers, you write the check as :
mixed_list('string', 'string', 'integer', 'integer')
and the value is unchanged.
It is also the default if no check is specified.
You specify this check with :
option('option 1', 'option 2', 'option 3')
You can supply a default value (returned if no value is supplied) using the default keyword argument.
You specify a list argument for default using a list constructor syntax in the check :
checkname(arg1, arg2, default=list('val 1', 'val 2', 'val 3'))
A badly formatted set of arguments will raise a VdtParamError.
Version: 0.2.3
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ValidateError This error indicates that the check failed. |
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VdtMissingValue No value was supplied to a check that needed one. |
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VdtUnknownCheckError An unknown check function was requested |
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VdtParamError An incorrect parameter was passed |
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VdtTypeError The value supplied was of the wrong type |
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VdtValueError The value supplied was of the correct type, but was not an allowed value. |
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VdtValueTooSmallError The value supplied was of the correct type, but was too small. |
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VdtValueTooBigError The value supplied was of the correct type, but was too big. |
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VdtValueTooShortError The value supplied was of the correct type, but was too short. |
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VdtValueTooLongError The value supplied was of the correct type, but was too long. |
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Validator Validator is an object that allows you to register a set of 'checks'. |
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__revision__ =
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INTP_VER =
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StringTypes =
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_list_arg = re.compile(r'
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_list_members = re.compile(r'
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_paramstring =
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_matchstring =
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bool_dict =
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fun_dict = {'integer': is_integer, 'float': is_float, 'ip_addr
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Return numbers from inputs or raise VdtParamError. Lets None pass through. Pass in keyword argument to_float=True to use float for the conversion rather than int. >>> _is_num_param(('', ''), (0, 1.0)) [0, 1] >>> _is_num_param(('', ''), (0, 1.0), to_float=True) [0.0, 1.0] >>> _is_num_param(('a'), ('a')) Traceback (most recent call last): VdtParamError: passed an incorrect value "a" for parameter "a". |
A check that tests that a given value is an integer (int, or long) and optionally, between bounds. A negative value is accepted, while a float will fail. If the value is a string, then the conversion is done - if possible. Otherwise a VdtError is raised. >>> vtor.check('integer', '-1') -1 >>> vtor.check('integer', '0') 0 >>> vtor.check('integer', 9) 9 >>> vtor.check('integer', 'a') Traceback (most recent call last): VdtTypeError: the value "a" is of the wrong type. >>> vtor.check('integer', '2.2') Traceback (most recent call last): VdtTypeError: the value "2.2" is of the wrong type. >>> vtor.check('integer(10)', '20') 20 >>> vtor.check('integer(max=20)', '15') 15 >>> vtor.check('integer(10)', '9') Traceback (most recent call last): VdtValueTooSmallError: the value "9" is too small. >>> vtor.check('integer(10)', 9) Traceback (most recent call last): VdtValueTooSmallError: the value "9" is too small. >>> vtor.check('integer(max=20)', '35') Traceback (most recent call last): VdtValueTooBigError: the value "35" is too big. >>> vtor.check('integer(max=20)', 35) Traceback (most recent call last): VdtValueTooBigError: the value "35" is too big. >>> vtor.check('integer(0, 9)', False) 0 |
A check that tests that a given value is a float (an integer will be accepted), and optionally - that it is between bounds. If the value is a string, then the conversion is done - if possible. Otherwise a VdtError is raised. This can accept negative values. >>> vtor.check('float', '2') 2.0 From now on we multiply the value to avoid comparing decimals >>> vtor.check('float', '-6.8') * 10 -68.0 >>> vtor.check('float', '12.2') * 10 122.0 >>> vtor.check('float', 8.4) * 10 84.0 >>> vtor.check('float', 'a') Traceback (most recent call last): VdtTypeError: the value "a" is of the wrong type. >>> vtor.check('float(10.1)', '10.2') * 10 102.0 >>> vtor.check('float(max=20.2)', '15.1') * 10 151.0 >>> vtor.check('float(10.0)', '9.0') Traceback (most recent call last): VdtValueTooSmallError: the value "9.0" is too small. >>> vtor.check('float(max=20.0)', '35.0') Traceback (most recent call last): VdtValueTooBigError: the value "35.0" is too big. |
Check that the supplied value is an Internet Protocol address, v.4, represented by a dotted-quad string, i.e. '1.2.3.4'. >>> vtor.check('ip_addr', '1 ') '1' >>> vtor.check('ip_addr', ' 1.2') '1.2' >>> vtor.check('ip_addr', ' 1.2.3 ') '1.2.3' >>> vtor.check('ip_addr', '1.2.3.4') '1.2.3.4' >>> vtor.check('ip_addr', '0.0.0.0') '0.0.0.0' >>> vtor.check('ip_addr', '255.255.255.255') '255.255.255.255' >>> vtor.check('ip_addr', '255.255.255.256') Traceback (most recent call last): VdtValueError: the value "255.255.255.256" is unacceptable. >>> vtor.check('ip_addr', '1.2.3.4.5') Traceback (most recent call last): VdtValueError: the value "1.2.3.4.5" is unacceptable. >>> vtor.check('ip_addr', '1.2.3. 4') Traceback (most recent call last): VdtValueError: the value "1.2.3. 4" is unacceptable. >>> vtor.check('ip_addr', 0) Traceback (most recent call last): VdtTypeError: the value "0" is of the wrong type. |
Check that the value is a list of values. You can optionally specify the minimum and maximum number of members. It does no check on list members. >>> vtor.check('list', ()) () >>> vtor.check('list', []) [] >>> vtor.check('list', (1, 2)) (1, 2) >>> vtor.check('list', [1, 2]) [1, 2] >>> vtor.check('list', '12') '12' >>> vtor.check('list(3)', (1, 2)) Traceback (most recent call last): VdtValueTooShortError: the value "(1, 2)" is too short. >>> vtor.check('list(max=5)', (1, 2, 3, 4, 5, 6)) Traceback (most recent call last): VdtValueTooLongError: the value "(1, 2, 3, 4, 5, 6)" is too long. >>> vtor.check('list(min=3, max=5)', (1, 2, 3, 4)) (1, 2, 3, 4) >>> vtor.check('list', 0) Traceback (most recent call last): VdtTypeError: the value "0" is of the wrong type. |
Check that the supplied value is a string. You can optionally specify the minimum and maximum number of members. >>> vtor.check('string', '0') '0' >>> vtor.check('string', 0) Traceback (most recent call last): VdtTypeError: the value "0" is of the wrong type. >>> vtor.check('string(2)', '12') '12' >>> vtor.check('string(2)', '1') Traceback (most recent call last): VdtValueTooShortError: the value "1" is too short. >>> vtor.check('string(min=2, max=3)', '123') '123' >>> vtor.check('string(min=2, max=3)', '1234') Traceback (most recent call last): VdtValueTooLongError: the value "1234" is too long. |
Check that the value is a list of integers. You can optionally specify the minimum and maximum number of members. Each list member is checked that it is an integer. >>> vtor.check('int_list', ()) [] >>> vtor.check('int_list', []) [] >>> vtor.check('int_list', (1, 2)) [1, 2] >>> vtor.check('int_list', [1, 2]) [1, 2] >>> vtor.check('int_list', [1, 'a']) Traceback (most recent call last): VdtTypeError: the value "a" is of the wrong type. |
Check that the value is a list of booleans. You can optionally specify the minimum and maximum number of members. Each list member is checked that it is a boolean. >>> vtor.check('bool_list', ()) [] >>> vtor.check('bool_list', []) [] >>> check_res = vtor.check('bool_list', (True, False)) >>> check_res == [True, False] 1 >>> check_res = vtor.check('bool_list', [True, False]) >>> check_res == [True, False] 1 >>> vtor.check('bool_list', [True, 'a']) Traceback (most recent call last): VdtTypeError: the value "a" is of the wrong type. |
Check that the value is a list of floats. You can optionally specify the minimum and maximum number of members. Each list member is checked that it is a float. >>> vtor.check('float_list', ()) [] >>> vtor.check('float_list', []) [] >>> vtor.check('float_list', (1, 2.0)) [1.0, 2.0] >>> vtor.check('float_list', [1, 2.0]) [1.0, 2.0] >>> vtor.check('float_list', [1, 'a']) Traceback (most recent call last): VdtTypeError: the value "a" is of the wrong type. |
Check that the value is a list of strings. You can optionally specify the minimum and maximum number of members. Each list member is checked that it is a string. >>> vtor.check('string_list', ()) [] >>> vtor.check('string_list', []) [] >>> vtor.check('string_list', ('a', 'b')) ['a', 'b'] >>> vtor.check('string_list', ['a', 1]) Traceback (most recent call last): VdtTypeError: the value "1" is of the wrong type. >>> vtor.check('string_list', 'hello') Traceback (most recent call last): VdtTypeError: the value "hello" is of the wrong type. |
Check that the value is a list of IP addresses. You can optionally specify the minimum and maximum number of members. Each list member is checked that it is an IP address. >>> vtor.check('ip_addr_list', ()) [] >>> vtor.check('ip_addr_list', []) [] >>> vtor.check('ip_addr_list', ('1.2.3.4', '5.6.7.8')) ['1.2.3.4', '5.6.7.8'] >>> vtor.check('ip_addr_list', ['a']) Traceback (most recent call last): VdtValueError: the value "a" is unacceptable. |
Check that the value is a list. Allow specifying the type of each member. Work on lists of specific lengths. You specify each member as a positional argument specifying type
So you can specify a list of two strings, followed by two integers as : mixed_list('string', 'string', 'integer', 'integer') The length of the list must match the number of positional arguments you supply. >>> mix_str = "mixed_list('integer', 'float', 'ip_addr', 'string', 'boolean')" >>> check_res = vtor.check(mix_str, (1, 2.0, '1.2.3.4', 'a', True)) >>> check_res == [1, 2.0, '1.2.3.4', 'a', True] 1 >>> check_res = vtor.check(mix_str, ('1', '2.0', '1.2.3.4', 'a', 'True')) >>> check_res == [1, 2.0, '1.2.3.4', 'a', True] 1 >>> vtor.check(mix_str, ('b', 2.0, '1.2.3.4', 'a', True)) Traceback (most recent call last): VdtTypeError: the value "b" is of the wrong type. >>> vtor.check(mix_str, (1, 2.0, '1.2.3.4', 'a')) Traceback (most recent call last): VdtValueTooShortError: the value "(1, 2.0, '1.2.3.4', 'a')" is too short. >>> vtor.check(mix_str, (1, 2.0, '1.2.3.4', 'a', 1, 'b')) Traceback (most recent call last): VdtValueTooLongError: the value "(1, 2.0, '1.2.3.4', 'a', 1, 'b')" is too long. >>> vtor.check(mix_str, 0) Traceback (most recent call last): VdtTypeError: the value "0" is of the wrong type. This test requires an elaborate setup, because of a change in error string output from the interpreter between Python 2.2 and 2.3 . >>> res_seq = ( ... 'passed an incorrect value "', ... 'yoda', ... '" for parameter "mixed_list".', ... ) >>> if INTP_VER == (2, 2): ... res_str = "".join(res_seq) ... else: ... res_str = "'".join(res_seq) >>> try: ... vtor.check('mixed_list("yoda")', ('a')) ... except VdtParamError, err: ... str(err) == res_str 1 |
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__revision__
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_list_arg
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bool_dict
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fun_dict
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