Set type

class pyasn1.type.univ.Set(componentType=NamedTypes(), tagSet=TagSet(), subtypeSpec=ConstraintsIntersection())

Create Set schema or value object.

Set class is based on ConstructedAsn1Type, its objects are mutable and duck-type Python dict objects.

Keyword Arguments

  • componentType (NamedType) – Object holding named ASN.1 types allowed within this collection

  • tagSet (TagSet) – Object representing non-default ASN.1 tag(s)

  • subtypeSpec (ConstraintsIntersection) – Object representing non-default ASN.1 subtype constraint(s). Constraints verification for Set type can only occur on explicit .isInconsistent call.

Examples

class Description(Sequence):  #  Set is similar
    '''
    ASN.1 specification:

    Description ::= SEQUENCE {
        surname    IA5String,
        first-name IA5String OPTIONAL,
        age        INTEGER DEFAULT 40
    }
    '''
    componentType = NamedTypes(
        NamedType('surname', IA5String()),
        OptionalNamedType('first-name', IA5String()),
        DefaultedNamedType('age', Integer(40))
    )

descr = Description()
descr['surname'] = 'Smith'
descr['first-name'] = 'John'

Note

The Set type models a collection of named ASN.1 components. Ordering of the components is not preserved upon de/serialisation.

clone(componentType=NamedTypes(), tagSet=TagSet(), subtypeSpec=ConstraintsIntersection())

Create a modified version of Set schema object.

The clone() method accepts the same set arguments as Set class takes on instantiation except that all arguments of the clone() method are optional.

Whatever arguments are supplied, they are used to create a copy of self taking precedence over the ones used to instantiate self.

Possible values of self are never copied over thus clone() can only create a new schema object.

Returns

new instance of Set type/value

Note

Due to the mutable nature of the Set object, even if no arguments are supplied, a new Set object will be created and returned.

subtype(componentType=NamedTypes(), implicitTag=Tag(), explicitTag=Tag(), subtypeSpec=ConstraintsIntersection())

Create a specialization of Set schema object.

The subtype() method accepts the same set arguments as Set class takes on instantiation except that all parameters of the subtype() method are optional.

With the exception of the arguments described below, the rest of supplied arguments they are used to create a copy of self taking precedence over the ones used to instantiate self.

The following arguments to subtype() create a ASN.1 subtype out of Set type.

Other Parameters

  • implicitTag (Tag) – Implicitly apply given ASN.1 tag object to self’s TagSet, then use the result as new object’s ASN.1 tag(s).

  • explicitTag (Tag) – Explicitly apply given ASN.1 tag object to self’s TagSet, then use the result as new object’s ASN.1 tag(s).

  • subtypeSpec (ConstraintsIntersection) – Add ASN.1 constraints object to one of the self’s, then use the result as new object’s ASN.1 constraints.

Returns

new instance of Set type/value

Note

Due to the mutable nature of the Set object, even if no arguments are supplied, a new Set object will be created and returned.

tagSet = <TagSet object, tags 0:32:17>

Set (on class, not on instance) or return a TagSet object representing ASN.1 tag(s) associated with Set type.

componentType = <NamedTypes object, types >

Default collection of ASN.1 types of component (e.g. NamedType) object representing ASN.1 type allowed within Set type

subtypeSpec = <ConstraintsIntersection object>

Set (on class, not on instance) or return a ConstraintsIntersection object imposing constraints on Set type initialization values.

getComponentByType(tagSet, default=<NoValue object>, instantiate=True, innerFlag=False)

Returns Set type component by ASN.1 tag.

Parameters

tagSet (TagSet) – Object representing ASN.1 tags to identify one of Set object component

Keyword Arguments

  • default (object) – If set and requested component is a schema object, return the default object instead of the requested component.

  • instantiate (bool) – If True (default), inner component will be automatically instantiated. If False either existing component or the noValue object will be returned.

Returns

PyAsn1Item – a pyasn1 object

setComponentByType(tagSet, value=<NoValue object>, verifyConstraints=True, matchTags=True, matchConstraints=True, innerFlag=False)

Assign Set type component by ASN.1 tag.

Parameters

tagSet (TagSet) – Object representing ASN.1 tags to identify one of Set object component

Keyword Arguments

  • value (object or PyAsn1Item derivative) – A Python value to initialize Set component with (if componentType is set) or ASN.1 value object to assign to Set component. If value is not given, schema object will be set as a component.

  • verifyConstraints (bool) – If False, skip constraints validation

  • matchTags (bool) – If False, skip component tags matching

  • matchConstraints (bool) – If False, skip component constraints matching

  • innerFlag (bool) – If True, search for matching tagSet recursively.

Returns

self

property isValue

Indicate that Set object represents ASN.1 value.

If isValue is False then this object represents just ASN.1 schema.

If isValue is True then, in addition to its ASN.1 schema features, this object can also be used like a Python built-in object (e.g. int, str, dict etc.).

Returns

bool – False if object represents just ASN.1 schema. True if object represents ASN.1 schema and can be used as a normal value.

Note

There is an important distinction between PyASN1 schema and value objects. The PyASN1 schema objects can only participate in ASN.1 schema-related operations (e.g. defining or testing the structure of the data). Most obvious uses of ASN.1 schema is to guide serialisation codecs whilst encoding/decoding serialised ASN.1 contents.

The PyASN1 value objects can additionally participate in many operations involving regular Python objects (e.g. arithmetic, comprehension etc).

It is sufficient for Set objects to have all non-optional and non-defaulted components being value objects to be considered as a value objects as a whole. In other words, even having one or more optional components not turned into value objects, Set object is still considered as a value object. Defaulted components are normally value objects by default.

isSameTypeWith(other, matchTags=True, matchConstraints=True)

Examine Set type for equality with other ASN.1 type.

ASN.1 tags (tag) and constraints (constraint) are examined when carrying out ASN.1 types comparison.

Python class inheritance relationship is NOT considered.

Parameters

other (a pyasn1 type object) – Class instance representing ASN.1 type.

Returns

bool – True if other is Set type, False otherwise.

isSuperTypeOf(other, matchTags=True, matchConstraints=True)

Examine Set type for subtype relationship with other ASN.1 type.

ASN.1 tags (tag) and constraints (constraint) are examined when carrying out ASN.1 types comparison.

Python class inheritance relationship is NOT considered.

Parameters

other (a pyasn1 type object) – Class instance representing ASN.1 type.

Returns

bool – True if other is a subtype of Set type, False otherwise.

property effectiveTagSet

For Set type is equivalent to tagSet

property tagMap

Return a TagMap object mapping ASN.1 tags to ASN.1 objects within callee object.

getComponentByPosition(idx, default=<NoValue object>, instantiate=True)

Returns Set type component by index.

Equivalent to Python sequence subscription operation (e.g. []).

Parameters

idx (int) – Component index (zero-based). Must either refer to an existing component or (if componentType is set) new ASN.1 schema object gets instantiated.

Keyword Arguments

  • default (object) – If set and requested component is a schema object, return the default object instead of the requested component.

  • instantiate (bool) – If True (default), inner component will be automatically instantiated. If False either existing component or the NoValue object will be returned.

Returns

PyAsn1Item – a PyASN1 object

Examples

# can also be Set
class MySequence(Sequence):
    componentType = NamedTypes(
        NamedType('id', OctetString())
    )

s = MySequence()

# returns component #0 with `.isValue` property False
s.getComponentByPosition(0)

# returns None
s.getComponentByPosition(0, default=None)

s.clear()

# returns noValue
s.getComponentByPosition(0, instantiate=False)

# sets component #0 to OctetString() ASN.1 schema
# object and returns it
s.getComponentByPosition(0, instantiate=True)

# sets component #0 to ASN.1 value object
s.setComponentByPosition(0, 'ABCD')

# returns OctetString('ABCD') value object
s.getComponentByPosition(0, instantiate=False)

s.clear()

# returns noValue
s.getComponentByPosition(0, instantiate=False)
setComponentByPosition(idx, value=<NoValue object>, verifyConstraints=True, matchTags=True, matchConstraints=True)

Assign Set type component by position.

Equivalent to Python sequence item assignment operation (e.g. []).

Parameters

idx (int) – Component index (zero-based). Must either refer to existing component (if componentType is set) or to N+1 component otherwise. In the latter case a new component of given ASN.1 type gets instantiated and appended to Set sequence.

Keyword Arguments

  • value (object or PyAsn1Item derivative) – A Python value to initialize Set component with (if componentType is set) or ASN.1 value object to assign to Set component. If value is not given, schema object will be set as a component.

  • verifyConstraints (bool) – If False, skip constraints validation

  • matchTags (bool) – If False, skip component tags matching

  • matchConstraints (bool) – If False, skip component constraints matching

Returns

self

getComponentByName(name, default=<NoValue object>, instantiate=True)

Returns Set type component by name.

Equivalent to Python dict subscription operation (e.g. []).

Parameters

name (str) – Set type component name

Keyword Arguments

  • default (object) – If set and requested component is a schema object, return the default object instead of the requested component.

  • instantiate (bool) – If True (default), inner component will be automatically instantiated. If False either existing component or the NoValue object will be returned.

Returns

PyAsn1Item – Instantiate Set component type or return existing component value

setComponentByName(name, value=<NoValue object>, verifyConstraints=True, matchTags=True, matchConstraints=True)

Assign Set type component by name.

Equivalent to Python dict item assignment operation (e.g. []).

Parameters

name (str) – Set type component name

Keyword Arguments

  • value (object or PyAsn1Item derivative) – A Python value to initialize Set component with (if componentType is set) or ASN.1 value object to assign to Set component. If value is not given, schema object will be set as a component.

  • verifyConstraints (bool) – If False, skip constraints validation

  • matchTags (bool) – If False, skip component tags matching

  • matchConstraints (bool) – If False, skip component constraints matching

Returns

self

clear()

Remove all components and become an empty Set value object.

Has the same effect on Set object as it does on dict built-in.

reset()

Remove all components and become a Set schema object.

See isValue() property for more information on the distinction between value and schema objects.

property isInconsistent

Run necessary checks to ensure Set object consistency.

Default action is to verify Set object against constraints imposed by subtypeSpec.

Raises

PyAsn1tError –