pynetdicom.pdu.A_ASSOCIATE_RQ

class pynetdicom.pdu.A_ASSOCIATE_RQ

An A-ASSOCIATE-RQ PDU.

An A-ASSOCIATE-RQ PDU is sent by an association requestor to initiate association negotiation with an acceptor.

application_context_name

The Application Context Item’s Application Context Name field value (if available).

Type

pydicom.uid.UID or None

called_ae_title

The Called AE Title field value, which is the destination DICOM application name as a fixed length 16-byte value (padded with trailing spaces 0x20). Leading and trailing spaces are non-significant and a value of 16 spaces is not allowed.

Type

bytes

calling_ae_title

The Calling AE Title field value, which is the destination DICOM application name as a fixed length 16-byte value (padded with trailing spaces 0x20). Leading and trailing spaces are non-significant and a value of 16 spaces is not allowed.

Type

bytes

pdu_length

The number of bytes from the first byte following the PDU Length field to the last byte of the PDU.

Type

int

pdu_type

The PDU Type field value (0x01).

Type

int

presentation_context

The Presentation Context Item(s).

Type

list of pdu_items.PresentationContextItemRQ

protocol_version

The Protocol Version field value (0x01).

Type

int

user_information

The User Information Item (if available).

Type

pdu_items.UserInformationItem

variable_items

A list containing the A-ASSOCIATE-RQ’s Variable Items. Contains one Application Context item, one or more Presentation Context items and one User Information item. The order of the items is not guaranteed.

Type

list

Notes

An A-ASSOCIATE-RQ PDU requires the following parameters:

• PDU type (1, fixed value, 0x01)

• PDU length (1)

• Protocol version (1, default value, 0x01)

• Called AE title (1)

• Calling AE title (1)

• Variable items (1)

  • Application Context Item (1)

    • Item type (1, fixed value, 0x10)

    • Item length (1)

    • Application Context Name (1, fixed in an application)

  • Presentation Context Item(s) (1 or more)

    • Item type (1, fixed value, 0x21)

    • Item length (1)

    • Context ID (1)

    • Abstract/Transfer Syntax Sub-items (1)

      • Abstract Syntax Sub-item (1)

        • Item type (1, fixed, 0x30)

        • Item length (1)

        • Abstract syntax name (1)

      • Transfer Syntax Sub-items (1 or more)

        • Item type (1, fixed, 0x40)

        • Item length (1)

        • Transfer syntax name(s) (1 or more)

  • User Information Item (1)

    • Item type (1, fixed, 0x50)

    • Item length (1)

    • User data Sub-items (2 or more)

      • Maximum Length Received Sub-item (1)

      • Implementation Class UID Sub-item (1)

      • Optional User Data Sub-items (0 or more)

Encoding

When encoded, an A-ASSOCIATE-RQ PDU has the following structure, taken from Table 9-11<part08/sect_9.3.2.html> (offsets shown with Python indexing). PDUs are always encoded using Big Endian.

Offset	Length	Description
0	1	PDU type
1	1	Reserved
2	4	PDU length
6	2	Protocol version
8	2	Reserved
10	16	Called AE title
26	16	Calling AE title
42	32	Reserved
74	Variable	Variable items

References

• DICOM Standard, Part 8, Sections 9.3.2 and 9.3.1

__init__()

Initialise a new A-ASSOCIATE-RQ PDU.

Methods

__init__()	Initialise a new A-ASSOCIATE-RQ PDU.
decode(bytestream)	Decode bytestream and use the result to set the field values of the PDU.
encode()	Return the encoded PDU as bytes.
from_primitive(primitive)	Setup the current PDU using an A-ASSOCIATE (request) primitive.
to_primitive()	Return an A-ASSOCIATE (request) primitive from the current PDU.

Attributes

application_context_name	Return the Application Context Name, if available.
called_ae_title	Return the Called AE Title field value as bytes.
calling_ae_title	Return the Calling AE Title field value as bytes.
pdu_length	Return the PDU Length field value as int.
pdu_type	Return the PDU Type field value as int.
presentation_context	Return a list of the Presentation Context items.
user_information	Return the User Information Item, if available.

property application_context_name

Return the Application Context Name, if available.

Returns

The requestor’s Application Context Name or None if not available.

Return type

pydicom.uid.UID or None

property called_ae_title

Return the Called AE Title field value as bytes.

property calling_ae_title

Return the Calling AE Title field value as bytes.

from_primitive(primitive)

Setup the current PDU using an A-ASSOCIATE (request) primitive.

Parameters

primitive (pdu_primitives.A_ASSOCIATE) – The primitive to use to set the current PDU field values.

property pdu_length

Return the PDU Length field value as int.

property presentation_context

Return a list of the Presentation Context items.

Returns

The Presentation Context items.

Return type

list of pdu_items.PresentationContextItemRQ

to_primitive()

Return an A-ASSOCIATE (request) primitive from the current PDU.

Returns

The primitive representation of the current PDU.

Return type

pdu_primitives.A_ASSOCIATE

property user_information

Return the User Information Item, if available.

Returns

The requestor’s User Information object or None, if not available.

Return type

pdu_items.UserInformationItem or None