Parser¶

The ISO8583Parser class converts raw ISO 8583 message strings into structured ISO8583Message objects.

Quick Start¶

from iso8583sim.core.parser import ISO8583Parser

parser = ISO8583Parser()

# Parse a raw message
message = parser.parse("0100702406C120E09000164111111111111111...")

print(f"MTI: {message.mti}")
print(f"PAN: {message.fields.get(2)}")
print(f"Amount: {message.fields.get(4)}")
print(f"Network: {message.network}")

Features¶

Auto Network Detection¶

The parser automatically detects the card network from the PAN (Field 2):

message = parser.parse(raw_message)
print(message.network)  # CardNetwork.VISA, CardNetwork.MASTERCARD, etc.

Network detection is based on PAN prefixes: - VISA: 4xxx - Mastercard: 51-55, 2221-2720 - AMEX: 34, 37 - Discover: 6011, 644-649, 65 - JCB: 3528-3589 - UnionPay: 62

Manual Network Specification¶

Override auto-detection by specifying the network:

from iso8583sim.core.types import CardNetwork

message = parser.parse(raw_message, network=CardNetwork.MASTERCARD)

Version Support¶

from iso8583sim.core.types import ISO8583Version

# Use ISO 8583:1993
parser = ISO8583Parser(version=ISO8583Version.V1993)

EMV Data Parsing¶

Field 55 (ICC Data) is automatically parsed into a dictionary:

message = parser.parse(emv_message)

if message.emv_data:
    print(f"Cryptogram: {message.emv_data.get('9F26')}")
    print(f"CID: {message.emv_data.get('9F27')}")

Object Pooling¶

For high-throughput scenarios:

from iso8583sim.core.pool import MessagePool

pool = MessagePool(size=1000)
parser = ISO8583Parser(pool=pool)

# Messages are recycled
message = parser.parse(raw)
# ... use message ...
pool.release(message)

Parsing Process¶

MTI Extraction: Read first 4 characters as Message Type Indicator
Bitmap Parsing: Parse 16-character hex bitmap (64 bits)
Secondary Bitmap: If bit 1 is set, parse additional 16 characters
Field Parsing: For each set bit, parse the corresponding field
Network Detection: Identify card network from PAN if present

Error Handling¶

from iso8583sim.core.types import ParseError

try:
    message = parser.parse(raw_message)
except ParseError as e:
    print(f"Parse error: {e}")

Common errors: - Invalid MTI format - Malformed bitmap - Field length exceeds maximum - Invalid hex characters

API Reference¶

See Core API Reference for complete API documentation.