Web Design & Development Guide

Action Message Format

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AMF is a binary format based loosely on the Simple Object Access Protocol (SOAP). It is used primarily to exchange data between a flash application and a database, using a Remote Procedure Call.

Each AMF message contains a body which holds the error or response, which will be expressed as an ActionScript Object.

Data Types

AMF includes several core data types which are always present throughout the serialization of data:

Byte - A simple 8-bit chunk of data. This is the simplest way to send AMF data.
Int - A 16-bit number made of two consecutive bytes. The first byte is the most significant byt, and the second byte is the least significant byt.
MediumInt - A 24-bit number, identical to the above except for the length.
Long - A 32-bit number, same as above, but longer.
Double - A 64-bit number made up of 8 consecutive bytes. It represents a floating point, signed number. The double is little-endian encoded.
UTF8 - A UTF8 string longer than 2^16 bytes. It is made of a an integer (two bytes) representing the string length, followed by the UTF8-encode string.
LongUTF8 - A UTF8 string possible longer than 2^16 bytes. It consists of a long integer (four bytes) representing the string length, followed by the UTF8 encoded string.

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