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AMF (Action Message Format) is a binary data serialization protocol. Simply put, it transforms objects in memory into a binary string, and can reverse this binary string into an object in memory. It can be used just likeJSON, and this library has been build to provide a similar API to that exposed by theJSON functionality inPHP.

The purpose of this library is to provide a consistent and symmetric implementation of theAMF specification in bothPHP &JSON.

Well, it's up to you.JSON is perfectly suited to the web, however it does have some shortcomings which are addressed byAMF. For starters,JSON cannot handle complex object graphs with circular references; additionally, it cannot serialize dates & byte arrays - you would need to do some additional work to support these inJSON (convert date to unix timestamp, byte arrays to base64).

Hells no.JSON is great;AMF can simply provide you with some additional funcitonality which could help you build your web app.

To begin using this library, you will need to install it viaComposer:

{"require": {"infomaniac-amf/php":"dev-master"}}

Once you have runcomposer install, you will be able to use the library by simply includingComposer's autoloader:

<?phprequire_once'vendor/autoload.php';

Here is a simple example of encoding an array toAMF:

<?phprequire_once'vendor/autoload.php';$data =array('any' =>'data','you' =>'like');header('Content-Type: application/x-amf');echoamf_encode($data);

This will produce a binary string which represents your given data.

If you were to inspect the HTTP traffic of a page that producesAMF data, using a tool such asCharles Proxy, you would see the following output:

To decode this string, simply do the following:

$data =array('any' =>'data','you' =>'like');$encodedData =amf_encode($data);$data =amf_decode($encodedData);

If you were tovar_dump this data, it would look identical to the input data given to theamf_encode function.

array (size=2)  'any' => string 'data' (length=4)  'you' => string 'like' (length=4)

AMF allows you to encode an object and retain some metadata about it; for example, when serializing an instance of a class (notstdClass) the library will retain the class' fully qualified namespace name and use it to reconstruct an object of that type upon decoding.

Consider the following class:

<?phpclass Person {public$name;}

If we encode an instance of this object, by default its class type will be ignored and when the data is decoded, the resulting value will be a plain PHPstdClass instance.

This is how the encoded data will look in Charles:

In order to retain the class type inAMF, you will need to add an additional flag to theamf_encode function call:

amf_encode($data,AMF_CLASS_MAPPING);

When theAMF_CLASS_MAPPING flag is given, the encoded data will look like this in Charles:

Notice the additionalPerson metadata in this response

Now, when this data is decoded, the library will attempt to create a new instance of thePerson class and set its public propertyname to"bob".

object(Person)[8]  public'name' => string'bob' (length=3)

TheAMF spec allows for the serialization of several different data-types.

Here is a link to the latest specification:AMF3 Spec - January 2013

This library implements10 of the18 data-types described in the specification. The reason for the support of only asubset of these types can be seen in two lights:utility andlimitation. Here is an exhaustive list of the data-types available:

This project is licensed under theMIT license.

While writing this library, I used several libraries to validate my progress, and to help me come unstuck. I would like to extend a special thanks to the following libraries and individuals:

• SabreAMF
• AmfPhp
• Charles Proxy's wonderful AMF implementation
• Arseny Vakhrushev (neoxic) for his patience, guidance, advice and help
• Robert Cesaric,Grant McMullin andAndre Venter for their insight and advice
• My esteemed colleagues atZando