IEContentAnalyzer Class Reference

This class simulates Microsoft Internet Explorer's terribly broken and insecure MIME type detection algorithm. More...

List of all members.

Public Member Functions

 __construct ()
 constructor
 getRealMimesFromData ($fileName, $chunk, $proposed)
 Get the MIME types from getMimesFromData(), but convert the result from IE's idiosyncratic private types into something other apps will understand.
 translateMimeType ($type)
 Translate a MIME type from IE's idiosyncratic private types into more commonly understood type strings.
 getMimesFromData ($fileName, $chunk, $proposed)
 Get the untranslated MIME types for all known versions.

Protected Member Functions

 getMimeTypeForVersion ($version, $fileName, $chunk, $proposed)
 Get the MIME type for a given named version.
 sampleData ($version, $chunk)
 Do heuristic checks on the bulk of the data sample.
 getDataFormat ($version, $type)

Protected Attributes

 $baseTypeTable
 Relevant data taken from the type table in IE 5.
 $addedTypes
 Changes to the type table in later versions of IE.
 $registry
 An approximation of the "Content Type" values in HKEY_CLASSES_ROOT in a typical Windows installation.
 $versions = array( 'ie05', 'ie06', 'ie07', 'ie07.strict', 'ie07.nohtml' )
 IE versions which have been analysed to bring you this class, and for which some substantive difference exists.
 $typeTable = array()
 Type table with versions expanded.

Private Member Functions

 checkTextHeaders ($version, $chunk)
 Check for text headers at the start of the chunk Confirmed same in 5 and 7.
 checkBinaryHeaders ($version, $chunk)
 Check for binary headers at the start of the chunk Confirmed same in 5 and 7.


Detailed Description

This class simulates Microsoft Internet Explorer's terribly broken and insecure MIME type detection algorithm.

It can be used to check web uploads with an apparently safe type, to see if IE will reinterpret them to produce something dangerous.

It is full of bugs and strange design choices should not under any circumstances be used to determine a MIME type to present to a user or client. (Apple Safari developers, this means you too.)

This class is based on a disassembly of IE 5.0, 6.0 and 7.0. Although I have attempted to ensure that this code works in exactly the same way as Internet Explorer, it does not share any source code, or creative choices such as variable names, thus I (Tim Starling) claim copyright on it.

It may be redistributed without restriction. To aid reuse, this class does not depend on any MediaWiki module.

Definition at line 21 of file IEContentAnalyzer.php.


Constructor & Destructor Documentation

IEContentAnalyzer::__construct (  ) 

constructor

Definition at line 309 of file IEContentAnalyzer.php.

References $addedTypes, and $version.


Member Function Documentation

IEContentAnalyzer::checkBinaryHeaders ( version,
chunk 
) [private]

Check for binary headers at the start of the chunk Confirmed same in 5 and 7.

Definition at line 567 of file IEContentAnalyzer.php.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::checkTextHeaders ( version,
chunk 
) [private]

Check for text headers at the start of the chunk Confirmed same in 5 and 7.

Definition at line 544 of file IEContentAnalyzer.php.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::getDataFormat ( version,
type 
) [protected]

Definition at line 811 of file IEContentAnalyzer.php.

References $type, and $version.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::getMimesFromData ( fileName,
chunk,
proposed 
)

Get the untranslated MIME types for all known versions.

Parameters:
string $fileName The file name (unused at present)
string $chunk The first 256 bytes of the file
string $proposed The MIME type proposed by the server
Returns:
array Map of IE version to detected mime type

Definition at line 368 of file IEContentAnalyzer.php.

References $version, and getMimeTypeForVersion().

Referenced by getRealMimesFromData().

IEContentAnalyzer::getMimeTypeForVersion ( version,
fileName,
chunk,
proposed 
) [protected]

Get the MIME type for a given named version.

Definition at line 379 of file IEContentAnalyzer.php.

References $ext, $result, $type, $version, checkBinaryHeaders(), checkTextHeaders(), getDataFormat(), and sampleData().

Referenced by getMimesFromData().

IEContentAnalyzer::getRealMimesFromData ( fileName,
chunk,
proposed 
)

Get the MIME types from getMimesFromData(), but convert the result from IE's idiosyncratic private types into something other apps will understand.

Parameters:
string $fileName The file name (unused at present)
string $chunk The first 256 bytes of the file
string $proposed The MIME type proposed by the server
Returns:
array Map of IE version to detected mime type

Definition at line 332 of file IEContentAnalyzer.php.

References getMimesFromData().

IEContentAnalyzer::sampleData ( version,
chunk 
) [protected]

Do heuristic checks on the bulk of the data sample.

Search for HTML tags.

Definition at line 665 of file IEContentAnalyzer.php.

References $offset, and $version.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::translateMimeType ( type  ) 

Translate a MIME type from IE's idiosyncratic private types into more commonly understood type strings.

Definition at line 342 of file IEContentAnalyzer.php.

References $type.


Member Data Documentation

IEContentAnalyzer::$addedTypes [protected]

Initial value:

 array(
                'ie07' => array(
                        'text' => array( 'text/xml', 'application/xml' )
                ),
        )
Changes to the type table in later versions of IE.

Definition at line 49 of file IEContentAnalyzer.php.

Referenced by __construct().

IEContentAnalyzer::$baseTypeTable [protected]

Initial value:

 array(
                'ambiguous'  => array(
                        'text/plain', 
                        'application/octet-stream', 
                        'application/x-netcdf', 
                ),
                'text'  => array(
                        'text/richtext', 'image/x-bitmap', 'application/postscript', 'application/base64',
                        'application/macbinhex40', 'application/x-cdf', 'text/scriptlet'
                ),
                'binary'  => array(
                        'application/pdf', 'audio/x-aiff', 'audio/basic', 'audio/wav', 'image/gif',
                        'image/pjpeg', 'image/jpeg', 'image/tiff', 'image/x-png', 'image/png', 'image/bmp', 
                        'image/x-jg', 'image/x-art', 'image/x-emf', 'image/x-wmf', 'video/avi', 
                        'video/x-msvideo', 'video/mpeg', 'application/x-compressed',
                        'application/x-zip-compressed', 'application/x-gzip-compressed', 'application/java',
                        'application/x-msdownload'
                ),
                'html'  => array( 'text/html' ),
        )
Relevant data taken from the type table in IE 5.

Definition at line 25 of file IEContentAnalyzer.php.

IEContentAnalyzer::$registry [protected]

An approximation of the "Content Type" values in HKEY_CLASSES_ROOT in a typical Windows installation.

Used for extension to MIME type mapping if detection fails.

Definition at line 61 of file IEContentAnalyzer.php.

IEContentAnalyzer::$typeTable = array() [protected]

Type table with versions expanded.

Definition at line 306 of file IEContentAnalyzer.php.

IEContentAnalyzer::$versions = array( 'ie05', 'ie06', 'ie07', 'ie07.strict', 'ie07.nohtml' ) [protected]

IE versions which have been analysed to bring you this class, and for which some substantive difference exists.

These will appear as keys in the return value of getRealMimesFromData(). The names are chosen to sort correctly.

Definition at line 301 of file IEContentAnalyzer.php.


The documentation for this class was generated from the following file:

Generated on Sat Sep 5 02:08:38 2009 for MediaWiki by  doxygen 1.5.9