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Public Member Functions | Protected Member Functions | Protected Attributes | Private Member Functions
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
 getMimesFromData ($fileName, $chunk, $proposed)
 Get the untranslated MIME types for all known versions.
 getRealMimesFromData ($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.

Protected Member Functions

 getDataFormat ($version, $type)
 getMimeTypeForVersion ($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.

Protected Attributes

 $addedTypes
 Changes to the type table in later versions of IE.
 $baseTypeTable
 Relevant data taken from the type table in IE 5.
 $registry
 An approximation of the "Content Type" values in HKEY_CLASSES_ROOT in a typical Windows installation.
 $typeTable = array()
 Type table with versions expanded.
 $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.

Private Member Functions

 checkBinaryHeaders ($version, $chunk)
 Check for binary headers at the start of the chunk Confirmed same in 5 and 7.
 checkTextHeaders ($version, $chunk)
 Check for text 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 27 of file IEContentAnalyzer.php.

Constructor & Destructor Documentation

IEContentAnalyzer::__construct ( )

constructor

Definition at line 315 of file IEContentAnalyzer.php.

References $addedTypes, and as.

Member Function Documentation

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

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

Parameters:
$version
$chunk
Returns:
bool|string

Definition at line 586 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.

Parameters:
$version
$chunk
Returns:
bool|string

Definition at line 560 of file IEContentAnalyzer.php.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::getDataFormat ( $  version,
$  type 
) [protected]
Parameters:
$version
$type
Returns:
int|string

Definition at line 838 of file IEContentAnalyzer.php.

References as.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::getMimesFromData ( $  fileName,
$  chunk,
$  proposed 
)

Get the untranslated MIME types for all known versions.

Parameters:
string$fileNamethe file name (unused at present)
string$chunkthe first 256 bytes of the file
string$proposedthe MIME type proposed by the server
Returns:
Array: map of IE version to detected mime type

Definition at line 376 of file IEContentAnalyzer.php.

References array(), as, and getMimeTypeForVersion().

Referenced by getRealMimesFromData().

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

Get the MIME type for a given named version.

Parameters:
$version
$fileName
$chunk
$proposed
Returns:
bool|string

Definition at line 392 of file IEContentAnalyzer.php.

References $ext, $result, 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$fileNamethe file name (unused at present)
string$chunkthe first 256 bytes of the file
string$proposedthe MIME type proposed by the server
Returns:
Array: map of IE version to detected mime type

Definition at line 338 of file IEContentAnalyzer.php.

References array(), and getMimesFromData().

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

Do heuristic checks on the bulk of the data sample.

Search for HTML tags.

Parameters:
$version
$chunk
Returns:
array

Definition at line 687 of file IEContentAnalyzer.php.

References array(), and as.

Referenced by getMimeTypeForVersion().

IEContentAnalyzer::translateMimeType ( $  type)

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

Parameters:
$type
Returns:
string

Definition at line 350 of file IEContentAnalyzer.php.

References array().

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 55 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 31 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 67 of file IEContentAnalyzer.php.

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

Type table with versions expanded.

Definition at line 312 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 307 of file IEContentAnalyzer.php.

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