This chapter discusses the MIME types file.
The sections are:
The MIME types file in the config directory contains mappings between MIME (Multipurpose Internet Mail Extensions) types and file extensions. For example, the MIME types file maps the extensions .html and .htm to the type text/html:
When the Sun Java System Web Server receives a request for a resource from a client, it uses the MIME type mappings to determine what kind of resource is being requested.
MIME types are defined by three attributes: language (lang), encoding (enc), and content-type (type). At least one of these attributes must be present for each type. The most commonly used attribute is type. The server frequently considers the type when deciding how to generate the response to the client. The enc and lang attributes are rarely used.
During the ObjectType step in the request handling process, the server determines the MIME type attributes of the resource requested by the client. Several different server application functions (SAFs) can be used to determine the MIME type, but the most commonly used one is type-by-extension. This function tells the server to look up the MIME type according to the requested resource’s file extension in the MIME types table.
The directive in obj.conf that tells the server to look up the MIME type according to the extension is:
If the server uses a different SAF, such as force-type, to determine the type, then the MIME types table is not used for that particular request.
For more details of the ObjectType step, see the Sun Java System Web Server 6.1 SP9 NSAPI Programmer’s Guide.
The server considers the value of the type attribute when deciding which Service directive in obj.conf to use to generate the response to the client.
By default, if the type does not start with magnus-internal/, the server just sends the requested file to the client. The directive in obj.conf that contains this instruction is:
Service method=(GET|HEAD|POST) type=*~magnus-internal/* fn=send-file
By convention, all values of type that require the server to do something other than just send the requested resource to the client start with magnus-internal/.
For example, if the requested resource’s file extension is .map, the type is mapped to magnus-internal/imagemap. If the extension is .cgi, .exe, or .bat, the type is set to magnus-internal/cgi:
type=magnus-internal/imagemap exts=map type=magnus-internal/cgi exts=cgi,exe,bat
If the type starts with magnus-internal/, the server executes the Service directive in obj.conf matches the specified type. For example, if the type is magnus-internal/imagemap, the server uses the imagemap function to generate the response to the client, as indicated by the following directive:
Service method=(GET|HEAD) type=magnus-internal/imagemap fn=imagemap
The Service function generates the data and sends it to the client that made the request. When the server sends the data to the client, it also sends headers. These headers include the MIME type attributes are known (which is usually type).
When the client receives the data, it uses the MIME type to decide what to do with the data. For browser clients, display the data in the browser window.
If the requested resource cannot be displayed in a browser but needs to be handled by another application, its type starts with application/, for example, application/octet-stream (for .bin file extensions) or application/x-maker (for .fm file extensions). The client has its own set of user-editable mappings that tells it which application to use to handle which types of data.
For example, if the type is application/x-maker, the client usually handles it by opening Adobe® FrameMaker® to display the file.
The first line in the MIME types file identifies the file format and must read:
#--Sun Microsystems MIME Information
Other non-comment lines have the following format:
type=type/subtype exts=[file extensions]
type/subtype is the type and subtype.
exts are the file extensions associated with this type.
Here is an example of a MIME types file:
#--Sun Microsystems MIME Information # Do not delete the above line. It is used to identify the file type. type=application/octet-stream exts=bin,exe type=application/oda exts=oda type=application/pdf exts=pdf type=application/postscript exts=ai,eps,ps type=application/rtf exts=rtf type=application/x-mif exts=mif,fm type=application/x-gtar exts=gtar type=application/x-shar exts=shar type=application/x-tar exts=tar type=application/mac-binhex40 exts=hqx type=audio/basic exts=au,snd type=audio/x-aiff exts=aif,aiff,aifc type=audio/x-wav exts=wav type=image/gif exts=gif type=image/ief exts=ief type=image/jpeg exts=jpeg,jpg,jpe type=image/tiff exts=tiff,tif type=image/x-rgb exts=rgb type=image/x-xbitmap exts=xbm type=image/x-xpixmap exts=xpm type=image/x-xwindowdump exts=xwd type=text/html exts=htm,html type=text/plain exts=txt type=text/richtext exts=rtx type=text/tab-separated-values exts=tsv type=text/x-setext exts=etx type=video/mpeg exts=mpeg,mpg,mpe type=video/quicktime exts=qt,mov type=video/x-msvideo exts=avi enc=x-gzip exts=gz enc=x-compress exts=z enc=x-uuencode exts=uu,uue type=magnus-internal/imagemap exts=map type=magnus-internal/parsed-html exts=shtml type=magnus-internal/cgi exts=cgi,exe,bat type=magnus-internal/jsp exts=jsp