Additional details in mod_mime about what all this stuff means. (e4629c17) · Commits · CYBER - Cyber Security / TS 103 523 MSP / TLMSP / TLMSP Apache Httpd

docs/manual/mod/mod_mime.html

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		@@ -8,7 +8,7 @@
		<body
		bgcolor="#FFFFFF"
		text="#000000"
		LINK="#0000FF"
		link="#0000FF"
		vlink="#000080"
		alink="#FF0000"
		>
		@@ -118,6 +118,75 @@ extension is mapped to the MIME-type "text/html", then the file
		the "imap-file" handler will be used, and so it will be treated as a
		mod_imap imagemap file.

		<h2><a name="contentencoding">Content encoding</a></h2>

		A file of a particular MIME type can additionally be encoded a
		particular way to simplify transmission over the Internet. While this
		usually will refer to compression, such as <samp>gzip</samp>, it can
		also refer to encryption, such a <samp>pgp</samp> or
		to an encoding such as UUencoding, which is designed for transmitting
		a binary file in an ASCII (text) format.<p>

		The MIME RFC puts it this way:
		<blockquote>
		The Content-Encoding entity-header field is used as a modifier to the
		media-type. When present, its value indicates what additional content
		coding has been applied to the resource, and thus what decoding mechanism
		must be applied in order to obtain the media-type referenced by the
		Content-Type header field. The Content-Encoding is primarily used to allow
		a document to be compressed without losing the identity of its underlying
		media type.
		</blockquote>

		By using more than one file extension (see
		<a href="#multipleext">section above about multiple file
		extensions</a>), you can indicate that a file is of a particular
		<em>type</em>, and also has a particular <em>encoding</em>.<p>

		For example, you may have a file which is a Microsoft Word document,
		which is pkzipped to reduce its size. If the <samp>.doc</samp> extension is
		associated with the Microsoft Word file type, and the
		<samp>.zip</samp> extension is associated with the pkzip file
		encoding, then the file <samp>Resume.doc.zip</samp>would be known to
		be a pkzip'ed Word document.<p>

		Apache send a <samp>Content-encoding</samp> header with the resource,
		in order to tell the client browser about the encoding method.
		<p>
		<samp>Content-encoding: pkzip</samp>
		<p>
		<h2>Character sets and languages</h2>

		Finally, in addition to file type, and the file encoding,
		another important piece of information is
		what language a particular document is in, and in what character set
		the file should be displayed. For example, the document might be
		written in the Vietnamese alphabet, or in Cyrillic, and should be
		displayed as such. This information, also, is transmitted in MIME
		headers.<p>

		While the character set is useful for the browser, in order to
		determine how to display the document, the language and the
		character set are also used in the process of content negotiation
		(See <a href="mod_negotiation.html">mod_negotiation</a>)
		to determine which document to give to the client, when there are
		alternative documents in more than one language, or more than
		one character set.<p>

		To convey this further information, Apache optionally sends a
		<samp>Content-Language</samp> header, to specify the language that the
		document is in, and can append additional information onto the
		<samp>Content-Type</samp> header to indicate the particular character
		set that should be used to correctly render the information.

		<pre>
		Content-Language: en, fr
		Content-Type: text/plain; charset=ISO-8859-2
		</pre>
		<p>
		The language specification is the two-letter abbreviation for the
		language. The <samp>charset</samp> is the name of the particular
		character set which should be used.

		<hr>

		@@ -556,7 +625,7 @@ config files. An example of its use might be:
		<code></Files></code></dd>
		</DL>
		<P>
		This will cause <code>foo.gz</code> to mark as being encoded with the
		This will cause <code>foo.gz</code> to be marked as being encoded with the
		gzip method, but <code>foo.gz.asc</code> as an unencoded plaintext file.
		</P>
		<p>