Page: http://wiki.cocoondev.org/Wiki.jsp?page=HowTos , version: 81 on Wed Mar
19 15:20:38 2003 by BruceRobertson
- * __[Embed SVG Fonts|Embedding_SVG_Fonts]__ -- description of Cocoon-based
tools that add the svg:glyph elements necessary to render its text elements on
a client lacking the specified fonts. [BruceRobertson]
?
---------
+ * __[Embed SVG Fonts|Embedding_SVG_Fonts]__ -- description of Cocoon-based
tools that add the svg:glyph elements necessary to render its text elements on
a client lacking the specif. [BruceRobertson]
+
+ * __[Gzipped Compress XML Output|Gzip_XML_Serializer]__ -- description of a
serializer that produces Gzipped XML output. Useful for generating *.svgz
files, among other things. [BruceRobertson]
Page: http://wiki.cocoondev.org/Wiki.jsp?page=BringMeThisExample , version: 30
on Wed Mar 19 15:34:47 2003 by NicolaKen
- #Beep Beep
- ''And now''
- __ Che bello questo cms :-) __
- [linksite]
-
- ghjhghjghjgjgj
-
Page: http://wiki.cocoondev.org/Wiki.jsp?page=Gzip_XML_Serializer , version: 1
on Wed Mar 19 15:59:58 2003 by BruceRobertson
New page created:
+ !Introduction
+ XML is meant to be human-readable. Often this means that the markup is
pointlessly verbose from the machine's standpoint. The common solution is to
compress the XML -- the SVG spec, for instance, stipulates that SVG viewers
need to be able to read gzipped files as well as uncompressed equivalent; and
numerous applications, from Gnumeric to OpenOffice, compress their XML before
saving. When files are being sent over the internet, compression can make the
difference between impracticality and practicality. Working with SVG maps at
the Heml Project, I found I was producing files well over 500k in size. These
could never be served to the modem-connected great unwashed, but their gzipped
equivalent, weighing in at less than 100k, could.
+
+ For more than a year, I used the mod_gzip module for Apache to do the
compression -- an effort partly described at [Cocoon_and_Apache_mod_gzip] --,
but this was never entirely satisfactory. mod_gzip is meant for compressing
html and is based on the httpd negotiation between client and server. A client
must declare in its request header that it can handle gzip content. However,
SVG viewers and plugins rightly won't send this information, yet they can all
digest svgz conent. Secondly, any post-cocoon solution means that cocoon's
cache will gobble up more of your RAM by caching the uncompressed XML. If we
could serialize the result within Cocoon, its cache would hold the smaller
gzipped version. (Someone correct me if Cocoon in fact compresses the contents
of its cache.)
+
+ !Enter GzipXMLSerializer
+ After some fiddling, I have come up with a hack on Cocoon's XMLSerializer
that serializes compressed XML content. For those interesting in the
programming, the code is available through a
+ [ViewCVS page
|http://heml.mta.ca/cgi-bin/viewcvs.cgi/heml_cvs/src/org/heml/cocoon/serialization/GzipXMLSerializer.java].
If this were to be integrated into Cocoon's API, I would recommend factoring
out what is common between XMLSerializer and this, then making both a subclass.
If you just want to use the darn thing to compress your own SVG, read on.
+
+ !Using GzipXMLSerializer
+
+ To use the GzipXMLSerializer, you'll need to download
{{heml-cocoon-0_5.4-dev-20030221.jar}} or later, found at
[http://heml.mta.ca/releases]. You __don't__ need the massive
{{heml-cocoon.war}} file. This should go in your {{$TOMCAT/cocoon/WEB-INF/lib}}
directory.
+
+ Next, you'll need to declare the serializer in the Serializers section of
your sitemap, thus:
+ {{ <map:serializers default="html">\\
+ <map:serializer name="gzip" mime-type="image/svg+xml"\\
src="org.heml.cocoon.serialization.GzipXMLSerializer"/>\\
+ <!-- all the other usual definitions go here -->\\
+ <!-- ... -->\\
+ </map:serializers>\\
+ }}
+
+ Finally, use the serializer as you would any other. I map the filename
extension in this way so that we can get png, svg or svgz :
+
+ {{
+ <!-- the part of the name after the dot indicates what sort of output we want
-->
+ <map:select type="parameter">
+ <map:parameter name="parameter-selector-test"
value="{../../../2}"/>
+ <map:when test="svg">
+ <map:serialize type="svgxml"/>
+ </map:when>
+ <map:when test="jpg">
+ <map:serialize type="svg2jpeg"/>
+ </map:when>
+ <map:when test="png">
+ <map:serialize type="svg2png"/>
+ </map:when>
+ <map:when test="rss">
+ <map:serialize type="xml"/>
+ </map:when>
+ <map:when test="xml">
+ <map:serialize type="xml"/>
+ </map:when>
+ <map:when test="svgz">
+ <map:serialize type="gzip"/>
+ </map:when>
+ </map:select>
+ }}
+
+
