zif.gzipper

This is a wsgi middleware application intended for use with paste.deploy, zope.paste, and zope3.

It serves as a wsgi filter to gzip output from a zope3 application.

Dependencies

for zope3, zif.gzipper requires Sidnei da Silva's zope.paste

zope.paste is available at http://svn.zope.org/zope.paste/trunk/

        cd [path.to.zope3.src.directory]/zope
        svn co http://svn.zope.org/zope.paste/trunk/ paste

zope.paste is also available at the cheese shop .

Instructions for zope.paste are at http://awkly.org/2006/01/25/zopepaste-wsgi-applications-in-zope-3-using-pastedeploy/

zope.paste requires paste.deploy. paste.deploy may be obtained from the cheese shop . Presuming you have setuptools installed,

        sudo easy_install.py PasteDeploy

This (zif.gzipper) package can be unzipped and installed anywhere on the Python path.

Setup

Follow Sidnei's instructions for setting up zope.paste. It involves putting the usual zope.paste-configure.zcml file in [zope3 instance]/etc/site-packages. There is also a parameter to change in [zope3 instance]/etc/zope.conf. The new twist is a paste.ini file in [zope3 instance]/etc

My paste.ini file looks like:

        [pipeline:Paste.Main]
        pipeline = gzipper jsmin main

        [app:main]
        paste.app_factory = zope.paste.application:zope_publisher_app_factory

        [filter:gzipper]
        paste.filter_factory=zif.gzipper.gzipper:filter_factory
        compress_level=6
        exclude=localimages
        nocompress=jp gz zip png
        tempfile=1048576

        [filter:jsmin]
        paste.filter_factory=zif.jsmin.jsmin:filter_factory
        compress_level=safe

Configuration

gzipper should be the first filter in the pipeline. Other filters will have a hard time reading compressed data output from this filter.

The paste.ini file above shows examples of the configuration options for gzipper .

compress_level is the level of compression for the gzip function. 6 is the default. 9 is max. 3 is often good enough. Higher numbers use more processor, but compress smaller.
exclude is a sequence of strings that appear in the a filename or path you wish to exclude from gzipping. If any of these strings appears in the path or filename, gzipper will not gzip the file.
nocompress is a sequence of strings that appear in content-types you wish to exclude from gzipping. If the string appears anywhere in the content-type, items with that content-type will not be gzipped. "jp" will exclude "image/jpg" and "image/jpeg". "application" will exclude any content-type with the word "application" in it.
tempfile is the file size above which gzipper will send the gzipped data to a tempfile on disk. This may help memory usage. It may not. tempfile=0 means do not use temporary file. Default is 1 megabyte (1048576).

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