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Technical Notes
ZOIS Technical Note TN-2002-06-26.
Author and Audience
1]. Some UNIX system programming
skills are assumed. Written by Martin Sullivan[2],
ZOIS Limited, Cockermouth.
Abstract
Upgrading to Lynx 2.8.4 (from a two year old 2.8.3) fixed a number
of problems that upgraded HTTP Servers were reporting. No further
investigation was required.
Introduction
The author is a long-time fan of Lynx, the text based web-browser. Its rendering of text is fast and who needs pictures anyway, they are probably adverts.
Lately a number of problems have been noted with Lynx browsing. It seemed that as a number of sites upgraded and patched their Hyper-text Transfer Protocol (HTTP) Servers that Lynx started reporting errors. This was particularly noted with sites running Microsoft's IIS and AOL's NES. It also was dependent upon the use and type of Proxy, especially if the HTTP had to cross a number of Proxies.
After a brief investigation is was suspected that Lynx and the various servers were not seeing eye-to-eye on parts of HTTP. The errors that were reported were:
The Lynx being used was the as distributed with Red Hat Linux 6.2
version, which was found to be 2.8.3. It was decided to upgrade and
should the errors continue to be present, investigate further.
Materials and Platform
The platform for this work was initially
Red Hat[3]
distribution of Linux (version 6.2, kernel 2.2.14) running on a
modestly specified Laptop.
Method
The source was downloaded from the Linux site (it comprised of a 2.5 MByte gzip'ed tar archive). After unpacking the configure program was run; followed by make and then, as root, make install. This was all as documented in the included INSTALLATION file. No problems were encountered and the new Lynx installed in the /usr/local hierarchy. As the old Red Hat 6.2 binary was to be found in /usr/bin only a slight PATH environment variable adjustment would be necessary to pick up the new program. The author prefers to run Lynx from a script, to adjust for individual platforms, so this was suitably modified ...
#!/bin/sh
#
# Script to invoke Lynx
#
# Setup proxy environment variables
proxy="http://proxy.zois.co.uk:8080/"
#proxy="http://www-cache.demon.co.uk:8080/"
export http_proxy=${proxy}
export ftp_proxy=${proxy}
export gopher_proxy=${proxy}
export wais_proxy=${proxy}
# export https_proxy=${proxy}
# export file_proxy=${proxy}
# export news_proxy=${proxy}
export no_proxy="web.zois.co.uk"
#
# Now start Lynx...
case `uname` in
BSD/OS)
exec /usr/local/bin/lynx -cfg=/usr/local/lib/lynx.cfg ${*}
;;
FreeBSD)
unset TERMCAP
exec /usr/local/bin/lynx ${*}
;;
*) if /usr/local/bin/lynx --help 2>/dev/null | grep -q nocolor
then exec /usr/local/bin/lynx -nocolor ${*}
else exec /usr/local/bin/lynx ${*}
fi
;;
esac
|
A number of tests were then made with sites that had previously
reported errors in HTTP. They were all found to serve their pages
correctly. No further investigation was required.
Conclusion
It would appear that the use of HTTP had been tightened on the Lynx
side and this no longer provokes errors in a selection of recently
patched or upgraded HTTP Servers. It is recommended that if anybody
sees unusual, recent, HTTP activity from Lynx, especially when running
through Proxies that they upgrade to 2.8.4.
References
$Date: 2009/12/06 11:27:50 $