Local web browsing

Advantages of browsing local files as web pages over plain files include improved file formatting, multimedia integration, interactive and dynamic navigation. Suppose for instance our directory contains a README.md (as in a GitHub repository) which can be converted to README.html via pandoc, then we can browse our directory as files + web page with README.html (allowing for explicit file download), or a web page when index.html is created as a symbolic link to README.html (files are invisible unless explicit links are given inside).

To proceed, we first start the web service, which is simply done (through the default Python 3.6.8) as follows:

python3 -m http.server 8080 &

assuming port number 8080 is available, e.g. lsof -i :8080 gives no output.

An almost equally simpler approach is also possible,

npm install -g http-server
http-server &

The firefox browser available at /usr/bin/firefox is dysfunctional, and when started many temporary files are generated which can be removed with

# only remove those dated on Dec 3:
ll -rt | grep "Dec  3" | awk '{print "rm -fr "$NF}' | bash

A close attempt is with 20.04.def but remains problematic.

# firefox/136.0 (64-bit) as of 26/3/2025
singularity build 20.04.sif 20.04.def
singularity run --bind $HPC_WORK/work:/mnt/tmp 20.04.sif`
# A showcase of instance
singularity instance start 20.04.sif 20.04
singularity instance list
## quit with 'exit'
singularity shell instance://20.04
## exec take commands such as 'bash', 'ls', 'apt-get'
singularity exec instance://20.04 firefox
singularity instance stop 20.04

Alternatively, it can be added to an existing container as follows,

singularity pull docker://ubuntu:20.04
singularity build --fakeroot --sandbox ubuntu_20.04_sandbox/ ubuntu_20.04.sif
singularity shell --fakeroot --writable ubuntu_20.04_sandbox/
# export LANG=en_US.UTF-8
# export LANGUAGE=en_US.UTF-8
# export LC_ALL=en_US.UTF-8
# apt update
# apt install -y firefox
# exit
singularity exec ubuntu_20.04_sandbox/ /usr/bin/firefox
singularity build 20.04.sif ubuntu_20.04_sandbox/
singularity exec 20.04.sif /usr/bin/firefox

Several alternatives are described below.

Firefox

A singularity get-around is possible with this,

module load ceuadmin/firefox/60.5.1esr
firefox &

Chrome

module load ceuadmin/chrome
chrome http://localhost:8080 &

Chromium

We are then capable to work with ceuadmin/chromium:

module load ceuadmin/chromium
chrome http://localhost:8080 &

using profile at ~/.config/chromium.

It might be helpful to clear browse history when chrome is repeatedly used, or to start a new profile, e.g.,

chrome --user-data-dir=/tmp/jhz22 http://localhost:8080 &

Microsoft Edge

This is also ready to use,

module load ceuadmin/edge
edge http://localhost:8080 &

where the customized edge works properly, unlike its aliases microsoft-edge and microsoft-edge-stable.

Note the profile is ~/.config/microsoft-edge, and the option --user-data-dir also applies since it is also based on Chromium.

Cytoscape

This is an earlier attempt but somewhat clumsy.

module load ceuadmin/Cytoscape/3.9.1
Cytoscape &

using Tools –> Open web page for http://127.0.0.1:8080.

Default browser(s)

A list of options is as follows,

xdg-settings --list
xdg-settings --manual
xdg-settings get default-web-browser
xdg-settings check default-web-browser firefox.desktop
xdg-settings set default-web-browser firefox.desktop
xdg-settings set default-web-browser chromium.desktop
xdg-settings set default-web-browser microsoft-edge.desktop
xdg-settings set default-web-browser google-chrome.desktop

System-wide and user-specific .desktop files are at /usr/share/applications and ~/.local/share/applications/, respectively.

For Microsoft Edge above, we see microsoft-edge.desktop, and an attempt is made as follows,

export src=/usr/local/Cluster-Apps/ceuadmin/edge/130.0.2849.56-1/usr/share/applications/
export dest=~/.local/share/applications
cp ${src}/microsoft-edge.desktop ${dest}
cd ${dest}
sed -i "s|/usr/bin/microsoft-edge|${src}/microsoft-edge --no-sandbox|" ${dest}/microsoft.desktop
export XDG_CURRENT_DESKTOP=GNOME
xdg-settings set default-web-browser microsoft-edge.desktop
xdg-settings get default-web-browser

Non-CSD3 browser(s)

This approach seems less problematic with user-data-dir mentioned above. We can again set up tunneling from CSD3 with

python3 -m http.server 8000 &
hostname

Once succeeded, we establish the connection elsewhere.

ssh -4 -L 8080:127.0.0.1:8000 -fN jhz22@${hostname}.hpc.cam.ac.uk

where hostname from CSD3 and ${hostname} have to be the same. We can then browse http://127.0.0.1:8080.