You can try Wireshark.

• Wireshark: http://www.wireshark.org/download.html
• Wireshark - Wikipedia: https://en.wikipedia.org/wiki/Wireshark

Try wireshark for that? Firefox is already nicely logging the HTTP sessions

What I need is for firefox not to delete the data feeds of html pages, js, ... as it finishes to process, show them.

There should be some sort of "about:cache_duration" or "about:cache_length" option,

What is it?

Probably, another MOZ_LOG parameter would do, but I don't know what would it be.

MOZ_LOG parameters don't look like about:config parameters

to me.

See:

• https://developer.mozilla.org/en-US/docs/Mozilla/Debugging/HTTP_logging

MOZ_LOG_FILE and MOZ_LOG_MODULES are now the environment variables for logging:

• https://groups.google.com/forum/#!topic/mozilla.dev.platform/lEV_p0PxbWw

• https://dxr.mozilla.org/mozilla-release/search?q=regexp:NSPR_LOG_MODULES&=mozilla-release

See:

• https://developer.mozilla.org/en-US/docs/Mozilla/Debugging/HTTP_logging

yes, but in that document it says:

Using about:networking This is available starting with Firefox 52. Navigate to about:networking and go to the Logging section. ...

and the most up to date version of firefox is 50.1 right now 

and the beta release is 51.0beta:

https://www.mozilla.org/en-US/firefox/50.1.0/releasenotes/ https://www.mozilla.org/en-US/firefox/51.0beta/releasenotes/

so I am not getting something right or you guys are 

not being clear enough to me.

There must be a way to do such a thing, which you 

are using while debugging  ;-)

You would have to install the Firefox Developer version (52.0a2) to set all parameters from within Firefox via about:networking. In the current release you only can do that via environment variables.

#!/bin/sh

# https://developer.mozilla.org/en/HTTP_Logging
# *https://developer.mozilla.org/en/Mozilla/Developer_guide/Gecko_Logging

# try one of these (remove the #)
# export MOZ_LOG=nsHttp:3
# export MOZ_LOG=nsHttp:5

export NSPR_LOG_FILE=~/loghttp.txt

# set the correct path to Firefox
cd /usr/local/firefox-RE

# start Firefox
./firefox -no-remote -P

Albretch said

I also need to save and keep the actual pages that are being downloaded by the browser (including the supporting css, javascript, images, ...)

I doubt that logging will give you a convenient format. I once turned on logging for something. After 25 seconds, I had a text file of nearly 392,000 lines consuming over 42 megabytes. The responses were encoded (sent with gzip encoding) so they are indecipherable -- if they are included in the file, which I can't confirm. Every so often I find decoded response headers but I don't see the actual response content (text or image, as the case may be).

Hopefully there is another way, such as an add-on, that is simpler than fishing around in the cache.

See also:

• https://addons.mozilla.org/firefox/addon/live-http-headers/

OK, I was finally able to do what I wanted.

Here is an outline for anyone to benefit from, improve it:

// __ latest firefox development version (aurora)

https://archive.mozilla.org/pub/firefox/nightly/latest-mozilla-aurora/firefox-52.0a2.en-US.linux-i686.tar.bz2

$ ls -l firefox-52.0a2.en-US.linux-i686.tar.bz2 -rw-r--r-- 1 knoppix knoppix 65124511 Dec 27 05:31 firefox-52.0a2.en-US.linux-i686.tar.bz2

$ md5sum -b firefox-52.0a2.en-US.linux-i686.tar.bz2 0877480001d91ebdb180011db8f84df5 *firefox-52.0a2.en-US.linux-i686.tar.bz2

// __ untar/install it

$ _LOG="tar_-xjvf_firefox-52.0a2.log"

$ date; time tar -xjvf firefox-52.0a2.en-US.linux-i686.tar.bz2 > "${_LOG}" Wed Dec 28 04:09:02 EST 2016

$ wc -l "${_LOG}" 78 tar_-xjvf_firefox-52.0a2.log

$ ls -l "${_LOG}"

// __ run/test it

$ cd firefox

$ pwd .../firefox

$ ./firefox --version Mozilla Firefox 52.0a2

// __ While developing, I find useful running tcpdump, wireshark and firefox in logging mode

// __ run firefox and set up logging via about:config

_DT=$(date +%Y%m%d_%H%M%S)

_LOGFL="${_ODIR}/${_DT}_firefox-52.0a2_MOZ.log" echo "// __ \$_LOGFL: |$_LOGFL|"

export MOZ_LOG=timestamp,rotate:200,nsHttp:5,nsSocketTransport:5,nsStreamPump:5,nsHostResolver:5

export MOZ_LOG_FILE="${_LOGFL}"

./firefox &

then the wireshark and tcpdump part

// __ You don't want to run wireshark as root!

$ sudo dpkg-reconfigure wireshark-common

$ sudo adduser -a $USER wireshark

// __ Set up logging file names for easy management

_NM="..."

_DATA_DIR=".../data"

_ODIR="${_DATA_DIR}/${_NM}"

mkdir "${_ODIR}"

_DT=$(date +%Y%m%d_%H%M%S)

_WSLOG="${_ODIR}/wireshark-gtk_${_DT}.log" echo "// __ \$_WSLOG: |$_WSLOG|"

// __ running wireshark

sudo wireshark-gtk -i eth0 -k -w "${_WSLOG}" &

// __ running tcpdump

sudo tcpdump -pni eth0 -s65535 -G 3600 -w "${_ODIR}/tcpdump_%Y%m%d_%H%M%S.pcap" &

jscher2000 said

Albretch said

I also need to save and keep the actual pages that are being downloaded by the browser (including the supporting css, javascript, images, ...)

I doubt that logging will give you a convenient format ...

That is why I am a bit more comfortable using more than 

one tool and keeping an eye on all of them. Also, gzip you can easily unzip

Using only "nsHttp:3" (LogLevel::Info) in the DE version with about:networking seems to give a log with the HTTP request and response headers and not that much extra data.