[[!meta title="How to change the tempdir for Mozilla (general) and conkeror"]]

Some weeks ago I got a good hint from
[[Axel Stefan Beckert|dokumentationen/axel-stefan-beckert]], to try [conkeror](http://conkeror.org/)
as an alternative for the
[Firefox](http://www.mozilla.com/en-US/firefox/firefox.html) browser.

Although I am not used to the [emacs](http://en.wikipedia.org/wiki/Emacs)
shortcuts, it is very good usable with the keyboard only.

In the last few days I have been missing one important feature,
one of the most important features of a browser:

    to be able to edit a textbox with an external editor
    
I often edit large wiki pages and rearange them, which is a pain
without a real editor.

Conkeror supports [external editing](http://conkeror.org/ExternalEditing),
but defaults to

 * $VISUAL
 * $EDITOR
 * or emacs

None of the is usable for me, because **$VISUAL** and **$EDITOR**
are set to [vim](http://www.vim.org/) and vim requires a terminal.

After I was told on [#conkeror](irc://irc.freenode.org/#conkeror)
to modify ***~/.conkerorrc/init.js*** to include

    editor_shell_command = "urxvt -e vim";

it worked like a charm (besides debugging it for some others days,
until I found out that there was always one instance of conkeror
running, so it never re-read the configuration file). I can now
edit textboxes in conkeror with vim!

But then I noticed, that conkeror creates a temporary file below
***/tmp***, which I do not like, because all my data should be
put on my [encrypted home directory](http://code.google.com/p/cryptsetup/),
not on the unencrypted root partition.

So I started to search for a configuration variable in the
[configuration window](about:config), but did not find any hint.

As I am running conkeror from the git source, I began to dig through it
and started in **modules/external-editor.js**, where I found the
function **open_with_external_editor()**:

    76 function open_with_external_editor (lspec) {
    77     keywords(arguments);
    78     let [file, temp] = yield download_as_temporary(lspec);
    79     yield open_file_with_external_editor(file, $line = arguments.$line, $temporary = temp);
    80 }

Ok, what is **download_as_temporary()** doing? The file **modules/save.js** helped
me:

    228 function download_as_temporary (lspec) {
    243     var file = get_temporary_file(suggest_file_name(lspec));

Well, well, so what's about the **get_temporary_file()** function? The file
**modules/utils.js** contains it:

    799 function get_temporary_file (name) {
    800     if (name == null)
    801         name = "temp.txt";
    802     var file = file_locator.get("TmpD", Ci.nsIFile);
    803     file.append(name);
    804     // Create the file now to ensure that no exploits are possible
    805     file.createUnique(Ci.nsIFile.NORMAL_FILE_TYPE, 0600);
    806     return file;
    807 }

Searching for **Ci.nsIFile** in conkerors source did not reveal
many information, so I got back to my **seoc** (search engine of choice) and
found some hints on the [mozilla developer center](https://developer.mozilla.org)
about [nsIFile](https://developer.mozilla.org/en/nsIFile) and
[TmpD](https://developer.mozilla.org/en/Code_snippets/File_I%2F%2FO)
and a reference to the IRC channel [#extdev](irc://irc.mozilla.org/extdev).

After I described my problem in that IRC channel,
[Michael Kaply](http://www.kaply.com/weblog/about/)
told me the answer to the question
"[What defines or where is the TmpD variable defined?](http://mxr.mozilla.org/mozilla1.9.2/source/xpcom/io/SpecialSystemDirectory.cpp#568)":

The temporary directory is OS specific and in my case (unix) defined by the
environment variables

 * $TMPDIR
 * $TMP
 * $TEMP (tried in that order)

After I set

    TMP=~/.tmp 

and restarted conkeror, pressed C-i in a textbox, the file is eventually saved
in the temporary directory **.tmp** in my home directory!

[[!tag eth net]]