*  [Wiki](./wikitheory.wiki) page changes
  *  New and edited [forum](./forum.wiki) posts
  *  Announcements

Subscribers can elect to receive emails as soon as these events happen,
or they can receive a daily digest of the events instead.

Email alerts are sent by a [Fossil server](./server/), which must be
[set up](#quick) by the Fossil administrator to send email.

Email alerts do not currently work if you are only using Fossil from the
command line.

A bit of terminology: Fossil uses the terms "email alerts" and
"notifications" interchangeably. We stick to the former term in this

render the page immediately, and will not wait for delayed scripts
to be run, thus will never enable the hyperlinks.

These two sub-settings can be used separately or together.  If used together,
then the delay timer does not start until after the first mouse movement
is detected.

See also [./loadmgmt.md|Managing Server Load] for a description
of how expensive pages can be disabled when the server is under heavy
load.

<h2>The ongoing struggle</h2>

Fossil currently does a very good job of providing easy access to humans
while keeping out troublesome robots and spiders.  However, spiders and

Backoffice
==========

This is technical documentation about the internal workings of Fossil.
Ordinary Fossil users do not need to know about anything covered by this
document.  The information here is intended for people who want to enhance
or extend the Fossil code, or who just want a deeper understanding of
the internal workings of Fossil.

What Is The Backoffice
----------------------

The backoffice is a mechanism used by a
[Fossil server](./server/) to do low-priority
background work that is not directly related to the user interface.  Here
are some examples of the kinds of work that backoffice performs:

  1.  Sending email alerts and notifications
  2.  Sending out daily digests of email notifications
  3.  Other background email handling chores
  4.  Automatic syncing of peer repositories

This happens for every webpage, regardless of how that webpage is launched,
and regardless of the purpose of the webpage.  This also happens on the
server for "[fossil sync](/help?cmd=sync)" and
[fossil clone](/help?cmd=clone)" commands which are implemented as
web requests - albeit requests that the human user never sees.
Web requests can arrive at the Fossil server via direct TCP/IP (for example
when Fossil is started using commands like "[fossil server](/help?cmd=server)")
or via [CGI](./server/any/cgi.md) or
[SCGI](./server/any/scgi.md) or via SSH.
A backoffice process might be started regardless of the origin of the
request.

The backoffice is not a daemon.  Each backoffice process runs for a short
while and then exits.  This helps keep Fossil easy to manage, since there
are no daemons to start and stop.  To upgrade Fossil to a new version,
you simply replace the older "fossil" executable with the newer one, and

<title>CGI Script Configuration Options</title>

<h1>Summary</h1>

It is not necessary to have a central server in order to use Fossil.
But a central server can help a project run more smoothly by giving developers
a common point of rendezvous for syncing, and by providing a web-based
portal where developers and non-developers alike can learn about the
project and its current state.

Setting up a server using Fossil is easy.
A [./server/|separate document] talks about all of the many different methods for
setting up a Fossil server, one of which is [./server/any/cgi.md | as a CGI
script].  CGI is the technique that the three
[./selfhost.wiki|self-hosting Fossil repositories] all use.

Setting up a Fossil server using CGI is mostly about writing a short
script (usually just 2 lines line) in the cgi-bin folder of an ordinary
web-browser.  But there are a lot of extra options that can be added
to this script, to customize the configuration.  This article descripts
those options.

     in the thread.  Provide sequential numbers for all messages in
     a forum thread.
  *  Add support for fenced code blocks and improved hyperlink
     processing to the [/md_rules|markdown formatter].
  *  Enhance the [/help?cmd=/stat|/stat] page so that it gives the
     option to show a breakdown of forum posts.
  *  Change the default [./hashpolicy.wiki|hash policy] to SHA3.
  *  Timeout [./server/any/cgi.md|CGI requests] after 300 seconds, or 
     some other value set by the 
     [./cgi.wiki#timeout|"timeout:" property] in the CGI script.
  *  Documentation improvements

<a name='v2_9'></a>
<h2>Changes for Version 2.9 (2019-07-13)</h2>

but you cannot make it skip the dropping of root privileges, on purpose.


[bld]: https://www.fossil-scm.org/fossil/doc/trunk/www/build.wiki
[cj]:  https://en.wikipedia.org/wiki/Chroot
[fls]: ./loadmgmt.md
[mnl]: https://fossil-scm.org/forum/forumpost/90caff30cb
[srv]: ./server/

SCGI requests from web-servers like Nginx.

<li><p><b>Inetd or Stunnel.</b>
Configure programs like inetd, xinetd, or stunnel to hand off HTTP requests
directly to the [/help?cmd=http|fossil http] command.
</ol>

See the [./server/ | How To Configure A Fossil Server] document
for details.

<h2>6.0 Review Of Key Concepts</h2>

<ul>
<li>The <b>fossil</b> program is a self-contained stand-alone executable.
    Just put it somewhere on your PATH to install it.</li>

CGI mode.  The "index.html" CGI script looks like this:

<blockquote><pre>
#!/usr/bin/fossil
repository: /fossil/fossil.fossil
</pre></blockquote>

This is one of the many ways to set up a
<a href="./server/">Fossil server</a>.

The "<b>/trunk/</b>" part of the URL tells fossil to use
the documentation files from the most recent trunk check-in.
If you wanted to see an historical version of this document,
you could substitute the name of a check-in for "<b>/trunk/</b>".
For example, to see the version of this document associated with
check-in [9be1b00392], simply replace the "<b>/trunk/</b>" with

These additional capabilities are available for Git as 3rd-party
add-ons, but with Fossil they are integrated into
the design.  One way to describe Fossil is that it is
"[https://github.com/ | GitHub]-in-a-box."

For developers who choose to self-host projects (rather than using a
3rd-party service such as GitHub) Fossil is much easier to set up, since
the stand-alone Fossil executable together with a [./server/any/cgi.md|2-line CGI script]
suffice to instantiate a full-featured developer website.  To accomplish
the same using Git requires locating, installing, configuring, integrating,
and managing a wide assortment of separate tools.  Standing up a developer
website using Fossil can be done in minutes, whereas doing the same using
Git requires hours or days.

Fossil is small, complete, and self-contained.  If you clone

      for network communications, so it works fine from behind
      restrictive firewalls, including [./quickstart.wiki#proxy|proxies].
      The protocol is
      [./stats.wiki | bandwidth efficient] to the point that Fossil can be
      used comfortably over dial-up or over the exceedingly slow Wifi on
      airliners.

  5.  <b>Simple Server Setup</b> -  No server is required, but if you want to
      set one up, Fossil supports [./server/ | several different server
      configurations] including CGI, SCGI, and direct HTTP.
      You can also easily set up your Fossil repository to automatically
      [./mirrortogithub.md | mirror content on GitHub].

  6.  <b>Autosync</b> -
      Fossil supports [./concepts.wiki#workflow | "autosync" mode]
      which helps to keep projects moving
      forward by reducing the amount of needless
      [./branching.wiki | forking and merging] often

     subsystems, including [./customskin.md | theming].
  *  List of [./th1.md | TH1 commands provided by Fossil itself] that expose
     its key functionality to TH1 scripts.
  *  List of [./th1-hooks.md | TH1 hooks exposed by Fossil] that enable
     customization of commands and web pages.
  *  A free hosting server for Fossil repositories is available at
     [http://chiselapp.com/].
  *  How to [./server/ | set up a server] for your repository.
  *  Customizing the [./custom_ticket.wiki | ticket system].
  *  Methods to [./checkin_names.wiki | identify a specific check-in].
  *  [./inout.wiki | Import and export] from and to Git.
  *  [./fossil-v-git.wiki | Fossil versus Git].
  *  [./fiveminutes.wiki | Up and running in 5 minutes as a single user]
     (contributed by Gilles Ganault on 2013-01-08).
  *  [./antibot.wiki | How Fossil defends against abuse by spiders and bots].

  quickstart.wiki {Fossil Quick Start Guide}
  quotes.wiki
      {Quotes: What People Are Saying About Fossil, Git, and DVCSes in General}
  ../test/release-checklist.wiki {Pre-Release Testing Checklist}
  reviews.wiki {Reviews}
  selfcheck.wiki {Fossil Repository Integrity Self Checks}
  selfhost.wiki {Fossil Self Hosting Repositories}
  server/ {How To Configure A Fossil Server}
  serverext.wiki {CGI Server Extensions}
  serverext.wiki {Adding Extensions To A Fossil Server Using CGI Scripts}
  settings.wiki {Fossil Settings}
  /sitemap {Site Map}
  shunning.wiki {Shunning: Deleting Content From Fossil}
  stats.wiki {Performance Statistics}
  style.wiki {Source Code Style Guidelines}

<li><a href="hashpolicy.wiki">Choosing Between SHA1 and SHA3-256 &mdash; Hash Policy:</a></li>
<li><a href="contribute.wiki">Code or Documentation To The Fossil Project &mdash; Contributing</a></li>
<li><a href="style.wiki">Code Style Guidelines &mdash; Source</a></li>
<li><a href="../../../help">Commands and Webpages &mdash; Lists of</a></li>
<li><a href="build.wiki"><b>Compiling and Installing Fossil</b></a></li>
<li><a href="concepts.wiki">Concepts &mdash; Fossil Core</a></li>
<li><a href="cgi.wiki">Configuration Options &mdash; CGI Script</a></li>
<li><a href="server/">Configure A Fossil Server &mdash; How To</a></li>
<li><a href="shunning.wiki">Content From Fossil &mdash; Shunning: Deleting</a></li>
<li><a href="contribute.wiki"><b>Contributing Code or Documentation To The Fossil Project</b></a></li>
<li><a href="copyright-release.html"><b>Contributor License Agreement</b></a></li>
<li><a href="whyusefossil.wiki">Control &mdash; Benefits Of Version</a></li>
<li><a href="concepts.wiki">Core Concepts &mdash; Fossil</a></li>
<li><a href="newrepo.wiki">Create A New Fossil Repository &mdash; How To</a></li>
<li><a href="private.wiki"><b>Creating, Syncing, and Deleting Private Branches</b></a></li>

<li><a href="adding_code.wiki"><b>Hacking Fossil</b></a></li>
<li><a href="hashpolicy.wiki"><b>Hash Policy: Choosing Between SHA1 and SHA3-256</b></a></li>
<li><a href="hints.wiki">Hints &mdash; Fossil Tips And Usage</a></li>
<li><a href="index.wiki"><b>Home Page</b></a></li>
<li><a href="selfhost.wiki">Hosting Repositories &mdash; Fossil Self</a></li>
<li><a href="aboutcgi.wiki"><b>How CGI Works In Fossil</b></a></li>
<li><a href="aboutdownload.wiki"><b>How The Download Page Works</b></a></li>
<li><a href="server/"><b>How To Configure A Fossil Server</b></a></li>
<li><a href="newrepo.wiki"><b>How To Create A New Fossil Repository</b></a></li>
<li><a href="mirrortogithub.md"><b>How To Mirror A Fossil Repository On GitHub</b></a></li>
<li><a href="encryptedrepos.wiki"><b>How To Use Encrypted Repositories</b></a></li>
<li><a href="hacker-howto.wiki">How-To &mdash; Hacker</a></li>
<li><a href="tls-nginx.md">HTTPS with nginx &mdash; Proxying Fossil via</a></li>
<li><a href="fossil-from-msvc.wiki">IDE &mdash; Integrating Fossil in the Microsoft Express 2010</a></li>
<li><a href="image-format-vs-repo-size.md"><b>Image Format vs Fossil Repo Size</b></a></li>

<li><a href="fiveminutes.wiki">Running in 5 Minutes as a Single User &mdash; Up and</a></li>
<li><a href="quotes.wiki">Saying About Fossil, Git, and DVCSes in General &mdash; Quotes: What People Are</a></li>
<li><a href="cgi.wiki">Script Configuration Options &mdash; CGI</a></li>
<li><a href="th1.md">Scripting Language &mdash; The TH1</a></li>
<li><a href="serverext.wiki">Scripts &mdash; Adding Extensions To A Fossil Server Using CGI</a></li>
<li><a href="selfcheck.wiki">Self Checks &mdash; Fossil Repository Integrity</a></li>
<li><a href="selfhost.wiki">Self Hosting Repositories &mdash; Fossil</a></li>
<li><a href="server/">Server &mdash; How To Configure A Fossil</a></li>
<li><a href="serverext.wiki">Server Extensions &mdash; CGI</a></li>
<li><a href="serverext.wiki">Server Using CGI Scripts &mdash; Adding Extensions To A Fossil</a></li>
<li><a href="settings.wiki">Settings &mdash; Fossil</a></li>
<li><a href="admin-v-setup.md">Setup and Admin User Capabilities &mdash; The Differences Between the</a></li>
<li><a href="hashpolicy.wiki">SHA1 and SHA3-256 &mdash; Hash Policy: Choosing Between</a></li>
<li><a href="hashpolicy.wiki">SHA3-256 &mdash; Hash Policy: Choosing Between SHA1 and</a></li>
<li><a href="shunning.wiki"><b>Shunning: Deleting Content From Fossil</b></a></li>

    address only (and thus makes the web interface visible only on the
    local machine) and it automatically start your web browser pointing at the
    server.  For cross-machine collaboration, use the <b>server</b> command,
    which binds on all IP addresses and does not try to start a web browser.</p>

    <p>Servers are also easily configured as:
    <ul>
    <li>[./server/any/inetd.md|inetd]
    <li>[./server/debian/service.md|systemd]
    <li>[./server/any/cgi.md|CGI]
    <li>[./server/any/scgi.md|SCGI]
    </ul>

    <p>The [./selfhost.wiki | self-hosting fossil repositories] use
    CGI.

<a name="proxy"></a>
<h2>HTTP Proxies</h2>

<title>CGI Server Extensions</title>

<h2>1.0 Introduction</h2>

If you have a [./server/Fossil server] for your project,
you can add [https://en.wikipedia.org/wiki/Common_Gateway_Interface|CGI]
extensions to that server.  These extensions work like
any other CGI program, except that they also have access to the Fossil
login information and can (optionally) leverage the "skins" of Fossil
so that they appear to be more tightly integrated into the project.

An example of where this is useful is the 

<h2>2.0 How It Works</h2>

CGI Extensions are disabled by default.
An administrator activates the CGI extension mechanism by specifying
an "Extension Root Directory" or "extroot" as part of the server setup.
If the Fossil server is itself run as 
[./server/any/cgi.md|CGI], then add a line to the 
[./cgi.wiki#extroot|CGI script file] that says:

<blockquote><pre>
extroot: <i>DIRECTORY</i>
</pre></blockquote>

Or, if the Fossil server is begin run as using the 
"[./server/any/none.md|fossil server]" or
"[./server/any/none.md|fossil ui]" or 
"[./server/any/inetd.md|fossil http]" commands, then add an extra 
"--extroot <i>DIRECTORY</i>" option to that command.

The <i>DIRECTORY</i> is the DOCUMENT_ROOT for the CGI.
Files in the DOCUMENT_ROOT are accessed via URLs like this:

<blockquote>
https://example-project.org/ext/<i>FILENAME</i>

<h2 id="server">Fossil TLS Configuration: Server Side</h2>

Fossil's built-in HTTP server feature does not currently have a built-in
way to serve via HTTP over TLS, a.k.a. HTTPS, even when you've linked
Fossil to OpenSSL. To serve a Fossil repository via HTTPS, you must put
it behind some kind of HTTPS proxy. We have a number of documents
elsewhere in this repository that cover your options for [./server/
| serving Fossil repositories]. A few of the most useful of these are:

  *  <a id="stunnel"  href="./server/any/stunnel.md">Serving via stunnel</a>
  *  <a id="althttpd" href="./server/any/althttpd.md">Serving via stunnel + althttpd</a>
  *  <a id="nginx"    href="./server/any/scgi.md">Serving via SCGI (nginx)</a>

issues one or more HTTP requests and receives replies for each
request.</p>

<p>The server might be running as an independent server
using the <b>server</b> command, or it might be launched from
inetd or xinetd using the <b>http</b> command.  Or the server might
be launched from CGI.
(See "[./server/|How To Configure A Fossil Server]" for details.)
The specifics of how the server listens
for incoming HTTP requests is immaterial to this protocol.
The important point is that the server is listening for requests and
the client is the issuer of the requests.</p>

<p>A single push, pull, or sync might involve multiple HTTP requests.
The client maintains state between all requests.  But on the server