GIT-HTTP-BACKEND(1) Git Manual GIT-HTTP-BACKEND(1)

NAME

git-http-backend - Server side implementation of Git over HTTP

SYNOPSIS

git http-backend

DESCRIPTION

A simple CGI program to serve the contents of a Git repository to Git
clients accessing the repository over http:// and https:// protocols.
The program supports clients fetching using both the smart HTTP
protocol and the backwards-compatible dumb HTTP protocol, as well as
clients pushing using the smart HTTP protocol. It also supports Git's
more-efficient "v2" protocol if properly configured; see the
discussion of GIT_PROTOCOL in the ENVIRONMENT section below.

It verifies that the directory has the magic file
"git-daemon-export-ok", and it will refuse to export any Git
directory that hasn't explicitly been marked for export this way
(unless the GIT_HTTP_EXPORT_ALL environment variable is set).

By default, only the upload-pack service is enabled, which serves git
fetch-pack and git ls-remote clients, which are invoked from git
fetch, git pull, and git clone. If the client is authenticated, the
receive-pack service is enabled, which serves git send-pack clients,
which is invoked from git push.

SERVICES

These services can be enabled/disabled using the per-repository
configuration file:

http.getanyfile
This serves Git clients older than version 1.6.6 that are unable
to use the upload pack service. When enabled, clients are able to
read any file within the repository, including objects that are
no longer reachable from a branch but are still present. It is
enabled by default, but a repository can disable it by setting
this configuration value to false.

http.uploadpack
This serves git fetch-pack and git ls-remote clients. It is
enabled by default, but a repository can disable it by setting
this configuration value to false.

http.receivepack
This serves git send-pack clients, allowing push. It is disabled
by default for anonymous users, and enabled by default for users
authenticated by the web server. It can be disabled by setting
this item to false, or enabled for all users, including anonymous
users, by setting it to true.

URL TRANSLATION

To determine the location of the repository on disk, git http-backend
concatenates the environment variables PATH_INFO, which is set
automatically by the web server, and GIT_PROJECT_ROOT, which must be
set manually in the web server configuration. If GIT_PROJECT_ROOT is
not set, git http-backend reads PATH_TRANSLATED, which is also set
automatically by the web server.

EXAMPLES

All of the following examples map http://$hostname/git/foo/bar.git to
/var/www/git/foo/bar.git.

Apache 2.x
Ensure mod_cgi, mod_alias, and mod_env are enabled, set
GIT_PROJECT_ROOT (or DocumentRoot) appropriately, and create a
ScriptAlias to the CGI:

SetEnv GIT_PROJECT_ROOT /var/www/git
SetEnv GIT_HTTP_EXPORT_ALL
ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/

# This is not strictly necessary using Apache and a modern version of
# git-http-backend, as the webserver will pass along the header in the
# environment as HTTP_GIT_PROTOCOL, and http-backend will copy that into
# GIT_PROTOCOL. But you may need this line (or something similar if you
# are using a different webserver), or if you want to support older Git
# versions that did not do that copying.
#
# Having the webserver set up GIT_PROTOCOL is perfectly fine even with
# modern versions (and will take precedence over HTTP_GIT_PROTOCOL,
# which means it can be used to override the client's request).
SetEnvIf Git-Protocol ".*" GIT_PROTOCOL=$0

To enable anonymous read access but authenticated write access,
require authorization for both the initial ref advertisement
(which we detect as a push via the service parameter in the query
string), and the receive-pack invocation itself:

RewriteCond %{QUERY_STRING} service=git-receive-pack [OR]
RewriteCond %{REQUEST_URI} /git-receive-pack$
RewriteRule ^/git/ - [E=AUTHREQUIRED:yes]

<LocationMatch "^/git/">
Order Deny,Allow
Deny from env=AUTHREQUIRED

AuthType Basic
AuthName "Git Access"
Require group committers
Satisfy Any
...
</LocationMatch>

If you do not have mod_rewrite available to match against the
query string, it is sufficient to just protect git-receive-pack
itself, like:

<LocationMatch "^/git/.*/git-receive-pack$">
AuthType Basic
AuthName "Git Access"
Require group committers
...
</LocationMatch>

In this mode, the server will not request authentication until
the client actually starts the object negotiation phase of the
push, rather than during the initial contact. For this reason,
you must also enable the http.receivepack config option in any
repositories that should accept a push. The default behavior, if
http.receivepack is not set, is to reject any pushes by
unauthenticated users; the initial request will therefore report
403 Forbidden to the client, without even giving an opportunity
for authentication.

To require authentication for both reads and writes, use a
Location directive around the repository, or one of its parent
directories:

<Location /git/private>
AuthType Basic
AuthName "Private Git Access"
Require group committers
...
</Location>

To serve gitweb at the same url, use a ScriptAliasMatch to only
those URLs that git http-backend can handle, and forward the rest
to gitweb:

ScriptAliasMatch \
"(?x)^/git/(.*/(HEAD | \
info/refs | \
objects/(info/[^/]+ | \
[0-9a-f]{2}/[0-9a-f]{38} | \
pack/pack-[0-9a-f]{40}\.(pack|idx)) | \
git-(upload|receive)-pack))$" \
/usr/libexec/git-core/git-http-backend/$1

ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/

To serve multiple repositories from different gitnamespaces(7) in
a single repository:

SetEnvIf Request_URI "^/git/([^/]*)" GIT_NAMESPACE=$1
ScriptAliasMatch ^/git/[^/]*(.*) /usr/libexec/git-core/git-http-backend/storage.git$1

Accelerated static Apache 2.x
Similar to the above, but Apache can be used to return static
files that are stored on disk. On many systems this may be more
efficient as Apache can ask the kernel to copy the file contents
from the file system directly to the network:

SetEnv GIT_PROJECT_ROOT /var/www/git

AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$ /var/www/git/$1
AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
ScriptAlias /git/ /usr/libexec/git-core/git-http-backend/

This can be combined with the gitweb configuration:

SetEnv GIT_PROJECT_ROOT /var/www/git

AliasMatch ^/git/(.*/objects/[0-9a-f]{2}/[0-9a-f]{38})$ /var/www/git/$1
AliasMatch ^/git/(.*/objects/pack/pack-[0-9a-f]{40}.(pack|idx))$ /var/www/git/$1
ScriptAliasMatch \
"(?x)^/git/(.*/(HEAD | \
info/refs | \
objects/info/[^/]+ | \
git-(upload|receive)-pack))$" \
/usr/libexec/git-core/git-http-backend/$1
ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/

Lighttpd
Ensure that mod_cgi, mod_alias, mod_auth, mod_setenv are loaded,
then set GIT_PROJECT_ROOT appropriately and redirect all requests
to the CGI:

alias.url += ( "/git" => "/usr/lib/git-core/git-http-backend" )
$HTTP["url"] =~ "^/git" {
cgi.assign = ("" => "")
setenv.add-environment = (
"GIT_PROJECT_ROOT" => "/var/www/git",
"GIT_HTTP_EXPORT_ALL" => ""
)
}

To enable anonymous read access but authenticated write access:

$HTTP["querystring"] =~ "service=git-receive-pack" {
include "git-auth.conf"
}
$HTTP["url"] =~ "^/git/.*/git-receive-pack$" {
include "git-auth.conf"
}

where git-auth.conf looks something like:

auth.require = (
"/" => (
"method" => "basic",
"realm" => "Git Access",
"require" => "valid-user"
)
)
# ...and set up auth.backend here

To require authentication for both reads and writes:

$HTTP["url"] =~ "^/git/private" {
include "git-auth.conf"
}

ENVIRONMENT

git http-backend relies upon the CGI environment variables set by the
invoking web server, including:

+o PATH_INFO (if GIT_PROJECT_ROOT is set, otherwise PATH_TRANSLATED)

+o REMOTE_USER

+o REMOTE_ADDR

+o CONTENT_TYPE

+o QUERY_STRING

+o REQUEST_METHOD

The GIT_HTTP_EXPORT_ALL environment variable may be passed to
git-http-backend to bypass the check for the "git-daemon-export-ok"
file in each repository before allowing export of that repository.

The GIT_HTTP_MAX_REQUEST_BUFFER environment variable (or the
http.maxRequestBuffer config option) may be set to change the largest
ref negotiation request that git will handle during a fetch; any
fetch requiring a larger buffer will not succeed. This value should
not normally need to be changed, but may be helpful if you are
fetching from a repository with an extremely large number of refs.
The value can be specified with a unit (e.g., 100M for 100
megabytes). The default is 10 megabytes.

Clients may probe for optional protocol capabilities (like the v2
protocol) using the Git-Protocol HTTP header. In order to support
these, the contents of that header must appear in the GIT_PROTOCOL
environment variable. Most webservers will pass this header to the
CGI via the HTTP_GIT_PROTOCOL variable, and git-http-backend will
automatically copy that to GIT_PROTOCOL. However, some webservers may
be more selective about which headers they'll pass, in which case
they need to be configured explicitly (see the mention of
Git-Protocol in the Apache config from the earlier EXAMPLES section).

The backend process sets GIT_COMMITTER_NAME to $REMOTE_USER and
GIT_COMMITTER_EMAIL to ${REMOTE_USER}@http.${REMOTE_ADDR}, ensuring
that any reflogs created by git-receive-pack contain some identifying
information of the remote user who performed the push.

All CGI environment variables are available to each of the hooks
invoked by the git-receive-pack.

GIT

Part of the git(1) suite

Git 2.48.1 2025-01-13 GIT-HTTP-BACKEND(1)