path: root/man1/git-http-backend.1

'\" t
.\"     Title: git-http-backend
.\"    Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 2024-04-24
.\"    Manual: Git Manual
.\"    Source: Git 2.45.0.rc1.1.g9f32d8da7a
.\"  Language: English
.\"
.TH "GIT\-HTTP\-BACKEND" "1" "2024\-04\-24" "Git 2\&.45\&.0\&.rc1\&.1\&.g9f" "Git Manual"
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.SH "NAME"
git-http-backend \- Server side implementation of Git over HTTP
.SH "SYNOPSIS"
.sp
.nf
\fIgit http\-backend\fR
.fi
.sp
.SH "DESCRIPTION"
.sp
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\(cqs more\-efficient "v2" protocol if properly configured; see the discussion of \fBGIT_PROTOCOL\fR in the ENVIRONMENT section below\&.
.sp
It verifies that the directory has the magic file "git\-daemon\-export\-ok", and it will refuse to export any Git directory that hasn\(cqt explicitly been marked for export this way (unless the \fBGIT_HTTP_EXPORT_ALL\fR environment variable is set)\&.
.sp
By default, only the \fBupload\-pack\fR service is enabled, which serves \fIgit fetch\-pack\fR and \fIgit ls\-remote\fR clients, which are invoked from \fIgit fetch\fR, \fIgit pull\fR, and \fIgit clone\fR\&. If the client is authenticated, the \fBreceive\-pack\fR service is enabled, which serves \fIgit send\-pack\fR clients, which is invoked from \fIgit push\fR\&.
.SH "SERVICES"
.sp
These services can be enabled/disabled using the per\-repository configuration file:
.PP
http\&.getanyfile
.RS 4
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
\fBfalse\fR\&.
.RE
.PP
http\&.uploadpack
.RS 4
This serves
\fIgit fetch\-pack\fR
and
\fIgit ls\-remote\fR
clients\&. It is enabled by default, but a repository can disable it by setting this configuration value to
\fBfalse\fR\&.
.RE
.PP
http\&.receivepack
.RS 4
This serves
\fIgit send\-pack\fR
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
\fBfalse\fR, or enabled for all users, including anonymous users, by setting it to
\fBtrue\fR\&.
.RE
.SH "URL TRANSLATION"
.sp
To determine the location of the repository on disk, \fIgit http\-backend\fR 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, \fIgit http\-backend\fR reads PATH_TRANSLATED, which is also set automatically by the web server\&.
.SH "EXAMPLES"
.sp
All of the following examples map \fBhttp://$hostname/git/foo/bar\&.git\fR to \fB/var/www/git/foo/bar\&.git\fR\&.
.PP
Apache 2\&.x
.RS 4
Ensure mod_cgi, mod_alias, and mod_env are enabled, set GIT_PROJECT_ROOT (or DocumentRoot) appropriately, and create a ScriptAlias to the CGI:
.sp
.if n \{\
.RS 4
.\}
.nf
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\*(Aqs request)\&.
SetEnvIf Git\-Protocol "\&.*" GIT_PROTOCOL=$0
.fi
.if n \{\
.RE
.\}
.sp
To enable anonymous read access but authenticated write access, require authorization for both the initial ref advertisement (which we detect as a push via the service parameter in the query string), and the receive\-pack invocation itself:
.sp
.if n \{\
.RS 4
.\}
.nf
RewriteCond %{QUERY_STRING} service=git\-receive\-pack [OR]
RewriteCond %{REQUEST_URI} /git\-receive\-pack$
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>
.fi
.if n \{\
.RE
.\}
.sp
If you do not have
\fBmod_rewrite\fR
available to match against the query string, it is sufficient to just protect
\fBgit\-receive\-pack\fR
itself, like:
.sp
.if n \{\
.RS 4
.\}
.nf
<LocationMatch "^/git/\&.*/git\-receive\-pack$">
        AuthType Basic
        AuthName "Git Access"
        Require group committers
        \&.\&.\&.
</LocationMatch>
.fi
.if n \{\
.RE
.\}
.sp
In this mode, the server will not request authentication until the client actually starts the object negotiation phase of the push, rather than during the initial contact\&. For this reason, you must also enable the
\fBhttp\&.receivepack\fR
config option in any repositories that should accept a push\&. The default behavior, if
\fBhttp\&.receivepack\fR
is not set, is to reject any pushes by unauthenticated users; the initial request will therefore report
\fB403 Forbidden\fR
to the client, without even giving an opportunity for authentication\&.
.sp
To require authentication for both reads and writes, use a Location directive around the repository, or one of its parent directories:
.sp
.if n \{\
.RS 4
.\}
.nf
<Location /git/private>
        AuthType Basic
        AuthName "Private Git Access"
        Require group committers
        \&.\&.\&.
</Location>
.fi
.if n \{\
.RE
.\}
.sp
To serve gitweb at the same url, use a ScriptAliasMatch to only those URLs that
\fIgit http\-backend\fR
can handle, and forward the rest to gitweb:
.sp
.if n \{\
.RS 4
.\}
.nf
ScriptAliasMatch \e
        "(?x)^/git/(\&.*/(HEAD | \e
                        info/refs | \e
                        objects/(info/[^/]+ | \e
                                 [0\-9a\-f]{2}/[0\-9a\-f]{38} | \e
                                 pack/pack\-[0\-9a\-f]{40}\e\&.(pack|idx)) | \e
                        git\-(upload|receive)\-pack))$" \e
        /usr/libexec/git\-core/git\-http\-backend/$1

ScriptAlias /git/ /var/www/cgi\-bin/gitweb\&.cgi/
.fi
.if n \{\
.RE
.\}
.sp
To serve multiple repositories from different
\fBgitnamespaces\fR(7)
in a single repository:
.sp
.if n \{\
.RS 4
.\}
.nf
SetEnvIf Request_URI "^/git/([^/]*)" GIT_NAMESPACE=$1
ScriptAliasMatch ^/git/[^/]*(\&.*) /usr/libexec/git\-core/git\-http\-backend/storage\&.git$1
.fi
.if n \{\
.RE
.\}
.sp
.RE
.PP
Accelerated static Apache 2\&.x
.RS 4
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:
.sp
.if n \{\
.RS 4
.\}
.nf
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/
.fi
.if n \{\
.RE
.\}
.sp
This can be combined with the gitweb configuration:
.sp
.if n \{\
.RS 4
.\}
.nf
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/$1
ScriptAliasMatch \e
        "(?x)^/git/(\&.*/(HEAD | \e
                        info/refs | \e
                        objects/info/[^/]+ | \e
                        git\-(upload|receive)\-pack))$" \e
        /usr/libexec/git\-core/git\-http\-backend/$1
ScriptAlias /git/ /var/www/cgi\-bin/gitweb\&.cgi/
.fi
.if n \{\
.RE
.\}
.sp
.RE
.PP
Lighttpd
.RS 4
Ensure that
\fBmod_cgi\fR,
\fBmod_alias\fR,
\fBmod_auth\fR,
\fBmod_setenv\fR
are loaded, then set
\fBGIT_PROJECT_ROOT\fR
appropriately and redirect all requests to the CGI:
.sp
.if n \{\
.RS 4
.\}
.nf
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" => ""
        )
}
.fi
.if n \{\
.RE
.\}
.sp
To enable anonymous read access but authenticated write access:
.sp
.if n \{\
.RS 4
.\}
.nf
$HTTP["querystring"] =~ "service=git\-receive\-pack" {
        include "git\-auth\&.conf"
}
$HTTP["url"] =~ "^/git/\&.*/git\-receive\-pack$" {
        include "git\-auth\&.conf"
}
.fi
.if n \{\
.RE
.\}
.sp
where
\fBgit\-auth\&.conf\fR
looks something like:
.sp
.if n \{\
.RS 4
.\}
.nf
auth\&.require = (
        "/" => (
                "method" => "basic",
                "realm" => "Git Access",
                "require" => "valid\-user"
               )
)
# \&.\&.\&.and set up auth\&.backend here
.fi
.if n \{\
.RE
.\}
.sp
To require authentication for both reads and writes:
.sp
.if n \{\
.RS 4
.\}
.nf
$HTTP["url"] =~ "^/git/private" {
        include "git\-auth\&.conf"
}
.fi
.if n \{\
.RE
.\}
.sp
.RE
.SH "ENVIRONMENT"
.sp
\fIgit http\-backend\fR relies upon the \fBCGI\fR environment variables set by the invoking web server, including:
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
PATH_INFO (if GIT_PROJECT_ROOT is set, otherwise PATH_TRANSLATED)
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
REMOTE_USER
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
REMOTE_ADDR
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
CONTENT_TYPE
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
QUERY_STRING
.RE
.sp
.RS 4
.ie n \{\
\h'-04'\(bu\h'+03'\c
.\}
.el \{\
.sp -1
.IP \(bu 2.3
.\}
REQUEST_METHOD
.RE
.sp
The \fBGIT_HTTP_EXPORT_ALL\fR environment variable may be passed to \fIgit\-http\-backend\fR to bypass the check for the "git\-daemon\-export\-ok" file in each repository before allowing export of that repository\&.
.sp
The \fBGIT_HTTP_MAX_REQUEST_BUFFER\fR environment variable (or the \fBhttp\&.maxRequestBuffer\fR 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\&., \fB100M\fR for 100 megabytes)\&. The default is 10 megabytes\&.
.sp
Clients may probe for optional protocol capabilities (like the v2 protocol) using the \fBGit\-Protocol\fR HTTP header\&. In order to support these, the contents of that header must appear in the \fBGIT_PROTOCOL\fR environment variable\&. Most webservers will pass this header to the CGI via the \fBHTTP_GIT_PROTOCOL\fR variable, and \fBgit\-http\-backend\fR will automatically copy that to \fBGIT_PROTOCOL\fR\&. However, some webservers may be more selective about which headers they\(cqll pass, in which case they need to be configured explicitly (see the mention of \fBGit\-Protocol\fR in the Apache config from the earlier EXAMPLES section)\&.
.sp
The backend process sets GIT_COMMITTER_NAME to \fI$REMOTE_USER\fR and GIT_COMMITTER_EMAIL to \fI${REMOTE_USER}@http\&.${REMOTE_ADDR}\fR, ensuring that any reflogs created by \fIgit\-receive\-pack\fR contain some identifying information of the remote user who performed the push\&.
.sp
All \fBCGI\fR environment variables are available to each of the hooks invoked by the \fIgit\-receive\-pack\fR\&.
.SH "GIT"
.sp
Part of the \fBgit\fR(1) suite