<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
    "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta http-equiv="Content-Type" content="application/xhtml+xml; charset=UTF-8" />
<meta name="generator" content="AsciiDoc 8.6.6" />
<title>HTTP transfer protocols</title>
<style type="text/css">
/* Shared CSS for AsciiDoc xhtml11 and html5 backends */

/* Default font. */
body {
  font-family: Georgia,serif;
}

/* Title font. */
h1, h2, h3, h4, h5, h6,
div.title, caption.title,
thead, p.table.header,
#toctitle,
#author, #revnumber, #revdate, #revremark,
#footer {
  font-family: Arial,Helvetica,sans-serif;
}

body {
  margin: 1em 5% 1em 5%;
}

a {
  color: blue;
  text-decoration: underline;
}
a:visited {
  color: fuchsia;
}

em {
  font-style: italic;
  color: navy;
}

strong {
  font-weight: bold;
  color: #083194;
}

h1, h2, h3, h4, h5, h6 {
  color: #527bbd;
  margin-top: 1.2em;
  margin-bottom: 0.5em;
  line-height: 1.3;
}

h1, h2, h3 {
  border-bottom: 2px solid silver;
}
h2 {
  padding-top: 0.5em;
}
h3 {
  float: left;
}
h3 + * {
  clear: left;
}
h5 {
  font-size: 1.0em;
}

div.sectionbody {
  margin-left: 0;
}

hr {
  border: 1px solid silver;
}

p {
  margin-top: 0.5em;
  margin-bottom: 0.5em;
}

ul, ol, li > p {
  margin-top: 0;
}
ul > li     { color: #aaa; }
ul > li > * { color: black; }

pre {
  padding: 0;
  margin: 0;
}

#author {
  color: #527bbd;
  font-weight: bold;
  font-size: 1.1em;
}
#email {
}
#revnumber, #revdate, #revremark {
}

#footer {
  font-size: small;
  border-top: 2px solid silver;
  padding-top: 0.5em;
  margin-top: 4.0em;
}
#footer-text {
  float: left;
  padding-bottom: 0.5em;
}
#footer-badges {
  float: right;
  padding-bottom: 0.5em;
}

#preamble {
  margin-top: 1.5em;
  margin-bottom: 1.5em;
}
div.imageblock, div.exampleblock, div.verseblock,
div.quoteblock, div.literalblock, div.listingblock, div.sidebarblock,
div.admonitionblock {
  margin-top: 1.0em;
  margin-bottom: 1.5em;
}
div.admonitionblock {
  margin-top: 2.0em;
  margin-bottom: 2.0em;
  margin-right: 10%;
  color: #606060;
}

div.content { /* Block element content. */
  padding: 0;
}

/* Block element titles. */
div.title, caption.title {
  color: #527bbd;
  font-weight: bold;
  text-align: left;
  margin-top: 1.0em;
  margin-bottom: 0.5em;
}
div.title + * {
  margin-top: 0;
}

td div.title:first-child {
  margin-top: 0.0em;
}
div.content div.title:first-child {
  margin-top: 0.0em;
}
div.content + div.title {
  margin-top: 0.0em;
}

div.sidebarblock > div.content {
  background: #ffffee;
  border: 1px solid #dddddd;
  border-left: 4px solid #f0f0f0;
  padding: 0.5em;
}

div.listingblock > div.content {
  border: 1px solid #dddddd;
  border-left: 5px solid #f0f0f0;
  background: #f8f8f8;
  padding: 0.5em;
}

div.quoteblock, div.verseblock {
  padding-left: 1.0em;
  margin-left: 1.0em;
  margin-right: 10%;
  border-left: 5px solid #f0f0f0;
  color: #888;
}

div.quoteblock > div.attribution {
  padding-top: 0.5em;
  text-align: right;
}

div.verseblock > pre.content {
  font-family: inherit;
  font-size: inherit;
}
div.verseblock > div.attribution {
  padding-top: 0.75em;
  text-align: left;
}
/* DEPRECATED: Pre version 8.2.7 verse style literal block. */
div.verseblock + div.attribution {
  text-align: left;
}

div.admonitionblock .icon {
  vertical-align: top;
  font-size: 1.1em;
  font-weight: bold;
  text-decoration: underline;
  color: #527bbd;
  padding-right: 0.5em;
}
div.admonitionblock td.content {
  padding-left: 0.5em;
  border-left: 3px solid #dddddd;
}

div.exampleblock > div.content {
  border-left: 3px solid #dddddd;
  padding-left: 0.5em;
}

div.imageblock div.content { padding-left: 0; }
span.image img { border-style: none; }
a.image:visited { color: white; }

dl {
  margin-top: 0.8em;
  margin-bottom: 0.8em;
}
dt {
  margin-top: 0.5em;
  margin-bottom: 0;
  font-style: normal;
  color: navy;
}
dd > *:first-child {
  margin-top: 0.1em;
}

ul, ol {
    list-style-position: outside;
}
ol.arabic {
  list-style-type: decimal;
}
ol.loweralpha {
  list-style-type: lower-alpha;
}
ol.upperalpha {
  list-style-type: upper-alpha;
}
ol.lowerroman {
  list-style-type: lower-roman;
}
ol.upperroman {
  list-style-type: upper-roman;
}

div.compact ul, div.compact ol,
div.compact p, div.compact p,
div.compact div, div.compact div {
  margin-top: 0.1em;
  margin-bottom: 0.1em;
}

tfoot {
  font-weight: bold;
}
td > div.verse {
  white-space: pre;
}

div.hdlist {
  margin-top: 0.8em;
  margin-bottom: 0.8em;
}
div.hdlist tr {
  padding-bottom: 15px;
}
dt.hdlist1.strong, td.hdlist1.strong {
  font-weight: bold;
}
td.hdlist1 {
  vertical-align: top;
  font-style: normal;
  padding-right: 0.8em;
  color: navy;
}
td.hdlist2 {
  vertical-align: top;
}
div.hdlist.compact tr {
  margin: 0;
  padding-bottom: 0;
}

.comment {
  background: yellow;
}

.footnote, .footnoteref {
  font-size: 0.8em;
}

span.footnote, span.footnoteref {
  vertical-align: super;
}

#footnotes {
  margin: 20px 0 20px 0;
  padding: 7px 0 0 0;
}

#footnotes div.footnote {
  margin: 0 0 5px 0;
}

#footnotes hr {
  border: none;
  border-top: 1px solid silver;
  height: 1px;
  text-align: left;
  margin-left: 0;
  width: 20%;
  min-width: 100px;
}

div.colist td {
  padding-right: 0.5em;
  padding-bottom: 0.3em;
  vertical-align: top;
}
div.colist td img {
  margin-top: 0.3em;
}

@media print {
  #footer-badges { display: none; }
}

#toc {
  margin-bottom: 2.5em;
}

#toctitle {
  color: #527bbd;
  font-size: 1.1em;
  font-weight: bold;
  margin-top: 1.0em;
  margin-bottom: 0.1em;
}

div.toclevel1, div.toclevel2, div.toclevel3, div.toclevel4 {
  margin-top: 0;
  margin-bottom: 0;
}
div.toclevel2 {
  margin-left: 2em;
  font-size: 0.9em;
}
div.toclevel3 {
  margin-left: 4em;
  font-size: 0.9em;
}
div.toclevel4 {
  margin-left: 6em;
  font-size: 0.9em;
}

span.aqua { color: aqua; }
span.black { color: black; }
span.blue { color: blue; }
span.fuchsia { color: fuchsia; }
span.gray { color: gray; }
span.green { color: green; }
span.lime { color: lime; }
span.maroon { color: maroon; }
span.navy { color: navy; }
span.olive { color: olive; }
span.purple { color: purple; }
span.red { color: red; }
span.silver { color: silver; }
span.teal { color: teal; }
span.white { color: white; }
span.yellow { color: yellow; }

span.aqua-background { background: aqua; }
span.black-background { background: black; }
span.blue-background { background: blue; }
span.fuchsia-background { background: fuchsia; }
span.gray-background { background: gray; }
span.green-background { background: green; }
span.lime-background { background: lime; }
span.maroon-background { background: maroon; }
span.navy-background { background: navy; }
span.olive-background { background: olive; }
span.purple-background { background: purple; }
span.red-background { background: red; }
span.silver-background { background: silver; }
span.teal-background { background: teal; }
span.white-background { background: white; }
span.yellow-background { background: yellow; }

span.big { font-size: 2em; }
span.small { font-size: 0.6em; }

span.underline { text-decoration: underline; }
span.overline { text-decoration: overline; }
span.line-through { text-decoration: line-through; }


/*
 * xhtml11 specific
 *
 * */

tt {
  font-family: monospace;
  font-size: inherit;
  color: navy;
}

div.tableblock {
  margin-top: 1.0em;
  margin-bottom: 1.5em;
}
div.tableblock > table {
  border: 3px solid #527bbd;
}
thead, p.table.header {
  font-weight: bold;
  color: #527bbd;
}
p.table {
  margin-top: 0;
}
/* Because the table frame attribute is overriden by CSS in most browsers. */
div.tableblock > table[frame="void"] {
  border-style: none;
}
div.tableblock > table[frame="hsides"] {
  border-left-style: none;
  border-right-style: none;
}
div.tableblock > table[frame="vsides"] {
  border-top-style: none;
  border-bottom-style: none;
}


/*
 * html5 specific
 *
 * */

.monospaced {
  font-family: monospace;
  font-size: inherit;
  color: navy;
}

table.tableblock {
  margin-top: 1.0em;
  margin-bottom: 1.5em;
}
thead, p.tableblock.header {
  font-weight: bold;
  color: #527bbd;
}
p.tableblock {
  margin-top: 0;
}
table.tableblock {
  border-width: 3px;
  border-spacing: 0px;
  border-style: solid;
  border-color: #527bbd;
  border-collapse: collapse;
}
th.tableblock, td.tableblock {
  border-width: 1px;
  padding: 4px;
  border-style: solid;
  border-color: #527bbd;
}

table.tableblock.frame-topbot {
  border-left-style: hidden;
  border-right-style: hidden;
}
table.tableblock.frame-sides {
  border-top-style: hidden;
  border-bottom-style: hidden;
}
table.tableblock.frame-none {
  border-style: hidden;
}

th.tableblock.halign-left, td.tableblock.halign-left {
  text-align: left;
}
th.tableblock.halign-center, td.tableblock.halign-center {
  text-align: center;
}
th.tableblock.halign-right, td.tableblock.halign-right {
  text-align: right;
}

th.tableblock.valign-top, td.tableblock.valign-top {
  vertical-align: top;
}
th.tableblock.valign-middle, td.tableblock.valign-middle {
  vertical-align: middle;
}
th.tableblock.valign-bottom, td.tableblock.valign-bottom {
  vertical-align: bottom;
}


/*
 * manpage specific
 *
 * */

body.manpage h1 {
  padding-top: 0.5em;
  padding-bottom: 0.5em;
  border-top: 2px solid silver;
  border-bottom: 2px solid silver;
}
body.manpage h2 {
  border-style: none;
}
body.manpage div.sectionbody {
  margin-left: 3em;
}

@media print {
  body.manpage div#toc { display: none; }
}
</style>
<script type="text/javascript">
/*<![CDATA[*/
var asciidoc = {  // Namespace.

/////////////////////////////////////////////////////////////////////
// Table Of Contents generator
/////////////////////////////////////////////////////////////////////

/* Author: Mihai Bazon, September 2002
 * http://students.infoiasi.ro/~mishoo
 *
 * Table Of Content generator
 * Version: 0.4
 *
 * Feel free to use this script under the terms of the GNU General Public
 * License, as long as you do not remove or alter this notice.
 */

 /* modified by Troy D. Hanson, September 2006. License: GPL */
 /* modified by Stuart Rackham, 2006, 2009. License: GPL */

// toclevels = 1..4.
toc: function (toclevels) {

  function getText(el) {
    var text = "";
    for (var i = el.firstChild; i != null; i = i.nextSibling) {
      if (i.nodeType == 3 /* Node.TEXT_NODE */) // IE doesn't speak constants.
        text += i.data;
      else if (i.firstChild != null)
        text += getText(i);
    }
    return text;
  }

  function TocEntry(el, text, toclevel) {
    this.element = el;
    this.text = text;
    this.toclevel = toclevel;
  }

  function tocEntries(el, toclevels) {
    var result = new Array;
    var re = new RegExp('[hH]([2-'+(toclevels+1)+'])');
    // Function that scans the DOM tree for header elements (the DOM2
    // nodeIterator API would be a better technique but not supported by all
    // browsers).
    var iterate = function (el) {
      for (var i = el.firstChild; i != null; i = i.nextSibling) {
        if (i.nodeType == 1 /* Node.ELEMENT_NODE */) {
          var mo = re.exec(i.tagName);
          if (mo && (i.getAttribute("class") || i.getAttribute("className")) != "float") {
            result[result.length] = new TocEntry(i, getText(i), mo[1]-1);
          }
          iterate(i);
        }
      }
    }
    iterate(el);
    return result;
  }

  var toc = document.getElementById("toc");
  if (!toc) {
    return;
  }

  // Delete existing TOC entries in case we're reloading the TOC.
  var tocEntriesToRemove = [];
  var i;
  for (i = 0; i < toc.childNodes.length; i++) {
    var entry = toc.childNodes[i];
    if (entry.nodeName == 'div'
     && entry.getAttribute("class")
     && entry.getAttribute("class").match(/^toclevel/))
      tocEntriesToRemove.push(entry);
  }
  for (i = 0; i < tocEntriesToRemove.length; i++) {
    toc.removeChild(tocEntriesToRemove[i]);
  }

  // Rebuild TOC entries.
  var entries = tocEntries(document.getElementById("content"), toclevels);
  for (var i = 0; i < entries.length; ++i) {
    var entry = entries[i];
    if (entry.element.id == "")
      entry.element.id = "_toc_" + i;
    var a = document.createElement("a");
    a.href = "#" + entry.element.id;
    a.appendChild(document.createTextNode(entry.text));
    var div = document.createElement("div");
    div.appendChild(a);
    div.className = "toclevel" + entry.toclevel;
    toc.appendChild(div);
  }
  if (entries.length == 0)
    toc.parentNode.removeChild(toc);
},


/////////////////////////////////////////////////////////////////////
// Footnotes generator
/////////////////////////////////////////////////////////////////////

/* Based on footnote generation code from:
 * http://www.brandspankingnew.net/archive/2005/07/format_footnote.html
 */

footnotes: function () {
  // Delete existing footnote entries in case we're reloading the footnodes.
  var i;
  var noteholder = document.getElementById("footnotes");
  if (!noteholder) {
    return;
  }
  var entriesToRemove = [];
  for (i = 0; i < noteholder.childNodes.length; i++) {
    var entry = noteholder.childNodes[i];
    if (entry.nodeName == 'div' && entry.getAttribute("class") == "footnote")
      entriesToRemove.push(entry);
  }
  for (i = 0; i < entriesToRemove.length; i++) {
    noteholder.removeChild(entriesToRemove[i]);
  }

  // Rebuild footnote entries.
  var cont = document.getElementById("content");
  var spans = cont.getElementsByTagName("span");
  var refs = {};
  var n = 0;
  for (i=0; i<spans.length; i++) {
    if (spans[i].className == "footnote") {
      n++;
      var note = spans[i].getAttribute("data-note");
      if (!note) {
        // Use [\s\S] in place of . so multi-line matches work.
        // Because JavaScript has no s (dotall) regex flag.
        note = spans[i].innerHTML.match(/\s*\[([\s\S]*)]\s*/)[1];
        spans[i].innerHTML =
          "[<a id='_footnoteref_" + n + "' href='#_footnote_" + n +
          "' title='View footnote' class='footnote'>" + n + "</a>]";
        spans[i].setAttribute("data-note", note);
      }
      noteholder.innerHTML +=
        "<div class='footnote' id='_footnote_" + n + "'>" +
        "<a href='#_footnoteref_" + n + "' title='Return to text'>" +
        n + "</a>. " + note + "</div>";
      var id =spans[i].getAttribute("id");
      if (id != null) refs["#"+id] = n;
    }
  }
  if (n == 0)
    noteholder.parentNode.removeChild(noteholder);
  else {
    // Process footnoterefs.
    for (i=0; i<spans.length; i++) {
      if (spans[i].className == "footnoteref") {
        var href = spans[i].getElementsByTagName("a")[0].getAttribute("href");
        href = href.match(/#.*/)[0];  // Because IE return full URL.
        n = refs[href];
        spans[i].innerHTML =
          "[<a href='#_footnote_" + n +
          "' title='View footnote' class='footnote'>" + n + "</a>]";
      }
    }
  }
},

install: function(toclevels) {
  var timerId;

  function reinstall() {
    asciidoc.footnotes();
    if (toclevels) {
      asciidoc.toc(toclevels);
    }
  }

  function reinstallAndRemoveTimer() {
    clearInterval(timerId);
    reinstall();
  }

  timerId = setInterval(reinstall, 500);
  if (document.addEventListener)
    document.addEventListener("DOMContentLoaded", reinstallAndRemoveTimer, false);
  else
    window.onload = reinstallAndRemoveTimer;
}

}
asciidoc.install();
/*]]>*/
</script>
</head>
<body class="article">
<div id="header">
<h1>HTTP transfer protocols</h1>
</div>
<div id="content">
<div id="preamble">
<div class="sectionbody">
<div class="paragraph"><p>Git supports two HTTP based transfer protocols.  A "dumb" protocol
which requires only a standard HTTP server on the server end of the
connection, and a "smart" protocol which requires a Git aware CGI
(or server module).  This document describes both protocols.</p></div>
<div class="paragraph"><p>As a design feature smart clients can automatically upgrade "dumb"
protocol URLs to smart URLs.  This permits all users to have the
same published URL, and the peers automatically select the most
efficient transport available to them.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_url_format">URL Format</h2>
<div class="sectionbody">
<div class="paragraph"><p>URLs for Git repositories accessed by HTTP use the standard HTTP
URL syntax documented by RFC 1738, so they are of the form:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>http://&lt;host&gt;:&lt;port&gt;/&lt;path&gt;?&lt;searchpart&gt;</tt></pre>
</div></div>
<div class="paragraph"><p>Within this documentation the placeholder <tt>$GIT_URL</tt> will stand for
the http:// repository URL entered by the end-user.</p></div>
<div class="paragraph"><p>Servers SHOULD handle all requests to locations matching <tt>$GIT_URL</tt>, as
both the "smart" and "dumb" HTTP protocols used by Git operate
by appending additional path components onto the end of the user
supplied <tt>$GIT_URL</tt> string.</p></div>
<div class="paragraph"><p>An example of a dumb client requesting for a loose object:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>$GIT_URL:     http://example.com:8080/git/repo.git
URL request:  http://example.com:8080/git/repo.git/objects/d0/49f6c27a2244e12041955e262a404c7faba355</tt></pre>
</div></div>
<div class="paragraph"><p>An example of a smart request to a catch-all gateway:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>$GIT_URL:     http://example.com/daemon.cgi?svc=git&amp;q=
URL request:  http://example.com/daemon.cgi?svc=git&amp;q=/info/refs&amp;service=git-receive-pack</tt></pre>
</div></div>
<div class="paragraph"><p>An example of a request to a submodule:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>$GIT_URL:     http://example.com/git/repo.git/path/submodule.git
URL request:  http://example.com/git/repo.git/path/submodule.git/info/refs</tt></pre>
</div></div>
<div class="paragraph"><p>Clients MUST strip a trailing <tt>/</tt>, if present, from the user supplied
<tt>$GIT_URL</tt> string to prevent empty path tokens (<tt>//</tt>) from appearing
in any URL sent to a server.  Compatible clients MUST expand
<tt>$GIT_URL/info/refs</tt> as <tt>foo/info/refs</tt> and not <tt>foo//info/refs</tt>.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_authentication">Authentication</h2>
<div class="sectionbody">
<div class="paragraph"><p>Standard HTTP authentication is used if authentication is required
to access a repository, and MAY be configured and enforced by the
HTTP server software.</p></div>
<div class="paragraph"><p>Because Git repositories are accessed by standard path components
server administrators MAY use directory based permissions within
their HTTP server to control repository access.</p></div>
<div class="paragraph"><p>Clients SHOULD support Basic authentication as described by RFC 2616.
Servers SHOULD support Basic authentication by relying upon the
HTTP server placed in front of the Git server software.</p></div>
<div class="paragraph"><p>Servers SHOULD NOT require HTTP cookies for the purposes of
authentication or access control.</p></div>
<div class="paragraph"><p>Clients and servers MAY support other common forms of HTTP based
authentication, such as Digest authentication.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_ssl">SSL</h2>
<div class="sectionbody">
<div class="paragraph"><p>Clients and servers SHOULD support SSL, particularly to protect
passwords when relying on Basic HTTP authentication.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_session_state">Session State</h2>
<div class="sectionbody">
<div class="paragraph"><p>The Git over HTTP protocol (much like HTTP itself) is stateless
from the perspective of the HTTP server side.  All state MUST be
retained and managed by the client process.  This permits simple
round-robin load-balancing on the server side, without needing to
worry about state management.</p></div>
<div class="paragraph"><p>Clients MUST NOT require state management on the server side in
order to function correctly.</p></div>
<div class="paragraph"><p>Servers MUST NOT require HTTP cookies in order to function correctly.
Clients MAY store and forward HTTP cookies during request processing
as described by RFC 2616 (HTTP/1.1).  Servers SHOULD ignore any
cookies sent by a client.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_general_request_processing">General Request Processing</h2>
<div class="sectionbody">
<div class="paragraph"><p>Except where noted, all standard HTTP behavior SHOULD be assumed
by both client and server.  This includes (but is not necessarily
limited to):</p></div>
<div class="paragraph"><p>If there is no repository at <tt>$GIT_URL</tt>, or the resource pointed to by a
location matching <tt>$GIT_URL</tt> does not exist, the server MUST NOT respond
with <tt>200 OK</tt> response.  A server SHOULD respond with
<tt>404 Not Found</tt>, <tt>410 Gone</tt>, or any other suitable HTTP status code
which does not imply the resource exists as requested.</p></div>
<div class="paragraph"><p>If there is a repository at <tt>$GIT_URL</tt>, but access is not currently
permitted, the server MUST respond with the <tt>403 Forbidden</tt> HTTP
status code.</p></div>
<div class="paragraph"><p>Servers SHOULD support both HTTP 1.0 and HTTP 1.1.
Servers SHOULD support chunked encoding for both request and response
bodies.</p></div>
<div class="paragraph"><p>Clients SHOULD support both HTTP 1.0 and HTTP 1.1.
Clients SHOULD support chunked encoding for both request and response
bodies.</p></div>
<div class="paragraph"><p>Servers MAY return ETag and/or Last-Modified headers.</p></div>
<div class="paragraph"><p>Clients MAY revalidate cached entities by including If-Modified-Since
and/or If-None-Match request headers.</p></div>
<div class="paragraph"><p>Servers MAY return <tt>304 Not Modified</tt> if the relevant headers appear
in the request and the entity has not changed.  Clients MUST treat
<tt>304 Not Modified</tt> identical to <tt>200 OK</tt> by reusing the cached entity.</p></div>
<div class="paragraph"><p>Clients MAY reuse a cached entity without revalidation if the
Cache-Control and/or Expires header permits caching.  Clients and
servers MUST follow RFC 2616 for cache controls.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_discovering_references">Discovering References</h2>
<div class="sectionbody">
<div class="paragraph"><p>All HTTP clients MUST begin either a fetch or a push exchange by
discovering the references available on the remote repository.</p></div>
<div class="sect2">
<h3 id="_dumb_clients">Dumb Clients</h3>
<div class="paragraph"><p>HTTP clients that only support the "dumb" protocol MUST discover
references by making a request for the special info/refs file of
the repository.</p></div>
<div class="paragraph"><p>Dumb HTTP clients MUST make a <tt>GET</tt> request to <tt>$GIT_URL/info/refs</tt>,
without any search/query parameters.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>C: GET $GIT_URL/info/refs HTTP/1.0</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>S: 200 OK
S:
S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31  refs/heads/maint
S: d049f6c27a2244e12041955e262a404c7faba355  refs/heads/master
S: 2cb58b79488a98d2721cea644875a8dd0026b115  refs/tags/v1.0
S: a3c2e2402b99163d1d59756e5f207ae21cccba4c  refs/tags/v1.0^{}</tt></pre>
</div></div>
<div class="paragraph"><p>The Content-Type of the returned info/refs entity SHOULD be
<tt>text/plain; charset=utf-8</tt>, but MAY be any content type.
Clients MUST NOT attempt to validate the returned Content-Type.
Dumb servers MUST NOT return a return type starting with
<tt>application/x-git-</tt>.</p></div>
<div class="paragraph"><p>Cache-Control headers MAY be returned to disable caching of the
returned entity.</p></div>
<div class="paragraph"><p>When examining the response clients SHOULD only examine the HTTP
status code.  Valid responses are <tt>200 OK</tt>, or <tt>304 Not Modified</tt>.</p></div>
<div class="paragraph"><p>The returned content is a UNIX formatted text file describing
each ref and its known value.  The file SHOULD be sorted by name
according to the C locale ordering.  The file SHOULD NOT include
the default ref named <tt>HEAD</tt>.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>info_refs   =  *( ref_record )
ref_record  =  any_ref / peeled_ref</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>any_ref     =  obj-id HTAB refname LF
peeled_ref  =  obj-id HTAB refname LF
               obj-id HTAB refname "^{}" LF</tt></pre>
</div></div>
</div>
<div class="sect2">
<h3 id="_smart_clients">Smart Clients</h3>
<div class="paragraph"><p>HTTP clients that support the "smart" protocol (or both the
"smart" and "dumb" protocols) MUST discover references by making
a parameterized request for the info/refs file of the repository.</p></div>
<div class="paragraph"><p>The request MUST contain exactly one query parameter,
<tt>service=$servicename</tt>, where <tt>$servicename</tt> MUST be the service
name the client wishes to contact to complete the operation.
The request MUST NOT contain additional query parameters.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0</tt></pre>
</div></div>
<div class="paragraph"><p>dumb server reply:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>S: 200 OK
S:
S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31  refs/heads/maint
S: d049f6c27a2244e12041955e262a404c7faba355  refs/heads/master
S: 2cb58b79488a98d2721cea644875a8dd0026b115  refs/tags/v1.0
S: a3c2e2402b99163d1d59756e5f207ae21cccba4c  refs/tags/v1.0^{}</tt></pre>
</div></div>
<div class="paragraph"><p>smart server reply:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>S: 200 OK
S: Content-Type: application/x-git-upload-pack-advertisement
S: Cache-Control: no-cache
S:
S: 001e# service=git-upload-pack\n
S: 004895dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint\0multi_ack\n
S: 0042d049f6c27a2244e12041955e262a404c7faba355 refs/heads/master\n
S: 003c2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0\n
S: 003fa3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{}\n</tt></pre>
</div></div>
<div class="sect3">
<h4 id="_dumb_server_response">Dumb Server Response</h4>
<div class="paragraph"><p>Dumb servers MUST respond with the dumb server reply format.</p></div>
<div class="paragraph"><p>See the prior section under dumb clients for a more detailed
description of the dumb server response.</p></div>
</div>
<div class="sect3">
<h4 id="_smart_server_response">Smart Server Response</h4>
<div class="paragraph"><p>If the server does not recognize the requested service name, or the
requested service name has been disabled by the server administrator,
the server MUST respond with the <tt>403 Forbidden</tt> HTTP status code.</p></div>
<div class="paragraph"><p>Otherwise, smart servers MUST respond with the smart server reply
format for the requested service name.</p></div>
<div class="paragraph"><p>Cache-Control headers SHOULD be used to disable caching of the
returned entity.</p></div>
<div class="paragraph"><p>The Content-Type MUST be <tt>application/x-$servicename-advertisement</tt>.
Clients SHOULD fall back to the dumb protocol if another content
type is returned.  When falling back to the dumb protocol clients
SHOULD NOT make an additional request to <tt>$GIT_URL/info/refs</tt>, but
instead SHOULD use the response already in hand.  Clients MUST NOT
continue if they do not support the dumb protocol.</p></div>
<div class="paragraph"><p>Clients MUST validate the status code is either <tt>200 OK</tt> or
<tt>304 Not Modified</tt>.</p></div>
<div class="paragraph"><p>Clients MUST validate the first five bytes of the response entity
matches the regex <tt>^[0-9a-f]{4}#</tt>.  If this test fails, clients
MUST NOT continue.</p></div>
<div class="paragraph"><p>Clients MUST parse the entire response as a sequence of pkt-line
records.</p></div>
<div class="paragraph"><p>Clients MUST verify the first pkt-line is <tt># service=$servicename</tt>.
Servers MUST set $servicename to be the request parameter value.
Servers SHOULD include an LF at the end of this line.
Clients MUST ignore an LF at the end of the line.</p></div>
<div class="paragraph"><p>Servers MUST terminate the response with the magic <tt>0000</tt> end
pkt-line marker.</p></div>
<div class="paragraph"><p>The returned response is a pkt-line stream describing each ref and
its known value.  The stream SHOULD be sorted by name according to
the C locale ordering.  The stream SHOULD include the default ref
named <tt>HEAD</tt> as the first ref.  The stream MUST include capability
declarations behind a NUL on the first ref.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>smart_reply     =  PKT-LINE("# service=$servicename" LF)
                   ref_list
                   "0000"
ref_list        =  empty_list / non_empty_list</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>empty_list      =  PKT-LINE(zero-id SP "capabilities^{}" NUL cap-list LF)</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>non_empty_list  =  PKT-LINE(obj-id SP name NUL cap_list LF)
                   *ref_record</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>cap-list        =  capability *(SP capability)
capability      =  1*(LC_ALPHA / DIGIT / "-" / "_")
LC_ALPHA        =  %x61-7A</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>ref_record      =  any_ref / peeled_ref
any_ref         =  PKT-LINE(obj-id SP name LF)
peeled_ref      =  PKT-LINE(obj-id SP name LF)
                   PKT-LINE(obj-id SP name "^{}" LF</tt></pre>
</div></div>
</div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_smart_service_git_upload_pack">Smart Service git-upload-pack</h2>
<div class="sectionbody">
<div class="paragraph"><p>This service reads from the repository pointed to by <tt>$GIT_URL</tt>.</p></div>
<div class="paragraph"><p>Clients MUST first perform ref discovery with
<tt>$GIT_URL/info/refs?service=git-upload-pack</tt>.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>C: POST $GIT_URL/git-upload-pack HTTP/1.0
C: Content-Type: application/x-git-upload-pack-request
C:
C: 0032want 0a53e9ddeaddad63ad106860237bbf53411d11a7\n
C: 0032have 441b40d833fdfa93eb2908e52742248faf0ee993\n
C: 0000</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>S: 200 OK
S: Content-Type: application/x-git-upload-pack-result
S: Cache-Control: no-cache
S:
S: ....ACK %s, continue
S: ....NAK</tt></pre>
</div></div>
<div class="paragraph"><p>Clients MUST NOT reuse or revalidate a cached response.
Servers MUST include sufficient Cache-Control headers
to prevent caching of the response.</p></div>
<div class="paragraph"><p>Servers SHOULD support all capabilities defined here.</p></div>
<div class="paragraph"><p>Clients MUST send at least one "want" command in the request body.
Clients MUST NOT reference an id in a "want" command which did not
appear in the response obtained through ref discovery unless the
server advertises capability <tt>allow-tip-sha1-in-want</tt>.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>compute_request   =  want_list
                     have_list
                     request_end
request_end       =  "0000" / "done"</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>want_list         =  PKT-LINE(want NUL cap_list LF)
                     *(want_pkt)
want_pkt          =  PKT-LINE(want LF)
want              =  "want" SP id
cap_list          =  *(SP capability) SP</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>have_list         =  *PKT-LINE("have" SP id LF)</tt></pre>
</div></div>
<div class="paragraph"><p>TODO: Document this further.</p></div>
<div class="sect2">
<h3 id="_the_negotiation_algorithm">The Negotiation Algorithm</h3>
<div class="paragraph"><p>The computation to select the minimal pack proceeds as follows
(C = client, S = server):</p></div>
<div class="paragraph"><p><em>init step:</em></p></div>
<div class="paragraph"><p>C: Use ref discovery to obtain the advertised refs.</p></div>
<div class="paragraph"><p>C: Place any object seen into set <tt>advertised</tt>.</p></div>
<div class="paragraph"><p>C: Build an empty set, <tt>common</tt>, to hold the objects that are later
   determined to be on both ends.</p></div>
<div class="paragraph"><p>C: Build a set, <tt>want</tt>, of the objects from <tt>advertised</tt> the client
   wants to fetch, based on what it saw during ref discovery.</p></div>
<div class="paragraph"><p>C: Start a queue, <tt>c_pending</tt>, ordered by commit time (popping newest
   first).  Add all client refs.  When a commit is popped from
   the queue its parents SHOULD be automatically inserted back.
   Commits MUST only enter the queue once.</p></div>
<div class="paragraph"><p><em>one compute step:</em></p></div>
<div class="paragraph"><p>C: Send one <tt>$GIT_URL/git-upload-pack</tt> request:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>C: 0032want &lt;want #1&gt;...............................
C: 0032want &lt;want #2&gt;...............................
....
C: 0032have &lt;common #1&gt;.............................
C: 0032have &lt;common #2&gt;.............................
....
C: 0032have &lt;have #1&gt;...............................
C: 0032have &lt;have #2&gt;...............................
....
C: 0000</tt></pre>
</div></div>
<div class="paragraph"><p>The stream is organized into "commands", with each command
appearing by itself in a pkt-line.  Within a command line
the text leading up to the first space is the command name,
and the remainder of the line to the first LF is the value.
Command lines are terminated with an LF as the last byte of
the pkt-line value.</p></div>
<div class="paragraph"><p>Commands MUST appear in the following order, if they appear
at all in the request stream:</p></div>
<div class="ulist"><ul>
<li>
<p>
"want"
</p>
</li>
<li>
<p>
"have"
</p>
</li>
</ul></div>
<div class="paragraph"><p>The stream is terminated by a pkt-line flush (<tt>0000</tt>).</p></div>
<div class="paragraph"><p>A single "want" or "have" command MUST have one hex formatted
SHA-1 as its value.  Multiple SHA-1s MUST be sent by sending
multiple commands.</p></div>
<div class="paragraph"><p>The <tt>have</tt> list is created by popping the first 32 commits
from <tt>c_pending</tt>.  Less can be supplied if <tt>c_pending</tt> empties.</p></div>
<div class="paragraph"><p>If the client has sent 256 "have" commits and has not yet
received one of those back from <tt>s_common</tt>, or the client has
emptied <tt>c_pending</tt> it SHOULD include a "done" command to let
the server know it won&#8217;t proceed:</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>C: 0009done</tt></pre>
</div></div>
<div class="paragraph"><p>S: Parse the git-upload-pack request:</p></div>
<div class="paragraph"><p>Verify all objects in <tt>want</tt> are directly reachable from refs.</p></div>
<div class="paragraph"><p>The server MAY walk backwards through history or through
the reflog to permit slightly stale requests.</p></div>
<div class="paragraph"><p>If no "want" objects are received, send an error:
TODO: Define error if no "want" lines are requested.</p></div>
<div class="paragraph"><p>If any "want" object is not reachable, send an error:
TODO: Define error if an invalid "want" is requested.</p></div>
<div class="paragraph"><p>Create an empty list, <tt>s_common</tt>.</p></div>
<div class="paragraph"><p>If "have" was sent:</p></div>
<div class="paragraph"><p>Loop through the objects in the order supplied by the client.</p></div>
<div class="paragraph"><p>For each object, if the server has the object reachable from
a ref, add it to <tt>s_common</tt>.  If a commit is added to <tt>s_common</tt>,
do not add any ancestors, even if they also appear in <tt>have</tt>.</p></div>
<div class="paragraph"><p>S: Send the git-upload-pack response:</p></div>
<div class="paragraph"><p>If the server has found a closed set of objects to pack or the
request ends with "done", it replies with the pack.
TODO: Document the pack based response</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>S: PACK...</tt></pre>
</div></div>
<div class="paragraph"><p>The returned stream is the side-band-64k protocol supported
by the git-upload-pack service, and the pack is embedded into
stream 1.  Progress messages from the server side MAY appear
in stream 2.</p></div>
<div class="paragraph"><p>Here a "closed set of objects" is defined to have at least
one path from every "want" to at least one "common" object.</p></div>
<div class="paragraph"><p>If the server needs more information, it replies with a
status continue response:
TODO: Document the non-pack response</p></div>
<div class="paragraph"><p>C: Parse the upload-pack response:
   TODO: Document parsing response</p></div>
<div class="paragraph"><p><em>Do another compute step.</em></p></div>
</div>
</div>
</div>
<div class="sect1">
<h2 id="_smart_service_git_receive_pack">Smart Service git-receive-pack</h2>
<div class="sectionbody">
<div class="paragraph"><p>This service reads from the repository pointed to by <tt>$GIT_URL</tt>.</p></div>
<div class="paragraph"><p>Clients MUST first perform ref discovery with
<tt>$GIT_URL/info/refs?service=git-receive-pack</tt>.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>C: POST $GIT_URL/git-receive-pack HTTP/1.0
C: Content-Type: application/x-git-receive-pack-request
C:
C: ....0a53e9ddeaddad63ad106860237bbf53411d11a7 441b40d833fdfa93eb2908e52742248faf0ee993 refs/heads/maint\0 report-status
C: 0000
C: PACK....</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>S: 200 OK
S: Content-Type: application/x-git-receive-pack-result
S: Cache-Control: no-cache
S:
S: ....</tt></pre>
</div></div>
<div class="paragraph"><p>Clients MUST NOT reuse or revalidate a cached response.
Servers MUST include sufficient Cache-Control headers
to prevent caching of the response.</p></div>
<div class="paragraph"><p>Servers SHOULD support all capabilities defined here.</p></div>
<div class="paragraph"><p>Clients MUST send at least one command in the request body.
Within the command portion of the request body clients SHOULD send
the id obtained through ref discovery as old_id.</p></div>
<div class="literalblock">
<div class="content">
<pre><tt>update_request  =  command_list
                   "PACK" &lt;binary data&gt;</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>command_list    =  PKT-LINE(command NUL cap_list LF)
                   *(command_pkt)
command_pkt     =  PKT-LINE(command LF)
cap_list        =  *(SP capability) SP</tt></pre>
</div></div>
<div class="literalblock">
<div class="content">
<pre><tt>command         =  create / delete / update
create          =  zero-id SP new_id SP name
delete          =  old_id SP zero-id SP name
update          =  old_id SP new_id SP name</tt></pre>
</div></div>
<div class="paragraph"><p>TODO: Document this further.</p></div>
</div>
</div>
<div class="sect1">
<h2 id="_references">References</h2>
<div class="sectionbody">
<div class="paragraph"><p><a href="http://www.ietf.org/rfc/rfc1738.txt">RFC 1738: Uniform Resource Locators (URL)</a>
<a href="http://www.ietf.org/rfc/rfc2616.txt">RFC 2616: Hypertext Transfer Protocol&#8201;&#8212;&#8201;HTTP/1.1</a>
link:technical/pack-protocol.html
link:technical/protocol-capabilities.html</p></div>
</div>
</div>
</div>
<div id="footnotes"><hr /></div>
<div id="footer">
<div id="footer-text">
Last updated 2014-01-27 13:30:07 PST
</div>
</div>
</body>
</html>