path: root/Documentation
diff options
authorJonathan Tan <>2017-10-16 17:55:32 (GMT)
committerJunio C Hamano <>2017-10-17 01:51:30 (GMT)
commit6464679d9620d91b639e2681b9cc6473f3856d09 (patch)
tree8e2c71d5968bdc21bbb22d176eb7255b24d3e207 /Documentation
parent94b8ae5aca41538cf78918663f8b8294f6dcaa21 (diff)
Documentation: document Extra Parameters
Document the server support for Extra Parameters, additional information that the client can send in its first message to the server during a Git client-server interaction. Signed-off-by: Jonathan Tan <> Signed-off-by: Brandon Williams <> Signed-off-by: Junio C Hamano <>
Diffstat (limited to 'Documentation')
2 files changed, 44 insertions, 7 deletions
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt
index 1c561bd..a0e45f2 100644
--- a/Documentation/technical/http-protocol.txt
+++ b/Documentation/technical/http-protocol.txt
@@ -219,6 +219,10 @@ smart server reply:
S: 003c2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0\n
S: 003fa3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{}\n
+The client may send Extra Parameters (see
+Documentation/technical/pack-protocol.txt) as a colon-separated string
+in the Git-Protocol HTTP header.
Dumb Server Response
Dumb servers MUST respond with the dumb server reply format.
@@ -269,7 +273,11 @@ the C locale ordering. The stream SHOULD include the default ref
named `HEAD` as the first ref. The stream MUST include capability
declarations behind a NUL on the first ref.
+The returned response contains "version 1" if "version=1" was sent as an
+Extra Parameter.
smart_reply = PKT-LINE("# service=$servicename" LF)
+ *1("version 1")
ref_list = empty_list / non_empty_list
diff --git a/Documentation/technical/pack-protocol.txt b/Documentation/technical/pack-protocol.txt
index ed1eae8..cd31edc 100644
--- a/Documentation/technical/pack-protocol.txt
+++ b/Documentation/technical/pack-protocol.txt
@@ -39,6 +39,19 @@ communicates with that invoked process over the SSH connection.
The file:// transport runs the 'upload-pack' or 'receive-pack'
process locally and communicates with it over a pipe.
+Extra Parameters
+The protocol provides a mechanism in which clients can send additional
+information in its first message to the server. These are called "Extra
+Parameters", and are supported by the Git, SSH, and HTTP protocols.
+Each Extra Parameter takes the form of `<key>=<value>` or `<key>`.
+Servers that receive any such Extra Parameters MUST ignore all
+unrecognized keys. Currently, the only Extra Parameter recognized is
Git Transport
@@ -46,18 +59,25 @@ The Git transport starts off by sending the command and repository
on the wire using the pkt-line format, followed by a NUL byte and a
hostname parameter, terminated by a NUL byte.
- 0032git-upload-pack /project.git\\0
+ 0033git-upload-pack /project.git\\0
+The transport may send Extra Parameters by adding an additional NUL
+byte, and then adding one or more NUL-terminated strings:
+ 003egit-upload-pack /project.git\\0\0version=1\0
- git-proto-request = request-command SP pathname NUL [ host-parameter NUL ]
+ git-proto-request = request-command SP pathname NUL
+ [ host-parameter NUL ] [ NUL extra-parameters ]
request-command = "git-upload-pack" / "git-receive-pack" /
"git-upload-archive" ; case sensitive
pathname = *( %x01-ff ) ; exclude NUL
host-parameter = "host=" hostname [ ":" port ]
+ extra-parameters = 1*extra-parameter
+ extra-parameter = 1*( %x01-ff ) NUL
-Only host-parameter is allowed in the git-proto-request. Clients
-MUST NOT attempt to send additional parameters. It is used for the
+host-parameter is used for the
git-daemon name based virtual hosting. See --interpolated-path
option to git daemon, with the %H/%CH format characters.
@@ -117,6 +137,12 @@ we execute it without the leading '/'.
ssh "git-upload-pack '~alice/project.git'"
+Depending on the value of the `protocol.version` configuration variable,
+Git may attempt to send Extra Parameters as a colon-separated string in
+the GIT_PROTOCOL environment variable. This is done only if
+the `ssh.variant` configuration variable indicates that the ssh command
+supports passing environment variables as an argument.
A few things to remember here:
- The "command name" is spelled with dash (e.g. git-upload-pack), but
@@ -137,11 +163,13 @@ Reference Discovery
When the client initially connects the server will immediately respond
-with a listing of each reference it has (all branches and tags) along
+with a version number (if "version=1" is sent as an Extra Parameter),
+and a listing of each reference it has (all branches and tags) along
with the object name that each reference currently points to.
- $ echo -e -n "0039git-upload-pack /schacon/gitbook.git\\0" |
+ $ echo -e -n "0044git-upload-pack /schacon/gitbook.git\\0\0version=1\0" |
nc -v 9418
+ 000aversion 1
00887217a7c7e582c46cec22a130adf4b9d7d950fba0 HEAD\0multi_ack thin-pack
side-band side-band-64k ofs-delta shallow no-progress include-tag
00441d3fcd5ced445d1abc402225c0b8a1299641f497 refs/heads/integration
@@ -165,7 +193,8 @@ immediately after the ref itself, if presented. A conforming server
MUST peel the ref if it's an annotated tag.
- advertised-refs = (no-refs / list-of-refs)
+ advertised-refs = *1("version 1")
+ (no-refs / list-of-refs)