otherwise noted the usual pkt-line LF rules apply: the sender SHOULD
include a LF, but the receiver MUST NOT complain if it is not present.
+An error packet is a special pkt-line that contains an error string.
+
+----
+ error-line = PKT-LINE("ERR" SP explanation-text)
+----
+
+Throughout the protocol, where `PKT-LINE(...)` is expected, an error packet MAY
+be sent. Once this packet is sent by a client or a server, the data transfer
+process defined in this protocol is terminated.
+
Transports
----------
There are three transports over which the packfile protocol is
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
+"version" with a value of '1' or '2'. See protocol-v2.txt for more
+information on protocol version 2.
+
Git Transport
-------------
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\0host=myserver.com\0
+ 0033git-upload-pack /project.git\0host=myserver.com\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\0host=myserver.com\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.
"0039git-upload-pack /schacon/gitbook.git\0host=example.com\0" |
nc -v example.com 9418
-If the server refuses the request for some reasons, it could abort
-gracefully with an error message.
-
-----
- error-line = PKT-LINE("ERR" SP explanation-text)
-----
-
SSH Transport
-------------
v
ssh user@example.com "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
-------------------
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\0host=example.com\0" |
+ $ echo -e -n "0044git-upload-pack /schacon/gitbook.git\0host=example.com\0\0version=1\0" |
nc -v example.com 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
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)
*shallow
flush-pkt
upload-request = want-list
*shallow-line
*1depth-request
+ [filter-request]
flush-pkt
want-list = first-want
additional-want = PKT-LINE("want" SP obj-id)
depth = 1*DIGIT
+
+ filter-request = PKT-LINE("filter" SP filter-spec)
----
Clients MUST send all the obj-ids it wants from the reference
result are defined as shallow and marked as such in the server. This
information is sent back to the client in the next step.
+The client can optionally request that pack-objects omit various
+objects from the packfile using one of several filtering techniques.
+These are intended for use with partial clone and partial fetch
+operations. An object that does not meet a filter-spec value is
+omitted unless explicitly requested in a 'want' line. See `rev-list`
+for possible filter-spec values.
+
Once all the 'want's and 'shallow's (and optional 'deepen') are
transferred, clients MUST send a flush-pkt, to tell the server side
that it is done sending the list.
Then the server will start sending its packfile data.
----
- server-response = *ack_multi ack / nak / error-line
+ server-response = *ack_multi ack / nak
ack_multi = PKT-LINE("ACK" SP obj-id ack_status)
ack_status = "continue" / "common" / "ready"
ack = PKT-LINE("ACK" SP obj-id)
nak = PKT-LINE("NAK")
- error-line = PKT-LINE("ERR" SP explanation-text)
----
A simple clone may look like this (with no 'have' lines):