1GITPROTOCOL-HTTP(5) Git Manual GITPROTOCOL-HTTP(5)
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6 gitprotocol-http - Git HTTP-based protocols
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9 <over-the-wire-protocol>
10
12 Git supports two HTTP based transfer protocols. A "dumb" protocol which
13 requires only a standard HTTP server on the server end of the
14 connection, and a "smart" protocol which requires a Git aware CGI (or
15 server module). This document describes both protocols.
16 As a design feature smart clients can automatically upgrade "dumb"
18 protocol URLs to smart URLs. This permits all users to have the same
19 published URL, and the peers automatically select the most efficient
20 transport available to them.
21
23 URLs for Git repositories accessed by HTTP use the standard HTTP URL
24 syntax documented by RFC 1738, so they are of the form:
25 http://<host>:<port>/<path>?<searchpart>
27 Within this documentation the placeholder $GIT_URL will stand for the
29 http:// repository URL entered by the end-user.
30 Servers SHOULD handle all requests to locations matching $GIT_URL, as
32 both the "smart" and "dumb" HTTP protocols used by Git operate by
33 appending additional path components onto the end of the user supplied
34 $GIT_URL string.
35 An example of a dumb client requesting for a loose object:
37 $GIT_URL: http://example.com:8080/git/repo.git
39 URL request: http://example.com:8080/git/repo.git/objects/d0/49f6c27a2244e12041955e262a404c7faba355
40 An example of a smart request to a catch-all gateway:
42 $GIT_URL: http://example.com/daemon.cgi?svc=git&q=
44 URL request: http://example.com/daemon.cgi?svc=git&q=/info/refs&service=git-receive-pack
45 An example of a request to a submodule:
47 $GIT_URL: http://example.com/git/repo.git/path/submodule.git
49 URL request: http://example.com/git/repo.git/path/submodule.git/info/refs
50 Clients MUST strip a trailing /, if present, from the user supplied
52 $GIT_URL string to prevent empty path tokens (//) from appearing in any
53 URL sent to a server. Compatible clients MUST expand $GIT_URL/info/refs
54 as foo/info/refs and not foo//info/refs.
55
57 Standard HTTP authentication is used if authentication is required to
58 access a repository, and MAY be configured and enforced by the HTTP
59 server software.
60 Because Git repositories are accessed by standard path components
62 server administrators MAY use directory based permissions within their
63 HTTP server to control repository access.
64 Clients SHOULD support Basic authentication as described by RFC 2617.
66 Servers SHOULD support Basic authentication by relying upon the HTTP
67 server placed in front of the Git server software.
68 Servers SHOULD NOT require HTTP cookies for the purposes of
70 authentication or access control.
71 Clients and servers MAY support other common forms of HTTP based
73 authentication, such as Digest authentication.
74
76 Clients and servers SHOULD support SSL, particularly to protect
77 passwords when relying on Basic HTTP authentication.
78
80 The Git over HTTP protocol (much like HTTP itself) is stateless from
81 the perspective of the HTTP server side. All state MUST be retained and
82 managed by the client process. This permits simple round-robin
83 load-balancing on the server side, without needing to worry about state
84 management.
85 Clients MUST NOT require state management on the server side in order
87 to function correctly.
88 Servers MUST NOT require HTTP cookies in order to function correctly.
90 Clients MAY store and forward HTTP cookies during request processing as
91 described by RFC 2616 (HTTP/1.1). Servers SHOULD ignore any cookies
92 sent by a client.
93
95 Except where noted, all standard HTTP behavior SHOULD be assumed by
96 both client and server. This includes (but is not necessarily limited
97 to):
98 If there is no repository at $GIT_URL, or the resource pointed to by a
100 location matching $GIT_URL does not exist, the server MUST NOT respond
101 with 200 OK response. A server SHOULD respond with 404 Not Found, 410
102 Gone, or any other suitable HTTP status code which does not imply the
103 resource exists as requested.
104 If there is a repository at $GIT_URL, but access is not currently
106 permitted, the server MUST respond with the 403 Forbidden HTTP status
107 code.
108 Servers SHOULD support both HTTP 1.0 and HTTP 1.1. Servers SHOULD
110 support chunked encoding for both request and response bodies.
111 Clients SHOULD support both HTTP 1.0 and HTTP 1.1. Clients SHOULD
113 support chunked encoding for both request and response bodies.
114 Servers MAY return ETag and/or Last-Modified headers.
116 Clients MAY revalidate cached entities by including If-Modified-Since
118 and/or If-None-Match request headers.
119 Servers MAY return 304 Not Modified if the relevant headers appear in
121 the request and the entity has not changed. Clients MUST treat 304 Not
122 Modified identical to 200 OK by reusing the cached entity.
123 Clients MAY reuse a cached entity without revalidation if the
125 Cache-Control and/or Expires header permits caching. Clients and
126 servers MUST follow RFC 2616 for cache controls.
127
129 All HTTP clients MUST begin either a fetch or a push exchange by
130 discovering the references available on the remote repository.
131 Dumb Clients
133 HTTP clients that only support the "dumb" protocol MUST discover
134 references by making a request for the special info/refs file of the
135 repository.
136 Dumb HTTP clients MUST make a GET request to $GIT_URL/info/refs,
138 without any search/query parameters.
139 C: GET $GIT_URL/info/refs HTTP/1.0
141 S: 200 OK
143 S:
144 S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint
145 S: d049f6c27a2244e12041955e262a404c7faba355 refs/heads/master
146 S: 2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0
147 S: a3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{}
148 The Content-Type of the returned info/refs entity SHOULD be text/plain;
150 charset=utf-8, but MAY be any content type. Clients MUST NOT attempt to
151 validate the returned Content-Type. Dumb servers MUST NOT return a
152 return type starting with application/x-git-.
153 Cache-Control headers MAY be returned to disable caching of the
155 returned entity.
156 When examining the response clients SHOULD only examine the HTTP status
158 code. Valid responses are 200 OK, or 304 Not Modified.
159 The returned content is a UNIX formatted text file describing each ref
161 and its known value. The file SHOULD be sorted by name according to the
162 C locale ordering. The file SHOULD NOT include the default ref named
163 HEAD.
164 info_refs = *( ref_record )
166 ref_record = any_ref / peeled_ref
167 any_ref = obj-id HTAB refname LF
169 peeled_ref = obj-id HTAB refname LF
170 obj-id HTAB refname "^{}" LF
171 Smart Clients
173 HTTP clients that support the "smart" protocol (or both the "smart" and
174 "dumb" protocols) MUST discover references by making a parameterized
175 request for the info/refs file of the repository.
176 The request MUST contain exactly one query parameter,
178 service=$servicename, where $servicename MUST be the service name the
179 client wishes to contact to complete the operation. The request MUST
180 NOT contain additional query parameters.
181 C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0
183 dumb server reply:
185 S: 200 OK
187 S:
188 S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint
189 S: d049f6c27a2244e12041955e262a404c7faba355 refs/heads/master
190 S: 2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0
191 S: a3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{}
192 smart server reply:
194 S: 200 OK
196 S: Content-Type: application/x-git-upload-pack-advertisement
197 S: Cache-Control: no-cache
198 S:
199 S: 001e# service=git-upload-pack\n
200 S: 0000
201 S: 004895dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint\0multi_ack\n
202 S: 003fd049f6c27a2244e12041955e262a404c7faba355 refs/heads/master\n
203 S: 003c2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0\n
204 S: 003fa3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{}\n
205 S: 0000
206 The client may send Extra Parameters (see gitprotocol-pack(5)) as a
208 colon-separated string in the Git-Protocol HTTP header.
209 Uses the --http-backend-info-refs option to git-upload-pack(1).
211 Dumb Server Response
213 Dumb servers MUST respond with the dumb server reply format.
214 See the prior section under dumb clients for a more detailed
216 description of the dumb server response.
217 Smart Server Response
219 If the server does not recognize the requested service name, or the
220 requested service name has been disabled by the server
221 administrator, the server MUST respond with the 403 Forbidden HTTP
222 status code.
223 Otherwise, smart servers MUST respond with the smart server reply
225 format for the requested service name.
226 Cache-Control headers SHOULD be used to disable caching of the
228 returned entity.
229 The Content-Type MUST be application/x-$servicename-advertisement.
231 Clients SHOULD fall back to the dumb protocol if another content
232 type is returned. When falling back to the dumb protocol clients
233 SHOULD NOT make an additional request to $GIT_URL/info/refs, but
234 instead SHOULD use the response already in hand. Clients MUST NOT
235 continue if they do not support the dumb protocol.
236 Clients MUST validate the status code is either 200 OK or 304 Not
238 Modified.
239 Clients MUST validate the first five bytes of the response entity
241 matches the regex ^[0-9a-f]{4}#. If this test fails, clients MUST
242 NOT continue.
243 Clients MUST parse the entire response as a sequence of pkt-line
245 records.
246 Clients MUST verify the first pkt-line is # service=$servicename.
248 Servers MUST set $servicename to be the request parameter value.
249 Servers SHOULD include an LF at the end of this line. Clients MUST
250 ignore an LF at the end of the line.
251 Servers MUST terminate the response with the magic 0000 end
253 pkt-line marker.
254 The returned response is a pkt-line stream describing each ref and
256 its known value. The stream SHOULD be sorted by name according to
257 the C locale ordering. The stream SHOULD include the default ref
258 named HEAD as the first ref. The stream MUST include capability
259 declarations behind a NUL on the first ref.
260 The returned response contains "version 1" if "version=1" was sent
262 as an Extra Parameter.
263 smart_reply = PKT-LINE("# service=$servicename" LF)
265 "0000"
266 *1("version 1")
267 ref_list
268 "0000"
269 ref_list = empty_list / non_empty_list
270 empty_list = PKT-LINE(zero-id SP "capabilities^{}" NUL cap-list LF)
272 non_empty_list = PKT-LINE(obj-id SP name NUL cap_list LF)
274 *ref_record
275 cap-list = capability *(SP capability)
277 capability = 1*(LC_ALPHA / DIGIT / "-" / "_")
278 LC_ALPHA = %x61-7A
279 ref_record = any_ref / peeled_ref
281 any_ref = PKT-LINE(obj-id SP name LF)
282 peeled_ref = PKT-LINE(obj-id SP name LF)
283 PKT-LINE(obj-id SP name "^{}" LF
284
286 This service reads from the repository pointed to by $GIT_URL.
287 Clients MUST first perform ref discovery with
289 $GIT_URL/info/refs?service=git-upload-pack.
290 C: POST $GIT_URL/git-upload-pack HTTP/1.0
292 C: Content-Type: application/x-git-upload-pack-request
293 C:
294 C: 0032want 0a53e9ddeaddad63ad106860237bbf53411d11a7\n
295 C: 0032have 441b40d833fdfa93eb2908e52742248faf0ee993\n
296 C: 0000
297 S: 200 OK
299 S: Content-Type: application/x-git-upload-pack-result
300 S: Cache-Control: no-cache
301 S:
302 S: ....ACK %s, continue
303 S: ....NAK
304 Clients MUST NOT reuse or revalidate a cached response. Servers MUST
306 include sufficient Cache-Control headers to prevent caching of the
307 response.
308 Servers SHOULD support all capabilities defined here.
310 Clients MUST send at least one "want" command in the request body.
312 Clients MUST NOT reference an id in a "want" command which did not
313 appear in the response obtained through ref discovery unless the server
314 advertises capability allow-tip-sha1-in-want or
315 allow-reachable-sha1-in-want.
316 compute_request = want_list
318 have_list
319 request_end
320 request_end = "0000" / "done"
321 want_list = PKT-LINE(want SP cap_list LF)
323 *(want_pkt)
324 want_pkt = PKT-LINE(want LF)
325 want = "want" SP id
326 cap_list = capability *(SP capability)
327 have_list = *PKT-LINE("have" SP id LF)
329 TODO: Document this further.
331 The Negotiation Algorithm
333 The computation to select the minimal pack proceeds as follows (C =
334 client, S = server):
335 init step:
337 C: Use ref discovery to obtain the advertised refs.
339 C: Place any object seen into set advertised.
341 C: Build an empty set, common, to hold the objects that are later
343 determined to be on both ends.
344 C: Build a set, want, of the objects from advertised the client wants
346 to fetch, based on what it saw during ref discovery.
347 C: Start a queue, c_pending, ordered by commit time (popping newest
349 first). Add all client refs. When a commit is popped from the queue its
350 parents SHOULD be automatically inserted back. Commits MUST only enter
351 the queue once.
352 one compute step:
354 C: Send one $GIT_URL/git-upload-pack request:
356 C: 0032want <want #1>...............................
358 C: 0032want <want #2>...............................
359 ....
360 C: 0032have <common #1>.............................
361 C: 0032have <common #2>.............................
362 ....
363 C: 0032have <have #1>...............................
364 C: 0032have <have #2>...............................
365 ....
366 C: 0000
367 The stream is organized into "commands", with each command appearing by
369 itself in a pkt-line. Within a command line, the text leading up to the
370 first space is the command name, and the remainder of the line to the
371 first LF is the value. Command lines are terminated with an LF as the
372 last byte of the pkt-line value.
373 Commands MUST appear in the following order, if they appear at all in
375 the request stream:
376 • "want"
378 • "have"
380 The stream is terminated by a pkt-line flush (0000).
382 A single "want" or "have" command MUST have one hex formatted object
384 name as its value. Multiple object names MUST be sent by sending
385 multiple commands. Object names MUST be given using the object format
386 negotiated through the object-format capability (default SHA-1).
387 The have list is created by popping the first 32 commits from
389 c_pending. Less can be supplied if c_pending empties.
390 If the client has sent 256 "have" commits and has not yet received one
392 of those back from s_common, or the client has emptied c_pending it
393 SHOULD include a "done" command to let the server know it won’t
394 proceed:
395 C: 0009done
397 S: Parse the git-upload-pack request:
399 Verify all objects in want are directly reachable from refs.
401 The server MAY walk backwards through history or through the reflog to
403 permit slightly stale requests.
404 If no "want" objects are received, send an error: TODO: Define error if
406 no "want" lines are requested.
407 If any "want" object is not reachable, send an error: TODO: Define
409 error if an invalid "want" is requested.
410 Create an empty list, s_common.
412 If "have" was sent:
414 Loop through the objects in the order supplied by the client.
416 For each object, if the server has the object reachable from a ref, add
418 it to s_common. If a commit is added to s_common, do not add any
419 ancestors, even if they also appear in have.
420 S: Send the git-upload-pack response:
422 If the server has found a closed set of objects to pack or the request
424 ends with "done", it replies with the pack. TODO: Document the pack
425 based response
426 S: PACK...
428 The returned stream is the side-band-64k protocol supported by the
430 git-upload-pack service, and the pack is embedded into stream 1.
431 Progress messages from the server side MAY appear in stream 2.
432 Here a "closed set of objects" is defined to have at least one path
434 from every "want" to at least one "common" object.
435 If the server needs more information, it replies with a status continue
437 response: TODO: Document the non-pack response
438 C: Parse the upload-pack response: TODO: Document parsing response
440 Do another compute step.
442
444 This service reads from the repository pointed to by $GIT_URL.
445 Clients MUST first perform ref discovery with
447 $GIT_URL/info/refs?service=git-receive-pack.
448 C: POST $GIT_URL/git-receive-pack HTTP/1.0
450 C: Content-Type: application/x-git-receive-pack-request
451 C:
452 C: ....0a53e9ddeaddad63ad106860237bbf53411d11a7 441b40d833fdfa93eb2908e52742248faf0ee993 refs/heads/maint\0 report-status
453 C: 0000
454 C: PACK....
455 S: 200 OK
457 S: Content-Type: application/x-git-receive-pack-result
458 S: Cache-Control: no-cache
459 S:
460 S: ....
461 Clients MUST NOT reuse or revalidate a cached response. Servers MUST
463 include sufficient Cache-Control headers to prevent caching of the
464 response.
465 Servers SHOULD support all capabilities defined here.
467 Clients MUST send at least one command in the request body. Within the
469 command portion of the request body clients SHOULD send the id obtained
470 through ref discovery as old_id.
471 update_request = command_list
473 "PACK" <binary data>
474 command_list = PKT-LINE(command NUL cap_list LF)
476 *(command_pkt)
477 command_pkt = PKT-LINE(command LF)
478 cap_list = *(SP capability) SP
479 command = create / delete / update
481 create = zero-id SP new_id SP name
482 delete = old_id SP zero-id SP name
483 update = old_id SP new_id SP name
484 TODO: Document this further.
486
488 RFC 1738: Uniform Resource Locators (URL)[1] RFC 2616: Hypertext
489 Transfer Protocol — HTTP/1.1[2]
490
492 gitprotocol-pack(5) gitprotocol-capabilities(5)
493
495 Part of the git(1) suite
496
498 1. RFC 1738: Uniform Resource Locators (URL)
499 http://www.ietf.org/rfc/rfc1738.txt
500 2. RFC 2616: Hypertext Transfer Protocol — HTTP/1.1
502 http://www.ietf.org/rfc/rfc2616.txt
503Git 2.39.1 2023-01-13 GITPROTOCOL-HTTP(5)