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-HTTP transfer protocols
-=======================
-
-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.
-
-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.
-
-
-URL Format
-----------
-
-URLs for Git repositories accessed by HTTP use the standard HTTP
-URL syntax documented by RFC 1738, so they are of the form:
-
-  http://<host>:<port>/<path>?<searchpart>
-
-Within this documentation the placeholder `$GIT_URL` will stand for
-the http:// repository URL entered by the end-user.
-
-Servers SHOULD handle all requests to locations matching `$GIT_URL`, as
-both the "smart" and "dumb" HTTP protocols used by Git operate
-by appending additional path components onto the end of the user
-supplied `$GIT_URL` string.
-
-An example of a dumb client requesting for a loose object:
-
-  $GIT_URL:     http://example.com:8080/git/repo.git
-  URL request:  http://example.com:8080/git/repo.git/objects/d0/49f6c27a2244e12041955e262a404c7faba355
-
-An example of a smart request to a catch-all gateway:
-
-  $GIT_URL:     http://example.com/daemon.cgi?svc=git&q=
-  URL request:  http://example.com/daemon.cgi?svc=git&q=/info/refs&service=git-receive-pack
-
-An example of a request to a submodule:
-
-  $GIT_URL:     http://example.com/git/repo.git/path/submodule.git
-  URL request:  http://example.com/git/repo.git/path/submodule.git/info/refs
-
-Clients MUST strip a trailing `/`, if present, from the user supplied
-`$GIT_URL` string to prevent empty path tokens (`//`) from appearing
-in any URL sent to a server.  Compatible clients MUST expand
-`$GIT_URL/info/refs` as `foo/info/refs` and not `foo//info/refs`.
-
-
-Authentication
---------------
-
-Standard HTTP authentication is used if authentication is required
-to access a repository, and MAY be configured and enforced by the
-HTTP server software.
-
-Because Git repositories are accessed by standard path components
-server administrators MAY use directory based permissions within
-their HTTP server to control repository access.
-
-Clients SHOULD support Basic authentication as described by RFC 2617.
-Servers SHOULD support Basic authentication by relying upon the
-HTTP server placed in front of the Git server software.
-
-Servers SHOULD NOT require HTTP cookies for the purposes of
-authentication or access control.
-
-Clients and servers MAY support other common forms of HTTP based
-authentication, such as Digest authentication.
-
-
-SSL
----
-
-Clients and servers SHOULD support SSL, particularly to protect
-passwords when relying on Basic HTTP authentication.
-
-
-Session State
--------------
-
-The Git over HTTP protocol (much like HTTP itself) is stateless
-from the perspective of the HTTP server side.  All state MUST be
-retained and managed by the client process.  This permits simple
-round-robin load-balancing on the server side, without needing to
-worry about state management.
-
-Clients MUST NOT require state management on the server side in
-order to function correctly.
-
-Servers MUST NOT require HTTP cookies in order to function correctly.
-Clients MAY store and forward HTTP cookies during request processing
-as described by RFC 2616 (HTTP/1.1).  Servers SHOULD ignore any
-cookies sent by a client.
-
-
-General Request Processing
---------------------------
-
-Except where noted, all standard HTTP behavior SHOULD be assumed
-by both client and server.  This includes (but is not necessarily
-limited to):
-
-If there is no repository at `$GIT_URL`, or the resource pointed to by a
-location matching `$GIT_URL` does not exist, the server MUST NOT respond
-with `200 OK` response.  A server SHOULD respond with
-`404 Not Found`, `410 Gone`, or any other suitable HTTP status code
-which does not imply the resource exists as requested.
-
-If there is a repository at `$GIT_URL`, but access is not currently
-permitted, the server MUST respond with the `403 Forbidden` HTTP
-status code.
-
-Servers SHOULD support both HTTP 1.0 and HTTP 1.1.
-Servers SHOULD support chunked encoding for both request and response
-bodies.
-
-Clients SHOULD support both HTTP 1.0 and HTTP 1.1.
-Clients SHOULD support chunked encoding for both request and response
-bodies.
-
-Servers MAY return ETag and/or Last-Modified headers.
-
-Clients MAY revalidate cached entities by including If-Modified-Since
-and/or If-None-Match request headers.
-
-Servers MAY return `304 Not Modified` if the relevant headers appear
-in the request and the entity has not changed.  Clients MUST treat
-`304 Not Modified` identical to `200 OK` by reusing the cached entity.
-
-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.
-
-
-Discovering References
-----------------------
-
-All HTTP clients MUST begin either a fetch or a push exchange by
-discovering the references available on the remote repository.
-
-Dumb Clients
-~~~~~~~~~~~~
-
-HTTP clients that only support the "dumb" protocol MUST discover
-references by making a request for the special info/refs file of
-the repository.
-
-Dumb HTTP clients MUST make a `GET` request to `$GIT_URL/info/refs`,
-without any search/query parameters.
-
-   C: GET $GIT_URL/info/refs HTTP/1.0
-
-   S: 200 OK
-   S:
-   S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31	refs/heads/maint
-   S: d049f6c27a2244e12041955e262a404c7faba355	refs/heads/master
-   S: 2cb58b79488a98d2721cea644875a8dd0026b115	refs/tags/v1.0
-   S: a3c2e2402b99163d1d59756e5f207ae21cccba4c	refs/tags/v1.0^{}
-
-The Content-Type of the returned info/refs entity SHOULD be
-`text/plain; charset=utf-8`, but MAY be any content type.
-Clients MUST NOT attempt to validate the returned Content-Type.
-Dumb servers MUST NOT return a return type starting with
-`application/x-git-`.
-
-Cache-Control headers MAY be returned to disable caching of the
-returned entity.
-
-When examining the response clients SHOULD only examine the HTTP
-status code.  Valid responses are `200 OK`, or `304 Not Modified`.
-
-The returned content is a UNIX formatted text file describing
-each ref and its known value.  The file SHOULD be sorted by name
-according to the C locale ordering.  The file SHOULD NOT include
-the default ref named `HEAD`.
-
-  info_refs   =  *( ref_record )
-  ref_record  =  any_ref / peeled_ref
-
-  any_ref     =  obj-id HTAB refname LF
-  peeled_ref  =  obj-id HTAB refname LF
-		 obj-id HTAB refname "^{}" LF
-
-Smart Clients
-~~~~~~~~~~~~~
-
-HTTP clients that support the "smart" protocol (or both the
-"smart" and "dumb" protocols) MUST discover references by making
-a parameterized request for the info/refs file of the repository.
-
-The request MUST contain exactly one query parameter,
-`service=$servicename`, where `$servicename` MUST be the service
-name the client wishes to contact to complete the operation.
-The request MUST NOT contain additional query parameters.
-
-   C: GET $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0
-
-dumb server reply:
-
-   S: 200 OK
-   S:
-   S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31	refs/heads/maint
-   S: d049f6c27a2244e12041955e262a404c7faba355	refs/heads/master
-   S: 2cb58b79488a98d2721cea644875a8dd0026b115	refs/tags/v1.0
-   S: a3c2e2402b99163d1d59756e5f207ae21cccba4c	refs/tags/v1.0^{}
-
-smart server reply:
-
-   S: 200 OK
-   S: Content-Type: application/x-git-upload-pack-advertisement
-   S: Cache-Control: no-cache
-   S:
-   S: 001e# service=git-upload-pack\n
-   S: 0000
-   S: 004895dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint\0multi_ack\n
-   S: 003fd049f6c27a2244e12041955e262a404c7faba355 refs/heads/master\n
-   S: 003c2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0\n
-   S: 003fa3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{}\n
-   S: 0000
-
-The client may send Extra Parameters (see
-Documentation/technical/pack-protocol.txt) as a colon-separated string
-in the Git-Protocol HTTP header.
-
-Dumb Server Response
-^^^^^^^^^^^^^^^^^^^^
-Dumb servers MUST respond with the dumb server reply format.
-
-See the prior section under dumb clients for a more detailed
-description of the dumb server response.
-
-Smart Server Response
-^^^^^^^^^^^^^^^^^^^^^
-If the server does not recognize the requested service name, or the
-requested service name has been disabled by the server administrator,
-the server MUST respond with the `403 Forbidden` HTTP status code.
-
-Otherwise, smart servers MUST respond with the smart server reply
-format for the requested service name.
-
-Cache-Control headers SHOULD be used to disable caching of the
-returned entity.
-
-The Content-Type MUST be `application/x-$servicename-advertisement`.
-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 `$GIT_URL/info/refs`, but
-instead SHOULD use the response already in hand.  Clients MUST NOT
-continue if they do not support the dumb protocol.
-
-Clients MUST validate the status code is either `200 OK` or
-`304 Not Modified`.
-
-Clients MUST validate the first five bytes of the response entity
-matches the regex `^[0-9a-f]{4}#`.  If this test fails, clients
-MUST NOT continue.
-
-Clients MUST parse the entire response as a sequence of pkt-line
-records.
-
-Clients MUST verify the first pkt-line is `# service=$servicename`.
-Servers MUST set $servicename to be the request parameter value.
-Servers SHOULD include an LF at the end of this line.
-Clients MUST ignore an LF at the end of the line.
-
-Servers MUST terminate the response with the magic `0000` end
-pkt-line marker.
-
-The returned response is a pkt-line stream describing each ref and
-its known value.  The stream SHOULD be sorted by name according to
-the C locale ordering.  The stream SHOULD include the default ref
-named `HEAD` as the first ref.  The stream MUST include capability
-declarations behind a NUL on the first ref.
-
-The returned response contains "version 1" if "version=1" was sent as an
-Extra Parameter.
-
-  smart_reply     =  PKT-LINE("# service=$servicename" LF)
-		     "0000"
-		     *1("version 1")
-		     ref_list
-		     "0000"
-  ref_list        =  empty_list / non_empty_list
-
-  empty_list      =  PKT-LINE(zero-id SP "capabilities^{}" NUL cap-list LF)
-
-  non_empty_list  =  PKT-LINE(obj-id SP name NUL cap_list LF)
-		     *ref_record
-
-  cap-list        =  capability *(SP capability)
-  capability      =  1*(LC_ALPHA / DIGIT / "-" / "_")
-  LC_ALPHA        =  %x61-7A
-
-  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
-
-
-Smart Service git-upload-pack
-------------------------------
-This service reads from the repository pointed to by `$GIT_URL`.
-
-Clients MUST first perform ref discovery with
-`$GIT_URL/info/refs?service=git-upload-pack`.
-
-   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
-
-   S: 200 OK
-   S: Content-Type: application/x-git-upload-pack-result
-   S: Cache-Control: no-cache
-   S:
-   S: ....ACK %s, continue
-   S: ....NAK
-
-Clients MUST NOT reuse or revalidate a cached response.
-Servers MUST include sufficient Cache-Control headers
-to prevent caching of the response.
-
-Servers SHOULD support all capabilities defined here.
-
-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 `allow-tip-sha1-in-want` or
-`allow-reachable-sha1-in-want`.
-
-  compute_request   =  want_list
-		       have_list
-		       request_end
-  request_end       =  "0000" / "done"
-
-  want_list         =  PKT-LINE(want SP cap_list LF)
-		       *(want_pkt)
-  want_pkt          =  PKT-LINE(want LF)
-  want              =  "want" SP id
-  cap_list          =  capability *(SP capability)
-
-  have_list         =  *PKT-LINE("have" SP id LF)
-
-TODO: Document this further.
-
-The Negotiation Algorithm
-~~~~~~~~~~~~~~~~~~~~~~~~~
-The computation to select the minimal pack proceeds as follows
-(C = client, S = server):
-
-'init step:'
-
-C: Use ref discovery to obtain the advertised refs.
-
-C: Place any object seen into set `advertised`.
-
-C: Build an empty set, `common`, to hold the objects that are later
-   determined to be on both ends.
-
-C: Build a set, `want`, of the objects from `advertised` the client
-   wants to fetch, based on what it saw during ref discovery.
-
-C: Start a queue, `c_pending`, 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.
-
-'one compute step:'
-
-C: Send one `$GIT_URL/git-upload-pack` request:
-
-   C: 0032want <want #1>...............................
-   C: 0032want <want #2>...............................
-   ....
-   C: 0032have <common #1>.............................
-   C: 0032have <common #2>.............................
-   ....
-   C: 0032have <have #1>...............................
-   C: 0032have <have #2>...............................
-   ....
-   C: 0000
-
-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.
-
-Commands MUST appear in the following order, if they appear
-at all in the request stream:
-
-* "want"
-* "have"
-
-The stream is terminated by a pkt-line flush (`0000`).
-
-A single "want" or "have" command MUST have one hex formatted
-object name as its value.  Multiple object names MUST be sent by sending
-multiple commands. Object names MUST be given using the object format
-negotiated through the `object-format` capability (default SHA-1).
-
-The `have` list is created by popping the first 32 commits
-from `c_pending`.  Less can be supplied if `c_pending` empties.
-
-If the client has sent 256 "have" commits and has not yet
-received one of those back from `s_common`, or the client has
-emptied `c_pending` it SHOULD include a "done" command to let
-the server know it won't proceed:
-
-   C: 0009done
-
-S: Parse the git-upload-pack request:
-
-Verify all objects in `want` are directly reachable from refs.
-
-The server MAY walk backwards through history or through
-the reflog to permit slightly stale requests.
-
-If no "want" objects are received, send an error:
-TODO: Define error if no "want" lines are requested.
-
-If any "want" object is not reachable, send an error:
-TODO: Define error if an invalid "want" is requested.
-
-Create an empty list, `s_common`.
-
-If "have" was sent:
-
-Loop through the objects in the order supplied by the client.
-
-For each object, if the server has the object reachable from
-a ref, add it to `s_common`.  If a commit is added to `s_common`,
-do not add any ancestors, even if they also appear in `have`.
-
-S: Send the git-upload-pack response:
-
-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
-
-   S: PACK...
-
-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.
-
-Here a "closed set of objects" is defined to have at least
-one path from every "want" to at least one "common" object.
-
-If the server needs more information, it replies with a
-status continue response:
-TODO: Document the non-pack response
-
-C: Parse the upload-pack response:
-   TODO: Document parsing response
-
-'Do another compute step.'
-
-
-Smart Service git-receive-pack
-------------------------------
-This service reads from the repository pointed to by `$GIT_URL`.
-
-Clients MUST first perform ref discovery with
-`$GIT_URL/info/refs?service=git-receive-pack`.
-
-   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....
-
-   S: 200 OK
-   S: Content-Type: application/x-git-receive-pack-result
-   S: Cache-Control: no-cache
-   S:
-   S: ....
-
-Clients MUST NOT reuse or revalidate a cached response.
-Servers MUST include sufficient Cache-Control headers
-to prevent caching of the response.
-
-Servers SHOULD support all capabilities defined here.
-
-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.
-
-  update_request  =  command_list
-		     "PACK" <binary data>
-
-  command_list    =  PKT-LINE(command NUL cap_list LF)
-		     *(command_pkt)
-  command_pkt     =  PKT-LINE(command LF)
-  cap_list        =  *(SP capability) SP
-
-  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
-
-TODO: Document this further.
-
-
-References
-----------
-
-http://www.ietf.org/rfc/rfc1738.txt[RFC 1738: Uniform Resource Locators (URL)]
-http://www.ietf.org/rfc/rfc2616.txt[RFC 2616: Hypertext Transfer Protocol -- HTTP/1.1]
-link:technical/pack-protocol.html
-link:technical/protocol-capabilities.html