./Documentation/technical/http-protocol.txt was missing from TECH_DOCS in Makefile. Add it and also improve HTML formatting while still retaining good readability of the ASCII text: - Use monospace font instead of italicized or roman font for machine output and source text - Use roman font for things which should be body text - Use double quotes consistently for "want" and "have" commands - Use uppercase "C" / "S" consistently for "client" / "server"; also use "C:" / "S:" instead of "(C)" / "(S)" for consistency and to avoid having formatted "(C)" as copyright symbol in HTML - Use only spaces and not a combination of tabs and spaces for whitespace Signed-off-by: Thomas Ackermann <th.acker@xxxxxxxx> --- Documentation/Makefile | 3 +- Documentation/technical/http-protocol.txt | 232 +++++++++++++++--------------- 2 files changed, 120 insertions(+), 115 deletions(-) diff --git a/Documentation/Makefile b/Documentation/Makefile index 36c58fc..b19d52a 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -60,7 +60,8 @@ SP_ARTICLES += howto/maintain-git API_DOCS = $(patsubst %.txt,%,$(filter-out technical/api-index-skel.txt technical/api-index.txt, $(wildcard technical/api-*.txt))) SP_ARTICLES += $(API_DOCS) -TECH_DOCS = technical/index-format +TECH_DOCS = technical/http-protocol +TECH_DOCS += technical/index-format TECH_DOCS += technical/pack-format TECH_DOCS += technical/pack-heuristics TECH_DOCS += technical/pack-protocol diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt index d21d77d..7f0cf0b 100644 --- a/Documentation/technical/http-protocol.txt +++ b/Documentation/technical/http-protocol.txt @@ -20,13 +20,13 @@ URL syntax documented by RFC 1738, so they are of the form: http://<host>:<port>/<path>?<searchpart> -Within this documentation the placeholder $GIT_URL will stand for +Within this documentation the placeholder `$GIT_URL` will stand for the http:// repository URL entered by the end-user. -Servers SHOULD handle all requests to locations matching $GIT_URL, as +Servers SHOULD handle all requests to locations matching `$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 $GIT_URL string. +supplied `$GIT_URL` string. An example of a dumb client requesting for a loose object: @@ -43,10 +43,10 @@ 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 +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'. +`$GIT_URL/info/refs` as `foo/info/refs` and not `foo//info/refs`. Authentication @@ -103,14 +103,14 @@ 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 $GIT_URL does not exist, the server MUST NOT respond -with '200 OK' response. A server SHOULD respond with -'404 Not Found', '410 Gone', or any other suitable HTTP status code +If there is no repository at `$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 $GIT_URL, but access is not currently -permitted, the server MUST respond with the '403 Forbidden' HTTP +If there is a repository at `$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. @@ -126,9 +126,9 @@ 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 +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. +`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 @@ -148,7 +148,7 @@ 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 $GIT_URL/info/refs, +Dumb HTTP clients MUST make a `GET` request to `$GIT_URL/info/refs`, without any search/query parameters. C: GET $GIT_URL/info/refs HTTP/1.0 @@ -161,28 +161,28 @@ without any search/query parameters. S: a3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{} The Content-Type of the returned info/refs entity SHOULD be -"text/plain; charset=utf-8", but MAY be any content type. +`text/plain; charset=utf-8`, but MAY be any content type. Clients MUST NOT attempt to validate the returned Content-Type. Dumb servers MUST NOT return a return type starting with -"application/x-git-". +`application/x-git-`. Cache-Control headers MAY be returned to disable caching of the returned entity. When examining the response clients SHOULD only examine the HTTP -status code. Valid responses are '200 OK', or '304 Not Modified'. +status code. Valid responses are `200 OK`, or `304 Not Modified`. The returned content is a UNIX formatted text file describing each ref and its known value. The file SHOULD be sorted by name according to the C locale ordering. The file SHOULD NOT include -the default ref named 'HEAD'. +the default ref named `HEAD`. info_refs = *( ref_record ) ref_record = any_ref / peeled_ref any_ref = obj-id HTAB refname LF peeled_ref = obj-id HTAB refname LF - obj-id HTAB refname "^{}" LF + obj-id HTAB refname "^{}" LF Smart Clients ~~~~~~~~~~~~~ @@ -192,13 +192,14 @@ HTTP clients that support the "smart" protocol (or both the a parameterized request for the info/refs file of the repository. The request MUST contain exactly one query parameter, -'service=$servicename', where $servicename MUST be the service +`service=$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 $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0 - dumb server reply: +dumb server reply: + S: 200 OK S: S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint @@ -206,7 +207,8 @@ The request MUST NOT contain additional query parameters. S: 2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0 S: a3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{} - smart server reply: +smart server reply: + S: 200 OK S: Content-Type: application/x-git-upload-pack-advertisement S: Cache-Control: no-cache @@ -228,7 +230,7 @@ Smart Server Response ^^^^^^^^^^^^^^^^^^^^^ If the server does not recognize the requested service name, or the requested service name has been disabled by the server administrator, -the server MUST respond with the '403 Forbidden' HTTP status code. +the server MUST respond with the `403 Forbidden` HTTP status code. Otherwise, smart servers MUST respond with the smart server reply format for the requested service name. @@ -236,46 +238,46 @@ format for the requested service name. Cache-Control headers SHOULD be used to disable caching of the returned entity. -The Content-Type MUST be 'application/x-$servicename-advertisement'. +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 $GIT_URL/info/refs, but +SHOULD NOT make an additional request to `$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 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 +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=$servicename". +Clients MUST verify the first pkt-line is `# service=$servicename`. Servers MUST set $servicename to be the request parameter value. Servers SHOULD include an LF at the end of this line. Clients MUST ignore an LF at the end of the line. -Servers MUST terminate the response with the magic "0000" end +Servers MUST terminate the response with the magic `0000` end pkt-line marker. The returned response is a pkt-line stream describing each ref and its known value. The stream SHOULD be sorted by name according to the C locale ordering. The stream SHOULD include the default ref -named 'HEAD' as the first ref. The stream MUST include capability +named `HEAD` as the first ref. The stream MUST include capability declarations behind a NUL on the first ref. smart_reply = PKT-LINE("# service=$servicename" LF) - ref_list - "0000" + 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 + *ref_record cap-list = capability *(SP capability) capability = 1*(LC_ALPHA / DIGIT / "-" / "_") @@ -284,14 +286,15 @@ declarations behind a NUL on the first ref. 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 + PKT-LINE(obj-id SP name "^{}" LF + Smart Service git-upload-pack ------------------------------ -This service reads from the repository pointed to by $GIT_URL. +This service reads from the repository pointed to by `$GIT_URL`. Clients MUST first perform ref discovery with -'$GIT_URL/info/refs?service=git-upload-pack'. +`$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 @@ -313,18 +316,18 @@ 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 +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". +server advertises capability `allow-tip-sha1-in-want`. compute_request = want_list - have_list - request_end + have_list + request_end request_end = "0000" / "done" want_list = PKT-LINE(want NUL cap_list LF) - *(want_pkt) + *(want_pkt) want_pkt = PKT-LINE(want LF) want = "want" SP id cap_list = *(SP capability) SP @@ -337,24 +340,28 @@ TODO: Don't use uppercase for variable names below. The Negotiation Algorithm ~~~~~~~~~~~~~~~~~~~~~~~~~ The computation to select the minimal pack proceeds as follows -(c = client, s = server): +(C = client, S = server): + +'init step:' + +C: Use ref discovery to obtain the advertised refs. + +C: Place any object seen into set ADVERTISED. - 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 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: 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. +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 $GIT_URL/git-upload-pack request: +'one compute step:' + +C: Send one `$GIT_URL/git-upload-pack` request: C: 0032want <WANT #1>............................... C: 0032want <WANT #2>............................... @@ -367,93 +374,90 @@ The computation to select the minimal pack proceeds as follows .... 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. +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: +Commands MUST appear in the following order, if they appear +at all in the request stream: - * want - * have +* "want" +* "have" - The stream is terminated by a pkt-line flush ("0000"). +The stream is terminated by a pkt-line flush (`0000`). - 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. +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. - The HAVE list is created by popping the first 32 commits - from C_PENDING. Less can be supplied if C_PENDING empties. +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: +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. +S: Parse the git-upload-pack request: - If no WANT objects are received, send an error: +Verify all objects in WANT are directly reachable from refs. -TODO: Define error if no want lines are requested. +The server MAY walk backwards through history or through +the reflog to permit slightly stale requests. - If any WANT object is not reachable, send an error: +If no WANT objects are received, send an error: +TODO: Define error if no "want" lines are requested. -TODO: Define error if an invalid want is 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. +Create an empty list, S_COMMON. - If 'have' was sent: +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. +Loop through the objects in the order supplied by the client. - (s) Send the git-upload-pack response: +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. - If the server has found a closed set of objects to pack or the - request ends with "done", it replies with the pack. +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. + S: PACK... - Here a "closed set of objects" is defined to have at least - one path from every WANT to at least one COMMON object. +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. - If the server needs more information, it replies with a - status continue response: +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 +C: Parse the upload-pack response: + TODO: Document parsing response - Do another compute step. +'Do another compute step.' Smart Service git-receive-pack ------------------------------ -This service reads from the repository pointed to by $GIT_URL. +This service reads from the repository pointed to by `$GIT_URL`. Clients MUST first perform ref discovery with -'$GIT_URL/info/refs?service=git-receive-pack'. +`$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 @@ -479,10 +483,10 @@ 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> + "PACK" <binary data> command_list = PKT-LINE(command NUL cap_list LF) - *(command_pkt) + *(command_pkt) command_pkt = PKT-LINE(command LF) cap_list = *(SP capability) SP -- 1.8.5.2.msysgit.0 --- Thomas -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html