diff options
Diffstat (limited to 'Documentation/technical/http-protocol.txt')
| -rw-r--r-- | Documentation/technical/http-protocol.txt | 229 |
1 files changed, 116 insertions, 113 deletions
diff --git a/Documentation/technical/http-protocol.txt b/Documentation/technical/http-protocol.txt index caf941a1c5..544373b16f 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 $GIT_URL/info/refs HTTP/1.0 @@ -161,21 +161,21 @@ without any search/query parameters. S: a3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{} The Content-Type of the returned info/refs entity SHOULD be -"text/plain; charset=utf-8", but MAY be any content type. +`text/plain; charset=utf-8`, but MAY be any content type. Clients MUST NOT attempt to validate the returned Content-Type. Dumb servers MUST NOT return a return type starting with -"application/x-git-". +`application/x-git-`. Cache-Control headers MAY be returned to disable caching of the returned entity. When examining the response clients SHOULD only examine the HTTP -status code. Valid responses are '200 OK', or '304 Not Modified'. +status code. Valid responses are `200 OK`, or `304 Not Modified`. The returned content is a UNIX formatted text file describing each ref and its known value. The file SHOULD be sorted by name according to the C locale ordering. The file SHOULD NOT include -the default ref named 'HEAD'. +the default ref named `HEAD`. info_refs = *( ref_record ) ref_record = any_ref / peeled_ref @@ -192,13 +192,14 @@ HTTP clients that support the "smart" protocol (or both the a parameterized request for the info/refs file of the repository. The request MUST contain exactly one query parameter, -'service=$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 $GIT_URL/info/refs?service=git-upload-pack HTTP/1.0 - dumb server reply: +dumb server reply: + S: 200 OK S: S: 95dcfa3633004da0049d3d0fa03f80589cbcaf31 refs/heads/maint @@ -206,7 +207,8 @@ The request MUST NOT contain additional query parameters. S: 2cb58b79488a98d2721cea644875a8dd0026b115 refs/tags/v1.0 S: a3c2e2402b99163d1d59756e5f207ae21cccba4c refs/tags/v1.0^{} - smart server reply: +smart server reply: + S: 200 OK S: Content-Type: application/x-git-upload-pack-advertisement S: Cache-Control: no-cache @@ -228,7 +230,7 @@ Smart Server Response ^^^^^^^^^^^^^^^^^^^^^ If the server does not recognize the requested service name, or the requested service name has been disabled by the server administrator, -the server MUST respond with the '403 Forbidden' HTTP status code. +the server MUST respond with the `403 Forbidden` HTTP status code. Otherwise, smart servers MUST respond with the smart server reply format for the requested service name. @@ -236,35 +238,35 @@ format for the requested service name. Cache-Control headers SHOULD be used to disable caching of the returned entity. -The Content-Type MUST be 'application/x-$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) @@ -286,12 +288,13 @@ declarations behind a NUL on the first ref. 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 $GIT_URL. +This service reads from the repository pointed to by `$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 @@ -307,16 +310,16 @@ Clients MUST first perform ref discovery with S: ....ACK %s, continue S: ....NAK -Clients MUST NOT reuse or revalidate a cached reponse. +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 +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 @@ -332,128 +335,128 @@ server advertises capability "allow-tip-sha1-in-want". have_list = *PKT-LINE("have" SP id LF) TODO: Document this further. -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 $GIT_URL/git-upload-pack request: +'one compute step:' - C: 0032want <WANT #1>............................... - C: 0032want <WANT #2>............................... +C: Send one `$GIT_URL/git-upload-pack` request: + + C: 0032want <want #1>............................... + C: 0032want <want #2>............................... .... - C: 0032have <COMMON #1>............................. - C: 0032have <COMMON #2>............................. + C: 0032have <common #1>............................. + C: 0032have <common #2>............................. .... - C: 0032have <HAVE #1>............................... - C: 0032have <HAVE #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. +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 @@ -468,7 +471,7 @@ Clients MUST first perform ref discovery with S: S: .... -Clients MUST NOT reuse or revalidate a cached reponse. +Clients MUST NOT reuse or revalidate a cached response. Servers MUST include sufficient Cache-Control headers to prevent caching of the response. |