Draft 1 of a complete [[P2P_protocol]] over HTTP.
-## git-annex protocol endpoint and version
-
-The git-annex protocol endpoint is "/git-annex" appended to the HTTP
-url of a git remote.
-
## authentication
A git-annex protocol endpoint can optionally operate in readonly mode without
## common request parameters
-Every request has some common parameters that are always included:
+Every request supports these common parameters, and unless documented
+otherwise, a request requires both of them to be included.
* `clientuuid`
the AUTH, VERSION, and BYPASS messages, leaving the session ready to
service requests.]
-## binary data framing
+## requests
+
+### GET /git-annex/key/$key
+
+This is a simple, unversioned interface to get a key from the server.
+It is not part of the P2P protocol per se, but is provided to let
+other clients than git-annex easily download the content of keys from the
+http server.
+
+This behaves the same as `GET /git-annex/v3/key/$key`, although its
+behavior may change in later versions.
+
+### GET /git-annex/v3/key/$key
+
+Get the content of a key from the server.
+
+This is designed so it can be used both by a peer in the P2P protocol,
+and by a regular HTTP client that just wants to download a file.
+
+Example:
+
+ > GET /git-annex/v3/key/SHA1--foo&associatedfile=bar&clientuuid=79a5a1f4-07e8-11ef-873d-97f93ca91925&serveruuid=ecf6d4ca-07e8-11ef-8990-9b8c1f696bf6 HTTP/1.1
+ < X-git-annex-data-length: 3
+ < Content-Type: application/octet-stream
+ <
+ < foo
+
+The key to get is the part of the url after "/git-annex/vN/key/"
+and before any url parameters.
+
+All parameters are optional, including the common parameters, and these:
+
+* `associatedfile`
+
+ The name of a file in the git repository, for informational purposes
+ only.
-When a request body or response body includes binary data, eg the content
-of a large file, the body is framed using
-[netstrings](http://cr.yp.to/proto/netstrings.txt).
+* `offset`
+
+ Number of bytes to skip sending from the beginning of the file.
-The netstring framing is simply the length of the string in ASCII
-digits, followed by the string, and then a comma.
+Request headers are currently ignored, so eg Range requests are
+not supported. (This would be possible to implement, up to a point.)
+
+The body of the request is empty.
+
+The server's response will have a `Content-Type` header of
+`application/octet-stream`.
-This allows efficiently sending binary data in one frame, followed by a
-second frame that can contain eg a JSON document.
+The server's response will have a `X-git-annex-data-length`
+header that indicates the number of bytes of content that are expected to
+be sent. Note that there is no Content-Length header.
-For example, a body containing the binary data "foo" followed by
-a JSON document `{"valid": true}` is framed like this:
-
- 3:foo,15:{"valid": true},
+The body of the response is the content of the key.
-## request messages
+If the length of the body is different than what the the
+X-git-annex-data-length header indicated, then the data is invalid and
+should not be used. This can happen when eg, the data was being sent from
+an unlocked annexed file, which got modified while it was being sent.
-All the requests below are sent with the HTTP POST method.
+When the content is not present, the server will respond with 404.
-### checkpresent
+### POST /git-annex/v3/checkpresent
Checks if a key is currently present on the server.
The server responds with a JSON object with a "present" field that is true
if the key is present, or false if it is not present.
-### lockcontent
+### POST /git-annex/v3/lockcontent
Locks the content of a key on the server, preventing it from being removed.
+Example:
+
+ > POST /git-annex/v3/lockcontent?key=SHA1--foo&clientuuid=79a5a1f4-07e8-11ef-873d-97f93ca91925&serveruuid=ecf6d4ca-07e8-11ef-8990-9b8c1f696bf6 HTTP/1.1
+ [websocket protocol follows]
+ < SUCCESS
+ > UNLOCKCONTENT
+
There is one required additional parameter, `key`.
This request opens a websocket between the client and the server.
server gets shut down before it can receive that, the content will remain
locked for at least 10 minutes from when the server sent "SUCCESS".
-### remove
+### POST /git-annex/v3/remove
Remove a key's content from the server.
(eg due to being read-only or append-only), it will respond with a JSON
object with an "error" field that has an error message as its value.
-## remove-before
+## POST /git-annex/v3/remove-before
Remove a key's content from the server, but only before a specified time.
This is used to avoid removing content after a point in
time where it is no longer locked in other repostitories.
-## gettimestamp
+## POST /git-annex/v3/gettimestamp
Gets the current timestamp from the server.
Important: If multiple servers are serving this protocol for the same
repository, they MUST all use the same monotonic clock.
-### put
+### POST /git-annex/v3/put
Store content on the server.
> POST /git-annex/v3/put?key=SHA1--foo&associatedfile=bar&clientuuid=79a5a1f4-07e8-11ef-873d-97f93ca91925&serveruuid=ecf6d4ca-07e8-11ef-8990-9b8c1f696bf6 HTTP/1.1
> Content-Type: application/octet-stream
- > Content-Length: 25
- > 3:foo,15:{"valid": true},
+ > X-git-annex-object-size: 3
+ >
+ > foo
< {"stored": true}
There is one required additional parameter, `key`.
Number of bytes that have been omitted from the beginning of the file.
Usually this will be determined by making a `putoffset` request.
-The body of the request is two items framed with netstrings.
-
-The first item is the content of the key, starting from the specified
-offset or from the beginning when no offset was specified.
-
-The second item is a JSON object.
-
-The JSON object has a field "valid" that is true when the content was not
-changed while it was being sent, or false when modified content was sent
-and should be disregarded by the server. (This corresponds to the `VALID`
-and `INVALID` messages in the P2P protocol.)
-
The `Content-Type` header should be `application/octet-stream`.
-The `Content-Length` header should be set to the length of the body.
+The `X-git-annex-data-length` must be included. It indicates the number
+of bytes of content that are expected to be sent.
+Note that there is no need to send a Content-Length header.
+
+If the length of the body is different than what the the
+X-git-annex-data-length header indicated, then the data is invalid and
+should not be used. This can happen when eg, the data was being sent from
+an unlocked annexed file, which got modified while it was being sent.
The server responds with a JSON object with a field "stored"
that is true if it received the data and stored the
The JSON object can have an additional field "plusuuids" that is a list of
UUIDs of other repositories that the content was stored to.
-If the server does not allow storing the key due to a policy
-(eg due to being read-only or append-only), it will respond with a JSON
-object with an "error" field that has an error message as its value.
+If the server does not allow storing the key due eg to a policy
+(eg due to being read-only or append-only), or due to the data being
+invalid, or because it ran out of disk space, it will respond with a
+JSON object with an "error" field that has an error message as its value.
-### putoffset
+### POST /git-annex/v3/putoffset
Asks the server what `offset` can be used in a `put` of a key.
will be used to get the P2P protocol back into a state where it will accept
any request.]
-### get
-
-Get content from the server.
-
-Example:
-
- > POST /git-annex/v3/get?key=SHA1--foo&associatedfile=bar&clientuuid=79a5a1f4-07e8-11ef-873d-97f93ca91925&serveruuid=ecf6d4ca-07e8-11ef-8990-9b8c1f696bf6 HTTP/1.1
- < Content-Type: application/octet-stream
- > Content-Length: 20
- > 3:foo,15:{"valid": true},
-
-There is one required additional parameter, `key`.
-
-There is are also these optional parameters:
-
-* `associatedfile`
-
- The name of a file in the git repository, for informational purposes
- only.
-
-* `offset`
-
- Number of bytes to skip sending from the beginning of the file.
-
-The body of the request is empty.
-
-The server's response will have a `Content-Type` header of
-`application/octet-stream`.
-
-The server's response will have a `Content-Length` header
-set to the length of the body.
-
-The body of the response is two items framed with netstrings.
-
-The first item is the content of the key, starting from the specified
-offset or from the beginning when no offset was specified.
-
-The second item is a JSON object.
-
-The JSON object has a field "valid" that is true when the content
-was not changed while it was being sent, or false when whatever
-content was sent is not the actual content of the key and should be
-disregared. (This corresponds to the `VALID` and `INVALID` messages
-in the P2P protocol.)
-
-## simple HTTP GET
-
-The git-annex protocol endpoint also supports a regular HTTP get
-of a key. This is not part of the P2P protocol, but is provided for
-convenience, to allow other clients than git-annex to easily download
-the content of a key.
-
- > GET /git-annex/key/SHA1--foo HTTP/1.1
- < Content-Type: application/octet-stream
- < Content-Length: 3
- < foo
-
## parts of P2P protocol that are not supported over HTTP
`NOTIFYCHANGE` is not supported, but it would be possible to extend
projects / git-annex.git / commitdiff