wireproto: define and implement HTTP handshake to upgrade protocol
When clients connect to repositories over HTTP, they issue a request
to the well-known URL "?cmd=capabilities" to fetch the repository
capabilities. This is the handshake portion of the HTTP protocol.
This commit defines a mechanism to use that HTTP request to return
information about modern server features.
If a client sends an X-HgUpgrade-* header containing a list of
client-supported API names, the server responds with a response
containing information about available services. This includes
the normal capabilities string. So if the server doesn't support
any newer services, the client can easily fall back.
By advertising supported services from clients, server operators
can see and log what client support exists in the wild. This will
also help with debugging.
The response contains the base path to API services. We know there
are potential issues with the <repo>/api/ URL space conflicting with
hgwebdir and subrepos. By making the API URL dynamic from the
perspective of the client, the URL for APIs is not subject to backwards
compatibility concerns - at least as long as a ?cmd=capabilities request
is made.
We've also defined the ``cbor`` client capability for the X-HgProto-*
header. This MUST be sent in order to get the modern response from
"?cmd=capabilities". During implementation, I initially always sent
an application/mercurial-cbor response. However, the handshake
mechanism will be more future compatible if the client is in charge
of which formats to request. We already perform content negotiation
from X-HgProto-*, so keying off this for the capabilities response
feels appropriate.
In addition, I initially used application/cbor. However, it is
conceivable that a non-Mercurial server could serve application/cbor.
To rule out this possibility, I've invented a new media type that
is Mercurial specific and can't be confused for generic CBOR.
Differential Revision: https://phab.mercurial-scm.org/D3242
#require serve
creating 'remote
$ hg init remote
$ cd remote
$ hg unbundle "$TESTDIR/bundles/remote.hg"
adding changesets
adding manifests
adding file changes
added 9 changesets with 7 changes to 4 files (+1 heads)
new changesets bfaf4b5cbf01:916f1afdef90
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg up tip
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
Starting server
$ hg serve -p $HGPORT -E ../error.log -d --pid-file=../hg1.pid
$ cd ..
$ cat hg1.pid >> $DAEMON_PIDS
clone remote via stream
$ for i in 0 1 2 3 4 5 6 7 8; do
> hg clone -r "$i" http://localhost:$HGPORT/ test-"$i"
> if cd test-"$i"; then
> hg verify
> cd ..
> fi
> done
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
new changesets bfaf4b5cbf01
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
new changesets bfaf4b5cbf01:21f32785131f
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 2 changesets, 2 total revisions
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 1 files
new changesets bfaf4b5cbf01:4ce51a113780
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 3 changesets, 3 total revisions
adding changesets
adding manifests
adding file changes
added 4 changesets with 4 changes to 1 files
new changesets bfaf4b5cbf01:93ee6ab32777
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 4 changesets, 4 total revisions
adding changesets
adding manifests
adding file changes
added 2 changesets with 2 changes to 1 files
new changesets bfaf4b5cbf01:c70afb1ee985
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 2 changesets, 2 total revisions
adding changesets
adding manifests
adding file changes
added 3 changesets with 3 changes to 1 files
new changesets bfaf4b5cbf01:f03ae5a9b979
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 3 changesets, 3 total revisions
adding changesets
adding manifests
adding file changes
added 4 changesets with 5 changes to 2 files
new changesets bfaf4b5cbf01:095cb14b1b4d
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
2 files, 4 changesets, 5 total revisions
adding changesets
adding manifests
adding file changes
added 5 changesets with 6 changes to 3 files
new changesets bfaf4b5cbf01:faa2e4234c7a
updating to branch default
2 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
3 files, 5 changesets, 6 total revisions
adding changesets
adding manifests
adding file changes
added 5 changesets with 5 changes to 2 files
new changesets bfaf4b5cbf01:916f1afdef90
updating to branch default
1 files updated, 0 files merged, 0 files removed, 0 files unresolved
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
2 files, 5 changesets, 5 total revisions
$ cd test-8
$ hg pull ../test-7
pulling from ../test-7
searching for changes
adding changesets
adding manifests
adding file changes
added 4 changesets with 2 changes to 3 files (+1 heads)
new changesets c70afb1ee985:faa2e4234c7a
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
4 files, 9 changesets, 7 total revisions
$ cd ..
$ cd test-1
$ hg pull -r 4 http://localhost:$HGPORT/
pulling from http://localhost:$HGPORT/
searching for changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 0 changes to 0 files (+1 heads)
new changesets c70afb1ee985
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 3 changesets, 2 total revisions
$ hg pull http://localhost:$HGPORT/
pulling from http://localhost:$HGPORT/
searching for changes
adding changesets
adding manifests
adding file changes
added 6 changesets with 5 changes to 4 files
new changesets 4ce51a113780:916f1afdef90
(run 'hg update' to get a working copy)
$ cd ..
$ cd test-2
$ hg pull -r 5 http://localhost:$HGPORT/
pulling from http://localhost:$HGPORT/
searching for changes
adding changesets
adding manifests
adding file changes
added 2 changesets with 0 changes to 0 files (+1 heads)
new changesets c70afb1ee985:f03ae5a9b979
(run 'hg heads' to see heads, 'hg merge' to merge)
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 5 changesets, 3 total revisions
$ hg pull http://localhost:$HGPORT/
pulling from http://localhost:$HGPORT/
searching for changes
adding changesets
adding manifests
adding file changes
added 4 changesets with 4 changes to 4 files
new changesets 93ee6ab32777:916f1afdef90
(run 'hg update' to get a working copy)
$ hg verify
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
4 files, 9 changesets, 7 total revisions
$ cd ..
no default destination if url has no path:
$ hg clone http://localhost:$HGPORT/
abort: empty destination path is not valid
[255]
$ cat error.log