Subject: Re: [PATCH 3/3] archive: allow archive over HTTP(S) with proto v2

From: Josh Steadmon <[email-masked]>
Date: Thu, 27 Sep 2018 13:28:15 -0700

On 2018.09.13 09:47, Junio C Hamano wrote:
> Josh Steadmon <[email-masked]> writes:
> 
> > Signed-off-by: Josh Steadmon <[email-masked]>
> > ---
> >  builtin/archive.c  |  8 +++++++-
> >  http-backend.c     | 10 +++++++++-
> >  transport-helper.c |  5 +++--
> >  3 files changed, 19 insertions(+), 4 deletions(-)
> >
> > diff --git a/builtin/archive.c b/builtin/archive.c
> > index 73831887d..5fa75b3f7 100644
> > --- a/builtin/archive.c
> > +++ b/builtin/archive.c
> > @@ -87,7 +87,13 @@ static int run_remote_archiver(int argc, const char **argv,
> >  		status = packet_reader_read(&reader);
> >  		if (status != PACKET_READ_FLUSH)
> >  			die(_("git archive: expected a flush"));
> > -	}
> > +	} else if (version == protocol_v2 &&
> > +		   starts_with(transport->url, "http"))
> > +		/*
> > +		 * Commands over HTTP require two requests, so there's an
> > +		 * additional server response to parse.
> > +		 */
> > +		discover_version(&reader);
> 
> What should happen if the version discovered here is different from
> v2 or the capabilities offered are different from what we saw
> before?  Perhaps we need some sanity checks, as we on this side of
> the connection know we are making two requests, and may even end up
> talking with an instance of "upload-archive" that is different from
> the one we talked with earlier.
> 
> > diff --git a/http-backend.c b/http-backend.c
> > index 458642ef7..d62d583c7 100644
> > --- a/http-backend.c
> > +++ b/http-backend.c
> > @@ -32,6 +32,7 @@ struct rpc_service {
> >  static struct rpc_service rpc_service[] = {
> >  	{ "upload-pack", "uploadpack", 1, 1 },
> >  	{ "receive-pack", "receivepack", 0, -1 },
> > +	{ "upload-archive", "uploadarchive", 1, 1 },
> >  };
> >  
> >  static struct string_list *get_parameters(void)
> > @@ -637,6 +638,12 @@ static void service_rpc(struct strbuf *hdr, char *service_name)
> >  	struct rpc_service *svc = select_service(hdr, service_name);
> >  	struct strbuf buf = STRBUF_INIT;
> >  
> > +	if (!strcmp(service_name, "git-upload-archive")) {
> > +		/* git-upload-archive doesn't need --stateless-rpc */
> > +		argv[1] = ".";
> > +		argv[2] = NULL;
> > +	}
> > +
> >  	strbuf_reset(&buf);
> >  	strbuf_addf(&buf, "application/x-git-%s-request", svc->name);
> >  	check_content_type(hdr, buf.buf);
> > @@ -713,7 +720,8 @@ static struct service_cmd {
> >  	{"GET", "/objects/pack/pack-[0-9a-f]{40}\\.idx$", get_idx_file},
> >  
> >  	{"POST", "/git-upload-pack$", service_rpc},
> > -	{"POST", "/git-receive-pack$", service_rpc}
> > +	{"POST", "/git-receive-pack$", service_rpc},
> > +	{"POST", "/git-upload-archive$", service_rpc},
> >  };
> >  
> >  static int bad_request(struct strbuf *hdr, const struct service_cmd *c)
> > diff --git a/transport-helper.c b/transport-helper.c
> > index 143ca008c..b4b96fc89 100644
> > --- a/transport-helper.c
> > +++ b/transport-helper.c
> > @@ -605,7 +605,8 @@ static int process_connect_service(struct transport *transport,
> >  		ret = run_connect(transport, &cmdbuf);
> >  	} else if (data->stateless_connect &&
> >  		   (get_protocol_version_config() == protocol_v2) &&
> > -		   !strcmp("git-upload-pack", name)) {
> > +		   (!strcmp("git-upload-pack", name) ||
> > +		    !strcmp("git-upload-archive", name))) {
> >  		strbuf_addf(&cmdbuf, "stateless-connect %s\n", name);
> >  		ret = run_connect(transport, &cmdbuf);
> >  		if (ret)
> > @@ -639,7 +640,7 @@ static int connect_helper(struct transport *transport, const char *name,
> >  
> >  	/* Get_helper so connect is inited. */
> >  	get_helper(transport);
> > -	if (!data->connect)
> > +	if (!data->connect && !data->stateless_connect)
> >  		die(_("operation not supported by protocol"));
> 
> This is somewhat curious.  The upload-pack going over HTTP also is
> triggered by the same "stateless-connect" remote helper command, as
> we just saw in the previous hunk, and that support is not new.  Why
> do we need this change then?  What's different between the "data"
> that is obtained by get_helper(transport) for driving upload-pack
> and upload-archive?  Presumably upload-pack was working without this
> change because it also sets the connect bit on, and upload-archive
> does not work without this change because it does not?  Why do these
> two behave differently?

The data struct is not different between upload-pack vs. upload-archive.
Neither of them set the connect bit. The difference is that upload-pack
doesn't need to call transport_connect(), so it never hits
connect_helper().