http: use the new httpclient

Untangle the notion of the http transport from the actual http
implementation.  The http transport now uses the httpclient.

2 files changed, 407 insertions, 1374 deletions

diff --git a/src/transports/http.c b/src/transports/http.c
index 9e35f23c2..c535f2a35 100644
--- a/src/transports/http.c
+++ b/src/transports/http.c
@@ -22,406 +22,82 @@
 #include "http.h"
 #include "auth_negotiate.h"
 #include "auth_ntlm.h"
+#include "trace.h"
 #include "streams/tls.h"
 #include "streams/socket.h"
+#include "httpclient.h"
 
 bool git_http__expect_continue = false;
 
-git_http_auth_scheme auth_schemes[] = {
-	{ GIT_HTTP_AUTH_NEGOTIATE, "Negotiate", GIT_CREDTYPE_DEFAULT, git_http_auth_negotiate },
-	{ GIT_HTTP_AUTH_NTLM, "NTLM", GIT_CREDTYPE_USERPASS_PLAINTEXT, git_http_auth_ntlm },
-	{ GIT_HTTP_AUTH_BASIC, "Basic", GIT_CREDTYPE_USERPASS_PLAINTEXT, git_http_auth_basic },
-};
-
-static const char *upload_pack_service = "upload-pack";
-static const char *upload_pack_ls_service_url = "/info/refs?service=git-upload-pack";
-static const char *upload_pack_service_url = "/git-upload-pack";
-static const char *receive_pack_service = "receive-pack";
-static const char *receive_pack_ls_service_url = "/info/refs?service=git-receive-pack";
-static const char *receive_pack_service_url = "/git-receive-pack";
-static const char *get_verb = "GET";
-static const char *post_verb = "POST";
-
-#define AUTH_HEADER_SERVER "Authorization"
-#define AUTH_HEADER_PROXY  "Proxy-Authorization"
-
-#define SERVER_TYPE_REMOTE "remote"
-#define SERVER_TYPE_PROXY  "proxy"
-
-#define OWNING_SUBTRANSPORT(s) ((http_subtransport *)(s)->parent.subtransport)
+typedef enum {
+	HTTP_STATE_NONE = 0,
+	HTTP_STATE_SENDING_REQUEST,
+	HTTP_STATE_RECEIVING_RESPONSE,
+	HTTP_STATE_DONE
+} http_state;
 
-#define PARSE_ERROR_GENERIC	-1
-#define PARSE_ERROR_REPLAY	-2
-/** Look at the user field */
-#define PARSE_ERROR_EXT         -3
-
-#define CHUNK_SIZE	4096
-
-enum last_cb {
-	NONE,
-	FIELD,
-	VALUE
-};
+typedef struct {
+	git_http_method method;
+	const char *url;
+	const char *request_type;
+	const char *response_type;
+	unsigned chunked : 1;
+} http_service;
 
 typedef struct {
 	git_smart_subtransport_stream parent;
-	const char *service;
-	const char *service_url;
-	char *redirect_url;
-	const char *verb;
-	char *chunk_buffer;
-	unsigned chunk_buffer_len;
-	unsigned sent_request : 1,
-		received_response : 1,
-		chunked : 1;
+	const http_service *service;
+	http_state state;
+	unsigned replay_count;
 } http_stream;
 
 typedef struct {
 	git_net_url url;
-	git_stream *stream;
-
-	git_http_auth_t authtypes;
-	git_credtype_t credtypes;
 
 	git_cred *cred;
-	unsigned url_cred_presented : 1,
-	    authenticated : 1;
-	git_http_authtype_t prior_authtype;
-
-	git_vector auth_challenges;
-	git_http_auth_context *auth_context;
+	unsigned auth_schemetypes;
+	unsigned url_cred_presented : 1;
 } http_server;
 
 typedef struct {
 	git_smart_subtransport parent;
 	transport_smart *owner;
-	git_stream *gitserver_stream;
-	bool connected;
 
 	http_server server;
-
 	http_server proxy;
-	char *proxy_url;
-	git_proxy_options proxy_opts;
-
-	/* Parser structures */
-	http_parser parser;
-	http_parser_settings settings;
-	gitno_buffer parse_buffer;
-	git_buf parse_header_name;
-	git_buf parse_header_value;
-	char parse_buffer_data[NETIO_BUFSIZE];
-	char *content_type;
-	char *content_length;
-	char *location;
-	enum last_cb last_cb;
-	int parse_error;
-	int error;
-	unsigned request_count;
-	unsigned parse_finished : 1,
-	    keepalive : 1,
-	    replay_count : 4;
-} http_subtransport;
-
-typedef struct {
-	http_stream *s;
-	http_subtransport *t;
-
-	/* Target buffer details from read() */
-	char *buffer;
-	size_t buf_size;
-	size_t *bytes_read;
-} parser_context;
-
-static git_http_auth_scheme *scheme_for_challenge(
-	const char *challenge,
-	git_cred *cred)
-{
-	git_http_auth_scheme *scheme = NULL;
-	size_t i;
-
-	for (i = 0; i < ARRAY_SIZE(auth_schemes); i++) {
-		const char *scheme_name = auth_schemes[i].name;
-		const git_credtype_t scheme_types = auth_schemes[i].credtypes;
-		size_t scheme_len;
-
-		scheme_len = strlen(scheme_name);
-
-		if ((!cred || (cred->credtype & scheme_types)) &&
-		    strncasecmp(challenge, scheme_name, scheme_len) == 0 &&
-		    (challenge[scheme_len] == '\0' || challenge[scheme_len] == ' ')) {
-			scheme = &auth_schemes[i];
-			break;
-		}
-	}
-
-	return scheme;
-}
-
-static int apply_credentials(
-	git_buf *buf,
-	http_server *server,
-	const char *header_name)
-{
-	git_buf token = GIT_BUF_INIT;
-	int error = 0;
 
-	if (!server->auth_context)
-		goto done;
-
-	if ((error = server->auth_context->next_token(&token, server->auth_context, server->cred)) < 0)
-		goto done;
-
-	error = git_buf_printf(buf, "%s: %s\r\n", header_name, token.ptr);
-
-done:
-	git_buf_dispose(&token);
-	return error;
-}
-
-static int gen_request(
-	git_buf *buf,
-	http_stream *s,
-	size_t content_length)
-{
-	http_subtransport *t = OWNING_SUBTRANSPORT(s);
-	const char *path = t->server.url.path ? t->server.url.path : "/";
-	const char *service_url = s->service_url;
-	size_t i;
-	/* If path already ends in /, remove the leading slash from service_url */
-	if ((git__suffixcmp(path, "/") == 0) && (git__prefixcmp(service_url, "/") == 0))
-		service_url++;
-
-	if (t->proxy_opts.type == GIT_PROXY_SPECIFIED)
-		git_buf_printf(buf, "%s %s://%s:%s%s%s HTTP/1.1\r\n",
-			s->verb,
-			t->server.url.scheme,
-			t->server.url.host,
-			t->server.url.port,
-			path, service_url);
-	else
-		git_buf_printf(buf, "%s %s%s HTTP/1.1\r\n",
-			s->verb, path, service_url);
-
-	git_buf_puts(buf, "User-Agent: ");
-	git_http__user_agent(buf);
-	git_buf_puts(buf, "\r\n");
-	git_buf_printf(buf, "Host: %s", t->server.url.host);
-
-	if (!git_net_url_is_default_port(&t->server.url))
-		git_buf_printf(buf, ":%s", t->server.url.port);
-
-	git_buf_puts(buf, "\r\n");
-
-	if (s->chunked || content_length > 0) {
-		git_buf_printf(buf, "Accept: application/x-git-%s-result\r\n", s->service);
-		git_buf_printf(buf, "Content-Type: application/x-git-%s-request\r\n", s->service);
-
-		if (s->chunked)
-			git_buf_puts(buf, "Transfer-Encoding: chunked\r\n");
-		else
-			git_buf_printf(buf, "Content-Length: %"PRIuZ "\r\n", content_length);
-	} else
-		git_buf_puts(buf, "Accept: */*\r\n");
-
-	for (i = 0; i < t->owner->custom_headers.count; i++) {
-		if (t->owner->custom_headers.strings[i])
-			git_buf_printf(buf, "%s\r\n", t->owner->custom_headers.strings[i]);
-	}
-
-	/* Apply proxy and server credentials to the request */
-	if (t->proxy_opts.type != GIT_PROXY_NONE &&
-	    apply_credentials(buf, &t->proxy, AUTH_HEADER_PROXY) < 0)
-		return -1;
-
-	if (apply_credentials(buf, &t->server, AUTH_HEADER_SERVER) < 0)
-		return -1;
-
-	git_buf_puts(buf, "\r\n");
-
-	if (git_buf_oom(buf))
-		return -1;
-
-	return 0;
-}
-
-static int set_authentication_challenge(http_server *server)
-{
-	const char *challenge;
-
-	if (git_vector_length(&server->auth_challenges) > 1) {
-		git_error_set(GIT_ERROR_NET, "received multiple authentication challenges");
-		return -1;
-	}
-
-	challenge = git_vector_get(&server->auth_challenges, 0);
-
-	if (server->auth_context->set_challenge)
-		return server->auth_context->set_challenge(server->auth_context, challenge);
-	else
-		return 0;
-}
-
-static int set_authentication_types(http_server *server)
-{
-	git_http_auth_scheme *scheme;
-	char *challenge;
-	size_t i;
-
-	git_vector_foreach(&server->auth_challenges, i, challenge) {
-		if ((scheme = scheme_for_challenge(challenge, NULL)) != NULL) {
-			server->authtypes |= scheme->type;
-			server->credtypes |= scheme->credtypes;
-		}
-	}
-
-	return 0;
-}
-
-static bool auth_context_complete(http_server *server)
-{
-	/* If there's no is_complete function, we're always complete */
-	if (!server->auth_context->is_complete)
-		return true;
-
-	if (server->auth_context->is_complete(server->auth_context))
-		return true;
-
-	return false;
-}
-
-static void free_auth_context(http_server *server)
-{
-	if (!server->auth_context)
-		return;
-
-	if (server->auth_context->free)
-		server->auth_context->free(server->auth_context);
-
-	server->auth_context = NULL;
-}
-
-static int parse_authenticate_response(http_server *server)
-{
-	/*
-	 * If we think that we've completed authentication (ie, we've either
-	 * sent a basic credential or we've sent the NTLM/Negotiate response)
-	 * but we've got an authentication request from the server then our
-	 * last authentication did not succeed.  Start over.
-	 */
-	if (server->auth_context && auth_context_complete(server)) {
-		free_auth_context(server);
-
-		server->authenticated = 0;
-	}
-
-	/*
-	 * If we've begun authentication, give the challenge to the context.
-	 * Otherwise, set up the types to prepare credentials.
-	 */
-	if (git_vector_length(&server->auth_challenges) == 0)
-		return 0;
-	else if (server->auth_context)
-		return set_authentication_challenge(server);
-	else
-		return set_authentication_types(server);
-}
-
-static int on_header_ready(http_subtransport *t)
-{
-	git_buf *name = &t->parse_header_name;
-	git_buf *value = &t->parse_header_value;
-
-	if (!strcasecmp("Content-Type", git_buf_cstr(name))) {
-		if (t->content_type) {
-			git_error_set(GIT_ERROR_NET, "multiple Content-Type headers");
-			return -1;
-		}
-
-		t->content_type = git__strdup(git_buf_cstr(value));
-		GIT_ERROR_CHECK_ALLOC(t->content_type);
-	}
-	else if (!strcasecmp("Content-Length", git_buf_cstr(name))) {
-		if (t->content_length) {
-			git_error_set(GIT_ERROR_NET, "multiple Content-Length headers");
-			return -1;
-		}
-
-		t->content_length = git__strdup(git_buf_cstr(value));
-		GIT_ERROR_CHECK_ALLOC(t->content_length);
-	}
-	else if (!strcasecmp("Proxy-Authenticate", git_buf_cstr(name))) {
-		char *dup = git__strdup(git_buf_cstr(value));
-		GIT_ERROR_CHECK_ALLOC(dup);
-
-		if (git_vector_insert(&t->proxy.auth_challenges, dup) < 0)
-			return -1;
-	}
-	else if (!strcasecmp("WWW-Authenticate", git_buf_cstr(name))) {
-		char *dup = git__strdup(git_buf_cstr(value));
-		GIT_ERROR_CHECK_ALLOC(dup);
-
-		if (git_vector_insert(&t->server.auth_challenges, dup) < 0)
-			return -1;
-	}
-	else if (!strcasecmp("Location", git_buf_cstr(name))) {
-		if (t->location) {
-			git_error_set(GIT_ERROR_NET, "multiple Location headers");
-			return -1;
-		}
-
-		t->location = git__strdup(git_buf_cstr(value));
-		GIT_ERROR_CHECK_ALLOC(t->location);
-	}
-
-	return 0;
-}
-
-static int on_header_field(http_parser *parser, const char *str, size_t len)
-{
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
-
-	/* Both parse_header_name and parse_header_value are populated
-	 * and ready for consumption */
-	if (VALUE == t->last_cb)
-		if (on_header_ready(t) < 0)
-			return t->parse_error = PARSE_ERROR_GENERIC;
-
-	if (NONE == t->last_cb || VALUE == t->last_cb)
-		git_buf_clear(&t->parse_header_name);
-
-	if (git_buf_put(&t->parse_header_name, str, len) < 0)
-		return t->parse_error = PARSE_ERROR_GENERIC;
-
-	t->last_cb = FIELD;
-	return 0;
-}
-
-static int on_header_value(http_parser *parser, const char *str, size_t len)
-{
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
-
-	assert(NONE != t->last_cb);
-
-	if (FIELD == t->last_cb)
-		git_buf_clear(&t->parse_header_value);
+	git_http_client *http_client;
+} http_subtransport;
 
-	if (git_buf_put(&t->parse_header_value, str, len) < 0)
-		return t->parse_error = PARSE_ERROR_GENERIC;
+static const http_service upload_pack_ls_service = {
+	GIT_HTTP_METHOD_GET, "/info/refs?service=git-upload-pack",
+	NULL,
+	"application/x-git-upload-pack-advertisement",
+	0
+};
+static const http_service upload_pack_service = {
+	GIT_HTTP_METHOD_POST, "/git-upload-pack",
+	"application/x-git-upload-pack-request",
+	"application/x-git-upload-pack-result",
+	0
+};
+static const http_service receive_pack_ls_service = {
+	GIT_HTTP_METHOD_GET, "/info/refs?service=git-receive-pack",
+	NULL,
+	"application/x-git-receive-pack-advertisement",
+	0
+};
+static const http_service receive_pack_service = {
+	GIT_HTTP_METHOD_POST, "/git-receive-pack",
+	"application/x-git-receive-pack-request",
+	"application/x-git-receive-pack-result",
+	1
+};
 
-	t->last_cb = VALUE;
-	return 0;
-}
+#define SERVER_TYPE_REMOTE "remote"
+#define SERVER_TYPE_PROXY  "proxy"
 
-GIT_INLINE(void) free_cred(git_cred **cred)
-{
-	if (*cred) {
-		git_cred_free(*cred);
-		(*cred) = NULL;
-	}
-}
+#define OWNING_SUBTRANSPORT(s) ((http_subtransport *)(s)->parent.subtransport)
 
 static int apply_url_credentials(
 	git_cred **cred,
@@ -438,1096 +114,466 @@ static int apply_url_credentials(
 	return GIT_PASSTHROUGH;
 }
 
-static int init_auth(http_server *server)
+GIT_INLINE(void) free_cred(git_cred **cred)
 {
-	git_http_auth_scheme *s, *scheme = NULL;
-	char *c, *challenge = NULL;
-	size_t i;
-	int error;
-
-	git_vector_foreach(&server->auth_challenges, i, c) {
-		s = scheme_for_challenge(c, server->cred);
-
-		if (s && !!(s->credtypes & server->credtypes)) {
-			scheme = s;
-			challenge = c;
-			break;
-		}
-	}
-
-	if (!scheme) {
-		git_error_set(GIT_ERROR_NET, "no authentication mechanism could be negotiated");
-		return -1;
+	if (*cred) {
+		git_cred_free(*cred);
+		(*cred) = NULL;
 	}
-
-	if ((error = scheme->init_context(&server->auth_context, &server->url)) == GIT_PASSTHROUGH)
-		return 0;
-	else if (error < 0)
-		return error;
-
-	if (server->auth_context->set_challenge &&
-		(error = server->auth_context->set_challenge(server->auth_context, challenge)) < 0)
-		return error;
-
-	return 0;
 }
 
-static int on_auth_required(
-	http_parser *parser,
+static int handle_auth(
 	http_server *server,
+	const char *server_type,
 	const char *url,
-	const char *type,
+	unsigned int allowed_schemetypes,
+	unsigned int allowed_credtypes,
 	git_cred_acquire_cb callback,
 	void *callback_payload)
 {
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
 	int error = 1;
 
-	if (parse_authenticate_response(server) < 0) {
-		t->parse_error = PARSE_ERROR_GENERIC;
-		return t->parse_error;
-	}
-
-	/* If we're in the middle of challenge/response auth, continue */
-	if (parser->status_code == 407 || parser->status_code == 401) {
-		if (server->auth_context && !auth_context_complete(server)) {
-			t->parse_error = PARSE_ERROR_REPLAY;
-			return 0;
-		}
-	}
-
-	/* Enforce a reasonable cap on the number of replays */
-	if (t->replay_count++ >= GIT_HTTP_REPLAY_MAX) {
-		git_error_set(GIT_ERROR_NET, "too many redirects or authentication replays");
-		return t->parse_error = PARSE_ERROR_GENERIC;
-	}
-
-	if (!server->credtypes) {
-		git_error_set(GIT_ERROR_NET, "%s requested authentication but did not negotiate mechanisms", type);
-		t->parse_error = PARSE_ERROR_GENERIC;
-		return t->parse_error;
-	}
-
-	free_auth_context(server);
-	free_cred(&server->cred);
+	if (server->cred)
+		free_cred(&server->cred);
 
 	/* Start with URL-specified credentials, if there were any. */
-	if (!server->url_cred_presented && server->url.username && server->url.password) {
-		error = apply_url_credentials(&server->cred, server->credtypes, server->url.username, server->url.password);
+	if ((allowed_credtypes & GIT_CREDTYPE_USERPASS_PLAINTEXT) &&
+	    !server->url_cred_presented &&
+	    server->url.username &&
+	    server->url.password) {
+		error = apply_url_credentials(&server->cred, allowed_credtypes, server->url.username, server->url.password);
 		server->url_cred_presented = 1;
 
-		if (error == GIT_PASSTHROUGH) {
-			/* treat GIT_PASSTHROUGH as if callback isn't set */
+		/* treat GIT_PASSTHROUGH as if callback isn't set */
+		if (error == GIT_PASSTHROUGH)
 			error = 1;
-		}
 	}
 
 	if (error > 0 && callback) {
-		error = callback(&server->cred, url, server->url.username, server->credtypes, callback_payload);
+		error = callback(&server->cred, url, server->url.username, allowed_credtypes, callback_payload);
 
-		if (error == GIT_PASSTHROUGH) {
-			/* treat GIT_PASSTHROUGH as if callback isn't set */
+		/* treat GIT_PASSTHROUGH as if callback isn't set */
+		if (error == GIT_PASSTHROUGH)
 			error = 1;
-		}
 	}
 
 	if (error > 0) {
-		git_error_set(GIT_ERROR_NET, "%s authentication required but no callback set",
-			type);
-		t->parse_error = PARSE_ERROR_GENERIC;
-		return t->parse_error;
-	} else if (error < 0) {
-		t->error = error;
-		t->parse_error = PARSE_ERROR_EXT;
-		return t->parse_error;
-	}
-
-	assert(server->cred);
-
-    if (!(server->cred->credtype & server->credtypes)) {
-		git_error_set(GIT_ERROR_NET, "%s credential provider returned an invalid cred type", type);
-		t->parse_error = PARSE_ERROR_GENERIC;
-		return t->parse_error;
-	}
-
-	/* Successfully acquired a credential. Start an auth context. */
-	if (init_auth(server) < 0) {
-		t->parse_error = PARSE_ERROR_GENERIC;
-		return t->parse_error;
+		git_error_set(GIT_ERROR_NET, "%s authentication required but no callback set", server_type);
+		error = -1;
 	}
 
-	t->parse_error = PARSE_ERROR_REPLAY;
-	return 0;
-}
+	if (!error)
+		server->auth_schemetypes = allowed_schemetypes;
 
-static void on_auth_success(http_server *server)
-{
-	server->url_cred_presented = 0;
-	server->authenticated = 1;
+	return error;
 }
 
-static int on_headers_complete(http_parser *parser)
+GIT_INLINE(int) handle_remote_auth(
+	http_stream *stream,
+	git_http_response *response)
 {
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
-	http_stream *s = ctx->s;
-	git_buf buf = GIT_BUF_INIT;
-
-	/* Both parse_header_name and parse_header_value are populated
-	 * and ready for consumption. */
-	if (t->last_cb == VALUE && on_header_ready(t) < 0)
-		return t->parse_error = PARSE_ERROR_GENERIC;
-
-	/* Check for a proxy authentication failure. */
-	if (parser->status_code == 407 && get_verb == s->verb)
-		return on_auth_required(
-		    parser,
-		    &t->proxy,
-		    t->proxy_opts.url,
-		    SERVER_TYPE_PROXY,
-		    t->proxy_opts.credentials,
-		    t->proxy_opts.payload);
-	else
-		on_auth_success(&t->proxy);
-
-	/* Check for an authentication failure. */
-	if (parser->status_code == 401 && get_verb == s->verb)
-		return on_auth_required(
-		    parser,
-		    &t->server,
-		    t->owner->url,
-		    SERVER_TYPE_REMOTE,
-		    t->owner->cred_acquire_cb,
-		    t->owner->cred_acquire_payload);
-	else
-		on_auth_success(&t->server);
-
-	/* Check for a redirect.
-	 * Right now we only permit a redirect to the same hostname. */
-	if ((parser->status_code == 301 ||
-	     parser->status_code == 302 ||
-	     (parser->status_code == 303 && get_verb == s->verb) ||
-	     parser->status_code == 307 ||
-	     parser->status_code == 308) &&
-	    t->location) {
-
-		if (git_net_url_apply_redirect(&t->server.url, t->location, s->service_url) < 0)
-			return t->parse_error = PARSE_ERROR_GENERIC;
-
-		t->connected = 0;
-		t->parse_error = PARSE_ERROR_REPLAY;
-		return 0;
-	}
-
-	/* Check for a 200 HTTP status code. */
-	if (parser->status_code != 200) {
-		git_error_set(GIT_ERROR_NET,
-			"unexpected HTTP status code: %d",
-			parser->status_code);
-		return t->parse_error = PARSE_ERROR_GENERIC;
-	}
-
-	/* The response must contain a Content-Type header. */
-	if (!t->content_type) {
-		git_error_set(GIT_ERROR_NET, "no Content-Type header in response");
-		return t->parse_error = PARSE_ERROR_GENERIC;
-	}
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
 
-	/* The Content-Type header must match our expectation. */
-	if (get_verb == s->verb)
-		git_buf_printf(&buf,
-			"application/x-git-%s-advertisement",
-			ctx->s->service);
-	else
-		git_buf_printf(&buf,
-			"application/x-git-%s-result",
-			ctx->s->service);
-
-	if (git_buf_oom(&buf))
-		return t->parse_error = PARSE_ERROR_GENERIC;
-
-	if (strcmp(t->content_type, git_buf_cstr(&buf))) {
-		git_buf_dispose(&buf);
-		git_error_set(GIT_ERROR_NET,
-			"invalid Content-Type: %s",
-			t->content_type);
-		return t->parse_error = PARSE_ERROR_GENERIC;
+	if (response->server_auth_credtypes == 0) {
+		git_error_set(GIT_ERROR_NET, "server requires authentication that we do not support");
+		return -1;
 	}
 
-	git_buf_dispose(&buf);
-
-	return 0;
-}
-
-static int on_message_complete(http_parser *parser)
-{
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
-
-	t->parse_finished = 1;
-	t->keepalive = http_should_keep_alive(parser);
-
-	return 0;
+	/* Otherwise, prompt for credentials. */
+	return handle_auth(
+		&transport->server,
+		SERVER_TYPE_REMOTE,
+		transport->owner->url,
+		response->server_auth_schemetypes,
+		response->server_auth_credtypes,
+		transport->owner->cred_acquire_cb,
+		transport->owner->cred_acquire_payload);
 }
 
-static int on_body_fill_buffer(http_parser *parser, const char *str, size_t len)
+GIT_INLINE(int) handle_proxy_auth(
+	http_stream *stream,
+	git_http_response *response)
 {
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
-
-	/* If there's no buffer set, we're explicitly ignoring the body. */
-	if (ctx->buffer) {
-		if (ctx->buf_size < len) {
-			git_error_set(GIT_ERROR_NET, "can't fit data in the buffer");
-			return t->parse_error = PARSE_ERROR_GENERIC;
-		}
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
 
-		memcpy(ctx->buffer, str, len);
-		ctx->buffer += len;
-		ctx->buf_size -= len;
+	if (response->proxy_auth_credtypes == 0) {
+		git_error_set(GIT_ERROR_NET, "proxy requires authentication that we do not support");
+		return -1;
 	}
 
-	*(ctx->bytes_read) += len;
-
-	return 0;
+	/* Otherwise, prompt for credentials. */
+	return handle_auth(
+		&transport->proxy,
+		SERVER_TYPE_PROXY,
+		transport->owner->proxy.url,
+		response->server_auth_schemetypes,
+		response->proxy_auth_credtypes,
+		transport->owner->proxy.credentials,
+		transport->owner->proxy.payload);
 }
 
-static void clear_parser_state(http_subtransport *t)
-{
-	http_parser_init(&t->parser, HTTP_RESPONSE);
-	gitno_buffer_setup_fromstream(t->server.stream,
-		&t->parse_buffer,
-		t->parse_buffer_data,
-		sizeof(t->parse_buffer_data));
-
-	t->last_cb = NONE;
-	t->parse_error = 0;
-	t->parse_finished = 0;
-	t->keepalive = 0;
-
-	git_buf_dispose(&t->parse_header_name);
-	git_buf_init(&t->parse_header_name, 0);
-
-	git_buf_dispose(&t->parse_header_value);
-	git_buf_init(&t->parse_header_value, 0);
-
-	git__free(t->content_type);
-	t->content_type = NULL;
-
-	git__free(t->content_length);
-	t->content_length = NULL;
-
-	git__free(t->location);
-	t->location = NULL;
-
-	git_vector_free_deep(&t->proxy.auth_challenges);
-	git_vector_free_deep(&t->server.auth_challenges);
-}
 
-static int write_chunk(git_stream *io, const char *buffer, size_t len)
+static int handle_response(
+	bool *complete,
+	http_stream *stream,
+	git_http_response *response,
+	bool allow_replay)
 {
-	git_buf buf = GIT_BUF_INIT;
-
-	/* Chunk header */
-	git_buf_printf(&buf, "%" PRIxZ "\r\n", len);
-
-	if (git_buf_oom(&buf))
-		return -1;
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
+	int error;
 
-	if (git_stream__write_full(io, buf.ptr, buf.size, 0) < 0) {
-		git_buf_dispose(&buf);
-		return -1;
-	}
+	*complete = false;
 
-	git_buf_dispose(&buf);
+	if (allow_replay && git_http_response_is_redirect(response)) {
+		if (!response->location) {
+			git_error_set(GIT_ERROR_NET, "redirect without location");
+			return -1;
+		}
 
-	/* Chunk body */
-	if (len > 0 && git_stream__write_full(io, buffer, len, 0) < 0)
-		return -1;
+		if (git_net_url_apply_redirect(&transport->server.url, response->location, stream->service->url) < 0) {
+			return -1;
+		}
 
-	/* Chunk footer */
-	if (git_stream__write_full(io, "\r\n", 2, 0) < 0)
+		return 0;
+	} else if (git_http_response_is_redirect(response)) {
+		git_error_set(GIT_ERROR_NET, "unexpected redirect");
 		return -1;
+	}
 
-	return 0;
-}
-
-static int load_proxy_config(http_subtransport *t)
-{
-	int error;
-
-	switch (t->owner->proxy.type) {
-	case GIT_PROXY_NONE:
+	/* If we're in the middle of challenge/response auth, continue. */
+	if (allow_replay && response->resend_credentials) {
 		return 0;
-
-	case GIT_PROXY_AUTO:
-		git__free(t->proxy_url);
-		t->proxy_url = NULL;
-
-		git_proxy_options_init(&t->proxy_opts, GIT_PROXY_OPTIONS_VERSION);
-
-		if ((error = git_remote__get_http_proxy(t->owner->owner,
-			!strcmp(t->server.url.scheme, "https"), &t->proxy_url)) < 0)
+	} else if (allow_replay && response->status == 401) {
+		if ((error = handle_remote_auth(stream, response)) < 0)
 			return error;
 
-		if (!t->proxy_url)
-			return 0;
-
-		t->proxy_opts.type = GIT_PROXY_SPECIFIED;
-		t->proxy_opts.url = t->proxy_url;
-		t->proxy_opts.credentials = t->owner->proxy.credentials;
-		t->proxy_opts.certificate_check = t->owner->proxy.certificate_check;
-		t->proxy_opts.payload = t->owner->proxy.payload;
-		break;
-
-	case GIT_PROXY_SPECIFIED:
-		memcpy(&t->proxy_opts, &t->owner->proxy, sizeof(git_proxy_options));
-		break;
+		return git_http_client_skip_body(transport->http_client);
+	} else if (allow_replay && response->status == 407) {
+		if ((error = handle_proxy_auth(stream, response)) < 0)
+			return error;
 
-	default:
-		assert(0);
+		return git_http_client_skip_body(transport->http_client);
+	} else if (response->status == 401 || response->status == 407) {
+		git_error_set(GIT_ERROR_NET, "unexpected authentication failure");
 		return -1;
 	}
 
-	git_net_url_dispose(&t->proxy.url);
-
-	return git_net_url_parse(&t->proxy.url, t->proxy_opts.url);
-}
-
-static int check_certificate(
-	git_stream *stream,
-	git_net_url *url,
-	int is_valid,
-	git_transport_certificate_check_cb cert_cb,
-	void *cert_cb_payload)
-{
-	git_cert *cert;
-	git_error_state last_error = {0};
-	int error;
-
-	if ((error = git_stream_certificate(&cert, stream)) < 0)
-		return error;
-
-	git_error_state_capture(&last_error, GIT_ECERTIFICATE);
-
-	error = cert_cb(cert, is_valid, url->host, cert_cb_payload);
-
-	if (error == GIT_PASSTHROUGH && !is_valid)
-		return git_error_state_restore(&last_error);
-	else if (error == GIT_PASSTHROUGH)
-		error = 0;
-	else if (error && !git_error_last())
-		git_error_set(GIT_ERROR_NET, "user rejected certificate for %s", url->host);
-
-	git_error_state_free(&last_error);
-	return error;
-}
-
-static int stream_connect(
-	git_stream *stream,
-	git_net_url *url,
-	git_transport_certificate_check_cb cert_cb,
-	void *cb_payload)
-{
-	int error;
-
-	GIT_ERROR_CHECK_VERSION(stream, GIT_STREAM_VERSION, "git_stream");
-
-	error = git_stream_connect(stream);
-
-	if (error && error != GIT_ECERTIFICATE)
-		return error;
-
-	if (git_stream_is_encrypted(stream) && cert_cb != NULL)
-		error = check_certificate(stream, url, !error, cert_cb, cb_payload);
-
-	return error;
-}
-
-static int gen_connect_req(git_buf *buf, http_subtransport *t)
-{
-	git_buf_printf(buf, "CONNECT %s:%s HTTP/1.1\r\n",
-		t->server.url.host, t->server.url.port);
-
-	git_buf_puts(buf, "User-Agent: ");
-	git_http__user_agent(buf);
-	git_buf_puts(buf, "\r\n");
-
-	git_buf_printf(buf, "Host: %s\r\n", t->proxy.url.host);
-
-	if (apply_credentials(buf, &t->proxy, AUTH_HEADER_PROXY) < 0)
+	if (response->status != 200) {
+		git_error_set(GIT_ERROR_NET, "unexpected http status code: %d", response->status);
 		return -1;
-
-	git_buf_puts(buf, "\r\n");
-
-	return git_buf_oom(buf) ? -1 : 0;
-}
-
-static int proxy_headers_complete(http_parser *parser)
-{
-	parser_context *ctx = (parser_context *) parser->data;
-	http_subtransport *t = ctx->t;
-
-	/* Both parse_header_name and parse_header_value are populated
-	 * and ready for consumption. */
-	if (t->last_cb == VALUE && on_header_ready(t) < 0)
-			return t->parse_error = PARSE_ERROR_GENERIC;
-
-	/*
-	 * Capture authentication headers for the proxy or final endpoint,
-	 * these may be 407/401 (authentication is not complete) or a 200
-	 * (informing us that auth has completed).
-	 */
-	if (parse_authenticate_response(&t->proxy) < 0)
-		return t->parse_error = PARSE_ERROR_GENERIC;
-
-	/* If we're in the middle of challenge/response auth, continue */
-	if (parser->status_code == 407) {
-		if (t->proxy.auth_context && !auth_context_complete(&t->proxy)) {
-			t->parse_error = PARSE_ERROR_REPLAY;
-			return 0;
-		}
 	}
 
-	/* Enforce a reasonable cap on the number of replays */
-	if (t->replay_count++ >= GIT_HTTP_REPLAY_MAX) {
-		git_error_set(GIT_ERROR_NET, "too many redirects or authentication replays");
-		return t->parse_error = PARSE_ERROR_GENERIC;
+	/* The response must contain a Content-Type header. */
+	if (!response->content_type) {
+		git_error_set(GIT_ERROR_NET, "no content-type header in response");
+		return -1;
 	}
 
-	/* Check for a proxy authentication failure. */
-	if (parser->status_code == 407)
-		return on_auth_required(
-			parser,
-			&t->proxy,
-			t->proxy_opts.url,
-			SERVER_TYPE_PROXY,
-			t->proxy_opts.credentials,
-			t->proxy_opts.payload);
-
-	if (parser->status_code != 200) {
-		git_error_set(GIT_ERROR_NET, "unexpected status code from proxy: %d",
-			parser->status_code);
-		return t->parse_error = PARSE_ERROR_GENERIC;
+	/* The Content-Type header must match our expectation. */
+	if (strcmp(response->content_type, stream->service->response_type) != 0) {
+		git_error_set(GIT_ERROR_NET, "invalid content-type: '%s'", response->content_type);
+		return -1;
 	}
 
-	if (!t->content_length || strcmp(t->content_length, "0") == 0)
-		t->parse_finished = 1;
-
+	*complete = true;
+	stream->state = HTTP_STATE_RECEIVING_RESPONSE;
 	return 0;
 }
 
-static int proxy_connect(
-	git_stream **out, git_stream *proxy_stream, http_subtransport *t)
+static int lookup_proxy(
+	bool *out_use,
+	http_subtransport *transport)
 {
-	git_buf request = GIT_BUF_INIT;
-	static http_parser_settings proxy_parser_settings = {0};
-	size_t bytes_read = 0, bytes_parsed;
-	parser_context ctx;
-	bool auth_replay;
-	int error;
-
-	/* Use the parser settings only to parser headers. */
-	proxy_parser_settings.on_header_field = on_header_field;
-	proxy_parser_settings.on_header_value = on_header_value;
-	proxy_parser_settings.on_headers_complete = proxy_headers_complete;
-	proxy_parser_settings.on_message_complete = on_message_complete;
-
-replay:
-	clear_parser_state(t);
-
-	auth_replay = false;
-
-	gitno_buffer_setup_fromstream(proxy_stream,
-		&t->parse_buffer,
-		t->parse_buffer_data,
-		sizeof(t->parse_buffer_data));
-
-	if ((error = gen_connect_req(&request, t)) < 0)
-		goto done;
-
-	if ((error = git_stream__write_full(proxy_stream, request.ptr,
-					    request.size, 0)) < 0)
-		goto done;
-
-	git_buf_dispose(&request);
+	const char *proxy;
+	git_remote *remote;
+	bool use_ssl;
+	char *config = NULL;
+	int error = 0;
 
-	while (!bytes_read && !t->parse_finished) {
-		t->parse_buffer.offset = 0;
+	*out_use = false;
+	git_net_url_dispose(&transport->proxy.url);
 
-		if ((error = gitno_recv(&t->parse_buffer)) < 0) {
-			goto done;
-		} else if (error == 0 && t->request_count > 0) {
-			/* Server closed a keep-alive socket; reconnect. */
-			auth_replay = true;
-			goto done;
-		} else if (error == 0) {
-			git_error_set(GIT_ERROR_NET, "unexpected disconnection from server");
-			error = -1;
-			goto done;
-		}
+	switch (transport->owner->proxy.type) {
+	case GIT_PROXY_SPECIFIED:
+		proxy = transport->owner->proxy.url;
+		break;
 
-		/*
-		 * This call to http_parser_execute will invoke the on_*
-		 * callbacks.  Since we don't care about the body of the response,
-		 * we can set our buffer to NULL.
-		 */
-		ctx.t = t;
-		ctx.s = NULL;
-		ctx.buffer = NULL;
-		ctx.buf_size = 0;
-		ctx.bytes_read = &bytes_read;
-
-		/* Set the context, call the parser, then unset the context. */
-		t->parser.data = &ctx;
-
-		bytes_parsed = http_parser_execute(&t->parser,
-			&proxy_parser_settings, t->parse_buffer.data, t->parse_buffer.offset);
-
-		t->parser.data = NULL;
-
-		/* Ensure that we didn't get a redirect; unsupported. */
-		if (t->location) {
-			git_error_set(GIT_ERROR_NET, "proxy server sent unsupported redirect during CONNECT");
-			error = -1;
-			goto done;
-		}
+	case GIT_PROXY_AUTO:
+		remote = transport->owner->owner;
+		use_ssl = !strcmp(transport->server.url.scheme, "https");
 
-		/* Replay the request with authentication headers. */
-		if (PARSE_ERROR_REPLAY == t->parse_error) {
-			auth_replay = true;
-		} else if (t->parse_error < 0) {
-			error = t->parse_error == PARSE_ERROR_EXT ? PARSE_ERROR_EXT : -1;
-			goto done;
-		}
+		error = git_remote__get_http_proxy(remote, use_ssl, &config);
 
-		if (bytes_parsed != t->parse_buffer.offset) {
-			git_error_set(GIT_ERROR_NET,
-				"HTTP parser error: %s",
-				http_errno_description((enum http_errno)t->parser.http_errno));
-			error = -1;
+		if (error || !config)
 			goto done;
-		}
-	}
-
-	t->request_count++;
 
-	if (auth_replay) {
-		if (t->keepalive && t->parse_finished)
-			goto replay;
+		proxy = config;
+		break;
 
-		return PARSE_ERROR_REPLAY;
+	default:
+		return 0;
 	}
 
-	if ((error = git_tls_stream_wrap(out, proxy_stream, t->server.url.host)) == 0)
-		error = stream_connect(*out, &t->server.url,
-		    t->owner->certificate_check_cb,
-			t->owner->message_cb_payload);
+	if (!proxy ||
+	    (error = git_net_url_parse(&transport->proxy.url, proxy)) < 0)
+		goto done;
 
-	/*
-	 * Since we've connected via a HTTPS proxy tunnel, we don't behave
-	 * as if we have an HTTP proxy.
-	 */
-	t->proxy_opts.type = GIT_PROXY_NONE;
-	t->replay_count = 0;
-	t->request_count = 0;
+	*out_use = true;
 
 done:
+	git__free(config);
 	return error;
 }
 
-static void reset_auth_connection(http_server *server)
-{
-	/*
-	 * If we've authenticated and we're doing "normal"
-	 * authentication with a request affinity (Basic, Digest)
-	 * then we want to _keep_ our context, since authentication
-	 * survives even through non-keep-alive connections.  If
-	 * we've authenticated and we're doing connection-based
-	 * authentication (NTLM, Negotiate) - indicated by the presence
-	 * of an `is_complete` callback - then we need to restart
-	 * authentication on a new connection.
-	 */
-
-	if (server->authenticated &&
-		server->auth_context &&
-	    server->auth_context->connection_affinity) {
-		server->prior_authtype = server->auth_context->type;
-
-		free_auth_context(server);
-
-		server->url_cred_presented = 0;
-		server->authenticated = 0;
-	}
-}
-
-static int http_connect(http_subtransport *t)
+static int generate_request(
+	git_net_url *url,
+	git_http_request *request,
+	http_stream *stream,
+	size_t len)
 {
-	git_net_url *url;
-	git_stream *proxy_stream = NULL, *stream = NULL;
-	git_transport_certificate_check_cb cert_cb;
-	void *cb_payload;
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
+	bool use_proxy = false;
 	int error;
 
-auth_replay:
-	if (t->connected && t->keepalive && t->parse_finished)
-		return 0;
-
-	if ((error = load_proxy_config(t)) < 0)
+	if ((error = git_net_url_joinpath(url,
+		&transport->server.url, stream->service->url)) < 0 ||
+	    (error = lookup_proxy(&use_proxy, transport)) < 0)
 		return error;
 
-	if (t->server.stream) {
-		git_stream_close(t->server.stream);
-		git_stream_free(t->server.stream);
-		t->server.stream = NULL;
-	}
-
-	if (t->proxy.stream) {
-		git_stream_close(t->proxy.stream);
-		git_stream_free(t->proxy.stream);
-		t->proxy.stream = NULL;
-	}
-
-	reset_auth_connection(&t->server);
-	reset_auth_connection(&t->proxy);
-
-	t->connected = 0;
-	t->keepalive = 0;
-	t->request_count = 0;
+	request->method = stream->service->method;
+	request->url = url;
+	request->credentials = transport->server.cred;
+	request->proxy = use_proxy ? &transport->proxy.url : NULL;
+	request->proxy_credentials = transport->proxy.cred;
 
-	if (t->proxy_opts.type == GIT_PROXY_SPECIFIED) {
-		url = &t->proxy.url;
-		cert_cb = t->proxy_opts.certificate_check;
-		cb_payload = t->proxy_opts.payload;
-	} else {
-		url = &t->server.url;
-		cert_cb = t->owner->certificate_check_cb;
-		cb_payload = t->owner->message_cb_payload;
+	if (stream->service->method == GIT_HTTP_METHOD_POST) {
+		request->chunked = stream->service->chunked;
+		request->content_length = stream->service->chunked ? 0 : len;
+		request->content_type = stream->service->request_type;
+		request->accept = stream->service->response_type;
+		request->expect_continue = git_http__expect_continue;
 	}
 
-	if (strcmp(url->scheme, "https") == 0)
-		error = git_tls_stream_new(&stream, url->host, url->port);
-	else
-		error = git_socket_stream_new(&stream, url->host, url->port);
-
-	if (error < 0)
-		goto on_error;
-
-	if ((error = stream_connect(stream, url, cert_cb, cb_payload)) < 0)
-		goto on_error;
-
-	/*
-	 * At this point we have a connection to the remote server or to
-	 * a proxy.  If it's a proxy and the remote server is actually
-	 * an HTTPS connection, then we need to build a CONNECT tunnel.
-	 */
-	if (t->proxy_opts.type == GIT_PROXY_SPECIFIED &&
-	    strcmp(t->server.url.scheme, "https") == 0) {
-		proxy_stream = stream;
-		stream = NULL;
-
-		error = proxy_connect(&stream, proxy_stream, t);
-
-		if (error == PARSE_ERROR_REPLAY) {
-			git_stream_close(proxy_stream);
-			git_stream_free(proxy_stream);
-			goto auth_replay;
-		} else if (error < 0) {
-			goto on_error;
-		}
-	}
-
-	t->proxy.stream = proxy_stream;
-	t->server.stream = stream;
-	t->connected = 1;
 	return 0;
-
-on_error:
-	if (stream) {
-		git_stream_close(stream);
-		git_stream_free(stream);
-	}
-
-	if (proxy_stream) {
-		git_stream_close(proxy_stream);
-		git_stream_free(proxy_stream);
-	}
-
-	return error;
 }
 
+/*
+ * Read from an HTTP transport - for the first invocation of this function
+ * (ie, when stream->state == HTTP_STATE_NONE), we'll send a GET request
+ * to the remote host.  We will stream that data back on all subsequent
+ * calls.
+ */
 static int http_stream_read(
-	git_smart_subtransport_stream *stream,
+	git_smart_subtransport_stream *s,
 	char *buffer,
-	size_t buf_size,
-	size_t *bytes_read)
-{
-	http_stream *s = (http_stream *)stream;
-	http_subtransport *t = OWNING_SUBTRANSPORT(s);
-	parser_context ctx;
-	size_t bytes_parsed;
-	git_buf request = GIT_BUF_INIT;
-	bool auth_replay;
-	int error = 0;
-
-replay:
-	*bytes_read = 0;
-	auth_replay = false;
-
-	assert(t->connected);
-
-	if (!s->sent_request) {
-		git_buf_clear(&request);
-		clear_parser_state(t);
-
-		if ((error = gen_request(&request, s, 0)) < 0 ||
-		    (error = git_stream__write_full(t->server.stream, request.ptr, request.size, 0)) < 0)
-			goto done;
-
-		s->sent_request = 1;
-	}
-
-	if (!s->received_response) {
-		if (s->chunked) {
-			assert(s->verb == post_verb);
-
-			/* Flush, if necessary */
-			if (s->chunk_buffer_len > 0) {
-				if ((error = write_chunk(t->server.stream, s->chunk_buffer, s->chunk_buffer_len)) < 0)
-					goto done;
-
-				s->chunk_buffer_len = 0;
-			}
+	size_t buffer_size,
+	size_t *out_len)
+{
+	http_stream *stream = (http_stream *)s;
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
+	git_net_url url = GIT_NET_URL_INIT;
+	git_net_url proxy_url = GIT_NET_URL_INIT;
+	git_http_request request = {0};
+	git_http_response response = {0};
+	bool complete;
+	int error;
 
-			/* Write the final chunk. */
-			if ((error = git_stream__write_full(t->server.stream,
-						   "0\r\n\r\n", 5, 0)) < 0)
-				goto done;
-		}
+	*out_len = 0;
 
-		s->received_response = 1;
+	if (stream->state == HTTP_STATE_NONE) {
+		stream->state = HTTP_STATE_SENDING_REQUEST;
+		stream->replay_count = 0;
 	}
 
-	while (!*bytes_read && !t->parse_finished) {
-		size_t data_offset;
-
-		/*
-		 * Make the parse_buffer think it's as full of data as
-		 * the buffer, so it won't try to recv more data than
-		 * we can put into it.
-		 *
-		 * data_offset is the actual data offset from which we
-		 * should tell the parser to start reading.
-		 */
-		if (buf_size >= t->parse_buffer.len)
-			t->parse_buffer.offset = 0;
-		else
-			t->parse_buffer.offset = t->parse_buffer.len - buf_size;
-
-		data_offset = t->parse_buffer.offset;
-
-		if ((error = gitno_recv(&t->parse_buffer)) < 0) {
-			goto done;
-		} else if (error == 0 && t->request_count > 0) {
-			/* Server closed a keep-alive socket; reconnect. */
-			auth_replay = true;
-			goto done;
-		} else if (error == 0) {
-			git_error_set(GIT_ERROR_NET, "unexpected disconnection from server");
-			error = -1;
+	/*
+	 * Formulate the URL, send the request and read the response
+	 * headers.  Some of the request body may also be read.
+	 */
+	while (stream->state == HTTP_STATE_SENDING_REQUEST &&
+	       stream->replay_count < GIT_HTTP_REPLAY_MAX) {
+		git_net_url_dispose(&url);
+		git_net_url_dispose(&proxy_url);
+		git_http_response_dispose(&response);
+
+		if ((error = generate_request(&url, &request, stream, 0)) < 0 ||
+		    (error = git_http_client_send_request(
+			transport->http_client, &request)) < 0 ||
+		    (error = git_http_client_read_response(
+			    &response, transport->http_client)) < 0 ||
+		    (error = handle_response(&complete, stream, &response, true)) < 0)
 			goto done;
-		}
 
-		/*
-		 * This call to http_parser_execute will result in invocations
-		 * of the on_* family of callbacks, including on_body_fill_buffer
-		 * which will write into the target buffer.  Set up the buffer
-		 * for it to write into _unless_ we got an auth failure; in
-		 * that case we only care about the headers and don't need to
-		 * bother copying the body.
-		 */
-		ctx.t = t;
-		ctx.s = s;
-		ctx.buffer = auth_replay ? NULL : buffer;
-		ctx.buf_size = auth_replay ? 0 : buf_size;
-		ctx.bytes_read = bytes_read;
-
-		/* Set the context, call the parser, then unset the context. */
-		t->parser.data = &ctx;
-
-		bytes_parsed = http_parser_execute(&t->parser,
-			&t->settings,
-			t->parse_buffer.data + data_offset,
-			t->parse_buffer.offset - data_offset);
-
-		t->parser.data = NULL;
-
-		/* On a 401, read the rest of the response then retry. */
-		if (t->parse_error == PARSE_ERROR_REPLAY) {
-			auth_replay = true;
-		} else if (t->parse_error == PARSE_ERROR_EXT) {
-			error = t->error;
-			goto done;
-		} else if (t->parse_error < 0) {
-			error = -1;
-			goto done;
-		}
+		if (complete)
+			break;
 
-		if (bytes_parsed != t->parse_buffer.offset - data_offset) {
-			git_error_set(GIT_ERROR_NET,
-				"HTTP parser error: %s",
-				http_errno_description((enum http_errno)t->parser.http_errno));
-			error = -1;
-			goto done;
-		}
+		stream->replay_count++;
 	}
 
-	t->request_count++;
+	if (stream->state == HTTP_STATE_SENDING_REQUEST) {
+		git_error_set(GIT_ERROR_NET, "too many redirects or authentication replays");
+		error = -1;
+		goto done;
+	}
 
-	if (auth_replay) {
-		s->sent_request = 0;
+	assert (stream->state == HTTP_STATE_RECEIVING_RESPONSE);
 
-		if ((error = http_connect(t)) < 0)
-			return error;
+	error = git_http_client_read_body(transport->http_client, buffer, buffer_size);
 
-		goto replay;
+	if (error > 0) {
+		*out_len = error;
+		error = 0;
 	}
 
 done:
-	git_buf_dispose(&request);
+	git_net_url_dispose(&url);
+	git_net_url_dispose(&proxy_url);
+	git_http_response_dispose(&response);
+
 	return error;
 }
 
-static int http_stream_write_chunked(
-	git_smart_subtransport_stream *stream,
+/*
+* Write to an HTTP transport - for the first invocation of this function
+* (ie, when stream->state == HTTP_STATE_NONE), we'll send a POST request
+* to the remote host.  If we're sending chunked data, then subsequent calls
+* will write the additional data given in the buffer.  If we're not chunking,
+* then the caller should have given us all the data in the original call.
+* The caller should call http_stream_read_response to get the result.
+*/
+static int http_stream_write(
+	git_smart_subtransport_stream *s,
 	const char *buffer,
 	size_t len)
 {
-	http_stream *s = GIT_CONTAINER_OF(stream, http_stream, parent);
-	http_subtransport *t = OWNING_SUBTRANSPORT(s);
-
-	assert(t->connected);
+	http_stream *stream = GIT_CONTAINER_OF(s, http_stream, parent);
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
+	git_net_url url = GIT_NET_URL_INIT;
+	git_http_request request = {0};
+	git_http_response response = {0};
+	int error;
 
-	/* Send the request, if necessary */
-	if (!s->sent_request) {
-		git_buf request = GIT_BUF_INIT;
+	while (stream->state == HTTP_STATE_NONE &&
+	       stream->replay_count < GIT_HTTP_REPLAY_MAX) {
 
-		clear_parser_state(t);
+		git_net_url_dispose(&url);
+		git_http_response_dispose(&response);
 
-		if (gen_request(&request, s, 0) < 0)
-			return -1;
+		if ((error = generate_request(&url, &request, stream, len)) < 0 ||
+		    (error = git_http_client_send_request(
+			transport->http_client, &request)) < 0)
+			goto done;
 
-		if (git_stream__write_full(t->server.stream, request.ptr,
-					   request.size, 0) < 0) {
-			git_buf_dispose(&request);
-			return -1;
+		if (request.expect_continue &&
+		    git_http_client_has_response(transport->http_client)) {
+			bool complete;
+
+			/*
+			 * If we got a response to an expect/continue, then
+			 * it's something other than a 100 and we should
+			 * deal with the response somehow.
+			 */
+			if ((error = git_http_client_read_response(&response, transport->http_client)) < 0 ||
+			    (error = handle_response(&complete, stream, &response, true)) < 0)
+			    goto done;
+		} else {
+			stream->state = HTTP_STATE_SENDING_REQUEST;
 		}
 
-		git_buf_dispose(&request);
-
-		s->sent_request = 1;
+		stream->replay_count++;
 	}
 
-	if (len > CHUNK_SIZE) {
-		/* Flush, if necessary */
-		if (s->chunk_buffer_len > 0) {
-			if (write_chunk(t->server.stream,
-			    s->chunk_buffer, s->chunk_buffer_len) < 0)
-				return -1;
-
-			s->chunk_buffer_len = 0;
-		}
-
-		/* Write chunk directly */
-		if (write_chunk(t->server.stream, buffer, len) < 0)
-			return -1;
+	if (stream->state == HTTP_STATE_NONE) {
+		git_error_set(GIT_ERROR_NET,
+		              "too many redirects or authentication replays");
+		error = -1;
+		goto done;
 	}
-	else {
-		/* Append as much to the buffer as we can */
-		int count = min(CHUNK_SIZE - s->chunk_buffer_len, len);
 
-		if (!s->chunk_buffer) {
-			s->chunk_buffer = git__malloc(CHUNK_SIZE);
-			GIT_ERROR_CHECK_ALLOC(s->chunk_buffer);
-		}
-
-		memcpy(s->chunk_buffer + s->chunk_buffer_len, buffer, count);
-		s->chunk_buffer_len += count;
-		buffer += count;
-		len -= count;
-
-		/* Is the buffer full? If so, then flush */
-		if (CHUNK_SIZE == s->chunk_buffer_len) {
-			if (write_chunk(t->server.stream,
-			    s->chunk_buffer, s->chunk_buffer_len) < 0)
-				return -1;
-
-			s->chunk_buffer_len = 0;
+	assert(stream->state == HTTP_STATE_SENDING_REQUEST);
 
-			if (len > 0) {
-				memcpy(s->chunk_buffer, buffer, len);
-				s->chunk_buffer_len = len;
-			}
-		}
-	}
+	error = git_http_client_send_body(transport->http_client, buffer, len);
 
-	return 0;
+done:
+	git_http_response_dispose(&response);
+	git_net_url_dispose(&url);
+	return error;
 }
 
-static int http_stream_write_single(
-	git_smart_subtransport_stream *stream,
-	const char *buffer,
-	size_t len)
+/*
+* Read from an HTTP transport after it has been written to.  This is the
+* response from a POST request made by http_stream_write.
+*/
+static int http_stream_read_response(
+	git_smart_subtransport_stream *s,
+	char *buffer,
+	size_t buffer_size,
+	size_t *out_len)
 {
-	http_stream *s = GIT_CONTAINER_OF(stream, http_stream, parent);
-	http_subtransport *t = OWNING_SUBTRANSPORT(s);
-	git_buf request = GIT_BUF_INIT;
-
-	assert(t->connected);
-
-	if (s->sent_request) {
-		git_error_set(GIT_ERROR_NET, "subtransport configured for only one write");
-		return -1;
-	}
-
-	clear_parser_state(t);
+	http_stream *stream = (http_stream *)s;
+	http_subtransport *transport = OWNING_SUBTRANSPORT(stream);
+	git_http_response response = {0};
+	bool complete;
+	int error;
 
-	if (gen_request(&request, s, len) < 0)
-		return -1;
+	*out_len = 0;
 
-	if (git_stream__write_full(t->server.stream, request.ptr, request.size, 0) < 0)
-		goto on_error;
+	if (stream->state == HTTP_STATE_SENDING_REQUEST) {
+		if ((error = git_http_client_read_response(&response, transport->http_client)) < 0 ||
+		    (error = handle_response(&complete, stream, &response, false)) < 0)
+		    goto done;
 
-	if (len && git_stream__write_full(t->server.stream, buffer, len, 0) < 0)
-		goto on_error;
+		assert(complete);
+		stream->state = HTTP_STATE_RECEIVING_RESPONSE;
+	}
 
-	git_buf_dispose(&request);
-	s->sent_request = 1;
+	error = git_http_client_read_body(transport->http_client, buffer, buffer_size);
 
-	return 0;
+	if (error > 0) {
+		*out_len = error;
+		error = 0;
+	}
 
-on_error:
-	git_buf_dispose(&request);
-	return -1;
+done:
+	git_http_response_dispose(&response);
+	return error;
 }
 
 static void http_stream_free(git_smart_subtransport_stream *stream)
 {
 	http_stream *s = GIT_CONTAINER_OF(stream, http_stream, parent);
-
-	if (s->chunk_buffer)
-		git__free(s->chunk_buffer);
-
 	git__free(s);
 }
 
-static int http_stream_alloc(http_subtransport *t,
-	git_smart_subtransport_stream **stream)
-{
-	http_stream *s;
-
-	if (!stream)
-		return -1;
-
-	s = git__calloc(sizeof(http_stream), 1);
-	GIT_ERROR_CHECK_ALLOC(s);
-
-	s->parent.subtransport = &t->parent;
-	s->parent.read = http_stream_read;
-	s->parent.write = http_stream_write_single;
-	s->parent.free = http_stream_free;
-
-	*stream = (git_smart_subtransport_stream *)s;
-	return 0;
-}
-
-static int http_uploadpack_ls(
-	http_subtransport *t,
-	git_smart_subtransport_stream **stream)
+static const http_service *select_service(git_smart_service_t action)
 {
-	http_stream *s;
-
-	if (http_stream_alloc(t, stream) < 0)
-		return -1;
-
-	s = (http_stream *)*stream;
-
-	s->service = upload_pack_service;
-	s->service_url = upload_pack_ls_service_url;
-	s->verb = get_verb;
-
-	return 0;
-}
-
-static int http_uploadpack(
-	http_subtransport *t,
-	git_smart_subtransport_stream **stream)
-{
-	http_stream *s;
-
-	if (http_stream_alloc(t, stream) < 0)
-		return -1;
-
-	s = (http_stream *)*stream;
-
-	s->service = upload_pack_service;
-	s->service_url = upload_pack_service_url;
-	s->verb = post_verb;
-
-	return 0;
-}
-
-static int http_receivepack_ls(
-	http_subtransport *t,
-	git_smart_subtransport_stream **stream)
-{
-	http_stream *s;
-
-	if (http_stream_alloc(t, stream) < 0)
-		return -1;
-
-	s = (http_stream *)*stream;
-
-	s->service = receive_pack_service;
-	s->service_url = receive_pack_ls_service_url;
-	s->verb = get_verb;
-
-	return 0;
-}
-
-static int http_receivepack(
-	http_subtransport *t,
-	git_smart_subtransport_stream **stream)
-{
-	http_stream *s;
-
-	if (http_stream_alloc(t, stream) < 0)
-		return -1;
-
-	s = (http_stream *)*stream;
-
-	/* Use Transfer-Encoding: chunked for this request */
-	s->chunked = 1;
-	s->parent.write = http_stream_write_chunked;
-
-	s->service = receive_pack_service;
-	s->service_url = receive_pack_service_url;
-	s->verb = post_verb;
+	switch (action) {
+	case GIT_SERVICE_UPLOADPACK_LS:
+		return &upload_pack_ls_service;
+	case GIT_SERVICE_UPLOADPACK:
+		return &upload_pack_service;
+	case GIT_SERVICE_RECEIVEPACK_LS:
+		return &receive_pack_ls_service;
+	case GIT_SERVICE_RECEIVEPACK:
+		return &receive_pack_service;
+	}
 
-	return 0;
+	return NULL;
 }
 
 static int http_action(
-	git_smart_subtransport_stream **stream,
-	git_smart_subtransport *subtransport,
+	git_smart_subtransport_stream **out,
+	git_smart_subtransport *t,
 	const char *url,
 	git_smart_service_t action)
 {
-	http_subtransport *t = GIT_CONTAINER_OF(subtransport, http_subtransport, parent);
-	int ret;
+	http_subtransport *transport = GIT_CONTAINER_OF(t, http_subtransport, parent);
+	http_stream *stream;
+	const http_service *service;
+	int error;
+
+	assert(out && t);
 
-	assert(stream);
+	*out = NULL;
 
 	/*
 	 * If we've seen a redirect then preserve the location that we've
@@ -1536,103 +582,89 @@ static int http_action(
 	 * have redirected us from HTTP->HTTPS and is using an auth mechanism
 	 * that would be insecure in plaintext (eg, HTTP Basic).
 	 */
-	if ((!t->server.url.host || !t->server.url.port || !t->server.url.path) &&
-	    (ret = git_net_url_parse(&t->server.url, url)) < 0)
-		return ret;
-
-	assert(t->server.url.host && t->server.url.port && t->server.url.path);
+	if (!git_net_url_valid(&transport->server.url) &&
+	    (error = git_net_url_parse(&transport->server.url, url)) < 0)
+		return error;
 
-	if ((ret = http_connect(t)) < 0)
-		return ret;
+	if ((service = select_service(action)) == NULL) {
+		git_error_set(GIT_ERROR_NET, "invalid action");
+		return -1;
+	}
 
-	switch (action) {
-	case GIT_SERVICE_UPLOADPACK_LS:
-		return http_uploadpack_ls(t, stream);
+	stream = git__calloc(sizeof(http_stream), 1);
+	GIT_ERROR_CHECK_ALLOC(stream);
 
-	case GIT_SERVICE_UPLOADPACK:
-		return http_uploadpack(t, stream);
+	if (!transport->http_client) {
+		git_http_client_options opts = {0};
 
-	case GIT_SERVICE_RECEIVEPACK_LS:
-		return http_receivepack_ls(t, stream);
+		opts.server_certificate_check_cb = transport->owner->certificate_check_cb;
+		opts.server_certificate_check_payload = transport->owner->message_cb_payload;
+		opts.proxy_certificate_check_cb = transport->owner->proxy.certificate_check;
+		opts.proxy_certificate_check_payload = transport->owner->proxy.payload;
 
-	case GIT_SERVICE_RECEIVEPACK:
-		return http_receivepack(t, stream);
+		if (git_http_client_new(&transport->http_client, &opts) < 0)
+			return -1;
 	}
 
-	*stream = NULL;
-	return -1;
-}
-
-static int http_close(git_smart_subtransport *subtransport)
-{
-	http_subtransport *t = GIT_CONTAINER_OF(subtransport, http_subtransport, parent);
-
-	clear_parser_state(t);
+	stream->service = service;
+	stream->parent.subtransport = &transport->parent;
 
-	t->connected = 0;
-
-	if (t->server.stream) {
-		git_stream_close(t->server.stream);
-		git_stream_free(t->server.stream);
-		t->server.stream = NULL;
+	if (service->method == GIT_HTTP_METHOD_GET) {
+		stream->parent.read = http_stream_read;
+	} else {
+		stream->parent.write = http_stream_write;
+		stream->parent.read = http_stream_read_response;
 	}
 
-	if (t->proxy.stream) {
-		git_stream_close(t->proxy.stream);
-		git_stream_free(t->proxy.stream);
-		t->proxy.stream = NULL;
-	}
+	stream->parent.free = http_stream_free;
 
-	free_cred(&t->server.cred);
-	free_cred(&t->proxy.cred);
+	*out = (git_smart_subtransport_stream *)stream;
+	return 0;
+}
 
-	free_auth_context(&t->server);
-	free_auth_context(&t->proxy);
+static int http_close(git_smart_subtransport *t)
+{
+	http_subtransport *transport = GIT_CONTAINER_OF(t, http_subtransport, parent);
 
-	t->server.url_cred_presented = false;
-	t->proxy.url_cred_presented = false;
+	free_cred(&transport->server.cred);
+	free_cred(&transport->proxy.cred);
 
-	git_net_url_dispose(&t->server.url);
-	git_net_url_dispose(&t->proxy.url);
+	transport->server.url_cred_presented = false;
+	transport->proxy.url_cred_presented = false;
 
-	git__free(t->proxy_url);
-	t->proxy_url = NULL;
+	git_net_url_dispose(&transport->server.url);
+	git_net_url_dispose(&transport->proxy.url);
 
 	return 0;
 }
 
-static void http_free(git_smart_subtransport *subtransport)
+static void http_free(git_smart_subtransport *t)
 {
-	http_subtransport *t = GIT_CONTAINER_OF(subtransport, http_subtransport, parent);
+	http_subtransport *transport = GIT_CONTAINER_OF(t, http_subtransport, parent);
 
-	http_close(subtransport);
-	git__free(t);
+	git_http_client_free(transport->http_client);
+
+	http_close(t);
+	git__free(transport);
 }
 
 int git_smart_subtransport_http(git_smart_subtransport **out, git_transport *owner, void *param)
 {
-	http_subtransport *t;
+	http_subtransport *transport;
 
 	GIT_UNUSED(param);
 
-	if (!out)
-		return -1;
-
-	t = git__calloc(sizeof(http_subtransport), 1);
-	GIT_ERROR_CHECK_ALLOC(t);
+	assert(out);
 
-	t->owner = (transport_smart *)owner;
-	t->parent.action = http_action;
-	t->parent.close = http_close;
-	t->parent.free = http_free;
+	transport = git__calloc(sizeof(http_subtransport), 1);
+	GIT_ERROR_CHECK_ALLOC(transport);
 
-	t->settings.on_header_field = on_header_field;
-	t->settings.on_header_value = on_header_value;
-	t->settings.on_headers_complete = on_headers_complete;
-	t->settings.on_body = on_body_fill_buffer;
-	t->settings.on_message_complete = on_message_complete;
+	transport->owner = (transport_smart *)owner;
+	transport->parent.action = http_action;
+	transport->parent.close = http_close;
+	transport->parent.free = http_free;
 
-	*out = (git_smart_subtransport *) t;
+	*out = (git_smart_subtransport *) transport;
 	return 0;
 }
 
diff --git a/src/transports/http.h b/src/transports/http.h
index 6f698c9dd..c02109cec 100644
--- a/src/transports/http.h
+++ b/src/transports/http.h
@@ -9,6 +9,7 @@
 #define INCLUDE_transports_http_h__
 
 #include "buffer.h"
+#include "httpclient.h"
 
 #define GIT_HTTP_REPLAY_MAX 15