h2: unify immortal stream tracking across SSE and ws substreams
It was already correct but add helpers to isolate and deduplicate
processing adding and closing a generically immortal stream.
Change the default 31s h2 network connection timeout to be settable
by .keepalive_timeout if nonzero.
Add a public api allowing a client h2 stream to transition to
half-closed LOCAL (by sending a 0-byte DATA with END_STREAM) and
mark itself as immortal to create a read-only long-poll stream
if the server allows it.
Add a vhost server option flag LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL
which allows the vhost to treat half-closed remotes as immortal long
poll streams.
diff --git a/READMEs/README.h2-long-poll.md b/READMEs/README.h2-long-poll.md
new file mode 100644
index 0000000..ab8c25f
--- /dev/null
+++ b/READMEs/README.h2-long-poll.md
@@ -0,0 +1,55 @@
+# h2 long poll in lws
+
+lws server and client can support "immortal" streams that are
+not subject to normal timeouts under a special condition. These
+are read-only (to the client).
+
+Network connections that contain at least one immortal stream
+are themselves not subject to timeouts until the last immortal
+stream they are carrying closes.
+
+Because of this, it's recommended there is some other way of
+confirming that the client is still active.
+
+## Setting up lws server for h2 long poll
+
+Vhosts that wish to allow clients to serve these immortal
+streams need to set the info.options flag `LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL`
+at vhost creation time. The JSON config equivalent is to set
+
+```
+"h2-half-closed-long-poll": "1"
+```
+
+on the vhost. That's all that is needed.
+
+Streams continue to act normally for timeout with the exception
+client streams are allowed to signal they are half-closing by
+sending a zero-length DATA frame with END_STREAM set. These
+streams are allowed to exist outside of any timeout and data
+can be sent on them at will in the server -> client direction.
+
+## Setting client streams for long poll
+
+An API is provided to allow established h2 client streams to
+transition to immortal mode and send the END_STREAM to the server
+to indicate it.
+
+```
+int
+lws_h2_client_stream_long_poll_rxonly(struct lws *wsi);
+```
+
+## Example applications
+
+You can confirm the long poll flow simply using example applications.
+Build and run `http-server/minimal-http-server-h2-long-poll` in one
+terminal.
+
+In another, build the usual `http-client/minimal-http-client` example
+and run it with the flags `-l --long-poll`
+
+The client will connect to the server and transition to the immortal mode.
+The server sends a timestamp every minute to the client, and that will
+stay up without timeouts.
+
diff --git a/include/libwebsockets/lws-context-vhost.h b/include/libwebsockets/lws-context-vhost.h
index bc9feff..6f741d6 100644
--- a/include/libwebsockets/lws-context-vhost.h
+++ b/include/libwebsockets/lws-context-vhost.h
@@ -212,6 +212,12 @@
/**< (VH) Indicates the connections using this vhost should ignore
* h2 WINDOW_UPDATE from broken peers and fix them up */
+#define LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL (1ll << 32)
+ /**< (VH) Tell the vhost to treat half-closed remote clients as
+ * entered into an immortal (ie, not subject to normal timeouts) long
+ * poll mode.
+ */
+
/****** add new things just above ---^ ******/
@@ -398,8 +404,9 @@
/**< VHOST: pointer to optional linked list of per-vhost
* options made accessible to protocols */
int keepalive_timeout;
- /**< VHOST: (default = 0 = 5s) seconds to allow remote
- * client to hold on to an idle HTTP/1.1 connection */
+ /**< VHOST: (default = 0 = 5s, 31s for http/2) seconds to allow remote
+ * client to hold on to an idle HTTP/1.1 connection. Timeout lifetime
+ * applied to idle h2 network connections */
const char *log_filepath;
/**< VHOST: filepath to append logs to... this is opened before
* any dropping of initial privileges */
diff --git a/include/libwebsockets/lws-http.h b/include/libwebsockets/lws-http.h
index 863655e..fce21d8 100644
--- a/include/libwebsockets/lws-http.h
+++ b/include/libwebsockets/lws-http.h
@@ -746,6 +746,24 @@
lws_http_mark_sse(struct lws *wsi);
/**
+ * lws_h2_client_stream_long_poll_rxonly() - h2 stream to immortal read-only
+ *
+ * \param wsi: h2 stream client wsi
+ *
+ * Send END_STREAM-flagged zero-length DATA frame to set client stream wsi into
+ * half-closed (local) and remote into half-closed (remote). Set the client
+ * stream wsi to be immortal (not subject to timeouts).
+ *
+ * Used if the remote server supports immortal long poll to put the stream into
+ * a read-only state where it can wait as long as needed for rx.
+ *
+ * Returns 0 if the process (which happens asynchronously) started or non-zero
+ * if it wasn't an h2 stream.
+ */
+LWS_VISIBLE LWS_EXTERN int
+lws_h2_client_stream_long_poll_rxonly(struct lws *wsi);
+
+/**
* lws_http_compression_apply() - apply an http compression transform
*
* \param wsi: the wsi to apply the compression transform to
diff --git a/lib/core-net/close.c b/lib/core-net/close.c
index 7803ccc..aeac2e4 100644
--- a/lib/core-net/close.c
+++ b/lib/core-net/close.c
@@ -254,6 +254,11 @@
lws_addrinfo_clean(wsi);
#endif
+#if defined(LWS_WITH_HTTP2)
+ if (wsi->h2_stream_immortal)
+ lws_http_close_immortal(wsi);
+#endif
+
/* if we have children, close them first */
if (wsi->child_list) {
wsi2 = wsi->child_list;
diff --git a/lib/core-net/private-lib-core-net.h b/lib/core-net/private-lib-core-net.h
index d6bc0a7..bcb73f0 100644
--- a/lib/core-net/private-lib-core-net.h
+++ b/lib/core-net/private-lib-core-net.h
@@ -676,8 +676,9 @@
unsigned int hdr_parsing_completed:1;
unsigned int http2_substream:1;
unsigned int upgraded_to_http2:1;
- unsigned int h2_stream_carries_ws:1;
- unsigned int h2_stream_carries_sse:1;
+ unsigned int h2_stream_immortal:1;
+ unsigned int h2_stream_carries_ws:1; /* immortal set as well */
+ unsigned int h2_stream_carries_sse:1; /* immortal set as well */
unsigned int seen_nonpseudoheader:1;
unsigned int listener:1;
unsigned int user_space_externally_allocated:1;
@@ -1086,20 +1087,25 @@
#define lws_access_log(_a)
#endif
-LWS_EXTERN int
+void
+lws_http_mark_immortal(struct lws *wsi);
+void
+lws_http_close_immortal(struct lws *wsi);
+
+int
lws_cgi_kill_terminated(struct lws_context_per_thread *pt);
-LWS_EXTERN void
+void
lws_cgi_remove_and_kill(struct lws *wsi);
-LWS_EXTERN void
+void
lws_plat_delete_socket_from_fds(struct lws_context *context,
struct lws *wsi, int m);
-LWS_EXTERN void
+void
lws_plat_insert_socket_into_fds(struct lws_context *context,
struct lws *wsi);
-LWS_EXTERN int
+int
lws_plat_change_pollfd(struct lws_context *context, struct lws *wsi,
struct lws_pollfd *pfd);
diff --git a/lib/core-net/wsi-timeout.c b/lib/core-net/wsi-timeout.c
index 1609142..db026c4 100644
--- a/lib/core-net/wsi-timeout.c
+++ b/lib/core-net/wsi-timeout.c
@@ -158,6 +158,8 @@
if (secs == LWS_TO_KILL_ASYNC)
secs = 0;
+ assert(!wsi->h2_stream_immortal);
+
lws_pt_lock(pt, __func__);
__lws_set_timeout(wsi, reason, secs);
lws_pt_unlock(pt);
diff --git a/lib/core-net/wsi.c b/lib/core-net/wsi.c
index 11c14f9..3051c48 100644
--- a/lib/core-net/wsi.c
+++ b/lib/core-net/wsi.c
@@ -830,20 +830,69 @@
return 0;
}
+void
+lws_http_close_immortal(struct lws *wsi)
+{
+ struct lws *nwsi;
+
+ if (!wsi->http2_substream)
+ return;
+
+ assert(wsi->h2_stream_immortal);
+ wsi->h2_stream_immortal = 0;
+
+ nwsi = lws_get_network_wsi(wsi);
+ lwsl_debug("%s: %p %p %d\n", __func__, wsi, nwsi,
+ nwsi->immortal_substream_count);
+ assert(nwsi->immortal_substream_count);
+ nwsi->immortal_substream_count--;
+ if (!nwsi->immortal_substream_count)
+ /*
+ * since we closed the only immortal stream on this nwsi, we
+ * need to reapply a normal timeout regime to the nwsi
+ */
+ lws_set_timeout(nwsi, PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE,
+ wsi->vhost->keepalive_timeout ?
+ wsi->vhost->keepalive_timeout : 31);
+}
+
+void
+lws_http_mark_immortal(struct lws *wsi)
+{
+ struct lws *nwsi;
+
+ lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
+
+ if (!wsi->http2_substream
+#if defined(LWS_WITH_CLIENT)
+ && !wsi->client_h2_substream
+#endif
+ ) {
+ lwsl_err("%s: not h2 substream\n", __func__);
+ return;
+ }
+
+ nwsi = lws_get_network_wsi(wsi);
+
+ lwsl_debug("%s: %p %p %d\n", __func__, wsi, nwsi,
+ nwsi->immortal_substream_count);
+
+ wsi->h2_stream_immortal = 1;
+ assert(nwsi->immortal_substream_count < 255); /* largest count */
+ nwsi->immortal_substream_count++;
+ if (nwsi->immortal_substream_count == 1)
+ lws_set_timeout(nwsi, NO_PENDING_TIMEOUT, 0);
+}
+
+
int
lws_http_mark_sse(struct lws *wsi)
{
lws_http_headers_detach(wsi);
- lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
+ lws_http_mark_immortal(wsi);
- if (wsi->http2_substream) {
- struct lws *nwsi = lws_get_network_wsi(wsi);
-
+ if (wsi->http2_substream)
wsi->h2_stream_carries_sse = 1;
- nwsi->immortal_substream_count++;
- if (nwsi->immortal_substream_count == 1)
- lws_set_timeout(nwsi, NO_PENDING_TIMEOUT, 0);
- }
return 0;
}
diff --git a/lib/roles/h2/http2.c b/lib/roles/h2/http2.c
index 331646c..29aa9e7 100644
--- a/lib/roles/h2/http2.c
+++ b/lib/roles/h2/http2.c
@@ -845,11 +845,9 @@
/* let the network wsi live a bit longer if subs are active */
if (!wsi->immortal_substream_count)
-#if defined(LWS_AMAZON_RTOS) || defined(LWS_AMAZON_LINUX)
- lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE, wsi->vhost->keepalive_timeout);
-#else
- lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE, 31);
-#endif
+ lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE,
+ wsi->vhost->keepalive_timeout ?
+ wsi->vhost->keepalive_timeout : 31);
if (h2n->sid)
h2n->swsi = lws_h2_wsi_from_id(wsi, h2n->sid);
@@ -1164,12 +1162,24 @@
assert(w->h2.sibling_list != w);
} lws_end_foreach_ll(w, h2.sibling_list);
+ if (lws_check_opt(h2n->swsi->vhost->options,
+ LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL)) {
- /* END_STREAM means after servicing this, close the stream */
- h2n->swsi->h2.END_STREAM =
+ /*
+ * We don't directly timeout streams that enter the
+ * half-closed remote state, allowing immortal long
+ * poll
+ */
+ lws_http_mark_immortal(h2n->swsi);
+ lwsl_info("%s: %p: h2 stream entering long poll\n",
+ __func__, h2n->swsi);
+
+ } else {
+ h2n->swsi->h2.END_STREAM =
!!(h2n->flags & LWS_H2_FLAG_END_STREAM);
- lwsl_info("%s: hdr END_STREAM = %d\n",__func__,
+ lwsl_debug("%s: hdr END_STREAM = %d\n",__func__,
h2n->swsi->h2.END_STREAM);
+ }
h2n->cont_exp = !(h2n->flags & LWS_H2_FLAG_END_HEADERS);
h2n->cont_exp_sid = h2n->sid;
@@ -1863,12 +1873,9 @@
*/
if (!wsi->immortal_substream_count)
lws_set_timeout(wsi,
- PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE,
-#if defined(LWS_AMAZON_RTOS) || defined(LWS_AMAZON_LINUX)
- wsi->vhost->keepalive_timeout);
-#else
- 31);
-#endif
+ PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE,
+ wsi->vhost->keepalive_timeout ?
+ wsi->vhost->keepalive_timeout : 31);
if (!h2n->swsi)
break;
@@ -2411,3 +2418,21 @@
return lws_ptr_diff(buf, oldbuf);
}
+int
+lws_h2_client_stream_long_poll_rxonly(struct lws *wsi)
+{
+
+ if (!wsi->http2_substream)
+ return 1;
+
+ /*
+ * Elect to send an empty DATA with END_STREAM, to force the stream
+ * into HALF_CLOSED LOCAL
+ */
+ wsi->h2.long_poll = 1;
+ wsi->h2.send_END_STREAM = 1;
+
+ lws_callback_on_writable(wsi);
+
+ return 0;
+}
diff --git a/lib/roles/h2/ops-h2.c b/lib/roles/h2/ops-h2.c
index dd57ce4..de65739 100644
--- a/lib/roles/h2/ops-h2.c
+++ b/lib/roles/h2/ops-h2.c
@@ -386,20 +386,22 @@
/* if not in a state to send stuff, then just send nothing */
- if (!lwsi_role_ws(wsi) &&
+ if (!lwsi_role_ws(wsi) && !wsi->h2_stream_immortal &&
base != LWS_WRITE_HTTP &&
base != LWS_WRITE_HTTP_FINAL &&
base != LWS_WRITE_HTTP_HEADERS_CONTINUATION &&
base != LWS_WRITE_HTTP_HEADERS &&
((lwsi_state(wsi) != LRS_RETURNED_CLOSE &&
lwsi_state(wsi) != LRS_WAITING_TO_SEND_CLOSE &&
+ lwsi_state(wsi) != LRS_ESTABLISHED &&
lwsi_state(wsi) != LRS_AWAITING_CLOSE_ACK)
#if defined(LWS_ROLE_WS)
|| base != LWS_WRITE_CLOSE
#endif
)) {
//assert(0);
- lwsl_notice("binning wsistate 0x%x %d\n", wsi->wsistate, *wp);
+ lwsl_notice("%s: binning wsistate 0x%x %d\n", __func__,
+ wsi->wsistate, *wp);
return 0;
}
@@ -486,7 +488,6 @@
rops_check_upgrades_h2(struct lws *wsi)
{
#if defined(LWS_ROLE_WS)
- struct lws *nwsi;
char *p;
/*
@@ -504,21 +505,16 @@
if (!p || strcmp(p, "websocket"))
return LWS_UPG_RET_CONTINUE;
- nwsi = lws_get_network_wsi(wsi);
-
#if defined(LWS_WITH_SERVER_STATUS)
wsi->vhost->conn_stats.ws_upg++;
#endif
lwsl_info("Upgrade h2 to ws\n");
+ lws_http_mark_immortal(wsi);
wsi->h2_stream_carries_ws = 1;
- nwsi->immortal_substream_count++;
+
if (lws_process_ws_upgrade(wsi))
return LWS_UPG_RET_BAIL;
- if (nwsi->immortal_substream_count == 1)
- lws_set_timeout(nwsi, NO_PENDING_TIMEOUT, 0);
-
- lws_set_timeout(wsi, NO_PENDING_TIMEOUT, 0);
lwsl_info("Upgraded h2 to ws OK\n");
return LWS_UPG_RET_DONE;
@@ -717,16 +713,6 @@
lws_free_set_NULL(wsi->h2.pending_status_body);
}
- if (wsi->h2_stream_carries_ws || wsi->h2_stream_carries_sse) {
- struct lws *nwsi = lws_get_network_wsi(wsi);
-
- nwsi->immortal_substream_count--;
- /* if no ws, then put a timeout on the parent wsi */
- if (!nwsi->immortal_substream_count)
- __lws_set_timeout(nwsi,
- PENDING_TIMEOUT_HTTP_KEEPALIVE_IDLE, 31);
- }
-
return 0;
}
@@ -1148,6 +1134,30 @@
goto next_child;
}
#endif
+
+ /*
+ * set client wsi to immortal long-poll mode; send END_STREAM
+ * flag on headers to indicate to a server, that allows
+ * it, that you want them to leave the stream in a long poll
+ * ro immortal state. We have to send headers so the client
+ * understands the http connection is ongoing.
+ */
+
+ if (w->h2.send_END_STREAM && w->h2.long_poll) {
+ uint8_t buf[LWS_PRE + 1];
+ enum lws_write_protocol wp = 0;
+
+ if (!rops_write_role_protocol_h2(w, buf + LWS_PRE, 0,
+ &wp)) {
+ lwsl_info("%s: wsi %p: entering ro long poll\n",
+ __func__, w);
+ lws_http_mark_immortal(w);
+ } else
+ lwsl_err("%s: wsi %p: failed to set long poll\n",
+ __func__, w);
+ goto next_child;
+ }
+
if (lws_callback_as_writeable(w)) {
lwsl_info("Closing POLLOUT child (end stream %d)\n",
w->h2.send_END_STREAM);
diff --git a/lib/roles/h2/private-lib-roles-h2.h b/lib/roles/h2/private-lib-roles-h2.h
index e572b1f..ff169ee 100644
--- a/lib/roles/h2/private-lib-roles-h2.h
+++ b/lib/roles/h2/private-lib-roles-h2.h
@@ -328,12 +328,13 @@
int my_priority;
uint32_t dependent_on;
- unsigned int END_STREAM:1;
- unsigned int END_HEADERS:1;
- unsigned int send_END_STREAM:1;
- unsigned int GOING_AWAY;
- unsigned int requested_POLLOUT:1;
- unsigned int skint:1;
+ uint16_t END_STREAM:1;
+ uint16_t END_HEADERS:1;
+ uint16_t send_END_STREAM:1;
+ uint16_t long_poll:1;
+ uint16_t GOING_AWAY;
+ uint16_t requested_POLLOUT:1;
+ uint16_t skint:1;
uint16_t round_robin_POLLOUT;
uint16_t count_POLLOUT_children;
diff --git a/lib/roles/http/server/lejp-conf.c b/lib/roles/http/server/lejp-conf.c
index 2e5a98c..e381940 100644
--- a/lib/roles/http/server/lejp-conf.c
+++ b/lib/roles/http/server/lejp-conf.c
@@ -132,6 +132,7 @@
"vhosts[].allow-http-on-https",
"vhosts[].disable-no-protocol-ws-upgrades",
+ "vhosts[].h2-half-closed-long-poll",
};
enum lejp_vhost_paths {
@@ -199,6 +200,7 @@
LEJPVP_FLAG_ALLOW_HTTP_ON_HTTPS,
LEJPVP_FLAG_DISABLE_NO_PROTOCOL_WS_UPGRADES,
+ LEJPVP_FLAG_H2_HALF_CLOSED_LONG_POLL,
};
#define MAX_PLUGIN_DIRS 10
@@ -864,6 +866,11 @@
a->reject_ws_with_no_protocol = 1;
return 0;
+ case LEJPVP_FLAG_H2_HALF_CLOSED_LONG_POLL:
+ set_reset_flag(&a->info->options, ctx->buf,
+ LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL);
+ return 0;
+
default:
return 0;
}
diff --git a/lib/roles/http/server/server.c b/lib/roles/http/server/server.c
index 26168ca..132e962 100644
--- a/lib/roles/http/server/server.c
+++ b/lib/roles/http/server/server.c
@@ -1340,8 +1340,9 @@
* if there is content supposed to be coming,
* put a timeout on it having arrived
*/
- lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_CONTENT,
- wsi->context->timeout_secs);
+ if (!wsi->h2_stream_immortal)
+ lws_set_timeout(wsi, PENDING_TIMEOUT_HTTP_CONTENT,
+ wsi->context->timeout_secs);
#ifdef LWS_WITH_TLS
if (wsi->tls.redirect_to_https) {
/*
diff --git a/minimal-examples/http-client/minimal-http-client/minimal-http-client.c b/minimal-examples/http-client/minimal-http-client/minimal-http-client.c
index 1dc1be7..2c89d29 100644
--- a/minimal-examples/http-client/minimal-http-client/minimal-http-client.c
+++ b/minimal-examples/http-client/minimal-http-client/minimal-http-client.c
@@ -17,6 +17,9 @@
#include <signal.h>
static int interrupted, bad = 1, status;
+#if defined(LWS_WITH_HTTP2)
+static int long_poll;
+#endif
static struct lws *client_wsi;
static int
@@ -35,11 +38,22 @@
case LWS_CALLBACK_ESTABLISHED_CLIENT_HTTP:
status = lws_http_client_http_response(wsi);
lwsl_user("Connected with server response: %d\n", status);
+#if defined(LWS_WITH_HTTP2)
+ if (long_poll) {
+ lwsl_user("%s: Client entering long poll mode\n", __func__);
+ lws_h2_client_stream_long_poll_rxonly(wsi);
+ }
+#endif
break;
/* chunks of chunked content, with header removed */
case LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ:
lwsl_user("RECEIVE_CLIENT_HTTP_READ: read %d\n", (int)len);
+#if defined(LWS_WITH_HTTP2)
+ if (long_poll)
+ lwsl_notice("long poll rx: '%.*s'\n",
+ (int)len, (const char *)in);
+#endif
#if 0 /* enable to dump the html */
{
const char *p = in;
@@ -155,8 +169,16 @@
memset(&i, 0, sizeof i); /* otherwise uninitialized garbage */
i.context = context;
- if (!lws_cmdline_option(argc, argv, "-n"))
+ if (!lws_cmdline_option(argc, argv, "-n")) {
i.ssl_connection = LCCSCF_USE_SSL;
+#if defined(LWS_WITH_HTTP2)
+ /* requires h2 */
+ if (lws_cmdline_option(argc, argv, "--long-poll")) {
+ lwsl_user("%s: long poll mode\n", __func__);
+ long_poll = 1;
+ }
+#endif
+ }
if (lws_cmdline_option(argc, argv, "-l")) {
i.port = 7681;
diff --git a/minimal-examples/http-server/minimal-http-server-h2-long-poll/CMakeLists.txt b/minimal-examples/http-server/minimal-http-server-h2-long-poll/CMakeLists.txt
new file mode 100644
index 0000000..4a30f9c
--- /dev/null
+++ b/minimal-examples/http-server/minimal-http-server-h2-long-poll/CMakeLists.txt
@@ -0,0 +1,80 @@
+cmake_minimum_required(VERSION 2.8)
+include(CheckCSourceCompiles)
+
+set(SAMP lws-minimal-http-server-h2-long-poll)
+set(SRCS minimal-http-server.c)
+
+# If we are being built as part of lws, confirm current build config supports
+# reqconfig, else skip building ourselves.
+#
+# If we are being built externally, confirm installed lws was configured to
+# support reqconfig, else error out with a helpful message about the problem.
+#
+MACRO(require_lws_config reqconfig _val result)
+
+ if (DEFINED ${reqconfig})
+ if (${reqconfig})
+ set (rq 1)
+ else()
+ set (rq 0)
+ endif()
+ else()
+ set(rq 0)
+ endif()
+
+ if (${_val} EQUAL ${rq})
+ set(SAME 1)
+ else()
+ set(SAME 0)
+ endif()
+
+ if (LWS_WITH_MINIMAL_EXAMPLES AND NOT ${SAME})
+ if (${_val})
+ message("${SAMP}: skipping as lws being built without ${reqconfig}")
+ else()
+ message("${SAMP}: skipping as lws built with ${reqconfig}")
+ endif()
+ set(${result} 0)
+ else()
+ if (LWS_WITH_MINIMAL_EXAMPLES)
+ set(MET ${SAME})
+ else()
+ CHECK_C_SOURCE_COMPILES("#include <libwebsockets.h>\nint main(void) {\n#if defined(${reqconfig})\n return 0;\n#else\n fail;\n#endif\n return 0;\n}\n" HAS_${reqconfig})
+ if (NOT DEFINED HAS_${reqconfig} OR NOT HAS_${reqconfig})
+ set(HAS_${reqconfig} 0)
+ else()
+ set(HAS_${reqconfig} 1)
+ endif()
+ if ((HAS_${reqconfig} AND ${_val}) OR (NOT HAS_${reqconfig} AND NOT ${_val}))
+ set(MET 1)
+ else()
+ set(MET 0)
+ endif()
+ endif()
+ if (NOT MET)
+ if (${_val})
+ message(FATAL_ERROR "This project requires lws must have been configured with ${reqconfig}")
+ else()
+ message(FATAL_ERROR "Lws configuration of ${reqconfig} is incompatible with this project")
+ endif()
+ endif()
+
+ endif()
+ENDMACRO()
+
+
+set(requirements 1)
+require_lws_config(LWS_ROLE_H1 1 requirements)
+require_lws_config(LWS_WITH_SERVER 1 requirements)
+require_lws_config(LWS_WITH_HTTP2 1 requirements)
+
+if (requirements)
+ add_executable(${SAMP} ${SRCS})
+
+ if (websockets_shared)
+ target_link_libraries(${SAMP} websockets_shared)
+ add_dependencies(${SAMP} websockets_shared)
+ else()
+ target_link_libraries(${SAMP} websockets)
+ endif()
+endif()
diff --git a/minimal-examples/http-server/minimal-http-server-h2-long-poll/README.md b/minimal-examples/http-server/minimal-http-server-h2-long-poll/README.md
new file mode 100644
index 0000000..cc8794b
--- /dev/null
+++ b/minimal-examples/http-server/minimal-http-server-h2-long-poll/README.md
@@ -0,0 +1,18 @@
+# lws minimal http server
+
+## build
+
+```
+ $ cmake . && make
+```
+
+## usage
+
+```
+ $ ./lws-minimal-http-server
+[2018/03/04 09:30:02:7986] USER: LWS minimal http server | visit http://localhost:7681
+[2018/03/04 09:30:02:7986] NOTICE: Creating Vhost 'default' port 7681, 1 protocols, IPv6 on
+```
+
+Visit http://localhost:7681
+
diff --git a/minimal-examples/http-server/minimal-http-server-h2-long-poll/localhost-100y.cert b/minimal-examples/http-server/minimal-http-server-h2-long-poll/localhost-100y.cert
new file mode 100644
index 0000000..6f372db
--- /dev/null
+++ b/minimal-examples/http-server/minimal-http-server-h2-long-poll/localhost-100y.cert
@@ -0,0 +1,34 @@
+-----BEGIN CERTIFICATE-----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+-----END CERTIFICATE-----
diff --git a/minimal-examples/http-server/minimal-http-server-h2-long-poll/localhost-100y.key b/minimal-examples/http-server/minimal-http-server-h2-long-poll/localhost-100y.key
new file mode 100644
index 0000000..148f859
--- /dev/null
+++ b/minimal-examples/http-server/minimal-http-server-h2-long-poll/localhost-100y.key
@@ -0,0 +1,52 @@
+-----BEGIN PRIVATE KEY-----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+-----END PRIVATE KEY-----
diff --git a/minimal-examples/http-server/minimal-http-server-h2-long-poll/minimal-http-server.c b/minimal-examples/http-server/minimal-http-server-h2-long-poll/minimal-http-server.c
new file mode 100644
index 0000000..197ce5d
--- /dev/null
+++ b/minimal-examples/http-server/minimal-http-server-h2-long-poll/minimal-http-server.c
@@ -0,0 +1,147 @@
+/*
+ * lws-minimal-http-server-h2-long-poll
+ *
+ * Written in 2010-2019 by Andy Green <andy@warmcat.com>
+ *
+ * This file is made available under the Creative Commons CC0 1.0
+ * Universal Public Domain Dedication.
+ *
+ * This demonstrates an h2 server that supports "long poll"
+ * immortal client connections. For simplicity it doesn't serve
+ * any regular files, you can add a mount to do it if you want.
+ *
+ * The protocol keeps the long poll h2 stream open, and sends
+ * the time on the stream once per minute. Normally idle h2
+ * connections are closed by default within 30s, so this demonstrates
+ * the stream and network connection are operating as "immortal"
+ * on both sides.
+ *
+ * See http-client/minimal-http-client-h2-long-poll for the
+ * client example that connects and transitions the stream to the
+ * immortal long poll mode.
+ */
+
+#include <libwebsockets.h>
+#include <string.h>
+#include <signal.h>
+
+static int interrupted;
+
+struct pss {
+ struct lws *wsi;
+ lws_sorted_usec_list_t sul;
+ char pending;
+};
+
+static void
+sul_cb(lws_sorted_usec_list_t *sul)
+{
+ struct pss *pss = (struct pss *)lws_container_of(sul, struct pss, sul);
+
+ pss->pending = 1;
+ lws_callback_on_writable(pss->wsi);
+ /* interval 1min... longer than any normal timeout */
+ lws_sul_schedule(lws_get_context(pss->wsi), 0, &pss->sul, sul_cb,
+ 60 * LWS_US_PER_SEC);
+}
+
+static int
+callback_http(struct lws *wsi, enum lws_callback_reasons reason, void *user,
+ void *in, size_t len)
+{
+ struct pss * pss = (struct pss *)user;
+ uint8_t buf[LWS_PRE + LWS_RECOMMENDED_MIN_HEADER_SPACE],
+ *start = &buf[LWS_PRE], *p = start,
+ *end = p + sizeof(buf) - LWS_PRE;
+ int m, n;
+
+ switch (reason) {
+ case LWS_CALLBACK_HTTP:
+ lwsl_user("%s: connect\n", __func__);
+ pss->wsi = wsi;
+
+ if (lws_add_http_common_headers(wsi, HTTP_STATUS_OK,
+ "text/html",
+ LWS_ILLEGAL_HTTP_CONTENT_LEN, /* no content len */
+ &p, end))
+ return 1;
+ if (lws_finalize_write_http_header(wsi, start, &p, end))
+ return 1;
+
+ sul_cb(&pss->sul);
+ return 0;
+
+ case LWS_CALLBACK_CLOSED_HTTP:
+ if (!pss)
+ break;
+ lws_sul_schedule(lws_get_context(wsi), 0, &pss->sul, sul_cb,
+ LWS_SET_TIMER_USEC_CANCEL);
+ break;
+
+ case LWS_CALLBACK_HTTP_WRITEABLE:
+ if (!pss->pending)
+ break;
+ n = lws_snprintf((char *)p, sizeof(buf) - LWS_PRE, "%llu",
+ (unsigned long long)lws_now_usecs());
+ m = lws_write(wsi, p, n, LWS_WRITE_HTTP);
+ if (m < n) {
+ lwsl_err("ERROR %d writing to socket\n", n);
+ return -1;
+ }
+ break;
+ default:
+ break;
+ }
+
+ return lws_callback_http_dummy(wsi, reason, user, in, len);
+}
+
+static struct lws_protocols protocols[] = {
+ { "http", callback_http, sizeof(struct pss), 0 },
+ { NULL, NULL, 0, 0 } /* terminator */
+};
+
+
+void sigint_handler(int sig)
+{
+ interrupted = 1;
+}
+
+int main(int argc, const char **argv)
+{
+ struct lws_context_creation_info info;
+ struct lws_context *context;
+ const char *p;
+ int n = 0, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE;
+
+ signal(SIGINT, sigint_handler);
+
+ if ((p = lws_cmdline_option(argc, argv, "-d")))
+ logs = atoi(p);
+
+ lws_set_log_level(logs, NULL);
+ lwsl_user("LWS minimal http server h2 long poll\n");
+
+ memset(&info, 0, sizeof info); /* otherwise uninitialized garbage */
+ info.port = 7681;
+ info.ssl_cert_filepath = "localhost-100y.cert";
+ info.ssl_private_key_filepath = "localhost-100y.key";
+ info.protocols = protocols;
+ info.options =
+ LWS_SERVER_OPTION_DO_SSL_GLOBAL_INIT |
+ LWS_SERVER_OPTION_VH_H2_HALF_CLOSED_LONG_POLL |
+ LWS_SERVER_OPTION_HTTP_HEADERS_SECURITY_BEST_PRACTICES_ENFORCE;
+
+ context = lws_create_context(&info);
+ if (!context) {
+ lwsl_err("lws init failed\n");
+ return 1;
+ }
+
+ while (n >= 0 && !interrupted)
+ n = lws_service(context, 0);
+
+ lws_context_destroy(context);
+
+ return 0;
+}