* Set access/subscribe base URL with: CLICON_STREAM_URL_PREFIX (default https\

://localhost/streams).
    * Example: new stream "foo" will get access URL: https://localhost/streams/\
foo
  * Optional pub/sub support enabled by ./configure --enable-publish
    * Set publish URL base with: CLICON_STREAM_PUB_PREFIX (default http://local\
host/pub)
    * Example: new stream "foo" will get pub URL: https://localhost/pub/foo

CHANGELOG.md

@@ -24,6 +24,11 @@
   * See clicon_stream.[ch] for details
   * Added stream discovery according to RFC 5277 for netconf and RFC 8040 for restconf
     * Enabled by CLICON_STREAM_DISCOVERY_RFC5277 and CLICON_STREAM_DISCOVERY_RFC8040.
+  * Set access/subscribe base URL with: CLICON_STREAM_URL_PREFIX (default https://localhost/streams).
+    * Example: new stream "foo" will get access URL: https://localhost/streams/foo
+  * Optional pub/sub support enabled by ./configure --enable-publish
+    * Set publish URL base with: CLICON_STREAM_PUB_PREFIX (default http://localhost/pub)
+    * Example: new stream "foo" will get pub URL: https://localhost/pub/foo
 
 ### API changes on existing features (you may need to change your code)
 * Netconf hello capability updated to YANG 1.1 RFC7950 Sec 5.6.4

apps/backend/backend_client.c

@@ -81,14 +81,20 @@ ce_find_bypid(struct client_entry *ce_list,
     return NULL;
 }
 
+/*! Stream callback for netconf stream notification (RFC 5277)
+ * @param[in]  h     Clicon handle
+ * @param[in]  event Event as XML
+ * @param[in]  arg   Extra argument provided in stream_cb_add
+ * @see stream_cb_add
+ */
 static int
 ce_event_cb(clicon_handle h,
-	    void         *event,
+	    cxobj        *event,
 	    void         *arg)
 {
     struct client_entry *ce = (struct client_entry *)arg;
     
-    if (send_msg_notify_xml(ce->ce_s, (cxobj*)event) < 0){
+    if (send_msg_notify_xml(ce->ce_s, event) < 0){
 	if (errno == ECONNRESET || errno == EPIPE){
 	    clicon_log(LOG_WARNING, "client %d reset", ce->ce_nr);
 #if 0

apps/backend/backend_main.c

@@ -91,6 +91,7 @@ backend_terminate(clicon_handle h)
 	yspec_free(yspec);
     if ((x = clicon_conf_xml(h)) != NULL)
 	xml_free(x);
+    stream_publish_exit();
     clixon_plugin_exit(h);
     /* Delete all backend plugin RPC callbacks */
     rpc_callback_delete_all(); 
@@ -720,9 +721,9 @@ main(int    argc,
 	return -1;
     }
 
-    if (stream_register(h, "NETCONF", "default NETCONF event stream") < 0)
+    /* Publish stream on pubsub channels XXX conditional? */
+    if (stream_publish_init() < 0)
 	goto done;
-	
     if ((xmldb_plugin = clicon_xmldb_plugin(h)) == NULL){
 	clicon_log(LOG_ERR, "No xmldb plugin given (specify option CLICON_XMLDB_PLUGIN).\n"); 
 	goto done;

apps/restconf/restconf_main.c

@@ -664,6 +664,7 @@ main(int    argc,
 	clicon_err(OE_CFG, errno, "FCGX_Init");
 	goto done;
     }
+    clicon_debug(1, "restconf_main: Opening FCGX socket: %s", sockpath);
     if ((sock = FCGX_OpenSocket(sockpath, 10)) < 0){
 	clicon_err(OE_CFG, errno, "FCGX_OpenSocket");
 	goto done;

configure

@@ -686,7 +686,6 @@ infodir
 docdir
 oldincludedir
 includedir
-runstatedir
 localstatedir
 sharedstatedir
 sysconfdir
@@ -711,6 +710,7 @@ ac_user_opts='
 enable_option_checking
 enable_debug
 with_cligen
+enable_publish
 with_restconf
 with_configfile
 '
@@ -763,7 +763,6 @@ datadir='${datarootdir}'
 sysconfdir='${prefix}/etc'
 sharedstatedir='${prefix}/com'
 localstatedir='${prefix}/var'
-runstatedir='${localstatedir}/run'
 includedir='${prefix}/include'
 oldincludedir='/usr/include'
 docdir='${datarootdir}/doc/${PACKAGE}'
@@ -1016,15 +1015,6 @@ do
   | -silent | --silent | --silen | --sile | --sil)
     silent=yes ;;
 
-  -runstatedir | --runstatedir | --runstatedi | --runstated \
-  | --runstate | --runstat | --runsta | --runst | --runs \
-  | --run | --ru | --r)
-    ac_prev=runstatedir ;;
-  -runstatedir=* | --runstatedir=* | --runstatedi=* | --runstated=* \
-  | --runstate=* | --runstat=* | --runsta=* | --runst=* | --runs=* \
-  | --run=* | --ru=* | --r=*)
-    runstatedir=$ac_optarg ;;
-
   -sbindir | --sbindir | --sbindi | --sbind | --sbin | --sbi | --sb)
     ac_prev=sbindir ;;
   -sbindir=* | --sbindir=* | --sbindi=* | --sbind=* | --sbin=* \
@@ -1162,7 +1152,7 @@ fi
 for ac_var in	exec_prefix prefix bindir sbindir libexecdir datarootdir \
 		datadir sysconfdir sharedstatedir localstatedir includedir \
 		oldincludedir docdir infodir htmldir dvidir pdfdir psdir \
-		libdir localedir mandir runstatedir
+		libdir localedir mandir
 do
   eval ac_val=\$$ac_var
   # Remove trailing slashes.
@@ -1315,7 +1305,6 @@ Fine tuning of the installation directories:
   --sysconfdir=DIR        read-only single-machine data [PREFIX/etc]
   --sharedstatedir=DIR    modifiable architecture-independent data [PREFIX/com]
   --localstatedir=DIR     modifiable single-machine data [PREFIX/var]
-  --runstatedir=DIR       modifiable per-process data [LOCALSTATEDIR/run]
   --libdir=DIR            object code libraries [EPREFIX/lib]
   --includedir=DIR        C header files [PREFIX/include]
   --oldincludedir=DIR     C header files for non-gcc [/usr/include]
@@ -1349,6 +1338,8 @@ Optional Features:
   --disable-FEATURE       do not include FEATURE (same as --enable-FEATURE=no)
   --enable-FEATURE[=ARG]  include FEATURE [ARG=yes]
   --enable-debug          Build with debug symbols, default: no
+  --enable-publish        Enable publish of notification streams using SSE and
+                          curl
 
 Optional Packages:
   --with-PACKAGE[=ARG]    use PACKAGE [ARG=yes]
@@ -2195,6 +2186,7 @@ _ACEOF
 
 
 
+# AC_SUBST(var) makes @var@ appear in makefiles.
 # clixon versions spread to Makefile's (.so files) and variable in build.c
 
 
@@ -3687,6 +3679,77 @@ if test "${with_cligen}"; then
   test -d "$with_cligen" && CLIGEN_PREFIX="$with_cligen"
 fi
 
+# Experimental: Curl publish notification stream to eg Nginx nchan.
+# Check whether --enable-publish was given.
+if test "${enable_publish+set}" = set; then :
+  enableval=$enable_publish;
+	  if test "$enableval" = no; then
+	      ac_enable_publish=no
+	  else
+	      ac_enable_publish=yes
+          fi
+
+else
+   ac_enable_publish=no
+fi
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: publish is $ac_enable_publish" >&5
+$as_echo "publish is $ac_enable_publish" >&6; }
+
+if test "$ac_enable_publish" = "yes"; then
+   # publish streams uses libcurl
+   { $as_echo "$as_me:${as_lineno-$LINENO}: checking for curl_global_init in -lcurl" >&5
+$as_echo_n "checking for curl_global_init in -lcurl... " >&6; }
+if ${ac_cv_lib_curl_curl_global_init+:} false; then :
+  $as_echo_n "(cached) " >&6
+else
+  ac_check_lib_save_LIBS=$LIBS
+LIBS="-lcurl  $LIBS"
+cat confdefs.h - <<_ACEOF >conftest.$ac_ext
+/* end confdefs.h.  */
+
+/* Override any GCC internal prototype to avoid an error.
+   Use char because int might match the return type of a GCC
+   builtin and then its argument prototype would still apply.  */
+#ifdef __cplusplus
+extern "C"
+#endif
+char curl_global_init ();
+int
+main ()
+{
+return curl_global_init ();
+  ;
+  return 0;
+}
+_ACEOF
+if ac_fn_c_try_link "$LINENO"; then :
+  ac_cv_lib_curl_curl_global_init=yes
+else
+  ac_cv_lib_curl_curl_global_init=no
+fi
+rm -f core conftest.err conftest.$ac_objext \
+    conftest$ac_exeext conftest.$ac_ext
+LIBS=$ac_check_lib_save_LIBS
+fi
+{ $as_echo "$as_me:${as_lineno-$LINENO}: result: $ac_cv_lib_curl_curl_global_init" >&5
+$as_echo "$ac_cv_lib_curl_curl_global_init" >&6; }
+if test "x$ac_cv_lib_curl_curl_global_init" = xyes; then :
+  cat >>confdefs.h <<_ACEOF
+#define HAVE_LIBCURL 1
+_ACEOF
+
+  LIBS="-lcurl $LIBS"
+
+else
+  as_fn_error $? "libcurl missing" "$LINENO" 5
+fi
+
+
+$as_echo "#define CLIXON_PUBLISH_STREAMS 1" >>confdefs.h
+
+fi
+
 
 { $as_echo "$as_me:${as_lineno-$LINENO}: checking for grep that handles long lines and -e" >&5
 $as_echo_n "checking for grep that handles long lines and -e... " >&6; }

configure.ac

@@ -63,6 +63,7 @@ AC_DEFINE_UNQUOTED(CLIXON_VERSION_MINOR, $CLIXON_VERSION_MINOR, [Clixon minor re
 AC_DEFINE_UNQUOTED(CLIXON_VERSION_PATCH, $CLIXON_VERSION_PATCH, [Clixon path version])
 
 
+# AC_SUBST(var) makes @var@ appear in makefiles.
 # clixon versions spread to Makefile's (.so files) and variable in build.c
 AC_SUBST(CLIXON_VERSION)
 AC_SUBST(CLIXON_VERSION_STRING)
@@ -144,6 +145,23 @@ if test "${with_cligen}"; then
   test -d "$with_cligen" && CLIGEN_PREFIX="$with_cligen"
 fi
 
+# Experimental: Curl publish notification stream to eg Nginx nchan. 
+AC_ARG_ENABLE(publish, AS_HELP_STRING([--enable-publish],[Enable publish of notification streams using SSE and curl]),[
+	  if test "$enableval" = no; then
+	      ac_enable_publish=no
+	  else	      
+	      ac_enable_publish=yes
+          fi
+        ],
+	[ ac_enable_publish=no])
+AC_MSG_RESULT(publish is $ac_enable_publish)	
+
+if test "$ac_enable_publish" = "yes"; then
+   # publish streams uses libcurl
+   AC_CHECK_LIB(curl, curl_global_init,, AC_MSG_ERROR([libcurl missing]))
+   AC_DEFINE(CLIXON_PUBLISH_STREAMS, 1, [Enable publish of notification streams using SSE and curl])
+fi
+
 AC_CHECK_HEADERS(cligen/cligen.h,, AC_MSG_ERROR(cligen missing. Try: git clone https://github.com/olofhagsand/cligen.git))
 
 AC_CHECK_LIB(cligen, cligen_init,, AC_MSG_ERROR([CLIgen${CLIGEN_VERSION} missing. Try: git clone https://github.com/olofhagsand/cligen.git]))

datastore/text/clixon_xmldb_text.c

@@ -125,7 +125,7 @@ text_db2file(struct text_handle *th,
 	     char              **filename)
 {
     int   retval = -1;
-    cbuf *cb;
+    cbuf *cb = NULL;
     char *dir;
 
     if ((cb = cbuf_new()) == NULL){

example/Makefile.in

@@ -59,7 +59,6 @@ NETCONF_PLUGIN  = $(APPNAME)_netconf.so
 RESTCONF_PLUGIN = $(APPNAME)_restconf.so
 
 
-
 # Example docker image. PLEASE CHANGE THIS
 IMAGE           = olofhagsand/clixon_example
 

example/example.yang

@@ -22,12 +22,38 @@ module example {
 	base if:interface-type;
     }
     /* Translation function example - See also example_cli */
-
     list translate{
 	leaf value{
 	    type string;
 	}
     }
+    /* State data (not config) for the example application*/
+    container state {
+         config false;
+         description "state data for the example application (must be here for example get operation)";
+         leaf-list op {
+            type string;
+         }
+    }
+    /* Example notification as used in RFC 5277 and RFC 8040 */
+    notification event {
+         description "Example notification event.";
+         leaf event-class {
+           type string;
+           description "Event class identifier.";
+         }
+         container reportingEntity {
+           description "Event specific information.";
+           leaf card {
+             type string;
+             description "Line card identifier.";
+           }
+         }
+         leaf severity {
+           type string;
+           description "Event severity description.";
+         }
+    }
     rpc client-rpc {
 	description "Example local client-side RPC that is processed by the
                      the netconf/restconf and not sent to the backend.

example/example_backend.c

@@ -31,17 +31,14 @@
 
   ***** END LICENSE BLOCK *****
 
- * 
- * IETF yang routing example
  */
-
-
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 #include <signal.h>
 #include <unistd.h>
+#include <assert.h>
 #include <sys/time.h>
 
 /* clicon */
@@ -54,7 +51,7 @@
 #include <clixon/clixon_backend.h> 
 
 /* forward */
-static int notification_timer_setup(clicon_handle h);
+static int example_stream_timer_setup(clicon_handle h);
 
 /*! This is called on validate (and commit). Check validity of candidate
  */
@@ -93,33 +90,33 @@ transaction_commit(clicon_handle    h,
 /*! Routing example notifcation timer handler. Here is where the periodic action is 
  */
 static int
-notification_timer(int   fd, 
+example_stream_timer(int   fd, 
-		   void *arg)
+		     void *arg)
 {
     int                    retval = -1;
     clicon_handle          h = (clicon_handle)arg;
 
     /* XXX Change to actual netconf notifications */
-    if (stream_notify(h, "NETCONF", "<event xmlns=\"http://example.com/event/1.0\"><event-class>fault</event-class><reportingEntity><card>Ethernet0</card></reportingEntity><severity>major</severity></event>") < 0)
+    if (stream_notify(h, "EXAMPLE", "<event><event-class>fault</event-class><reportingEntity><card>Ethernet0</card></reportingEntity><severity>major</severity></event>") < 0)
 	goto done;
-    if (notification_timer_setup(h) < 0)
+    if (example_stream_timer_setup(h) < 0)
 	goto done;
     retval = 0;
  done:
     return retval;
 }
 
-/*! Set up routing notification timer 
+/*! Set up example stream notification timer 
  */
 static int
-notification_timer_setup(clicon_handle h)
+example_stream_timer_setup(clicon_handle h)
 {
     struct timeval t, t1;
 
     gettimeofday(&t, NULL);
     t1.tv_sec = 5; t1.tv_usec = 0;
     timeradd(&t, &t1, &t);
-    return event_reg_timeout(t, notification_timer, h, "notification timer");
+    return event_reg_timeout(t, example_stream_timer, h, "example stream timer");
 }
 
 /*! IETF Routing fib-route rpc 
@@ -230,8 +227,8 @@ example_reset(clicon_handle h,
     cxobj *xt = NULL;
 
     if (xml_parse_string("<config><interfaces><interface>"
-			     "<name>lo</name><type>ex:loopback</type>"
+			 "<name>lo</name><type>ex:loopback</type>"
-			     "</interface></interfaces></config>", NULL, &xt) < 0)
+			 "</interface></interfaces></config>", NULL, &xt) < 0)
 	goto done;
     /* Replace parent w fiorst child */
     if (xml_rootchild(xt, 0, &xt) < 0)
@@ -266,13 +263,19 @@ example_start(clicon_handle h,
     return 0;
 }
 
+int 
+example_exit(clicon_handle h)
+{
+    return 0;
+}
+
 clixon_plugin_api *clixon_plugin_init(clicon_handle h);
 
 static clixon_plugin_api api = {
     "example",                              /* name */    
     clixon_plugin_init,                     /* init - must be called clixon_plugin_init */
     example_start,                          /* start */
-    NULL,                                   /* exit */
+    example_exit,                           /* exit */
     .ca_reset=example_reset,                /* reset */
     .ca_statedata=example_statedata,        /* statedata */
     .ca_trans_begin=NULL,                   /* trans begin */
@@ -292,8 +295,21 @@ clixon_plugin_api *
 clixon_plugin_init(clicon_handle h)
 {
     clicon_debug(1, "%s backend", __FUNCTION__);
-    if (notification_timer_setup(h) < 0)
+
+    /* Example stream initialization:
+     * 1) Register EXAMPLE stream 
+     * 2) setup timer for notifications, so something happens on stream
+     * 3) setup stream callbacks for notification to push channel
+     */
+    if (stream_register(h, "EXAMPLE", "Example event stream") < 0)
 	goto done;
+    /* assumes: CLIXON_PUBLISH_STREAMS, eg configure --enable-publish
+     */
+    if (stream_publish(h, "EXAMPLE") < 0)
+	goto done;
+    if (example_stream_timer_setup(h) < 0)
+	goto done;
+
     /* Register callback for routing rpc calls */
     if (rpc_callback_register(h, fib_route, 
 			      NULL, 
@@ -310,6 +326,7 @@ clixon_plugin_init(clicon_handle h)
 			      "empty"/* Xml tag when callback is made */
 			      ) < 0)
 	goto done;
+
     /* Return plugin API */
     return &api;
  done:

include/clixon_config.h.in

@@ -6,6 +6,9 @@
 /* Location for apps to find default config file */
 #undef CLIXON_DEFAULT_CONFIG
 
+/* Enable publish of notification streams using SSE and curl */
+#undef CLIXON_PUBLISH_STREAMS
+
 /* Clixon major release */
 #undef CLIXON_VERSION_MAJOR
 

lib/clixon/clixon_stream.h

@@ -39,8 +39,13 @@
 /*
  * Types
  */
-/* subscription callback */
+/* Subscription callback 
-typedef	int (*stream_fn_t)(clicon_handle h, void *event, void *arg);
+ * @param[in]  h     Clicon handle
+ * @param[in]  event Event as XML
+ * @param[in]  arg   Extra argument provided in stream_cb_add
+ * @see stream_cb_add
+ */
+typedef	int (*stream_fn_t)(clicon_handle h, cxobj *event, void *arg);
 
 struct stream_subscription{
     struct stream_subscription *ss_next;
@@ -76,6 +81,11 @@ int stream_notify(clicon_handle h, char *stream, const char *event, ...)  __attr
 int stream_notify(clicon_handle h, char *stream, const char *event, ...);
 #endif
 
+/* Experimental publish streams using SSE */
+int stream_publish(clicon_handle h, char *stream);
+int stream_publish_init();
+int stream_publish_exit();
+
 /* Backward compatible macro for <1.8 */
 #define backend_notify_xml(h, stream, level, x) stream_notify_xml(h, stream, x)
 #define backend_notify(h, stream, level, event) stream_notify(h, stream, event)

lib/src/clixon_stream.c

@@ -44,6 +44,7 @@
 #include <string.h>
 #include <errno.h>
 #include <inttypes.h>
+#include <syslog.h>
 #include <sys/time.h>
 
 /* cligen */
@@ -52,6 +53,7 @@
 /* clicon */
 #include "clixon_queue.h"
 #include "clixon_err.h"
+#include "clixon_log.h"
 #include "clixon_string.h"
 #include "clixon_hash.h"
 #include "clixon_handle.h"
@@ -146,6 +148,7 @@ stream_get_xml(clicon_handle h,
 	       cbuf         *cb)
 {
     event_stream_t *es = NULL;
+    char           *url_prefix;
 
     cprintf(cb, "<streams>");
     for (es=clicon_stream(h); es; es=es->es_next){
@@ -157,11 +160,9 @@ stream_get_xml(clicon_handle h,
 	if (access){
 	    cprintf(cb, "<access>");
 	    cprintf(cb, "<encoding>xml</encoding>");
-	    /* Note /stream need to be in http proxy declaration 
+	    url_prefix = clicon_option_str(h, "CLICON_STREAM_URL_PREFIX");
-	     * XXX
+	    cprintf(cb, "<location>%s/%s</location>", 
-	     */
+		    url_prefix, es->es_name);
-	    cprintf(cb, "<location>/stream/%s</location>", es->es_name);
-	    
 	    cprintf(cb, "</access>");
 	}
 	cprintf(cb, "</stream>");
@@ -377,3 +378,207 @@ stream_notify(clicon_handle h,
 	free(str);
     return retval;
 }
+
+#ifdef CLIXON_PUBLISH_STREAMS
+
+#include <curl/curl.h>
+
+/*
+ * Types (curl)
+ */
+struct curlbuf{
+    size_t b_len;
+    char  *b_buf;
+};
+
+/*
+ * For the asynchronous case. I think we must handle the case where of many of these
+ * come in before we can handle them in the upper-level polling routine.
+ * realloc. Therefore, we append new data to the userdata buffer.
+ */
+static size_t
+curl_get_cb(void *ptr, 
+	    size_t size, 
+	    size_t nmemb, 
+	    void *userdata)
+{
+    struct curlbuf *buf = (struct curlbuf *)userdata;
+    int len;
+
+    len = size*nmemb;
+    if ((buf->b_buf = realloc(buf->b_buf, buf->b_len+len+1)) == NULL)
+	return 0;
+    memcpy(buf->b_buf+buf->b_len, ptr, len);
+    buf->b_len += len;
+    buf->b_buf[buf->b_len] = '\0';
+    fprintf(stderr, "%s: %s\n", __FUNCTION__, buf->b_buf);
+    return len;
+}
+
+/*! Send a curl POST request
+ * @retval  -1   fatal error
+ * @retval   0   expect set but did not expected return or other non-fatal error
+ * @retval   1   ok
+ * Note: curl_easy_perform blocks
+ * Note: New handle is created every time, the handle can be re-used for better TCP performance
+ * @see same function (url_post) in grideye_curl.c
+ */
+static int
+url_post(char *url, 
+	 char *postfields, 
+	 char **getdata)
+{
+    int            retval = -1;
+    CURL          *curl = NULL;
+    char          *err = NULL;
+    struct curlbuf cb = {0, };
+    CURLcode       errcode;
+
+    /* Try it with  curl -X PUT -d '*/
+    clicon_debug(1, "%s:  curl -X POST -d '%s' %s",
+	__FUNCTION__, postfields, url);
+    /* Set up curl for doing the communication with the controller */
+    if ((curl = curl_easy_init()) == NULL) {
+	clicon_debug(1, "curl_easy_init");
+	goto done;
+    }
+    if ((err = malloc(CURL_ERROR_SIZE)) == NULL) {
+	clicon_debug(1, "%s: malloc", __FUNCTION__);
+	goto done;
+    }
+    curl_easy_setopt(curl, CURLOPT_URL, url);
+    curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, curl_get_cb);
+    curl_easy_setopt(curl, CURLOPT_WRITEDATA, &cb);
+    curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, err);
+    curl_easy_setopt(curl, CURLOPT_POST, 1);
+    curl_easy_setopt(curl, CURLOPT_POSTFIELDS, postfields);
+    curl_easy_setopt(curl, CURLOPT_POSTFIELDSIZE, strlen(postfields));
+
+    if (debug)
+	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);   
+    if ((errcode = curl_easy_perform(curl)) != CURLE_OK){
+	clicon_debug(1, "%s: curl: %s(%d)", __FUNCTION__, err, errcode);
+	retval = 0;
+	goto done; 
+    }
+    if (getdata && cb.b_buf){
+	*getdata = cb.b_buf;
+	cb.b_buf = NULL;
+    }
+    retval = 1;
+  done:
+    if (err)
+	free(err);
+    if (cb.b_buf)
+	free(cb.b_buf);
+    if (curl)
+	curl_easy_cleanup(curl);   /* cleanup */ 
+    return retval;
+}
+
+/*! Stream callback for example stream notification 
+ * Push via curl_post to publish stream event
+ * @param[in]  h     Clicon handle
+ * @param[in]  event Event as XML
+ * @param[in]  arg   Extra argument provided in stream_cb_add
+ * @see stream_cb_add
+ */
+static int 
+stream_publish_cb(clicon_handle h, 
+		  cxobj        *event,
+		  void         *arg)
+{
+    int   retval = -1;
+    cbuf *u = NULL; /* stream pub (push) url */
+    cbuf *d = NULL; /* (XML) data to push */
+    char *pub_prefix;
+    char *result = NULL;
+    char *stream = (char*)arg;
+
+    clicon_debug(1, "%s", __FUNCTION__); 
+
+    /* Create pub url */
+    if ((u = cbuf_new()) == NULL){
+	clicon_err(OE_XML, errno, "cbuf_new");
+	goto done;
+    }
+    if ((pub_prefix = clicon_option_str(h, "CLICON_STREAM_PUB_PREFIX")) == NULL){
+	clicon_err(OE_CFG, ENOENT, "CLICON_STREAM_PUB_PREFIX not defined");
+	goto done;
+    }
+
+    cprintf(u, "%s/%s", pub_prefix, stream);
+    /* Create XML data as string */
+    if ((d = cbuf_new()) == NULL){
+	clicon_err(OE_XML, errno, "cbuf_new");
+	goto done;
+    }
+    if (clicon_xml2cbuf(d, event, 0, 0) < 0)
+	goto done;
+    if (url_post(cbuf_get(u),     /* url+stream */
+		 cbuf_get(d),     /* postfields */
+		 &result) < 0)    /* result as xml */
+	goto done;
+    if (result)
+	clicon_debug(1, "%s: %s", __FUNCTION__, result);
+    retval = 0;
+ done:
+    if (u)
+	cbuf_free(u);
+    if (d)
+	cbuf_free(d);
+    if (result)
+	free(result);
+    return retval;
+}
+#endif /* CLIXON_PUBLISH_STREAMS */
+
+/*! Publish all streams on a pubsub channel, eg using SSE
+ */
+int
+stream_publish(clicon_handle h,
+	       char         *stream)
+{
+#ifdef CLIXON_PUBLISH_STREAMS
+    int retval = -1;
+
+    if (stream_cb_add(h, stream, NULL, stream_publish_cb, (void*)stream) < 0)
+	goto done;
+    retval = 0;
+ done:
+    return retval;
+#else
+   clicon_log(LOG_WARNING, "%s called but CLIXON_PUBLISH_STREAMS not enabled (enable with configure --enable-publish)", __FUNCTION__);
+   clicon_log_init("xpath", LOG_WARNING, CLICON_LOG_STDERR); 
+   return 0;
+#endif
+}
+
+int 
+stream_publish_init()
+{
+#ifdef CLIXON_PUBLISH_STREAMS
+    int retval = -1;
+
+    if (curl_global_init(CURL_GLOBAL_ALL) != 0){
+	clicon_err(OE_PLUGIN, errno, "curl_global_init");
+	goto done;
+    }    
+    retval = 0;
+ done:
+    return retval;
+#else
+    return 0;
+#endif
+}
+
+int 
+stream_publish_exit()
+{
+#ifdef CLIXON_PUBLISH_STREAMS
+    curl_global_cleanup();
+#endif 
+    return 0;
+}
+
+

test/test_event.sh

@@ -1,6 +1,11 @@
 #!/bin/bash
-# Restconf basic functionality
+# Tests for event streams using notifications
-# Assume http server setup, such as nginx described in apps/restconf/README.md
+# Assumptions:
+# 1. http server setup, such as nginx described in apps/restconf/README.md
+#    especially SSE - ngchan setup
+# 2. Example stream as Clixon example which needs registration, callback and
+#    notification generating code
+
 APPNAME=example
 # include err() and new() functions and creates $dir
 . ./lib.sh
@@ -8,6 +13,7 @@ cfg=$dir/conf.xml
 fyang=$dir/restconf.yang
 xml=$dir/xml.xml
 
+
 #  <CLICON_YANG_MODULE_MAIN>example</CLICON_YANG_MODULE_MAIN>
 cat <<EOF > $cfg
 <config>
@@ -62,7 +68,7 @@ cat <<EOF > $fyang
        }
        container state {
          config false;
-         description "state data for example application";
+         description "state data for the example application (must be here for example get operation)";
          leaf-list op {
             type string;
          }
@@ -92,28 +98,30 @@ sudo start-stop-daemon -S -q -o -b -x /www-data/clixon_restconf -d /www-data -c
 sleep 1
 
 new "netconf event stream discovery RFC5277 Sec 3.2.5"
-expecteof "$clixon_netconf -qf $cfg -y $fyang" 0 '<rpc><get><filter type="xpath" select="netconf/streams" xmlns="urn:ietf:params:xml:ns:netmod:notification"/></get></rpc>]]>]]>' '<rpc-reply><data><netconf><streams><stream><name>NETCONF</name><description>default NETCONF event stream</description><replay-support>false</replay-support></stream></streams></netconf></data></rpc-reply>]]>]]>'
+expecteof "$clixon_netconf -qf $cfg -y $fyang" 0 '<rpc><get><filter type="xpath" select="netconf/streams" xmlns="urn:ietf:params:xml:ns:netmod:notification"/></get></rpc>]]>]]>' '<rpc-reply><data><netconf><streams><stream><name>EXAMPLE</name><description>Example event stream</description><replay-support>false</replay-support></stream></streams></netconf></data></rpc-reply>]]>]]>'
 
 new "netconf event stream discovery RFC8040 Sec 6.2"
-expecteof "$clixon_netconf -qf $cfg -y $fyang" 0 '<rpc><get><filter type="xpath" select="restconf-state/streams" xmlns="urn:ietf:params:xml:ns:netmod:notification"/></get></rpc>]]>]]>' '<rpc-reply><data><restconf-state><streams><stream><name>NETCONF</name><description>default NETCONF event stream</description><replay-support>false</replay-support><access><encoding>xml</encoding><location>/stream/NETCONF</location></access></stream></streams></restconf-state></data></rpc-reply>]]>]]>'
+expecteof "$clixon_netconf -qf $cfg -y $fyang" 0 '<rpc><get><filter type="xpath" select="restconf-state/streams" xmlns="urn:ietf:params:xml:ns:netmod:notification"/></get></rpc>]]>]]>' '<rpc-reply><data><restconf-state><streams><stream><name>EXAMPLE</name><description>Example event stream</description><replay-support>false</replay-support><access><encoding>xml</encoding><location>https://localhost/streams/EXAMPLE</location></access></stream></streams></restconf-state></data></rpc-reply>]]>]]>'
 
 new "restconf event stream discovery RFC8040 Sec 6.2"
-expectfn "curl -s -X GET http://localhost/restconf/data/ietf-restconf-monitoring:restconf-state/streams" 0 '{"streams": {"stream": \[{"name": "NETCONF","description": "default NETCONF event stream","replay-support": false,"access": \[{"encoding": "xml","location": "/stream/NETCONF"}\]}\]}'
+expectfn "curl -s -X GET http://localhost/restconf/data/ietf-restconf-monitoring:restconf-state/streams" 0 '{"streams": {"stream": \[{"name": "EXAMPLE","description": "Example event stream","replay-support": false,"access": \[{"encoding": "xml","location": "https://localhost/streams/EXAMPLE"}\]}\]}'
 
 new "restconf subscribe RFC8040 Sec 6.3, get location"
-expectfn "curl -s -X GET http://localhost/restconf/data/ietf-restconf-monitoring:restconf-state/streams/stream=NETCONF/access=xml/location" 0 '{"location": "/stream/NETCONF"}'
+expectfn "curl -s -X GET http://localhost/restconf/data/ietf-restconf-monitoring:restconf-state/streams/stream=EXAMPLE/access=xml/location" 0 '{"location": "https://localhost/streams/EXAMPLE"}'
 
-new "netconf NETCONF subscription"
+if false; then
-expectwait "$clixon_netconf -qf $cfg -y $fyang" '<rpc><create-subscription><stream>NETCONF</stream></create-subscription></rpc>]]>]]>' '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
+new "netconf EXAMPLE subscription"
+expectwait "$clixon_netconf -qf $cfg -y $fyang" '<rpc><create-subscription><stream>EXAMPLE</stream></create-subscription></rpc>]]>]]>' '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
 
-new "netconf NETCONF subscription with simple filter"
+new "netconf EXAMPLE subscription with simple filter"
-expectwait "$clixon_netconf -qf $cfg -y $fyang" "<rpc><create-subscription><stream>NETCONF</stream><filter type=\"xpath\" select=\"event\"/></create-subscription></rpc>]]>]]>" '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
+expectwait "$clixon_netconf -qf $cfg -y $fyang" "<rpc><create-subscription><stream>EXAMPLE</stream><filter type=\"xpath\" select=\"event\"/></create-subscription></rpc>]]>]]>" '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
 
-new "netconf NETCONF subscription with filter classifier"
+new "netconf EXAMPLE subscription with filter classifier"
-expectwait "$clixon_netconf -qf $cfg -y $fyang" "<rpc><create-subscription><stream>NETCONF</stream><filter type=\"xpath\" select=\"event[event-class='fault']\"/></create-subscription></rpc>]]>]]>" '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
+expectwait "$clixon_netconf -qf $cfg -y $fyang" "<rpc><create-subscription><stream>EXAMPLE</stream><filter type=\"xpath\" select=\"event[event-class='fault']\"/></create-subscription></rpc>]]>]]>" '^<rpc-reply><ok/></rpc-reply>]]>]]><notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>20' 5
+fi
 
-#new "restconf monitor event stream RFC8040 Sec 6.3"
+new "restconf monitor event stream RFC8040 Sec 6.3"
-#XXX expectfn "curl -s -X GET http://localhost/stream/NETCONF" 0 ''
+expectfn "curl  -H \"Accept: text/event-stream\" -s -X GET http://localhost/streams/EXAMPLE" 0 '<notification xmlns="urn:ietf:params:xml:ns:netconf:notification:1.0"><eventTime>2018-10-14T14:17:50.875370</eventTime><event><event-class>fault</event-class><reportingEntity><card>Ethernet0</card></reportingEntity><severity>major</severity></event></notification>'
 
 new "Kill restconf daemon"
 sudo pkill -u www-data clixon_restconf

yang/clixon-config@2018-04-30.yang

@@ -390,5 +390,23 @@ module clixon-config {
                          sections 3.2. If enabled, available streams will appear
                          when doing netconf get or restconf GET";
 	}
+	leaf CLICON_STREAM_URL_PREFIX {
+	    type string;
+	    default "https://localhost/streams";
+    	    description "See RFC 8040 Sec 9.3 location leaf: 
+	          'Contains a URL that represents the entry point for 
+		  establishing notification delivery via server-sent events.'
+		  Prepend this constant to name of stream.
+                  Example: https://localhost/streams/NETCONF. Note this is the
+		  external URL, not local behind a reverse-proxy";
+	}
+	leaf CLICON_STREAM_PUB_PREFIX {
+	    type string;
+	    default "http://localhost/pub";
+    	    description "For stream publish using eg nchan, the base address
+	          to publish to. 
+                  Example: http://localhost/pub/NETCONF. Note this may
+		  be local URL behind reverse-proxy";
+	}
     }
 }