api: started work on creating a common API framework

The idea is that this will become a common API framework for both HTTP
and HTSP. And anything else we might think off.

The only real constraint at the moment is both assume a JSON like input
format (for simplicity) since they currently have that in common.

Makefile

@@ -109,6 +109,9 @@ SRCS =  src/version.c \
 	src/descrambler/descrambler.c \
 	src/service_mapper.c \
 
+SRCS += \
+	src/api.c \
+
 SRCS += \
 	src/parsers/parsers.c \
 	src/parsers/bitstream.c \
@@ -136,6 +139,7 @@ SRCS += src/webui/webui.c \
 	src/webui/simpleui.c \
 	src/webui/statedump.c \
 	src/webui/html.c\
+	src/webui/api.c\
 
 SRCS += src/muxer.c \
 	src/muxer/muxer_pass.c \

src/api.c

@@ -0,0 +1,110 @@
+/*
+ *  API - Common functions for control/query API
+ *
+ *  Copyright (C) 2013 Adam Sutton
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "tvheadend.h"
+#include "api.h"
+#include "access.h"
+
+#include <string.h>
+
+typedef struct api_link {
+  const api_hook_t   *hook;
+  RB_ENTRY(api_link)  link;
+} api_link_t;
+
+RB_HEAD(,api_link) api_hook_tree;
+
+static int ah_cmp
+  ( api_link_t *a, api_link_t *b )
+{
+  return strcmp(a->hook->ah_subsystem, b->hook->ah_subsystem);
+}
+
+void
+api_register ( const api_hook_t *hooks )
+{
+  static api_link_t *t, *skel = NULL;
+  while (hooks->ah_subsystem) {
+    if (!skel)
+      skel = calloc(1, sizeof(api_link_t));
+    skel->hook = hooks;
+    t = RB_INSERT_SORTED(&api_hook_tree, skel, link, ah_cmp);
+    if (t)
+      tvherror("api", "trying to re-register subsystem");
+    else
+      skel = NULL;
+    hooks++;
+  }
+}
+
+int
+api_exec ( const char *subsystem, htsmsg_t *args, htsmsg_t **resp )
+{
+  api_hook_t h;
+  api_link_t *ah, skel;
+  const char *op;
+
+  /* Args and response must be set */
+  if (!args || !resp)
+    return EINVAL;
+
+  // Note: there is no locking while checking the hook tree, its assumed
+  //       this is all setup during init (if this changes the code will
+  //       need updating)
+  h.ah_subsystem = subsystem;
+  skel.hook      = &h;
+  ah = RB_FIND(&api_hook_tree, &skel, link, ah_cmp);
+
+  if (!ah) {
+    tvhwarn("api", "failed to find subsystem [%s]", subsystem);
+    return ENOSYS; // TODO: is this really the right error code?
+  }
+
+  /* Extract method */
+  op = htsmsg_get_str(args, "method");
+  if (!op)
+    op = htsmsg_get_str(args, "op");
+  // Note: this is not required (so no final validation)
+
+  /* Execute */
+  return ah->hook->ah_callback(ah->hook->ah_opaque, op, args, resp);
+}
+
+static int
+api_serverinfo
+  ( void *opaque, const char *op, htsmsg_t *args, htsmsg_t **resp )
+{
+  *resp = htsmsg_create_map();
+  htsmsg_add_str(*resp, "sw_version",   tvheadend_version);
+  htsmsg_add_u32(*resp, "api_version",  TVH_API_VERSION);
+  htsmsg_add_str(*resp, "name",         "Tvheadend");
+  if (tvheadend_webroot)
+    htsmsg_add_str(*resp, "webroot",      tvheadend_webroot);
+  htsmsg_add_msg(*resp, "capabilities", tvheadend_capabilities_list(1));
+  return 0;
+}
+
+void api_init ( void )
+{
+  static api_hook_t h[] = {
+    { "serverinfo", ACCESS_ANONYMOUS, api_serverinfo, NULL },
+    { NULL, 0, NULL, NULL }
+  };
+  api_register(h);
+}

src/api.h

@@ -0,0 +1,58 @@
+/*
+ *  API - Common functions for control/query API
+ *
+ *  Copyright (C) 2013 Adam Sutton
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __TVH_API_H__
+#define __TVH_API_H__
+
+#include "htsmsg.h"
+#include "redblack.h"
+
+#define TVH_API_VERSION 12
+
+/*
+ * Command hook
+ */
+
+typedef int (*api_callback_t)
+  ( void *opaque, const char *op, htsmsg_t *args, htsmsg_t **resp );
+
+typedef struct api_hook
+{
+  const char         *ah_subsystem;
+  int                 ah_access;
+  api_callback_t      ah_callback;
+  void               *ah_opaque;
+} api_hook_t;
+
+/*
+ * Regsiter handler
+ */
+void api_register ( const api_hook_t *hooks );
+
+/*
+ * Execute
+ */
+int  api_exec ( const char *subsystem, htsmsg_t *args, htsmsg_t **resp );
+
+/*
+ * Initialise
+ */
+void api_init ( void );
+
+#endif /* __TVH_API_H__ */

src/main.c

@@ -37,6 +37,7 @@
 #include <arpa/inet.h>
 
 #include "tvheadend.h"
+#include "api.h"
 #include "tcp.h"
 #include "access.h"
 #include "http.h"
@@ -687,6 +688,8 @@ main(int argc, char **argv)
   /**
    * Initialize subsystems
    */
+  
+  api_init();
 
 #if ENABLE_LIBAV
   libav_init();

src/webui/api.c

@@ -0,0 +1,83 @@
+/*
+ *  tvheadend, WebAPI access point
+ *
+ *  Copyright (C) 2013 Adam Sutton
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "tvheadend.h"
+#include "webui.h"
+#include "access.h"
+#include "http.h"
+#include "api.h"
+#include "htsmsg.h"
+#include "htsmsg_json.h"
+
+static int
+webui_api_handler
+  ( http_connection_t *hc, const char *remain, void *opaque )
+{
+  int r;
+  htsmsg_t *args, *resp;
+  const char *a  = http_arg_get(&hc->hc_req_args, "args");
+  const char *op = http_arg_get(&hc->hc_req_args, "method");
+
+  // Compat
+  if (!op)
+    op = http_arg_get(&hc->hc_req_args, "op");
+
+
+  /* Parse arguments */
+  if (a)
+    args = htsmsg_json_deserialize(a);
+  else
+    args = htsmsg_create_map();
+  if (!args)
+    return HTTP_STATUS_BAD_REQUEST;
+
+  /* Add operation */
+  if (!htsmsg_get_str(args, "method") && op)
+    htsmsg_add_str(args, "method", op);
+
+  /* Call */
+  r = api_exec(remain, args, &resp);
+  
+  /* Convert error */
+  if (r) {
+    switch (r) {
+      case EACCES:
+        r = HTTP_STATUS_UNAUTHORIZED;
+      case ENOENT:
+      case ENOSYS:
+        r = HTTP_STATUS_NOT_FOUND;
+      default:
+        r = HTTP_STATUS_BAD_REQUEST;
+    }
+
+  /* Output response */
+  } else {
+    htsmsg_json_serialize(resp, &hc->hc_reply, 0);
+    http_output_content(hc, "text/x-json; charset=UTF-8");
+    htsmsg_destroy(resp);
+  }
+  
+  return r;
+}
+
+void
+webui_api_init ( void )
+{
+  http_path_add("/api", NULL, webui_api_handler, ACCESS_WEB_INTERFACE);
+}

src/webui/webui.c

@@ -974,5 +974,6 @@ webui_init(void)
   simpleui_start();
   extjs_start();
   comet_init();
+  webui_api_init();
 
 }

src/webui/webui.h

@@ -46,6 +46,8 @@ void extjs_service_update(htsmsg_t *in);
 
 void extjs_service_delete(htsmsg_t *in);
 
+void webui_api_init ( void );
+
 
 /**
  *