Added device/port_stack API endpoint. Updated documentation

doc/API/API-Docs.md

@@ -13,6 +13,7 @@
         - [`get_graphs`](#api-route-5)
         - [`get_graph_generic_by_hostname`](#api-route-6)
         - [`get_port_graphs`](#api-route-7)
+        - [`get_port_stack`](#api-route-29)
         - [`get_components`](#api-route-25)
         - [`add_components`](#api-route-26)
         - [`edit_components`](#api-route-27)
@@ -275,6 +276,47 @@ Output:
 }
 ```
 
+### <a name="api-route-29">Function: `get_port_stack`</a> [`top`](#top)
+
+Get a list of port mappings for a device.  This is useful for showing physical ports that are in a virtual port-channel.
+
+Route: /api/v0/devices/:hostname/port_stack
+
+- hostname can be either the device hostname or id
+
+Input:
+
+ - valid_mappings: Filter the result by only showing valid mappings ("0" values not shown).
+
+Example:
+```curl
+curl -H 'X-Auth-Token: YOURAPITOKENHERE' https://librenms.org/api/v0/devices/localhost/port_stack?valid_mappings
+```
+
+Output:
+
+```text
+{
+  "status": "ok",
+  "err-msg": "",
+  "count": 2,
+  "mappings": [
+    {
+      "device_id": "3742",
+      "port_id_high": "1001000",
+      "port_id_low": "51001",
+      "ifStackStatus": "active"
+    },
+    {
+      "device_id": "3742",
+      "port_id_high": "1001000",
+      "port_id_low": "52001",
+      "ifStackStatus": "active"
+    }
+  ]
+}
+```
+
 ### <a name="api-route-25">Function: `get_components`</a> [`top`](#top)
 
 Get a list of components for a particular device.

html/includes/api_functions.inc.php

@@ -726,10 +726,15 @@ function get_port_stack() {
     $app      = \Slim\Slim::getInstance();
     $router   = $app->router()->getCurrentRoute()->getParams();
     $hostname = $router['hostname'];
-
     // use hostname as device_id if it's all digits
     $device_id      = ctype_digit($hostname) ? $hostname : getidbyname($hostname);
+
+    if (isset($_GET['valid_mappings'])) {
+        $mappings       = dbFetchRows("SELECT * FROM `ports_stack` WHERE (`device_id` = ? AND `ifStackStatus` = 'active' AND (`port_id_high` != '0' AND `port_id_low` != '0')) ORDER BY `port_id_high` ASC", array($device_id));
+    } else {
         $mappings       = dbFetchRows("SELECT * FROM `ports_stack` WHERE `device_id` = ? AND `ifStackStatus` = 'active' ORDER BY `port_id_high` ASC", array($device_id));
+    }
+
     $total_mappings = count($mappings);
     $output         = array(
         'status'  => 'ok',