tests/examples: add example on how to set node "params" under Props

tests/examples/meson.build

@@ -0,0 +1,5 @@
+executable('node-extra-params',
+  'node-extra-params.c',
+  install: false,
+  dependencies : [wp_dep],
+)

tests/examples/node-extra-params.c

@@ -0,0 +1,179 @@
+/* WirePlumber
+ *
+ * Copyright © 2024 Collabora Ltd.
+ *    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * This is an example that shows how to correctly set additional node properties
+ * that reside in a special "Props" field that is called "params". These show up
+ * in pw-dump as an array, like this:
+ *
+ *  "Props": [
+ *    {
+ *      ...
+ *      "params": [
+ *        "key1",
+ *        value1,
+ *        "key2",
+ *        value2,
+ *        ...
+ *      ]
+ *    },
+ *    {
+ *      "params": [
+ *        "additional_key",
+ *        additional_value,
+ *      ]
+ *    }
+ *  ],
+ *
+ * The correct way to set them is to construct a Props object that has a "params"
+ * property and inside that property add a POD structure with the key/value
+ * pairs listed in order.
+ *
+ * This example also parses the key/value pairs from a JSON array that is provided
+ * on the command line, so you can call this like this:
+ *
+ *  $ ./filter-chain-params NODE_ID '["key1", value1, "key2", value2]'
+ *
+ */
+
+#include <wp/wp.h>
+#include <stdio.h>
+
+typedef struct
+{
+  GMainLoop *loop;
+  WpCore *core;
+  WpObjectManager *om;
+
+  gint arg_id;
+  WpSpaJson *arg_params;
+} Data;
+
+static void
+async_quit (WpCore * core, GAsyncResult * res, Data * data)
+{
+  g_main_loop_quit (data->loop);
+}
+
+static WpSpaPod *
+construct_params_pod (WpSpaJson * params_j)
+{
+  // the inner POD is a struct
+  g_autoptr (WpSpaPodBuilder) b_struct = wp_spa_pod_builder_new_struct ();
+
+  // iterate the JSON array and fill the inner POD
+  int state = 0;
+  g_autoptr (WpIterator) it = wp_spa_json_new_iterator (params_j);
+  g_auto (GValue) val = G_VALUE_INIT;
+
+  for (; wp_iterator_next (it, &val); g_value_unset (&val)) {
+    WpSpaJson *val_json = g_value_get_boxed (&val);
+    switch (state) {
+      case 0: { //parsing key
+        g_autofree gchar * key = wp_spa_json_parse_string (val_json);
+        wp_spa_pod_builder_add_string (b_struct, key);
+        break;
+      }
+      case 1: //parsing value
+        if (wp_spa_json_is_int (val_json)) {
+          gint value = 0;
+          wp_spa_json_parse_int (val_json, &value);
+          wp_spa_pod_builder_add_int (b_struct, value);
+        }
+        else if (wp_spa_json_is_float (val_json)) {
+          gfloat value = 0.0;
+          wp_spa_json_parse_float (val_json, &value);
+          wp_spa_pod_builder_add_float (b_struct, value);
+        }
+        else if (wp_spa_json_is_boolean (val_json)) {
+          gboolean value = FALSE;
+          wp_spa_json_parse_boolean (val_json, &value);
+          wp_spa_pod_builder_add_boolean (b_struct, value);
+        }
+        else {
+          g_autofree gchar * value = wp_spa_json_parse_string (val_json);
+          wp_spa_pod_builder_add_string (b_struct, value);
+        }
+        break;
+      default:
+        break;
+    }
+    state = (state + 1) % 2;
+  }
+
+  if (state == 1)
+    printf ("WARNING: last key didn't have a value!\n");
+
+  g_autoptr (WpSpaPod) pod_struct = wp_spa_pod_builder_end (b_struct);
+
+  // now fill the outer POD, which is an object of type Props
+  g_autoptr (WpSpaPodBuilder) b_obj =
+      wp_spa_pod_builder_new_object ("Spa:Pod:Object:Param:Props", "Props");
+  wp_spa_pod_builder_add (b_obj, "params", "P", pod_struct, NULL);
+
+  return wp_spa_pod_builder_end (b_obj);
+}
+
+static void
+on_om_installed (WpObjectManager * om, Data * data)
+{
+  g_autoptr (WpPipewireObject) pwobj = wp_object_manager_lookup (om, WP_TYPE_NODE,
+      WP_CONSTRAINT_TYPE_G_PROPERTY, "bound-id", "=u", data->arg_id, NULL);
+
+  wp_pipewire_object_set_param (pwobj, "Props", 0,
+      construct_params_pod (data->arg_params));
+
+  wp_core_sync (data->core, NULL, (GAsyncReadyCallback) async_quit, data);
+}
+
+static void
+on_core_activated (WpObject * core, GAsyncResult * res, Data * data)
+{
+  g_autoptr (GError) error = NULL;
+
+  if (!wp_object_activate_finish (core, res, &error)) {
+    fprintf (stderr, "%s\n", error->message);
+    g_main_loop_quit (data->loop);
+    return;
+  }
+
+  data->om = wp_object_manager_new ();
+  wp_object_manager_add_interest (data->om, WP_TYPE_NODE,
+      WP_CONSTRAINT_TYPE_G_PROPERTY, "bound-id", "=u", data->arg_id, NULL);
+  wp_object_manager_request_object_features (data->om, WP_TYPE_NODE,
+      WP_PIPEWIRE_OBJECT_FEATURES_ALL);
+  g_signal_connect (data->om, "installed", G_CALLBACK (on_om_installed), data);
+  wp_core_install_object_manager (data->core, data->om);
+}
+
+int
+main (int argc, char **argv)
+{
+  Data data = {0};
+
+  wp_init (WP_INIT_ALL);
+
+  if (argc < 2) {
+    printf ("Usage: %s ID '[param1, value1, param2, value2, ...]'\n", argv[0]);
+    return 1;
+  }
+
+  data.loop = g_main_loop_new (NULL, FALSE);
+  data.core = wp_core_new (NULL, NULL, NULL);
+
+  data.arg_id = atoi (argv[1]);
+  data.arg_params = wp_spa_json_new_wrap_string (argv[2]);
+
+  wp_object_activate (WP_OBJECT (data.core), WP_CORE_FEATURE_CONNECTED, NULL,
+      (GAsyncReadyCallback) on_core_activated, &data);
+
+  g_main_loop_run (data.loop);
+
+  wp_spa_json_unref (data.arg_params);
+  g_object_unref (data.core);
+  g_main_loop_unref (data.loop);
+  return 0;
+}

tests/meson.build

@@ -64,3 +64,4 @@ if build_modules
   subdir('scripts')
   subdir('modules')
 endif
+subdir('examples')