examples: add an example interactive lua script

tests/examples/interactive.lua

@@ -0,0 +1,151 @@
+-- WirePlumber
+--
+-- Copyright © 2021 Collabora Ltd.
+--    @author George Kiagiadakis <george.kiagiadakis@collabora.com>
+--
+-- SPDX-License-Identifier: MIT
+--
+-- This is an example of an interactive script
+--
+-- Execute with:
+-- wireplumber -e /path/to/interactive.lua option1=value1 option2=value2 ...
+--
+-- Using an absolute path to the script is necessary, otherwise
+-- wireplumber will try to locate the script in $WIREPLUMBER_DATA_DIR/scripts
+-----------------------------------------------------------------------------
+
+--
+-- Collects arguments passed in from the command line
+-- Assuming option1=value1 option2=value2 were passed, this will be a table
+-- like this: { ["option1"] = "value1", ["option2"] = "value2" }
+--
+local argv = ...
+
+print ("Command-line arguments:")
+for k, v in pairs(argv) do
+  print ("\t" .. k .. ": " .. v)
+end
+
+--
+-- Retrieve remote core info
+--
+local info = Core.get_info()
+
+print ("\nPipeWire daemon info:")
+for k, v in pairs(info) do
+  if k == "properties" then
+    print ("\tproperties:")
+    for kk, vv in pairs(v) do
+      print ("\t\t" .. kk .. ": " .. vv)
+    end
+  else
+    print ("\t" .. k .. ": " .. v)
+  end
+end
+
+--
+-- Retrieve objects using an ObjectManager
+--
+-- Note: obj_mgr here cannot be a local variable; we need it to stay alive
+-- after the execution has returned to the main loop
+--
+obj_mgr = ObjectManager {
+  Interest { type = "client" },
+  Interest { type = "device" },
+  Interest { type = "node" },
+}
+
+-- Listen for the 'installed' signal from the ObjectManager
+-- and execute a function when it is fired
+-- This function will be called from the main loop at some point later
+obj_mgr:connect("installed", function (om)
+
+  --
+  -- Print connected clients
+  --
+  print ("\nClients:")
+  for obj in om:iterate_filtered(Interest { type = "client" }) do
+
+    --
+    -- 'bound-id' and 'global-properties' are GObject
+    -- properties of WpProxy / WpGlobalProxy
+    --
+    local id = obj["bound-id"]
+    local global_props = obj["global-properties"]
+
+    print ("\t" .. id .. ": " .. global_props["application.name"]
+                .. " (PID: " .. global_props["pipewire.sec.pid"] .. ")")
+  end
+
+  --
+  -- Print devices
+  --
+  print ("\nDevices:")
+  for obj in om:iterate_filtered(Interest { type = "device" }) do
+    local id = obj["bound-id"]
+    local global_props = obj["global-properties"]
+
+    print ("\t" .. id .. ": " .. global_props["device.name"]
+                .. " (" .. global_props["device.description"] .. ")")
+  end
+
+  -- Common function to print nodes
+  local function printNode(node)
+    local id = node["bound-id"]
+    local global_props = node["global-properties"]
+
+    -- standard lua string.match() function used here
+    if global_props["media.class"]:match("Stream/.*") then
+      print ("\t" .. id .. ": " .. global_props["application.name"])
+    else
+      print ("\t" .. id .. ": " .. global_props["object.path"]
+                .. " (" .. global_props["node.description"] .. ")")
+    end
+  end
+
+  --
+  -- Print device sinks
+  --
+  print ("\nSinks:")
+  --
+  -- Interest can have additional constraints that can be used to filter
+  -- the results. In this case we are only interested in nodes with their
+  -- "media.class" global property matching the glob expression "*/Sink"
+  --
+  local interest = Interest { type = "node",
+    Constraint { "media.class", "matches", "*/Sink" }
+  }
+  for obj in om:iterate_filtered(interest) do
+    printNode(obj)
+  end
+
+  --
+  -- Print device sources
+  --
+  print ("\nSources:")
+  local interest = Interest { type = "node",
+    Constraint { "media.class", "matches", "*/Source" }
+  }
+  for obj in om:iterate_filtered(interest) do
+    printNode(obj)
+  end
+
+  --
+  -- Print client streams
+  --
+  print ("\nStreams:")
+  local interest = Interest { type = "node",
+    Constraint { "media.class", "matches", "Stream/*" }
+  }
+  for obj in om:iterate_filtered(interest) do
+    printNode(obj)
+  end
+
+  -- Disconnect from pipewire and quit wireplumber
+  -- This only works in script interactive mode
+  Core.quit()
+end)
+
+-- Activate the object manager. This is required to start it,
+-- otherwise it doesn't do anything
+obj_mgr:activate()