MinimServerControl.kt

85 lines · 3.9 KB

Changed in: 0.5.0

1	package dev.stave.upnp
2
3	import kotlinx.coroutines.Dispatchers
4	import kotlinx.coroutines.withContext
5	import okhttp3.MediaType.Companion.toMediaType
6	import okhttp3.OkHttpClient
7	import okhttp3.Request
8	import okhttp3.RequestBody.Companion.toRequestBody
9	import java.util.concurrent.TimeUnit
10
11	/**
12	* Client for MinimServer's [Web API](https://minimserver.com/ug-scripting.html#Web%20API).
13	* Ported from Earhorn Android (`dev.stave.upnp.MinimServerControl`) so the desktop
14	* can trigger a library rescan on the server without leaving the app.
15	*
16	* MinimServer exposes a tiny HTTP/POST control endpoint on its HTTP server port
17	* (default 9790, set by the `http.port` property). The body is a plain-text
18	* command script — for our purposes a single line: `rescan`. The receiver
19	* restarts the server and begins indexing; a 200 OK comes back when the rescan
20	* has started (not finished). MinimServer briefly disappears from the UPnP
21	* registry during the rescan, then reappears when indexing is complete —
22	* that's how [dev.stave.ui.servers.ServersViewModel] observes the cycle.
23	*
24	* Port-discovery strategy: try the UPnP descriptor URL's port first (for a
25	* stock MinimServer config usually 9791 — the ohnet.port — but custom setups
26	* sometimes collapse both onto 9790). Fall back to 9790 if the descriptor port
27	* refuses or 404s.
28	*
29	* The request only ever goes to the host the server's own UPnP descriptor
30	* names — never to an address the user typed or a third party supplied.
31	*/
32	class MinimServerControl(
33	private val holder: UpnpServiceHolder,
34	) {
35	sealed class Result {
36	data object Success : Result()
37	data class Failure(val message: String) : Result()
38	}
39
40	private val http: OkHttpClient = OkHttpClient.Builder()
41	.connectTimeout(5, TimeUnit.SECONDS)
42	// Longer read timeout: the server takes the POST, restarts internally,
43	// and only then responds 200. That round-trip can be 5–15 s on a busy
44	// server.
45	.readTimeout(30, TimeUnit.SECONDS)
46	.build()
47
48	/** POST `rescan` to the server identified by [udn]. Returns when the
49	* receiver acknowledges the command (the rescan has STARTED, not
50	* finished — wait for the server to leave and rejoin the registry). */
51	suspend fun rescanLibrary(udn: String): Result = withContext(Dispatchers.IO) {
52	val device = holder.findDevice(udn)
53	?: return@withContext Result.Failure("Server is no longer on the network")
54	val descriptor = device.identity.descriptorURL
55	?: return@withContext Result.Failure("Server didn't say where its control page is")
56	val host = descriptor.host
57	?: return@withContext Result.Failure("Server didn't say where its control page is")
58
59	val descriptorPort = descriptor.port.takeIf { it > 0 } ?: 80
60	val portsToTry = linkedSetOf(descriptorPort, MINIMSERVER_DEFAULT_HTTP_PORT)
61
62	var lastError: String? = null
63	for (port in portsToTry) {
64	val url = "http://$host:$port/"
65	val request = Request.Builder()
66	.url(url)
67	.post("rescan\n".toRequestBody(TEXT_PLAIN))
68	.build()
69	try {
70	http.newCall(request).execute().use { response ->
71	if (response.isSuccessful) return@withContext Result.Success
72	lastError = "server answered HTTP ${response.code}"
73	}
74	} catch (e: java.io.IOException) {
75	lastError = e.message?.let { "couldn't reach it ($it)" } ?: "couldn't reach it"
76	}
77	}
78	Result.Failure(lastError ?: "the request failed")
79	}
80
81	companion object {
82	private const val MINIMSERVER_DEFAULT_HTTP_PORT = 9790
83	private val TEXT_PLAIN = "text/plain; charset=utf-8".toMediaType()
84	}
85	}