MainActivity: proper alerts for each error type

Also moved the PageViewModel into its own file? What's the norm?

app/src/main/java/dev/lowrespalmtree/comet/Gemtext.kt

@@ -1,5 +1,6 @@
 package dev.lowrespalmtree.comet
 
+import android.util.Log
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.launch
@@ -18,6 +19,8 @@ class PreTextLine(val text: String) : Line
 class BlockquoteLine(val text: String) : Line
 class ListItemLine(val text: String) : Line
 
+const val TAG = "Gemtext"
+
 fun parseData(
     inChannel: Channel<ByteArray>,
     charset: Charset,
@@ -27,6 +30,7 @@ fun parseData(
     scope.launch {
         var isPref = false
         var buffer = ByteArray(0)
+        Log.d(TAG, "parseData: start getting data from channel")
         for (data in inChannel) {
             buffer += data
             var nextLineFeed: Int = -1
@@ -41,6 +45,7 @@ fun parseData(
                 channel.send(line)
             }
         }
+        Log.d(TAG, "parseData: channel closed")
         channel.close()
     }
     return channel

app/src/main/java/dev/lowrespalmtree/comet/MainActivity.kt

@@ -11,17 +11,12 @@ import android.view.inputmethod.EditorInfo
 import android.view.inputmethod.InputMethodManager
 import androidx.appcompat.app.AlertDialog
 import androidx.appcompat.app.AppCompatActivity
-import androidx.lifecycle.MutableLiveData
-import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
-import androidx.lifecycle.viewModelScope
 import androidx.recyclerview.widget.LinearLayoutManager
 import dev.lowrespalmtree.comet.databinding.ActivityMainBinding
-import kotlinx.coroutines.*
-import java.net.ConnectException
-import java.net.UnknownHostException
-import java.nio.charset.Charset
+import kotlinx.coroutines.ExperimentalCoroutinesApi
 
+@ExperimentalCoroutinesApi
 class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
     private lateinit var binding: ActivityMainBinding
     private lateinit var pageViewModel: PageViewModel
@@ -92,10 +87,7 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
         }
 
         when (uri.scheme) {
-            "gemini" -> {
-                currentUrl = uri.toString()
-                pageViewModel.sendGeminiRequest(uri)
-            }
+            "gemini" -> pageViewModel.sendGeminiRequest(uri)
             else -> openUnknownScheme(uri)
         }
     }
@@ -125,17 +117,27 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
         Log.d(TAG, "handleEvent: $event")
         if (!event.handled) {
             when (event) {
-                is PageViewModel.SuccessEvent -> visitedUrls.add(event.uri)
-                is PageViewModel.RedirectEvent -> openUrl(event.uri, redirections = event.redirects)
-                is PageViewModel.FailureEvent -> alert(event.message)
+                is PageViewModel.SuccessEvent -> {
+                    currentUrl = event.uri
+                    visitedUrls.add(event.uri)
+                }
+                is PageViewModel.RedirectEvent -> {
+                    openUrl(event.uri, base = currentUrl, redirections = event.redirects)
+                }
+                is PageViewModel.FailureEvent -> {
+                    var message = event.details
+                    if (!event.serverDetails.isNullOrEmpty())
+                        message += "\n\n" + "Server details: ${event.serverDetails}"
+                    alert(message, title = event.short)
+                }
             }
             event.handled = true
         }
     }
 
-    private fun alert(message: String) {
+    private fun alert(message: String, title: String? = null) {
         AlertDialog.Builder(this)
-            .setTitle(R.string.error_alert_title)
+            .setTitle(title ?: getString(R.string.error_alert_title))
             .setMessage(message)
             .create()
             .show()
@@ -149,121 +151,6 @@ class MainActivity : AppCompatActivity(), ContentAdapter.ContentAdapterListen {
         }
     }
 
-    class PageViewModel : ViewModel() {
-        private var requestJob: Job? = null
-        val state: MutableLiveData<State> by lazy { MutableLiveData<State>(State.IDLE) }
-        private var linesList = ArrayList<Line>()
-        val lines: MutableLiveData<List<Line>> by lazy { MutableLiveData<List<Line>>() }
-        val event: MutableLiveData<Event> by lazy { MutableLiveData<Event>() }
-
-        enum class State {
-            IDLE, CONNECTING, RECEIVING
-        }
-
-        abstract class Event(var handled: Boolean = false)
-        data class SuccessEvent(val uri: String) : Event()
-        data class RedirectEvent(val uri: String, val redirects: Int) : Event()
-        data class FailureEvent(val message: String) : Event()
-
-        /**
-         * Perform a request against this URI.
-         *
-         * The URI must be valid, absolute and with a gemini scheme.
-         */
-        fun sendGeminiRequest(uri: Uri, redirects: Int = 0) {
-            Log.d(TAG, "sendRequest: URI \"$uri\"")
-            state.postValue(State.CONNECTING)
-            requestJob?.apply { if (isActive) cancel() }
-            requestJob = viewModelScope.launch(Dispatchers.IO) {
-                val response = try {
-                    val request = Request(uri)
-                    val socket = request.connect()
-                    val channel = request.proceed(socket, this)
-                    Response.from(channel, viewModelScope)
-                } catch (e: Exception) {
-                    Log.e(TAG, "sendGeminiRequest coroutine: ${e.stackTraceToString()}")
-                    // If we got cancelled, die silently.
-                    if (!isActive)
-                        return@launch
-                    signalError(
-                        when (e) {
-                            is UnknownHostException -> "Unknown host \"${uri.authority}\"."
-                            is ConnectException -> "Can't connect to this server: ${e.message}."
-                            else -> "Oops, something failed!"
-                        }
-                    )
-                    return@launch
-                }
-                if (!isActive)
-                    return@launch
-                if (response == null) {
-                    signalError("Can't parse server response.")
-                    return@launch
-                }
-
-                Log.i(TAG, "sendRequest: got ${response.code} with meta \"${response.meta}\"")
-                when (response.code.getCategory()) {
-                    Response.Code.Category.SUCCESS -> handleRequestSuccess(response, uri)
-                    Response.Code.Category.REDIRECT -> handleRedirect(response, redirects = redirects + 1)
-                    Response.Code.Category.SERVER_ERROR -> handleError(response)
-                    else -> signalError("Can't handle code ${response.code}.")
-                }
-            }
-        }
-
-        private fun signalError(message: String) {
-            event.postValue(FailureEvent(message))
-            state.postValue(State.IDLE)
-        }
-
-        private suspend fun handleRequestSuccess(response: Response, uri: Uri) {
-            state.postValue(State.RECEIVING)
-
-            linesList.clear()
-            lines.postValue(linesList)
-            val charset = Charset.defaultCharset()
-            var mainTitle: String? = null
-            var lastUpdate = System.currentTimeMillis()
-            for (line in parseData(response.data, charset, viewModelScope)) {
-                linesList.add(line)
-                if (mainTitle == null && line is TitleLine && line.level == 1)
-                    mainTitle = line.text
-                val time = System.currentTimeMillis()
-                if (time - lastUpdate >= 100) {  // Throttle to 100ms the recycler view updates…
-                    lines.postValue(linesList)
-                    lastUpdate = time
-                }
-            }
-            lines.postValue(linesList)
-
-            // We record the history entry here: it's nice because we have the main title available
-            // and we're already in a coroutine for database access.
-            History.record(uri.toString(), mainTitle)
-            event.postValue(SuccessEvent(uri.toString()))
-            state.postValue(State.IDLE)
-        }
-
-        private fun handleRedirect(response: Response, redirects: Int) {
-            event.postValue(RedirectEvent(response.meta, redirects))
-        }
-
-        private fun handleError(response: Response) {
-            event.postValue(FailureEvent(when (response.code) {
-                Response.Code.TEMPORARY_FAILURE -> "40: the server encountered a temporary failure."
-                Response.Code.SERVER_UNAVAILABLE -> "41: the server is currently unavailable."
-                Response.Code.CGI_ERROR -> "42: a CGI script encountered an error."
-                Response.Code.PROXY_ERROR -> "43: the server failed to proxy the request."
-                Response.Code.SLOW_DOWN -> "44: slow down!"
-                Response.Code.PERMANENT_FAILURE -> "50: this request failed and similar requests will likely fail as well."
-                Response.Code.NOT_FOUND -> "51: this page can't be found."
-                Response.Code.GONE -> "52: this page is gone."
-                Response.Code.PROXY_REQUEST_REFUSED -> "53: the server refused to proxy the request."
-                Response.Code.BAD_REQUEST -> "59: bad request."
-                else -> "${response.code}: unknown error code."
-            }))
-        }
-    }
-
     companion object {
         const val TAG = "MainActivity"
     }

app/src/main/java/dev/lowrespalmtree/comet/Request.kt

@@ -7,6 +7,7 @@ import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.channels.Channel
 import kotlinx.coroutines.launch
 import java.io.BufferedInputStream
+import java.net.InetSocketAddress
 import java.net.SocketTimeoutException
 import java.security.cert.X509Certificate
 import javax.net.ssl.SSLContext
@@ -20,8 +21,9 @@ class Request(private val uri: Uri) {
         Log.d(TAG, "connect")
         val context = SSLContext.getInstance("TLSv1.2")
         context.init(null, arrayOf(TrustManager()), null)
-        val socket = context.socketFactory.createSocket(uri.host, port) as SSLSocket
+        val socket = context.socketFactory.createSocket() as SSLSocket
         socket.soTimeout = 10000
+        socket.connect(InetSocketAddress(uri.host, port), 10000)
         socket.startHandshake()
         return socket
     }
@@ -39,13 +41,11 @@ class Request(private val uri: Uri) {
                     try {
                         @Suppress("BlockingMethodInNonBlockingContext")  // what u gonna do
                         while ((bis.read(buffer).also { numRead = it }) >= 0) {
-                            Log.d(TAG, "proceed coroutine: received $numRead bytes")
                             val received = buffer.sliceArray(0 until numRead)
                             channel.send(received)
                         }
                     } catch (e: SocketTimeoutException) {
-                        Log.i(TAG, "Socket timeout.")
-                        channel.cancel()
+                        Log.i(TAG, "proceed coroutine: socket timeout.")
                     }
                 }
             }
@@ -58,7 +58,8 @@ class Request(private val uri: Uri) {
     @SuppressLint("CustomX509TrustManager")
     class TrustManager : X509TrustManager {
         @SuppressLint("TrustAllX509TrustManager")
-        override fun checkClientTrusted(chain: Array<out X509Certificate>?, authType: String?) {}
+        override fun checkClientTrusted(chain: Array<out X509Certificate>?, authType: String?) {
+        }
 
         override fun checkServerTrusted(chain: Array<out X509Certificate>?, authType: String?) {
             Log.d(TAG, "cool cert, please continue")

app/src/main/java/dev/lowrespalmtree/comet/Response.kt

@@ -3,7 +3,7 @@ package dev.lowrespalmtree.comet
 import android.util.Log
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.channels.Channel
-import kotlinx.coroutines.channels.consumeEach
+import kotlinx.coroutines.channels.ClosedReceiveChannelException
 import kotlinx.coroutines.launch
 import java.nio.ByteBuffer
 import java.nio.charset.Charset
@@ -51,45 +51,57 @@ class Response(val code: Code, val meta: String, val data: Channel<ByteArray>) {
 
     companion object {
         private const val TAG = "Response"
+        private const val MAX_META_LEN = 1024
+        private const val MAX_HEADER_LEN = 2 + 1 + MAX_META_LEN + 2
 
         /** Return a response object from the incoming server data, served through the channel. */
         suspend fun from(channel: Channel<ByteArray>, scope: CoroutineScope): Response? {
             var received = 0
             val headerBuffer = ByteBuffer.allocate(1024)
-            for (data in channel) {
+            var lfIndex: Int
+            // While we don't have a response object (i.e. no header parsed), keep reading.
+            while (true) {
+                val data = try {
+                    channel.receive()
+                } catch (e: ClosedReceiveChannelException) {
+                    Log.i(TAG, "companion from: channel closed during initial receive")
+                    return null
+                }
+                if (received + data.size > MAX_HEADER_LEN) {
+                    Log.i(TAG, "companion from: received too much data for a valid header")
+                    return null
+                }
                 // Push some data into our buffer.
                 headerBuffer.put(data)
                 received += data.size
                 // Check if there is enough data to parse a Gemini header from it (e.g. has \r\n).
-                val lfIndex = headerBuffer.array().indexOf(0x0D)  // \r
+                lfIndex = headerBuffer.array().indexOf(0x0D)  // \r
                 if (lfIndex == -1)
                     continue
                 if (headerBuffer.array()[lfIndex + 1] != (0x0A.toByte()))  // \n
                     continue
+                break
+            }
             // We have our header! Parse it to create our Response object.
             val bytes = headerBuffer.array()
             val headerData = bytes.sliceArray(0 until lfIndex)
             val (code, meta) = parseHeader(headerData)
-                    ?: return null.also { Log.e(TAG, "Failed to parse header") }
-                val responseChannel = Channel<ByteArray>()
-                val response = Response(code, meta, responseChannel)
+                ?: return null .also { Log.i(TAG, "companion from: can't parse header") }
+            val response = Response(code, meta, Channel())
             scope.launch {
                 // If we got too much data from the channel: push the trailing data first.
                 val trailingIndex = lfIndex + 2
                 if (trailingIndex < received) {
                     val trailingData = bytes.sliceArray(trailingIndex until received)
-                        responseChannel.send(trailingData)
+                    response.data.send(trailingData)
                 }
                 // Forward all incoming data to the Response channel.
-                    channel.consumeEach { responseChannel.send(it) }
-                    responseChannel.close()
+                for (data in channel)
+                    response.data.send(data)
+                response.data.close()
             }
-                // Return the response here; this stops consuming the channel from this for-loop so
-                // that the coroutine above can take care of it.
             return response
         }
-            return null
-        }
 
         /** Return the code and meta from this header if it could be parsed correctly. */
         private fun parseHeader(data: ByteArray): Pair<Code, String>? {