Smartcraft-Media-Tech/ntfysh-windows
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Implement error handling and notification

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This commit is contained in:
Alexander Horner
2022-12-07 23:20:36 +00:00
parent 1e1187e71f
commit ecbde9509f
3 changed files with 188 additions and 68 deletions
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26
ntfysh_client/MainForm.cs
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@@ -19,10 +19,29 @@ namespace ntfysh_client
{
_notificationListener = notificationListener;
_notificationListener.OnNotificationReceive += OnNotificationReceive;
_notificationListener.OnConnectionMultiAttemptFailure += OnConnectionMultiAttemptFailure;
_notificationListener.OnConnectionCredentialsFailure += OnConnectionCredentialsFailure;
InitializeComponent();
}
private void OnNotificationReceive(object sender, NotificationReceiveEventArgs e)
{
notifyIcon.ShowBalloonTip(3000, e.Title, e.Message, ToolTipIcon.Info);
}
private void OnConnectionMultiAttemptFailure(NotificationListener sender, SubscribedTopic topic)
{
MessageBox.Show($"Connecting to topic ID '{topic.TopicId}' on server '{topic.ServerUrl}' failed after multiple attempts.\n\nThis topic ID will be ignored and you will not receive notifications for it until you restart the application.", "Connection Failure", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
private void OnConnectionCredentialsFailure(NotificationListener sender, SubscribedTopic topic)
{
string reason = string.IsNullOrWhiteSpace(topic.Username) ? "credentials are required but were not provided" : "the entered credentials are incorrect";
MessageBox.Show($"Connecting to topic ID '{topic.TopicId}' on server '{topic.ServerUrl}' failed because {reason}.\n\nThis topic ID will be ignored and you will not receive notifications for it until you correct the credentials.", "Connection Authentication Failure", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
private void MainForm_Load(object sender, EventArgs e) => LoadTopics();
private void subscribeNewTopic_Click(object sender, EventArgs e)
@@ -137,7 +156,7 @@ namespace ntfysh_client
}
//Assemble new format
List<SubscribedTopic> newTopics = legacyTopics.Select(lt => new SubscribedTopic(lt, "https://ntfy.sh", null, null, null, null)).ToList();
List<SubscribedTopic> newTopics = legacyTopics.Select(lt => new SubscribedTopic(lt, "https://ntfy.sh", null, null)).ToList();
string newFormatSerialised = JsonConvert.SerializeObject(newTopics, Formatting.Indented);
@@ -196,11 +215,6 @@ namespace ntfysh_client
}
}
private void OnNotificationReceive(object sender, NotificationReceiveEventArgs e)
{
notifyIcon.ShowBalloonTip(3000, e.Title, e.Message, ToolTipIcon.Info);
}
private void MainForm_FormClosed(object sender, FormClosedEventArgs e)
{
notifyIcon.Dispose();

215
ntfysh_client/NotificationListener.cs
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@@ -15,124 +15,230 @@ using System.Web;
namespace ntfysh_client
{
public class NotificationListener : IDisposable
public class NotificationListener
{
private readonly HttpClient _httpClient = new();
private bool _isDisposed;
public readonly Dictionary<string, SubscribedTopic?> SubscribedTopicsByUnique = new();
public delegate void NotificationReceiveHandler(object sender, NotificationReceiveEventArgs e);
public delegate void NotificationReceiveHandler(NotificationListener sender, NotificationReceiveEventArgs e);
public event NotificationReceiveHandler? OnNotificationReceive;
public delegate void ConnectionErrorHandler(NotificationListener sender, SubscribedTopic topic);
public event ConnectionErrorHandler? OnConnectionMultiAttemptFailure;
public event ConnectionErrorHandler? OnConnectionCredentialsFailure;
public NotificationListener()
{
_httpClient.Timeout = TimeSpan.FromMilliseconds(Timeout.Infinite);
ServicePointManager.DefaultConnectionLimit = 100;
}
private async Task ListenToTopicWithHttpLongJsonAsync(HttpRequestMessage message, CancellationToken cancellationToken)
private async Task ListenToTopicWithHttpLongJsonAsync(HttpRequestMessage message, CancellationToken cancellationToken, SubscribedTopic topic)
{
if (_isDisposed) throw new ObjectDisposedException(nameof(NotificationListener));
int connectionAttempts = 0;
while (!cancellationToken.IsCancellationRequested)
{
using HttpResponseMessage response = await _httpClient.SendAsync(message, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
await using Stream body = await response.Content.ReadAsStreamAsync(cancellationToken);
//See if we have exceeded maximum attempts
if (connectionAttempts >= 10)
{
//10 connection failures (1 initial + 9 reattempts)! Do not retry
OnConnectionMultiAttemptFailure?.Invoke(this, topic);
return;
}
try
{
StringBuilder mainBuffer = new();
//Establish connection
using HttpClient client = new();
client.Timeout = TimeSpan.FromMilliseconds(Timeout.Infinite); //This will not prevent us from failing to connect, luckily
using HttpResponseMessage response = await client.SendAsync(message, HttpCompletionOption.ResponseHeadersRead, cancellationToken);
await using Stream body = await response.Content.ReadAsStreamAsync(cancellationToken);
//Ensure successful connect
response.EnsureSuccessStatusCode();
//Reset connection attempts after a successful connect
connectionAttempts = 0;
//Begin listening
StringBuilder mainBuffer = new();
while (!cancellationToken.IsCancellationRequested)
{
//Read as much as possible
byte[] buffer = new byte[8192];
int readBytes = await body.ReadAsync(buffer, 0, buffer.Length, cancellationToken);
//Append it to our main buffer
mainBuffer.Append(Encoding.UTF8.GetString(buffer, 0, readBytes));
List<string> lines = mainBuffer.ToString().Split('\n').ToList();
//If we have not yet received a full line, meaning theres only 1 part, go back to reading
if (lines.Count <= 1) continue;
//We now have at least 1 line! Count how many full lines. There will always be a partial line at the end, even if that partial line is empty
//Separate the partial line from the full lines
int partialLineIndex = lines.Count - 1;
string partialLine = lines[partialLineIndex];
lines.RemoveAt(partialLineIndex);
//Process the full lines
foreach (string line in lines) ProcessMessage(line);
//Write back the partial line
mainBuffer.Clear();
mainBuffer.Append(partialLine);
}
}
catch (Exception ex)
catch (HttpRequestException hre)
{
if (hre.StatusCode is HttpStatusCode.Unauthorized or HttpStatusCode.Forbidden)
{
//Our credentials either aren't present when they need to be or are invalid
//Credential Failure! Do not retry
OnConnectionCredentialsFailure?.Invoke(this, topic);
return;
}
#if DEBUG
Debug.WriteLine(ex);
Debug.WriteLine(hre);
#endif
//Fall back to the outer loop to restart the listen, or cancel if requested
//We will not hit the finally block which will increment the connection failure counter and attempt a reconnect if applicable
}
catch (Exception e)
{
#if DEBUG
Debug.WriteLine(e);
#endif
//We will not hit the finally block which will increment the connection failure counter and attempt a reconnect if applicable
}
finally
{
//We land here if we fail to connect or our connection gets closed (and if we are canceeling, but that gets ignored)
if (!cancellationToken.IsCancellationRequested)
{
//Not cancelling, legitimate connection failure or termination
if (connectionAttempts != 0)
{
//On our first reconnect attempt, try instantly. On consecutive, wait 3 seconds before each attempt
await Task.Delay(TimeSpan.FromSeconds(3), cancellationToken);
}
//Increment attempts
connectionAttempts++;
//Proceed to reattempt
}
}
}
}
private async Task ListenToTopicWithWebsocketAsync(Uri uri, NetworkCredential credentials, CancellationToken cancellationToken)
private async Task ListenToTopicWithWebsocketAsync(Uri uri, NetworkCredential credentials, CancellationToken cancellationToken, SubscribedTopic topic)
{
if (_isDisposed) throw new ObjectDisposedException(nameof(NotificationListener));
int connectionAttempts = 0;
while (!cancellationToken.IsCancellationRequested)
{
using ClientWebSocket socket = new();
socket.Options.Credentials = credentials;
//See if we have exceeded maximum attempts
if (connectionAttempts >= 10)
{
//10 connection failures (1 initial + 9 reattempts)! Do not retry
OnConnectionMultiAttemptFailure?.Invoke(this, topic);
return;
}
try
{
StringBuilder mainBuffer = new();
//Establish connection
using ClientWebSocket socket = new();
socket.Options.Credentials = credentials;
await socket.ConnectAsync(uri, cancellationToken);
//Reset connection attempts after a successful connect
connectionAttempts = 0;
//Begin listening
StringBuilder mainBuffer = new();
while (!cancellationToken.IsCancellationRequested)
{
//Read as much as possible
byte[] buffer = new byte[8192];
WebSocketReceiveResult? result = await socket.ReceiveAsync(new ArraySegment<byte>(buffer), cancellationToken);
//Append it to our main buffer
mainBuffer.Append(Encoding.UTF8.GetString(buffer, 0, result.Count));
List<string> lines = mainBuffer.ToString().Split('\n').ToList();
//If we have not yet received a full line, meaning theres only 1 part, go back to reading
if (lines.Count <= 1) continue;
//We now have at least 1 line! Count how many full lines. There will always be a partial line at the end, even if that partial line is empty
//Separate the partial line from the full lines
int partialLineIndex = lines.Count - 1;
string partialLine = lines[partialLineIndex];
lines.RemoveAt(partialLineIndex);
//Process the full lines
foreach (string line in lines) ProcessMessage(line);
//Write back the partial line
mainBuffer.Clear();
mainBuffer.Append(partialLine);
}
}
catch (Exception ex)
catch (WebSocketException wse)
{
if (wse.WebSocketErrorCode is WebSocketError.NotAWebSocket)
{
//We haven't achieved a connection with a websocket. TODO Seems ntfy doesn't report unauthorised properly, and responds 200
//Credential Failure! Do not retry
OnConnectionCredentialsFailure?.Invoke(this, topic);
return;
}
#if DEBUG
Debug.WriteLine(ex);
Debug.WriteLine(wse);
#endif
//Fall back to the outer loop to restart the listen, or cancel if requested
//We will not hit the finally block which will increment the connection failure counter and attempt a reconnect if applicable
}
catch (Exception e)
{
#if DEBUG
Debug.WriteLine(e);
#endif
//We will not hit the finally block which will increment the connection failure counter and attempt a reconnect if applicable
}
finally
{
//We land here if we fail to connect or our connection gets closed (and if we are canceeling, but that gets ignored)
if (!cancellationToken.IsCancellationRequested)
{
//Not cancelling, legitimate connection failure or termination
if (connectionAttempts != 0)
{
//On our first reconnect attempt, try instantly. On consecutive, wait 3 seconds before each attempt
await Task.Delay(TimeSpan.FromSeconds(3), cancellationToken);
}
//Increment attempts
connectionAttempts++;
//Proceed to reattempt
}
}
}
}
@@ -156,8 +262,6 @@ namespace ntfysh_client
public void SubscribeToTopicUsingLongHttpJson(string unique, string topicId, string serverUrl, string? username, string? password)
{
if (_isDisposed) throw new ObjectDisposedException(nameof(NotificationListener));
if (SubscribedTopicsByUnique.ContainsKey(unique)) throw new InvalidOperationException("A topic with this unique already exists");
if (string.IsNullOrWhiteSpace(username)) username = null;
@@ -172,31 +276,35 @@ namespace ntfysh_client
message.Headers.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(boundCredentialsBytes));
}
CancellationTokenSource listenCanceller = new();
Task listenTask = ListenToTopicWithHttpLongJsonAsync(message, listenCanceller.Token);
SubscribedTopic newTopic = new(topicId, serverUrl, username, password);
SubscribedTopicsByUnique.Add(unique, new SubscribedTopic(topicId, serverUrl, username, password, listenTask, listenCanceller));
CancellationTokenSource listenCanceller = new();
Task listenTask = ListenToTopicWithHttpLongJsonAsync(message, listenCanceller.Token, newTopic);
newTopic.SetAssociatedRunner(listenTask, listenCanceller);
SubscribedTopicsByUnique.Add(unique, newTopic);
}
public void SubscribeToTopicUsingWebsocket(string unique, string topicId, string serverUrl, string? username, string? password)
{
if (_isDisposed) throw new ObjectDisposedException(nameof(NotificationListener));
if (SubscribedTopicsByUnique.ContainsKey(unique)) throw new InvalidOperationException("A topic with this unique already exists");
if (string.IsNullOrWhiteSpace(username)) username = null;
if (string.IsNullOrWhiteSpace(password)) password = null;
Uri targetUri = new($"{serverUrl}/{HttpUtility.UrlEncode(topicId)}/ws");
SubscribedTopic newTopic = new(topicId, serverUrl, username, password);
CancellationTokenSource listenCanceller = new();
Task listenTask = ListenToTopicWithWebsocketAsync(targetUri, new NetworkCredential(username, password), listenCanceller.Token);
SubscribedTopicsByUnique.Add(unique, new SubscribedTopic(topicId, serverUrl, username, password, listenTask, listenCanceller));
Task listenTask = ListenToTopicWithWebsocketAsync(new Uri($"{serverUrl}/{HttpUtility.UrlEncode(topicId)}/ws"), new NetworkCredential(username, password), listenCanceller.Token, newTopic);
newTopic.SetAssociatedRunner(listenTask, listenCanceller);
SubscribedTopicsByUnique.Add(unique, newTopic);
}
public async Task UnsubscribeFromTopicAsync(string topicUniqueString)
{
if (_isDisposed) throw new ObjectDisposedException(nameof(NotificationListener));
#if DEBUG
Debug.WriteLine($"Removing topic {topicUniqueString}");
#endif
@@ -208,12 +316,12 @@ namespace ntfysh_client
if (!SubscribedTopicsByUnique.TryGetValue(topicUniqueString, out topic!)) return;
//Cancel and dispose the task runner
topic.RunnerCanceller.Cancel();
topic.RunnerCanceller?.Cancel();
//Wait for the task runner to shut down
try
{
await topic.Runner;
if (topic.Runner is not null) await topic.Runner;
}
catch (Exception)
{
@@ -221,19 +329,10 @@ namespace ntfysh_client
}
//Dispose task
topic.Runner.Dispose();
topic.Runner?.Dispose();
//Remove the old topic
SubscribedTopicsByUnique.Remove(topicUniqueString);
}
public void Dispose()
{
if (_isDisposed) return;
_httpClient.Dispose();
_isDisposed = true;
}
}
}

15
ntfysh_client/SubscribedTopic.cs
View File

@@ -1,4 +1,5 @@
using System.Threading;
using System;
using System.Threading;
using System.Threading.Tasks;
using Newtonsoft.Json;
@@ -6,12 +7,18 @@ namespace ntfysh_client
{
public class SubscribedTopic
{
public SubscribedTopic(string topicId, string serverUrl, string? username, string? password, Task runner, CancellationTokenSource runnerCanceller)
public SubscribedTopic(string topicId, string serverUrl, string? username, string? password)
{
TopicId = topicId;
ServerUrl = serverUrl;
Username = username;
Password = password;
}
public void SetAssociatedRunner(Task runner, CancellationTokenSource runnerCanceller)
{
if (Runner is not null || RunnerCanceller is not null) throw new InvalidOperationException("Runner already associated");
Runner = runner;
RunnerCanceller = runnerCanceller;
}
@@ -22,9 +29,9 @@ namespace ntfysh_client
public string? Password { get; }
[JsonIgnore]
public Task Runner { get; }
public Task? Runner { get; private set; }
[JsonIgnore]
public CancellationTokenSource RunnerCanceller { get; }
public CancellationTokenSource? RunnerCanceller { get; private set; }
}
}