Extensions for Reactive Extensions (Rxx)

Commented Feature: Generalize Internal Collect into Public Merge [24399]

davedev — Mon, 17 Jun 2013 01:15:27 GMT

See if it's possible to generalize the internal Collect operator into a public overloaded Merge operator that takes either an enumerable (or an observable) and merges it with another observable using an internal dictionary for reconciliation, an optional comparer and an optional query parameter (for filtering, projection, etc.), producing a flattened observable. The internal Collect operator should be able to call into one of these overloaded Merge operators.

Consider possibly returning an IObservable<T> instead of a ReadOnlyListSubject<T>, assuming that the latter isn't actually needed. Though if it's going to be used in the implementation anyway then it might as well be exposed to callers since it offers much more functionality than a raw observable.
Comments: ** Comment from web user: davedev **

Provide overloads with add-only semantics, avoiding use of CollectionNotification and CollectionModification altogether. This is kind of a like a Merge operator with mathematical set semantics as opposed to just sequence semantics.

Commented Feature: Generalize Internal Collect into Public Merge [24399]

davedev — Sat, 15 Jun 2013 15:48:16 GMT

Consider calling it Reconcile or MergeReconcile.

Created Feature: Generalize Internal Collect into Public Merge [24399]

davedev — Sat, 15 Jun 2013 15:19:33 GMT

Reviewed: Rxx 1.3 (May 31, 2013)

KeithW — Fri, 31 May 2013 15:17:36 GMT

Rated 5 Stars (out of 5) - This library is a must have for serious Rx development. You can be assured of the quality of the code, these guys know what they’re doing. Well done guys.

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

rolpereira — Wed, 17 Apr 2013 16:06:02 GMT

davedev wrote:

Hello davedev,

Try this instead:

receiveContentObservable.Subscribe(subject.OnNext, subject.OnError);

Yup, that worked. Thank you!

Note that sometimes LINQPad doesn't correctly close the socket [snip]

You can avoid orphaned sockets by disposing of the subscription yourself.
using (tcpListenerPool.Subscribe(
    (TcpClient tcpClient) =>
    {
        // ...
    }))
{
    Console.WriteLine("waiting");
    Console.Read();
}

Weird I thought I had tried that and it had failed. Thanks again.

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

rolpereira — Wed, 17 Apr 2013 16:06:02 GMT

davedev wrote:

Hello davedev,

Try this instead:

receiveContentObservable.Subscribe(subject.OnNext, subject.OnError);

Yup, that worked. Thank you!

Note that sometimes LINQPad doesn't correctly close the socket [snip]

You can avoid orphaned sockets by disposing of the subscription yourself.
using (tcpListenerPool.Subscribe(
    (TcpClient tcpClient) =>
    {
        // ...
    }))
{
    Console.WriteLine("waiting");
    Console.Read();
}

Weird I thought I had tried that and it had failed. Thanks again.

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

davedev — Wed, 17 Apr 2013 15:29:17 GMT

Hi,

Note that sometimes LINQPad doesn't correctly close the socket [snip]

You can avoid orphaned sockets by disposing of the subscription yourself.

using (tcpListenerPool.Subscribe(
    (TcpClient tcpClient) =>
    {
        // ...
    }))
{
    Console.WriteLine("waiting");
    Console.Read();
}

- Dave

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

davedev — Wed, 17 Apr 2013 15:29:17 GMT

Hi,

Note that sometimes LINQPad doesn't correctly close the socket [snip]

You can avoid orphaned sockets by disposing of the subscription yourself.

using (tcpListenerPool.Subscribe(
    (TcpClient tcpClient) =>
    {
        // ...
    }))
{
    Console.WriteLine("waiting");
    Console.Read();
}

- Dave

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

davedev — Wed, 17 Apr 2013 15:25:36 GMT

Hi,

It's probably because the subject is receiving OnCompleted and ignoring subsequent notifications.

In other words, this:

receiveContentObservable.Subscribe(subject);

is essentially the same as this:

receiveContentObservable.Subscribe(subject.OnNext, subject.OnError, subject.OnCompleted);

Try this instead:

receiveContentObservable.Subscribe(subject.OnNext, subject.OnError);

It's a fairly common mistake that I make too :)

- Dave

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

davedev — Wed, 17 Apr 2013 15:25:36 GMT

Hi,

It's probably because the subject is receiving OnCompleted and ignoring subsequent notifications.

In other words, this:

receiveContentObservable.Subscribe(subject);

is essentially the same as this:

receiveContentObservable.Subscribe(subject.OnNext, subject.OnError, subject.OnCompleted);

Try this instead:

receiveContentObservable.Subscribe(subject.OnNext, subject.OnError);

It's a fairly common mistake that I make too :)

- Dave

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

rolpereira — Wed, 17 Apr 2013 14:04:34 GMT

Hello all,

I'm trying to pass the output of ObservableTcpListener to a Subject<byte[]>. That subject will then be used in a query.

The problem is that while the ObservableTcpListener receives every socket contents that I send, the query doesn't output anything besides the first two or three events.

This code shows the problem that I'm mentioning. It should be ran in LINQPad as a "C# Program".

void Main()
{
    // Create the subject and the query
    var subject = new Subject<byte[]>();
    var query = subject.Select(reading => reading);
    
    query.Subscribe(Console.WriteLine);
    
    var tcpListenerPool = ObservableTcpListener.Start(IPAddress.Loopback, 20001);
    
    tcpListenerPool.Subscribe(
        (TcpClient tcpClient) =>
        {
            // Debug information just to check if the socket actually has anything in it
            Console.WriteLine("tcpSocket.Avaliable: " + tcpClient.Available);
            
            var receiveContentObservable = tcpClient.Client.ReceiveUntilCompleted(SocketFlags.None);
            
            // Send socket content to the subject
            receiveContentObservable.Subscribe(subject);
        });
        
    Console.WriteLine("waiting");
    Console.Read();
}

// Define other methods and classes here

Note that sometimes LINQPad doesn't correctly close the socket, and gives the error: "Only one usage of each socket address (protocol/network address/port) is normally permitted". If that happens go to the "Query" menu and choose "Cancel All Threads and Reset".

The program that I'm using to send the sockets to the ObservableTcpListener is this python program:

import socket
import random

payload = ["foo", "bar"];

def sendPayload(payload):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect(("localhost", 20001))
    
    s.send(payload)
    
    s.close()

# Send 10 sockets with either "foo" or "bar"    
map(lambda x: sendPayload(random.choice(payload)), range(10))

Is this a bug, or am I doing something wrong?

Edit: I'm using the "Rxx Class Library for .NET 4.0" available in the Downloads section.

New Post: Subject doesn't output events when it's reading an ObservableTcpListener

rolpereira — Wed, 17 Apr 2013 14:04:34 GMT

void Main()
{
    // Create the subject and the query
    var subject = new Subject<byte[]>();
    var query = subject.Select(reading => reading);
    
    query.Subscribe(Console.WriteLine);
    
    var tcpListenerPool = ObservableTcpListener.Start(IPAddress.Loopback, 20001);
    
    tcpListenerPool.Subscribe(
        (TcpClient tcpClient) =>
        {
            // Debug information just to check if the socket actually has anything in it
            Console.WriteLine("tcpSocket.Avaliable: " + tcpClient.Available);
            
            var receiveContentObservable = tcpClient.Client.ReceiveUntilCompleted(SocketFlags.None);
            
            // Send socket content to the subject
            receiveContentObservable.Subscribe(subject);
        });
        
    Console.WriteLine("waiting");
    Console.Read();
}

// Define other methods and classes here

import socket
import random

payload = ["foo", "bar"];

def sendPayload(payload):
    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    s.connect(("localhost", 20001))
    
    s.send(payload)
    
    s.close()

# Send 10 sockets with either "foo" or "bar"    
map(lambda x: sendPayload(random.choice(payload)), range(10))

Is this a bug, or am I doing something wrong?

Edit: I'm using the "Rxx Class Library for .NET 4.0" available in the Downloads section.

New Post: IObservable> conversion

grantchik — Wed, 17 Apr 2013 12:27:08 GMT

Good stuff, worked, thanks

New Post: IObservable> conversion

grantchik — Wed, 17 Apr 2013 12:27:08 GMT

Good stuff, worked, thanks

New Post: IObservable> conversion

grantchik — Wed, 17 Apr 2013 12:27:08 GMT

Good stuff, worked, thanks

New Post: IObservable> conversion

davedev — Wed, 17 Apr 2013 12:10:12 GMT

Hi,

You can use this overload of Select. It allows you to project both sides of Either.

For example:

IObservable<Either<T, Exception>> xs = GetObservableFromExternalSource();

IObservable<Either<T, MyAppException>> ys = xs.Select(t => t, ex => new MyAppException(ex));

See also:
https://rxx.codeplex.com/discussions/401272

- Dave

New Post: IObservable> conversion

davedev — Wed, 17 Apr 2013 12:10:12 GMT

Hi,

You can use this overload of Select. It allows you to project both sides of Either.

For example:

IObservable<Either<T, Exception>> xs = GetObservableFromExternalSource();

IObservable<Either<T, MyAppException>> ys = xs.Select(t => t, ex => new MyAppException(ex));

See also:
https://rxx.codeplex.com/discussions/401272

- Dave

New Post: IObservable> conversion

davedev — Wed, 17 Apr 2013 12:10:12 GMT

Hi,

You can use this overload of Select. It allows you to project both sides of Either.

For example:

IObservable<Either<T, Exception>> xs = GetObservableFromExternalSource();

IObservable<Either<T, MyAppException>> ys = xs.Select(t => t, ex => new MyAppException(ex));

See also:
https://rxx.codeplex.com/discussions/401272

- Dave

New Post: IObservable> conversion

grantchik — Wed, 17 Apr 2013 11:15:04 GMT

so i have a subscription that returns IObservable<Either<T, Exception>> from an external source, and i would like to convert that into IObservable<Either<T, MyAppException>>, where MyAppException takes Exception as a parameter in ctor.

can you please advise a way of doing this? thanks

New Post: IObservable> conversion

grantchik — Wed, 17 Apr 2013 11:15:04 GMT