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    Vishnu Prassad
    @vishnuprasad73_twitter
    i was able to send a message to value lane
    brohitbrose
    @brohitbrose
    valueLane.close(); should work from node client
    Vishnu Prassad
    @vishnuprasad73_twitter
    @brohitbrose Thanks
    Vishnu Prassad
    @vishnuprasad73_twitter
    Can someone give me a real-world example of how SWIM is faster than traditional REST APIs or apps? I want to do POC to show how SWIM is faster than traditional REST based apps.
    Ajay.Gov
    @ajay-gov
    @vishnuprasad73_twitter Swim is a stateful platform for Real-Time Applications at scale. Swim provides Stateful Services (Web Agents), Streaming (using WARP) APIs and Real-time UIs (swim UI toolkit).
    For example you can take a look at the traffic (https://github.com/swimos/traffic), here changes to the state of an intersection (red/green/yellow) is propagated from the intersection to the cloud and then to your browser within 100 milliseconds and this is done for over a hundred intersections.
    Similarly you can take a look at the traffic (https://github.com/swimos/transit), here changes to the location of buses is propagated from the bus to the cloud and then to your browser within 100 milliseconds and this is done for over 8000 buses.
    Doing this with REST would involve polling endlessly from the browser for each intersection/bus which will overload the server and the browser.
    The traffic and transit are just sample applications. We have customers that use swim in production at a much larger scale. Please look here for a brief summary of some of our customer applications- https://www.swim.ai/customers/
    Vishnu Prassad
    @vishnuprasad73_twitter
    @ajay-gov Thanks for the detailed info. I'm working on an e-commerce platform. Can you tell me how swim ai will be useful in e-commerce , can u suggest some use cases ?
    Ajay.Gov
    @ajay-gov
    @vishnuprasad73_twitter swimOS can be used for all use-cases in the e-commerce platform that require real-time processing with stateful entities. First thing to do would be to model your application using Web Agents, a simple start would be to have a WebAgent for each User, Product(item with a serial number) and a ProductType. You could then compute real-time analytics at each level
    • At the User WebAgent level you could analyze the pattern (using some algorithm) of purchases made by a user to build a real-time profile of a user that gets updated on every purchase . This may help in promoting the right types of Products for this user
    • At the Product WebAgent level you could get real-time metrics eg: how many purchases were made (raw number), purchases made by state/country (if you have the user's location info). You could have time-series for these as well. This maybe useful to determine the general trends for when a product gets bought.
    • At the ProductType WebAgent level it is similar to the ProductWebAgent except you can compute these real-time metrics for each ProductType
    These are just some ideas. I'm sure you can come up with more scenarios based on your application.
    Vishnu Prassad
    @vishnuprasad73_twitter
    @ajay-gov thanks for the detailed explanation
    var swim = require("@swim/client");
    var structure = require("@swim/structure");
    
    const client = new swim.WarpClient();
    
    let valueLane = client.downlinkValue()
                        .hostUri("warp://localhost:9001").nodeUri("/welcome/user").laneUri("info")
                        .didSet((newValue, oldValue) => {
                            console.log("link watched info change to " + newValue + " from " + oldValue);
                          })
                        .open();
    
    let oldvalue = valueLane.get()
    
    valueLane.set("john");
    
    console.log(oldvalue)
    
    client.close()
    Im trying to work with value lane. above is the client code. When i run the code the old value comes
    as empty (link watched info change to john from Value.absent()). Am i missing anything here. i can see the old and new value in the server side log
    and console.log(oldvalue) returns Absent {}
    Scott Clarke
    @scottswim
    what data type is your info lane (String or Value)? Based on the name I am guessing that you have a Value lane but are sending a String. If you are sending to a Value lane, then use valuelane.set(swim.Value.fromAny("john")) instead. This will convert your string to a Swim Value.
    Ajay.Gov
    @ajay-gov
    @vishnuprasad73_twitter the oldValue is being assigned before you call valueLane.set. So the oldValue has the initial value of the valueLane which is Absent (indicates that it is absent).
    let oldvalue = valueLane.get();
    valueLane.set("john");
    console.log(oldvalue);
    oldvalue = valueLane.get();
    console.log(oldvalue);
    This should print Absent and then "john".
    valueLane.get() returns the current value of that valueLane()
    Vishnu Prassad
    @vishnuprasad73_twitter

    @ajay-gov got it. what im trying to achieve is, to get the old and new value on the client side.

    on the server side,

      @SwimLane("info")
      ValueLane<String> info = this.<String>valueLane()
          .didSet((newValue, oldValue) -> {
            logMessage("`info` set to " + newValue + " from " + oldValue);
          });

    this prints the old and new value every time i set a new value. like this, [/welcome/user]infoset to hello from world

    but on client side,

    .didSet((newValue, oldValue) => {
                            console.log("link watched info change to " + newValue + " from " + oldValue);
                          })

    this always comes as absent.

    Maybe I'm understanding the purpose of value lane incorrectly?

    Vishnu Prassad
    @vishnuprasad73_twitter
    is there a way to get the current remote state? that i can show as old value while setting new value
    Ajay.Gov
    @ajay-gov

    @vishnuprasad73_twitter

    const client = new swim.WarpClient();
    
    let valueLane = client.downlinkValue()
                        .hostUri("warp://localhost:9001").nodeUri("/welcome/user").laneUri("info")
                        .didSet((newValue, oldValue) => {
                            console.log("link watched info change to " + newValue + " from " + oldValue);
                          })
                        .open();

    is all you need. Whenever the "info" lane for the node "/welcome/user" gets updated on the server then the didSet callback in the valueLane reference in the client should get invoked with the oldValue and the newValue. Are you not seeing this?

    Vishnu Prassad
    @vishnuprasad73_twitter

    @ajay-gov i tried that. but when i set a new value, the callback im getting on the client side is,
    link watched info change to john from Value.absent()

    i have the same callback on server side, which works correctly.

    @SwimLane("info")
      ValueLane<String> info = this.<String>valueLane()
          .didSet((newValue, oldValue) -> {
            logMessage("`info` set to " + newValue + " from " + oldValue);
          });

    which logs out put as below,

    [/welcome/user] `info` set to doe from john

    i tried setting the value as @scottswim mentioned above, valuelane.set(swim.Value.fromAny("john")) still it shows as absent on client side though
    Ajay.Gov
    @ajay-gov
    hmm..strange that it's not working. How are you setting the value lane i.e is it done on the server side? Also hopefully you are not calling client.close() before the value lane gets set.
    Vishnu Prassad
    @vishnuprasad73_twitter
    Ohhh!. I was calling client.close() at the end of the code!. Removed it and now i can see the old value though.
    @ajay-gov
    Ajay.Gov
    @ajay-gov
    @vishnuprasad73_twitter Great, so it works now?
    Vishnu Prassad
    @vishnuprasad73_twitter
    Yes. Thank a lot.
    Vishnu Prassad
    @vishnuprasad73_twitter
    @ajay-gov Do you know any services or any simulator which provides sample IoT data which i can use and play around with swim ?
    Ajay.Gov
    @ajay-gov
    Sure, glad to hear that it works. A bit more detail- when you open a downlink the swim client establishes a connection to the server. The data is streamed from the server to the client using that connection. You may open multiple downlinks i.e to other nodes/lanes on the same host and the swim client will use the same connection to stream data to the different downlinks. However when you call client.close the connection to the server is closed and all downlinks will stop getting the data from the server.
    Ajay.Gov
    @ajay-gov
    @vishnuprasad73_twitter we work with customer related data for our enterprise apps. We have built a couple of sample apps that use public data sources.
    1. Swim Transit (Repo for code here: https://github.com/swimos/transit) is a real-time application that uses bus location information from multiple cities in the US. The bus location is sent from sensors on these buses. The docs for their API is here: https://gist.github.com/grantland/7cf4097dd9cdf0dfed14. You can look at the https://github.com/swimos/transit code to see how you can create web-agents from it and then build a real-time streaming web application using those web agents from a REST API data source.
    2. Swim Flight Tracker is a real-time application that uses flight location information. The flight location information is available here: https://opensky-network.org/apidoc/
    Vishnu Prassad
    @vishnuprasad73_twitter
    @ajay-gov Thanks again.SWIM is really interesting :) Does swim have any plans to have support for the server-side in other languages other than Java?
    Vishnu Prassad
    @vishnuprasad73_twitter
    Im a noob at Java, Learned a bit of basic of it for SWIM. :)
    Ajay.Gov
    @ajay-gov
    @vishnuprasad73_twitter We are working on moving the swim-core into Rust. Since Rust will run natively, we plan on supporting other language bindings into Rust. At that point you could use other languages on the server-side
    @vishnuprasad73_twitter Glad you like swim! Please do spread the word.
    Scott Clarke
    @scottswim
    you can find the source for the Flight Tracker demo here https://github.com/swimos/flight-tracker. It demos using both 3rd party APIs (OpenSky) as well as static CSV files. The project itself is split into 2 parts. The main webapp and a data simulator. The data simulator takes data from the APIs and CSV files and sends data into the main app in a timed way using swim command lanes. This allows for starting/stopping/replaying the data in the main app.
    We also have a simpler demo where we use NodeJS to bridge sensor data from an Arduino into Swim. The code for that demo is here: https://github.com/swimos/plant-monitor
    Pasquale Vazzana
    @Pasvaz
    @scottswim are you guys aware that the flight-tracker doesn't work on Safari?
    Brad Johnson
    @johnson_brad_twitter
    Hey @Pasvaz - just tagged @scottswim and some of our other devs in Slack. I think it's a known issue?
    Scott Clarke
    @scottswim
    I was just made aware of that a few days ago :D I have not had a chance to fix it yet.
    Pasquale Vazzana
    @Pasvaz
    I'll check the code and see if it's a real issue, it doesn't seem to like Classes but afaik Safari supports classes since v9
    Scott Clarke
    @scottswim
    thanks for letting us know.
    Pasquale Vazzana
    @Pasvaz
    no I stand corrected, classes are supported but no public/private fields, which is where it complains indeed
    Scott Clarke
    @scottswim
    yeah, safari does not like how i am doing member vars in the class.
    Pasquale Vazzana
    @Pasvaz
    yeah
    Scott Clarke
    @scottswim
    should be an easy enough fix, just have not had the time just yet.
    Pasquale Vazzana
    @Pasvaz
    I guess only babel can, there is no way to make Safari use public members apart transpiling them
    anyway, it's not a major issue, Chrome works fine
    Scott Clarke
    @scottswim
    firefox works as well.
    Pasquale Vazzana
    @Pasvaz
    not on android apparently
    Scott Clarke
    @scottswim
    oh, yeah, i am not surprised there. I have not done any optimization for mobile for flight-tracker
    that is another good thing to add to the list however.