swimos/community

Official Gitter for the Swim platform and WARP streaming protocol

Vishnu Prassad

@vishnuprasad73_twitter

@ajay-gov yes, im seeing the above error on the server console.

var swim = require("@swim/client");
var structure = require("@swim/structure");

var msg = structure.Text.from('Hello World')
const hostRef = swim.hostRef("warp://localhost:9001");

const client = new swim.WarpClient();
client.command("warp://localhost:9001", "/user/john", "getSurname", msg);

this is the sample client im using

Vishnu Prassad

@vishnuprasad73_twitter

I also tried with java client, that worked well without any issue though

Ajay.Gov

@ajay-gov

@vishnuprasad73_twitter so the exception doesn't affect the functionality?

Vishnu Prassad

@vishnuprasad73_twitter

Yeah. it doesnt affect functionality. I can see the received msg on the console. Trying to figure out what causing the exception when i try with nodejs client. Am I missing anything in the node code?

@ajay-gov

Ajay.Gov

@ajay-gov

your code looks good. I think this is due to the web-socket lib that comes with node, will confirm this.

Vishnu Prassad

@vishnuprasad73_twitter

cool. the exception comes right after the message received and logged.

[/user/john] Surname of John is "Hello World"
swim.codec.DecoderException: incomplete

Ajay.Gov

@ajay-gov

it's related to the websocket close frame i think.

will let you know, thanks for pointing this out

Ajay.Gov

@ajay-gov

you could use that js code in an html page and run it from a browser, think you won't see the exceptions then.

Vishnu Prassad

@vishnuprasad73_twitter

Cool. Let me try that.

Ajay.Gov

@ajay-gov

@vishnuprasad73_twitter is the node ws library(https://www.npmjs.com/package/ws) one of the dependencies in your node application? If so can you try without having that as a dependency?

Vishnu Prassad

@vishnuprasad73_twitter

@ajay-gov I don't use the WS library in the client app. My whole node client is the 8 lines of code i mentioned above. But i can see ws library inside node_modules when i install @swim/client

Ajay.Gov

@ajay-gov

oh ok, so it's that websocket library from node which the swim-client is depending on.

Do try it from the browser when you get a chance. We will fix that issue with the swim-client and node.

Vishnu Prassad

@vishnuprasad73_twitter

Sure will do and update

Ajay.Gov

@ajay-gov

@vishnuprasad73_twitter thanks! Also which version of the swim-server library are you using on the server-side. You may get that from the build.gradle and gradle.properties file.

@vishnuprasad73_twitter we fixed a similar issue in February. Please check swimos/swim#48. It is available in our latest release version of the swim-server library which is 3.10.2.

Vishnu Prassad

@vishnuprasad73_twitter

@ajay-gov im using these versions

compile group: 'org.swimos', name: 'swim-server', version: '3.10.0'
compile group: 'org.swimos', name: 'swim-api', version: '3.10.0'
compile group: 'org.swimos', name: 'swim-client', version: '3.10.0'

i will try 3.10.2 and update

@ajay-gov Just tried updating to 3.10.2 and it worked like a charm!!!

And with that, I have successfully implemented a hello world app on SWIM :)

Thanks a lot

Vishnu Prassad

@vishnuprasad73_twitter

Btw on maven repo the latest version is 3.10.0. people might not be aware of 3.10.2

Ajay.Gov

@ajay-gov

@vishnuprasad73_twitter great to know it worked!

So we moved our namespace from ai.swim to org.swimos. org. The latest version for org.swimos should be 3.10.2 (https://mvnrepository.com/artifact/org.swimos/swim-server)

Latest version for ai.swim is 3.10.0 (https://mvnrepository.com/artifact/ai.swim/swim-server). Going forward we will be using org.swimos.

Vishnu Prassad

@vishnuprasad73_twitter

Ah Got it.

nmehta1993

@nmehta1993

any one help me to setup swim

api

brohitbrose

@brohitbrose

Hi, could you please be a little more specific?
Are you trying to get a Swim application working on your machine for the first time? Then we recommend the tutorial application on Github: https://github.com/swimos/tutorial
If you're trying to architect Web Agents / Lanes (i.e. a Swim API) to solve a problem, then we recommend reading these cookbooks: https://www.swimos.org/tutorials/ . Or, we can help you further if you tell us your specific problem.

Vishnu Prassad

@vishnuprasad73_twitter

let valueLane = client.downlinkValue()
                    .hostUri("warp://localhost:9001").nodeUri("/welcome/valueLane").laneUri("info")
                    .open();

valueLane.set(structure.Text.from("YYY"));

Once i open a connection to a valueLane how can i close it. Trying with nodejs

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).

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