New record notify?

[mvaughn]

Can a server automagically push new data to a browser or must the browser always pull?

[lvasic]

Re: New record notify?

Browser must pull.

[pettechservices]

Re: New record notify?

Actually, browsers are able to PUSH now apparently. I have not tested this but have read a lot about it recently.

Google for: SERVER SENT EVENTS

[bea2701]

Re: New record notify?

Browser must pull.

If you want to sent notifications to the clients best option is to use NodeJS with socket.io. There are some opensource projects with good examples how to implement this but understand you need some good knowledge how NodeJS works to implement this as the WAS side.
Perhaps a better and more stable solution is you ask Selwyn to take a look what the possibilities are.

[kkfin]

Re: New record notify?

This problem has been discussed in an earlier thread. Post #7 explains one way to solve problem with AA

[bea2701]

Re: New record notify?

This problem has been discussed in an earlier thread. Post #7 explains one way to solve problem with AA

Ken,

Correct i saw the same website as Jim mentioned i mist the earlier post thanks.

[mvaughn]

Re: New record notify?

Thanks for the link, Ken. One interesting part of that post is this:

...example using node.js (now built into AA in the pre-release version)...

I wonder if that was cut from the final release? I can't find mention of it anywhere.

[Jim Coltz]

Re: New record notify?

I wonder if that was cut from the final release? I can't find mention of it anywhere.

It's in the release notes from the 29 September official release.

Xbasic - Node.JS - Extending Server-side Functionality using Node.js - Node.js is a popular program for writing server side utilities in Javascript. Alpha Anywhere now has tight integration with Node and you can now define your own Node modules that can be called from Xbasic.

Watch Video - Part 1
Watch Video - Part 2
Watch Video - Part 3

To create a new 'Node Service' that can be called from Xbaisc, you create a new .js file in the Node_Services folder in the Alpha Anywhere executable folder. The syntax for this .js file is the syntax you would use for any Node module.

To call a Node service from Xbasic, you:

dim an instances of the helper::V8 object
construct a JSON string that defines the Node service you want to call and the parameters you wan to pass to the Node service
call the .NodeRequest() method of the helper::V8 object instance



In the following example, we have defined a trivial Node service that takes as its input two variables, 'firstname' and 'lastname' and sends back a string showing: Hello firstname lastname.

The Node service in this example is called 'hello'. Therefore the '_command' property of the JSON command object is set to 'hello'

You must also set an '_id' property in the JSON command object. This can be any value. Using a UUID for this value is convenient.

The Node service is called using the .NodeRequest() method and the result is returned as a JSON string with properties for the error text (if there was an error) and 'result' - the result of the request. The JSON response can be parsed to get Xbasic varibles, or the json_extract() function can be used to extract the 'result' property.







dim n as helper::V8
dim p as p

'generate an id for the request we are about to send to Node.

'we just use a GUID for convenience
p._id = api_uuidcreate()



'set the _command property. This is the name of the Node service we want to call
p._command = "hello"




'specify any variables you want to pass to the Node service

p.firstname = "Nellie"
p.lastname = "Jones"


'convert the Xbasic .dot variable to a JSON string.

dim jsonCommand as c

jsonCommand = json_generate(p)


?n.NodeRequest(jsonCommand)
= {"_id":"id1","error":"","result":"Hello Nellie Joness"}




Here is how the corresponding Hello.js file is defined. This file must be in the Node_Services folder in the Alpha Anywhere executable folder. This is a standard Node module. It can 'require' any other Node modules that you have written, or that have been installed using NPM (the Node Package Manager).



exports.handler = function(packet,response,sendResponse) {
var e;
var attachments = null;

var msg = 'Hello ' + packet.firstname + ' ' + packet.lastname;
response.result = msg;

sendResponse(response,attachments);
};




If you edit the .js file in the Node_Services folder after having called it, your edits will not be seen until you shutdown the Node service. The next time you call the Node service you will see a short delay as Node starts up.

To shut down the Node service you can all the .NodeShutDown() method on the helper::V8 object instance. For example, in the above example the helper::V8 object instance was called 'n', so the following command will shut Node down.



n.NodeShutdown()



NOTE: Node.exe is automatically installed in the Alpha Anywhere executable folder when you install Node. You do not need to install Node yourself.

[mvaughn]

Re: New record notify?

Thank you Jim, I watched the videos and used your code as my template. Works great in working preview but not live, which is odd.
After publishing the UX I'll open two instances of dlg_Chat to try chatting, but nothing at all appears to happen.

XBasic function in a UX:

function chat as c (e as p)

if len(e.dataSubmitted.txtmsg) > 0 then
	dim n as helper::V8
	dim p as p
	p._id = api_uuidcreate()
	p._command = "hello"
	p.firstname = e.dataSubmitted.txtname
	p.msg = e.dataSubmitted.txtmsg
	dim jsonCommand as c
	jsonCommand = json_generate(p)
	p.return = n.NodeRequest(jsonCommand)
	
	dim p2 as p
	p2 = json_parse(p.return)
	dim result as c = p2.result
	dim firstname as c = p.firstname
	
	dim display as c = e.dataSubmitted.textbox + crlf() + result
	chat = "{dialog.Object}.setValue('TEXTBOX',display);"
end if

'n.NodeShutdown()

end function

hello.js located in C:\Program Files (x86)\a5V12\node_services

hello.js:

exports.handler = function(packet,response,sendResponse) {
var e;
var attachments = null;

var msg = packet.firstname + ': ' + packet.msg;
response.result = msg;

sendResponse(response,attachments);
};

I've noticed that most if not all services in node_services have corresponding folders in node_modules which include package.json for that service. My hello.js has no such module.

Dialog Chat: dlg_chat.a5wcmp