How to bind dynamic data created in remote adapter in LS client

rvkvino

I'm having below json data structure, this will update the dynamically. In this structure dynamically add or delete the stock rows.This data contains multiple clients data. Now I need to display connected clients data to users.For example if vb clients web page open means they need to get the data of vb clients data(

"vb" :Smile_Ah: {"com_id":"41","com_name":"GOLD - SALEM","selling_rate":"4977.00","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"},{"com_id":"38","com_name":"SILVER - SALEM","selling_rate":"49880.00","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"}]

). Whether the command update is possible using this type data structure or I need to change the structure

{"vb" :Smile_Ah: {"com_id":"41","com_name":"GOLD - SALEM","selling_rate":"4977.00","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"},{"com_id":"38","com_name":"SILVER - SALEM","selling_rate":"49880.00","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"}],"akumar" :Smile_Ah: {"com_id":"33","com_name":"GSUT999KG1","selling_rate":"48147","buying_rate":"48311","delivery":"25-06-2020","retail_rate":"-"},{"com_id":"37","com_name":"GAHD999KG1","selling_rate":"48147","buying_rate":"48311","delivery":"25-06-2020","retail_rate":"-"},{"com_id":"38","com_name":"GRKT999KG1","selling_rate":"48147","buying_rate":"48311","delivery":"25-06-2020","retail_rate":"-"}],"kb" :Smile_Ah: {"com_id":"19","com_name":"ONLINE GOLD BAR","selling_rate":"4967.00","buying_rate":"-","delivery":"26-06-2020","retail_rate":"-"},{"com_id":"26","com_name":"SABARISH JEWELLERY","selling_rate":"4970.00","buying_rate":"-","delivery":"26-06-2020","retail_rate":"-"}],"novnath" :Smile_Ah: {"com_id":"57","com_name":"Gold  ","selling_rate":"4969","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"}]}

Giuseppe Corti

Hi

From Lightstreamer point of view, the most natural mapping for a dynamic list of stocks is definitely an item in COMMAND mode.
Obviously this requires that in your adapter you have to unpack the json structure and detect all the changes that have occurred: new stock added, deletion of an existing stock, update of the values for an existing stock, and push these updates to the Lightstreamer server as ADD, DELETE, and UPDATE commands.
In this case the key field should be associated with com_id.

Then in the client you will no longer need the json structure at all.
Unless, maybe because you already have some client code based on the json, you actually need it; however in this case it should be easy to obtain back the json structure from the updates received through the Item in COMMAND mode.

Regards,
Giuseppe

rvkvino

Hello,
Could you please clarify in data structure in the second point how to I have to change the structure for clients rates.

Giuseppe Corti

In vb there is some system utilities (this for example) that help to serialize and deserialize from json to a common collection object, such a Dictionary, or a List, ...
In this case you could keep up to date a dictionary with the updates received by the server and serialize to a json for display if that helps.

Regards,
Giuseppe

rvkvino

Hello,
Now I have created structure like this,

[{"com_id":"33","com_name":"GOLD BAR","selling_rate":"4952","buying_rate":"-","delivery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_33"},{"com_id":"36","com_name":"GOLD FT","selling_rate":"4952","buying_rate":"4751","delivery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_36"},{"com_id":"37","com_name":"GOLD RTGS","selling_rate":"4852","buying_rate":"-","delivery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_37"},{"com_id":"38","com_name":"SILVER","selling_rate":"48955","buying_rate":"48428","delivery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_38"},{"com_id":"33","com_name":"GOLD CBE RTGS ","selling_rate":"4943","buying_rate":"4831","delivery":"30-06-2020","retail_rate":"-","client":"kkvtrade","client_com_id":"kkvtrade_33"},{"com_id":"36","com_name":"GOLD FT","selling_rate":"4943","buying_rate":"4841","delivery":"30-06-2020","retail_rate":"-","client":"kkvtrade","client_com_id":"kkvtrade_36"},{"com_id":"37","com_name":"GOLD RTGS","selling_rate":"4843","buying_rate":"4941","delivery":"30-06-2020","retail_rate":"-","client":"kkvtrade","client_com_id":"kkvtrade_37"},{"com_id":"38","com_name":"SILVER","selling_rate":"48455","buying_rate":"48428","delivery":"30-06-2020","retail_rate":"-","client":"kkvtrade","client_com_id":"kkvtrade_38"}]
wlclientrates : "[{\"com_id\":\"33\",\"com_name\":\"GOLD BAR\",\"selling_rate\":\"4952\",\"buying_rate\":\"-\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"lmxtrade\",\"client_com_id\":\"lmxtrade_33\"},{\"com_id\":\"36\",\"com_name\":\"GOLD FT\",\"selling_rate\":\"4952\",\"buying_rate\":\"4751\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"lmxtrade\",\"client_com_id\":\"lmxtrade_36\"},{\"com_id\":\"37\",\"com_name\":\"GOLD RTGS\",\"selling_rate\":\"4852\",\"buying_rate\":\"-\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"lmxtrade\",\"client_com_id\":\"lmxtrade_37\"},{\"com_id\":\"38\",\"com_name\":\"SILVER\",\"selling_rate\":\"48955\",\"buying_rate\":\"48428\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"lmxtrade\",\"client_com_id\":\"lmxtrade_38\"},{\"com_id\":\"33\",\"com_name\":\"GOLD CBE RTGS \",\"selling_rate\":\"4943\",\"buying_rate\":\"4831\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\"kkvtrade_33\"},{\"com_id\":\"36\",\"com_name\":\"GOLD FT\",\"selling_rate\":\"4943\",\"buying_rate\":\"4841\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\"kkvtrade_36\"},{\"com_id\":\"37\",\"com_name\":\"GOLD RTGS\",\"selling_rate\":\"4843\",\"buying_rate\":\"4941\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\"kkvtrade_37\"},{\"com_id\":\"38\",\"com_name\":\"SILVER\",\"selling_rate\":\"48455\",\"buying_rate\":\"48428\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\"kkvtrade_38\"}]"

here client_com_id will be unique for every clients. Can you please help me on the logic to connect the client and serve only respected clients rates. Here in this list will be having all the clients rates. Is this possible to connect the client who is passing the client name with request and send represent client data from server.

Giuseppe Corti

Hi,

The scenario you described requires a personalized Item. I mean that each user subscribes to a specific Item reserved to the specific user.
The Item name could be the client_com_id itself, if the client knows it this makes things easy; otherwise you have to make a customization in the Metadata Adapter (getItem method).

Then in the adapter when you parse the json, for each element you first check the client_com_id, and then you will update the personalized Item with Command mode 'ADD', 'UPDATE', or 'DELETE' depending on the com_id.

Please let us know if you need any further clarifications.

Regards,
Giuseppe

rvkvino

Hello,
Need to subscribe set of items, in this above json list "client":"lmxtrade", this lmxtrade will be send from client this have to connect with LS server and need to server lmxtrade list, this list will have n number of row.

Giuseppe Corti

You have both options available.
Or have different Items all customized according to the user, and the client must explicitly subscribe to all of these.
Or manage only one Item, obviously also customized for the user, with the list managed dynamically on the server side. In this case you need to use the COMMAND subscribe mode.
For further details about COMMAND mode you can refer to Portfolio example: https://github.com/Lightstreamer/Lightstreamer-example-Portfolio-client-javascript#basic-portfolio-demo---html-client

Regards,
Giuseppe

rvkvino

I have previously used COMMAND mode and I have created separate remote adapter for individual clients. For example in this above data structure there having 2 clients lmxtrade and kkvtrade . For each clients I have created individual adapter and run the adapter in separate port numbers.

Now I have planned to run in single adapter to subscribe multiple client account. For example I have 2 domains to show their commodity trading data. But this both LS client request to get data from single LS server. In this case how I need to bind the data to serve respected clients.
And I need to know how the client name send to LS server from LS client. Whether via request header or any other method is there.
And also I need to know whether I have to change the data structure in LS server like

{"vb" :Smile_Ah: {"com_id":"41","com_name":"GOLD - SALEM","selling_rate":"4977.00","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"},{"com_id":"38","com_name":"SILVER - SALEM","selling_rate":"49880.00","buying_rate":"-","delivery":"25-06-2020","retail_rate":"-"}],"akumar" :Smile_Ah: {"com_id":"33","com_name":"GSUT999KG1","selling_rate":"48147","buying_rate":"48311","delivery":"25-06-2020","retail_rate":"-"}],"kb" :Smile_Ah: {"com_id":"19","com_name":"ONLINE GOLD BAR","selling_rate":"4967.00","buying_rate":"-","delivery":"26-06-2020","retail_rate":"-"}]}

I feel this above data structure is difficult to do ADD, DELETE and UPDATE in COMMAND mode. So only I have changed the structure as like below structure

[{"com_id":"33","com_name":"GOLD BAR","selling_rate":"4952","buying_rate":"-","delivery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_33"},{"com_id":"36","com_name":"GOLD FT","selling_rate":"4952","buying_rate":"4751","de livery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_36 "},{\"com_id\":\"36\",\"com_name\":\"GOLD FT\",\"selling_rate\":\"4943\",\"buying_rate\":\"4 841\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\"kkv trade_36\"},{\"com_id\":\"38\",\"com_name\":\"SILV ER\",\"selling_rate\":\"48455\",\"buying_rate\":\" 48428\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\"kkv trade_38\"}]

In this above structure client_com_id will be unique. I have to subscribe by using "client" column.

Giuseppe Corti

Hi,

Perhaps the most appropriate way to pass client information to the adapter is through extra http headers.
Please check out the documentation of this method https://lightstreamer.com/api/ls-web-client/latest/ConnectionOptions.html#setHttpExtraHeaders
But in the case if you are not already using it for real authentication, you can use the user info: https://lightstreamer.com/api/ls-web-client/latest/ConnectionDetails.html#setUser

Then you need to keep a structure in your metadata that associates each client session with the client name.
At this point in the getItems method you can customize the Item subscribed by the client name pertaining to the involved client session.

I understand the change to the data structure, I think it makes sense.

Regards,
Giuseppe

rvkvino

Hello,
In previously I have subscribed clients with server using the prefix string as Item for every row key

@ Override public void subscribe(String itemName) throws SubscriptionException, FailureException {
logger.debug("Subscribing to " + itemName);
if (itemName.startsWith("Item")) {
myFeed.sendRates(itemName);
}
}

I have used above method to subscribe clients with server.

In my client I have used like

var liverateId = "Item";
var liverateSubscription = new Subscription("COMMAND",liverateId,fieldList);
liverateSubscription.setDataAdapter("ABQUOTE_ADAPTER");
liverateSubscription.setRequestedSnapshot("yes");
liverateSubscription.addListener(liverateGrid);
lsClient.subscribe(liverateSubscription);

So it was easy to get subscribe the items from my server. Previously I have created individual adapter so that it was was easy to get connect. Now I have created single adapter for all of my clients.
And my structure looks like now is,

[{"com_id":"33","com_name":"GOLD BAR","selling_rate":"4952","buying_rate":"-","delivery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_33 "},{"com_id":"36","com_name":"GOLD FT","selling_rate":"4952","buying_rate":"4751"," de livery":"30-06-2020","retail_rate":"-","client":"lmxtrade","client_com_id":"lmxtrade_36 "},{\"com_id\":\"36\",\"com_name\":\"GOLD FT\",\"selling_rate\":\"4943\",\"buying_rate\":\" 4 841\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\" kkv trade_36\"},{\"com_id\":\"38\",\"com_name\":\"SILV ER\",\"selling_rate\":\"48455\",\"buying_rate\":\ " 48428\",\"delivery\":\"30-06-2020\",\"retail_rate\":\"-\",\"client\":\"kkvtrade\",\"client_com_id\":\" kkv trade_38\"}]

Here my key is client_com_id field. Now how I need to connect LS server from my client. Can you please help me on this.

Giuseppe Corti

Is your client aware of its typology? Ie. it can do something like this:

var liverateId = "lmxtrade"; // 
var liverateSubscription = new Subscription("COMMAND",liverateId,fieldList);
liverateSubscription.setDataAdapter("ABQUOTE_ADAPT ER");
liverateSubscription.setRequestedSnapshot("yes");
liverateSubscription.addListener(liverateGrid);
lsClient.subscribe(liverateSubscription);

If yes the subscribe method should be something similar to this:

Override public void subscribe(String itemName) throws SubscriptionException, FailureException {
logger.debug("Subscribing to " + itemName);
if (itemName.startsWith("lmxtrade")) {
 // push only "client":"lmxtrade" elements
 } else if (itemName.startsWith("kkvtrade")) {
 // push only "client":"kkvtrade" elements
 }
}

rvkvino

This client name will be more than 100. like lmxtrade, kkvtrade, svg, sln etc.

For this only i'm thinking how to use this in this case. I'm storing this client name in redis. So I can get array of clients in LS server. Can I check itemName.startsWith array of item.

Now I have client list as ["lmxtrade", "kkvtrade", "vb", "lmx", "svg", "kb", "sln"]

List<String> list = myFeed.getClientsList();
for (int i = 0; i < list.size(); i++) {
if (itemName.startsWith(list.get(i))) {
myFeed.sendRates(itemName);
}
}

I have written the subscription logic as like this, is this okay to subscribe client with LS server.

In previously I have given OnUpdate, OnAdd and OnDelete static name as "Item"

private void onUpdate(Object handle, String key, ClientsRateRow rates) {
// An update was received from the feed
// Check for late calls
// if (isSubscribed(handle)) {
// Create a new HashMap instance that will represent the update
HashMap<String, String> update = new HashMap<String, String>();
// We have to set the key
update.put("key", key);
// The UPDATE command
update.put("command", "UPDATE");
// And the new quantity value

update.put("desc", rates.getCom_name());
update.put("bid", rates.getBuying_rate());
update.put("ask", rates.getSelling_rate());
update.put("low", rates.getLow_rate());
update.put("high", rates.getHigh_rate());
update.put("delivery", rates.getDelivery());
update.put("retail_rate", rates.getRetail_rate());
update.put("comweight", rates.getCom_weight());
update.put("comid", rates.getCom_id());
update.put("order", rates.getCom_order());

// Pass everything to the kernel
// listener.smartUpdate(handle, update, false);
listener.update("Item", update, false);
// }
}

Whether I have to change Instead of Item I need to change anything. Please help me on this struggling from last week.