I'm posting data on my ElasticSearch database.
I've noticed that data is not immediately available, it requires some milliseconds to show up in a GET request. I can live with that (after all, the calls are asynchronous so this behavior is expected) but in my test code I need to POST some data and immediately after retrieve it. At the moment I'm using a sleep(5) just to be sure data is available but how can I synchronize with the db?
To ensure data is available, you can make a refresh request to corresponding index before GET/SEARCH:
http://localhost:9200/your_index/_refresh
Or refresh all indexes:
http://localhost:9200/_refresh
Related
I'm sending data from my backend every 10 seconds and I wanted to display that data in reactjs. I've searched on the net to use socket.io to display real-time data. Is there a better way to use it?
If you're dead set on updating your data every 10 seconds, it would make more sense to make a request from the client to the server, as HTTP requests can only be opened from client to server. By using HTTP requests, you won't need to use socket.io, but socket.io is an easy alternative if you need much faster requests.
Depending on how you are generating the data being sent from your backend, specifically if you are using a database, there is most likely a way to subscribe to changes in the database. This would actually update the data in realtime, without a 10 second delay.
If you want a more detailed answer, you'll have to provide more detail regarding your question: what data are you sending? where is it coming from or how are you generating it?
I'm working on an autodialer feature, in which an agent will get a call when I trigger the button from the frontend (using react js language), and then automatically all the leads in the agent assigned portal will get back-to-back calls from agent number. However, because this process is automatic, the agent won't know who the agent has called, so I want to establish a real-time connection so that I can show a popup on the frontend that contains information about the lead who was called.
I have a page with multiple widgets, each receiving data from a different query in the backend. Doing a request for each will consume the limit the browser puts on the number of parallel connections and will serialize some of them. On the other hand, doing one request that will return one response means it will be as slow as the slowest query (I have no apriori knowledge about which query will be slowest).
So I want to create one request such that the backend runs the queries in parallel and writes each result as it is ready and for the frontend to handle each result as it arrives. At the HTTP level I believe it can be just one body with serveral json, or maybe multipart response.
Is there an angularjs extension that handles the frontend side of things? Optimally something that works well with whatever can be done in the Java backend (didn't start investigating my options there)
I have another suggestion to solve your problem, but I am not sure you would be able to implement such a thing as from you question it is not very clear what you can or cannot do.
You could implement WebSockets and the server would be able to notify the front-end about the data being fetched or it could send the data via WebSockets right away.
In the first example, you would send a request to the server to fetch all the data for your dashboard. Once a piece of data is available, you could make a request for that particular piece and given that the data was fetched couple of seconds ago, it could be cached on the server and the response would be fast.
The second approach seems a more reasonable one. You would make an HTTP/WebSocket request to the server and wait for the data to arrive over WebSocket.
I believe this would be the most robust an efficient way to implement what you are asking for.
https://github.com/dfltr/jQuery-MXHR
This plugin allows to parse a response that contains several parts (multipart) by having a callback to parse each part. This can be used in all our frontends to support responses for multiple data (widgets) in one requests. The server side will receive one request and use servlet 3 async support (or whatever exists in other languages) to ‘park’ it, sending multiple queries, writing each response to the request as each query returns (and with the right multipart boundary).
Another example can be found here: https://github.com/anentropic/stream.
While both of these may not be compatible with angularjs, the code does not seem complex to port there.
I need to know how to update UI with the status of a batch update operation. For example i am sending a request to WebApi to update multiple records (could be any number of records), now i want to show the status of each record to client side.
Please suggest me the best way of doing that. I am using WebApi, Angular. I am thinking about implementing SignalR that can update Client UI with respect to the status but is there an another way of doing that ??
signalr may be overkill for what could be a simple polling request to your api.
It's a little ambiguous as to exactly what it is you are doing with your batch update operation, but since your looking to get status back I'm going to assume it's a long slow operation that your not waiting on a response for in the initial request.
Web api has REST principles baked into it from the start so I imagine your batch update operation is using a PUT with a set of objects that need to be updated. If so you could simply request those objects back from your api to check their state and see if the operation has updated them yet.
If your not doing a simple PUT on an entity and it's more like a POST to submit a batch operation you should persist the operation entity and return a reference to it in the initial call then subsequently poll for that operation by id to get its current status.
signalr might let it feel a little more realtime by immediately pushing completed events down to the client but it can also bring a lot more overhead for what you are trying to achieve
I have in my application a cart, it currently works for me, though the issue my colleague is having is that it is too "slow". I have been thinking of a better way to implement this to make it faster and efficient.
Currently this is how my page loads:
Product/Ticket page loads.
AJAX function gets products/tickets from server and displays on the page.
Each product has a buy button like this:
<button ng-click="buyTicket(id)" class="btn">Buy Ticket</button>
This is how the buyticket works:
I pass the id of the product/ticket to my function.
AJAX function posts id to server.
Server runs a database query to retrieve product/ticket information based on id.
Product/ticket information is saved into "cart" table.
AJAX function returns with data "true" as the response.
I broadcast this:
$rootScope.$broadcast('TICKET_ADDED', true);
Cart directive listens to broadcast and makes an AJAX call to server to get cart data:
$scope.$on('TICKET_ADDED', function(response) {
$scope.loadCart();
})
Data returned is assigned to an array and displayed in the cart.
Each user cart is identified by a randomly generated string of length 25.
That is how my cart works for now, i would like a faster, better way to do this please.
Edit: (used a debug bar to get these statistics)
When page loads:
No. of queries run: 1
Memory Usage: 12.25 MB
Request Duration: 1.04s
No. of AJAX requests: 3
When buy ticket function is clicked:
No. of queries run: 5
Memory Usage: 12.75 MB
Request Duration: 934.41 ms
No. of AJAX requests: 2
The approach you are using is fine, just the thing is you might not have used caching. Use caching & you will get a good Speed. Also check your server response time, speed etc. on Google Speed Insights. It will tell you how you can make it more fact. Hope it helps.
vJ
You can improve performance by introducing caching, both server side and client side.
Server side caching: instead of doing a DB query every time, keep objects in memory for some period of time. You can define a 'time to live' for an object and if the object has 'expired', you requery the db.
There are probably plenty of libraries out there that support this kind of functionality, but I would simply build it myself, because it's not that complicated. The trickiest part is making sure that nothing breaks down when multiple threads are trying to modify your collection of cached objects.
Client side caching is a breeze when you use angular. This is from the documentation of $http:
To enable caching, set the request configuration cache property to
true (to use default cache) or to a custom cache object (built with
$cacheFactory). When the cache is enabled, $http stores the response
from the server in the specified cache. The next time the same request
is made, the response is served from the cache without sending a
request to the server.
After reading about how CodeIgniter handles sessions, it has me concerned about the performance impact when sessions are configured to be stored and retrieved from the database.
This is from the CI documentation: "When session data is available in a database, every time a valid session is found in the user's cookie, a database query is performed to match it."
So every AJAX call, every HTML fragment I request is going to have this overhead? That is potentially a huge issue for systems that are trying to scale!
I would have guessed that CI would have implemented it better: include the MD5 hash to cover both the sessionID+timestamp when encoding them in the session record. Then only check the database for the session record every X minutes whenever the sessionID gets regenerated. Am I missing something?
You can make your AJAX requests use a different controller, for example Ajax_Controller instead of MY_Controller. MY_Controller would load the Session class but the Ajax_Controller doesn't. That way when you call to your AJAX, it doesn't touch session data and therefore doesn't make any erroneous calls to the database that aren't necessary.
If you are autoloading the Session class, maybe you can try unloading it for the AJAX requests? I've never tried it but it's talked about here http://codeigniter.com/forums/viewthread/65191/#320552 and then do something like this
if($this->input->is_ajax_request()){
// unload session class code goes here
}