Prior to the idea of Live Queries
was made, developers utilized long polling and comet with a specific end goal
to simulate real time website. The issue was that these technologies desired approximately
constant communication with the server, which was not resource-friendly and incredibly
fast. At that time Live Queries came and the Parse Server turned out to real-time.
Imagine an app game, which needs to update in real time non-stop. As you most
likely are aware, games should work incredibly fast so that each and every source
is essential.
Why Live Queries?
One of the essential reasons behind
driving Parse Server is the Query, which enables you to inform the Parse Server
about which of the object you require. The Query depends on a "pull"
model, which is not reasonable for applications that need real-time support. Assume
you are building an application that enables multiple clients to alter a similar
file at the meantime. Parse Query would not be a perfect tool since you cannot
know when to query from the server to get the updates. To resolve this issue,
Parse Live Query is then presented. This tool enables you to subscribe to a Parse
Query you are keen in. Once subscribed, the server will notify customers
whenever a Parse Object that matches the Parse Query is created or updated, in
real-time.
Parse Live Query contains 2 sections,
first is the Live Query server and the second is Live Query clients. Keeping in
mind the end goal is to use live queries that you want to set up both of them. Each
time you desire to get new information, you run one more query. On the off
chance if you want to use Live Queries then you need to build a Query as it is
as you usually would and rather than of find() call subscribe();This implies
each time an object alike this query is changed that time the server will see this instantly and drive
the new object data to you real-time.
Setting Live Queries
There are numerous approaches to set
up Live Queries with Parse Server--in the similar process, in various
processes, or with discrete servers. The easiest path is to set it up in an
indistinguishable procedure as Parse Server.
let api = new ParseServer({
...,
liveQuery: {
classNames: ['Player']
}
});
Once your application gets larger,
you may need a very complex setup with additional Live Query servers. You
shouldn't need to stress over that for some time, but there are few approaches to
set up additional Live Query servers.
