# Protocols

Protocols define how DataSources should connect to retrieve their data. The main properties passed in the DataSource are used, and even depend on the connector used.

Connectors are created and used inside WebWorker so that the main thread is not blocked.

# How it works

Connectors, whatever their type, are only intended to create a connection (when it is a remote access to a server) or to open a stream (to a file for example). For this, it is necessary to define a certain number of properties in the DataSource. For ease of use, their implementation is hidden and their configuration will be done via the DataSources.

Once the connector retrieves the data, it sends the data to the Broadcast channel of the DataSource that will serve the DataSynchronizer or View.

# Types

Property	Name	Description
ws	WebSocket	WebSocket connector
http	HTTP	Http connector
topic	Topic	Broadcast channel connector
file	File	File connector

These connectors have some common properties and some more specific ones

API Reference

# WebSocket protocol: 'ws'

The WebSocket connector is used to open a connection to a WebSocket feed.

Within the Toolkit, some options of the dataSources allow to define the remote address of the server, some properties depend on the SOS standard that the OSH server needs to retrieve the data.

See an example

# HTTP protocol: 'http'

The HTTP connector is used to open a connection to a HTTP feed.

Within the Toolkit, some options of the dataSources allow to define the remote address of the server, some properties depend on the SOS standard that the OSH server needs to retrieve the data.

# Topic protocol: 'topic'

The Topic connector is used to listen to a BroadcastChannel given a specific topic name.

Example:

import SosGetResultJson from 'osh-js/core/datasource/SosGetResultJson';

new SosGetResultJson('Example',{
  replaySpeed: 1.0,
  name: 'Example',
  protocol: 'topic',
  topicName: 'channel-test'
});

# File protocol: 'file'

The File connector is used to read a file.

It uses the loaders.gl (opens new window) library to parse different file types

import File from 'osh-js/core/datasource/File';

new File('Example',{
  name: 'Example',
  paths: ['http://opensensorhub.github.io/osh-js/dev/demos/earthquakes/data/earthquakes.1.csv']
});

Note: By default, the DataSource File object defines the 'file' protocol. It is therefore not necessary to define it in its properties.

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