jhvrequest

jhvrequest is a javascript package for sending SAMP requests to JHelioviewer

Usage

Install the package with npm

npm i jhvrequest

Import and make requests.

import { JhvRequestBuilder } from "jhvrequest";

// Load AIA 304 between 2023-01-1 and 2023-01-02 every hour.
let requestBuilder = new JhvRequestBuilder();
requestBuilder
  .SetTimeRange("2023-01-01 00:00:00", "2023-01-02 00:00:00")
  .SetCadence(3600)
  .AddSource("SDO", "AIA 304")
  .Build()
  .Send();

You can add multiple sources to the request:

let requestBuilder = new JhvRequestBuilder();
requestBuilder.SetTimeRange('2023-01-01 00:00:00', '2023-01-02 00:00:00')
    .SetCadence(3600)e
    .AddSource("SDO", "AIA 304")
    .AddSource("SOHO", "LASCO C2")
    .AddSource("SOHO", "LASCO C3")
    .Build().Send();

You can check if JHelioviewer is alive before making any requests

import { IsJhvRunning } from "jhvrequest";

// IsJhvRunning returns true/false
let isJhvRunning = await IsJhvRunning();
if (isJhvRunning) {
  // Send request
} else {
  // Jhv is not running
}

Nodejs vs Browser environments

The dependency sampjs currently only supports a browser environment because it depends on xmlhttprequest and parsing xml via the DOM. But you can get this to work in a nodejs environment with the xmlhttprequest and xmldom package by adding XMLHttpRequest to the the global variable and hooking the xmldom.DOMParser into XMLHttpRequest.prototype.responseXML.

See test/jhvrequest.test.ts as an example.

IsJhvRunning

async function checks if JHelioviewer is running and returns a boolean.

import { IsJhvRunning } from "jhvrequest";
// result is a true/false
let result = await IsJhvRunning();

JhvRequestBuilder

Method	Description
SetName(appName)	Sets the application name. This is the name which appears in the JHelioviewer request popup.
SetTimeRange(start, end)	Set the time range to query. Start and end are strings to remove ambiguity with js dates
SetCadence(seconds)	Set the time step to use between start and end. in seconds.
AddSource(observatory, dataset, (Optional) server)	Add an image layer to the request.
Build()	Construct a JhvRequest from the builder

JhvRequest

Method	Description
Send()	Send the request to JHelioviewer. This is an async operation and will complete after the user accepts or declines the request in JHelioviewer.