AppStudio_20190605_PromiseNesting.qml

AppStudio_20190605_PromiseNesting.qml

import QtQuick 2.12
import QtQuick.Controls 2.5
import ArcGIS.AppFramework 1.0

Item {
    Button {
        text: qsTr("Test Promise nesting")
        onClicked: {
            download( "GET", "https://community.esri.com/groups/appstudio" )
            .then( (data) => {
                showTitle( data )
                download( "GET", "https://appstudio.arcgis.com" )
                .then( (data) => {
                    showTitle( data )
                    download( "GET", "https://community.esri.com/groups/survey123" )
                    .then( (data) => {
                        showTitle( data )
                    } )
                    .catch( handleError )
                } )
                .catch( handleError )
            } )
            .catch( handleError )
        }
    }

    function showTitle( networkRequest ) {
        let responseText = networkRequest.responseText
        let [ , title ] = responseText.match(/<title.*>(.*)<\/title>/)
        console.log( title )
    }
    
    function handleError(error) {
        console.log( "Caught Exception: ", error.message )
        console.log( "Stack: ", error.stack )
        throw error
    }

    function download( method, url, ...form ) {
        networkRequestWithPromise.method = method
        networkRequestWithPromise.url = url
        return networkRequestWithPromise.sendPromise( ...form )
    }

    NetworkRequest {
        id: networkRequestWithPromise

        property var _resolve
        property var _reject

        uploadPrefix: "file://"

        onReadyStateChanged: {
            if (readyState !== 4) return
            if (status < 200 || status >= 299) {
                _reject( new Error( qsTr("Download failure %1: Status Code %2: %3").arg(url).arg(status).arg(statusText) ) )
                return
            }
            if (errorCode !== 0)
            {
                _reject( new Error( qsTr("Download failure %1: Error Code %2: %3").arg(url).arg(error).arg(errorText) ) )
                return
            }
            _resolve( networkRequestWithPromise )
        }

        function sendPromise( ...form ) {
            return new Promise( function (resolve, reject) {
                _resolve = resolve
                _reject = reject
                send( ...form )
            } )
        }
    }
}