riverReader.js

const urlRiver = "https://feedland.org/getriverfromreadinglist?url=https://lists.feedcorps.org/artshow.opml";

function httpRequest (url, timeout, headers, callback) { 
	timeout = (timeout === undefined) ? 30000 : timeout;
	var jxhr = $.ajax ({ 
		url: url,
		dataType: "text", 
		headers,
		timeout
		}) 
	.success (function (data, status) { 
		callback (undefined, data);
		}) 
	.error (function (status) { 
		var message;
		try { //9/18/21 by DW
			message = JSON.parse (status.responseText).message;
			}
		catch (err) {
			message = status.responseText;
			}
		if ((message === undefined) || (message.length == 0)) { //7/22/22 by DW & 8/31/22 by DW
			message = "There was an error communicating with the server.";
			}
		var err = {
			code: status.status,
			message
			};
		callback (err);
		});
	}

function getRiver (urlRiver, callback) {
	httpRequest (urlRiver, undefined, undefined, function (err, jsontext) {
		if (err) {
			console.log ("servercall: url == " + url + ", err.message == " + err.message);
			callback (err);
			}
		else {
			callback (undefined, JSON.parse (jsontext));
			}
		});
	}

function startup () {
	console.log ("startup");
	getRiver (urlRiver, function (err, river) {
		var ct = 0;
		if (err) {
			console.log (err.message);
			}
		else {
			river.feeds.forEach (function (feed) {
				feed.items.forEach (function (item) {
					if (item.enclosure !== undefined) {
						if (item.enclosure.type !== undefined) {
							if (beginsWith (item.enclosure.type, "image/")) {
								console.log (padWithZeros (++ct, 3) + ": " + item.enclosure.url);
								}
							}
						}
					});
				});
			}
		});
	}