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main.js
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main.js
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/*
*
*/
var DukeOfHazardLAF = "<head><style>table { font-family: arial, sans-serif; border-collapse: collapse; ;}" +
"td, th { border: 1px solid #dddddd; text-align: left; padding: 8px;}tr:nth-child(even) { background-color: #dddddd;}" +
"title {font-family: arial, sans-serif;} " +
"h1 {font-family: arial, sans-serif;}" +
"h2 {font-family: arial, sans-serif;}" +
"p {font-family: arial, sans-serif;}" +
"</style><title>Duke of Hazard</title></head>";
// For ease of testing from inside the firewall
var useProxy = true;
var weatherHost = 'graphical.weather.gov';
var weatherPort = 80;
var proxyHost = 'proxy-host';
var proxyPort = 80;
/**
* Composes a response using the provided zip code.
* @param {type} request
* @param {type} response
* @param {type} zipcode
* @return {undefined}
*/
function respondUsingZip(request, response, zipcode) {
// console.log('In respondUsingZip with zipcode = ' + zipcode);
processWeather(weatherPathForZip(zipcode), response, respond, zipcode);
}
/**
* Callback which converts weather info retrieved from the NWS site into
* HTML output and writes it to the HTTP response.
* @param {type} response
* @param {type} location
* @param {type} weatherInfo
* @return {undefined}
*/
function respond(response, location, weatherInfo) {
//console.log('In respond with weatherInfo ========\n' + weatherInfo + '\n========\n');
response.writeHead(200, {'Content-Type': 'text/html'});
var alerts = extractAlerts(weatherInfo);
response.write(formatAlerts(alerts, location));
//console.log('About to end response');
response.end();
}
/**
* Extracts alert times and alerts from all the weather info returned by the query to the NWS site
* and retains only the earliest entry that refer to the same alert.
* @param {type} weatherInfo
* @return {Array|trimHazards.trimmedHazards}
*/
function extractAlerts(weatherInfo) {
var startValidTimes = extractStartValidTimes(weatherInfo);
var hazards = extractHazards(weatherInfo);
return trimHazards(startValidTimes, hazards);
}
/**
* Formats the provided alert objects as HTML for display to the client.
* @param {type} alerts
* @param {type} location
* @return {DukeOfHazardLAF|String}
*/
function formatAlerts(alerts, location) {
var result = DukeOfHazardLAF;
result += "<body><h1>Duke of Hazard</h1><h2>Alerts for " + location + "</h2><table><tr><th>Time</th><th>Alert</th></tr>\n";
for (var i = 0; i < alerts.length; i++) {
result += "<tr><td>" + makeLink(alerts[i].time.toUTCString(),alerts[i].hazard.url) + "</td>";
result += "<td>" + makeLink(alerts[i].hazard.phen + " " + alerts[i].hazard.sign, alerts[i].hazard.url) + "</td></tr>";
}
result += "</table>";
if (alerts.length > 0) {
result += "<iframe src='" + alerts[0].hazard.url + "' width='100%' height='500' frameborder='1' allowfullscreen sandbox>" +
"</iframe>";
}
result += "</body>";
//console.log("formatAlerts result is \n-----" + result + "\n-----");
return result;
}
function makeLink(text, url) {
return "<a href='" + url + "'>" + text + "</a>";
}
/**
* Extracts the start times for the alert entries into an array of Date objects.
* @param {type} weatherInfo
* @return {Array|extractStartValidTimes.times}
*/
function extractStartValidTimes(weatherInfo) {
var re = new RegExp("<start-valid-time>(.*?)</start-valid-time>","g");
var matcher;
var times = [];
while (matcher = re.exec(weatherInfo)) {
var timeString = matcher[1];
var time = new Date(timeString);
times.push(time);
}
return times;
}
/**
* Extracts hazard entries from the returned weather info.
*
* The returned array has to be paralle with the array of timestamps (the returned
* data expresses them separately in the XML) so empty hazard entries still need
* to be represented in the result. The returned array contains nulls in those slots.
*
* @param {type} weatherInfo
* @return {Array|extractHazards.hazards}
*/
function extractHazards(weatherInfo) {
var re = new RegExp("<hazard-conditions>([\\s\\S]*?)</hazard-conditions>|<hazard-conditions/>","g");
var innerRE = new RegExp('<hazard.*?phenomena="(.*?)".*?significance="(.*?)"[\\s\\S]*?<hazardTextURL>(.*?)</hazardTextURL>','g');
var outerMatcher;
var hazards = [];
while (outerMatcher = re.exec(weatherInfo)) {
var innerMatcher;
var hazardInfo = {
phen: null,
sign: null,
url: null
};
while (innerMatcher = innerRE.exec(outerMatcher[1])) {
// console.log(" phen is " + innerMatcher[1] + ", signif is " + innerMatcher[2] +
// ", url is " + innerMatcher[3]);
hazardInfo.phen = innerMatcher[1];
hazardInfo.sign = innerMatcher[2];
hazardInfo.url = innerMatcher[3];
}
if (hazardInfo.phen === null) {
hazardInfo = null;
}
hazards.push(hazardInfo);
// if (hazardInfo == null) {
// console.log("Pushed null hazard");
// } else {
// console.log("Pushed hazard " + hazardInfo.phen + " " + hazardInfo.sign + " " + hazardInfo.url);
// }
}
return hazards;
}
/**
* Converts parallel arrays of times and hazards into a single result
* array that is pruned so any given hazard appears only once. (The input
* arrays might refer to the same hazard multiple times.)
* @param {type} times
* @param {type} hazards
* @return {Array|trimHazards.trimmedHazards}
*/
function trimHazards(times, hazards) {
var trimmedHazards = [];
var previousHazard = null;
for (var i = 0; i < hazards.length; i++) {
if (hazards[i] != null) {
var trimmedHazard = {
time: times[i],
hazard: hazards[i]
};
if (previousHazard == null || previousHazard.hazard.url !== trimmedHazard.hazard.url) {
trimmedHazards.push(trimmedHazard);
}
previousHazard = trimmedHazard;
}
}
return trimmedHazards;
}
function weatherPathForZip(zipcode) {
var path = weatherPathPrefix() + 'zipCodeList=' + zipcode + weatherPathSuffix();
console.log('Computed path for zip is ' + path);
return path;
}
function weatherPathForLatLong(latitude, longitude) {
var path = weatherPathPrefix() + 'lat=' + latitude + '&lon=' + longitude + weatherPathSuffix();
console.log('Computed path for lat/long is ' + path);
return path;
}
function weatherPathSuffix() {
var now = new Date();
var oneHourAgo = new Date();
oneHourAgo.setTime(oneHourAgo.getTime() - 60 * 60 * 1000);
var oneHourAgoString = oneHourAgo.toISOString();
var nowString = now.toISOString();
return "&product=time-series&begin=" + oneHourAgoString.substr(0,oneHourAgoString.length-1) +
// "&end=" + nowString.substr(0,nowString.length-1) +
"&wwa=wwa";
}
function weatherPathPrefix() {
return '/xml/sample_products/browser_interface/ndfdXMLclient.php?';
}
/**
* Sends a ReST request to the NWS site using the path specified (it varies
* based on how the user is requesting the data -- zip code vs. lat/long) and
* passes the returned response to the callback for processing once the full
* response has arrived.
* @param {type} path
* @param {type} response
* @param {type} callback
* @param {type} location
* @return {undefined}
*/
function processWeather(path, response, callback, location) {
var options = {
host: weatherHost,
port: weatherPort,
path: path,
method: 'GET'
};
var weatherURL = 'http://' + weatherHost + ":" + weatherPort + path;
if (useProxy) {
options.host = proxyHost;
options.port = proxyPort;
options.path = weatherURL;
}
// console.log('About to send request to get weather: ' + weatherURL);
var req = http.request(options, function (res) {
// console.log('Just inside the callback for response event');
res.setEncoding('utf8');
var result = '';
res.on('data', (chunk) => {
result += chunk;
//console.log('Received weather info \n--------\n' + chunk + '\n--------\n');
});
res.on('end', () => {
//console.log('Found end of weather response; about to invoke callback');
callback(response, location, result);
});
});
req.end();
req.on('error', (e) => {
console.log('Error during request: ' + e.message);
});
}
function respondUsingLatLong(request, response, latitude, longitude) {
processWeather(weatherPathForLatLong(latitude, longitude), response, respond, latitude + ',' + longitude);
}
function handleRequest(request, response) {
var parsedURL = url.parse(request.url, true /* parseQueryString */);
var path = parsedURL.path;
console.log('In handleRequest with path ' + path );
var query = parsedURL.query;
var zipcode = query.zip;
if (typeof query.zipcode !== "undefined" && query.zipcode !== "") {
zipcode = query.zipcode;
}
var latitude = query.lat;
var longitude = query.lon;
if (typeof query.long !== "undefined") {
longitude = query.long;
}
if (typeof zipcode !== "undefined" && zipcode !== "") {
respondUsingZip(request, response, zipcode);
} else if (typeof latitude !== "undefined" && typeof longitude !== "undefined") {
respondUsingLatLong(request, response, latitude, longitude);
} else if (parsedURL.path === "/") {
respondWithPrompt(request, response);
} else if (parsedURL.path.substr(1,1) !== '?') {
respondWithPathContent(request, path, response);
} else {
respondWithPrompt(request, response);
}
//console.log('Zip is ' + zipcode + ', lat/long are ' + latitude + "/" + longitude);
// response.writeHead(200, {'Content-Type': 'text/plain'});
// response.end('Hello World\n');
}
function respondWithPrompt(request, response) {
respondWithPathContent(request, "/public/index.html", response);
}
function respondWithPathContent(request, path, response) {
console.log('Responding with content for path ' + path);
fs.readFile(path.substr(1,path.length - 1), function (error, pgResp) {
if (error) {
response.writeHead(404);
response.write('Sorry, I could not find the content ' + path);
} else {
response.writeHead(200, { 'Content-Type': 'text/html' });
response.write(pgResp);
}
response.end();
});
// response.writeHead(200, {'Content-Type': 'text/plain'});
// response.write('Please specify either a zip code or a latitude/longitude pair');
// response.end();
}
var http = require('http');
var url = require('url');
var os = require('os');
var fs = require('fs');
var port=8080;
http.createServer(function (request, response) {
handleRequest(request, response);
}).listen(port);
console.log('Server running at http://127.0.0.1:'+port);