Question

Is it possible to use an if isset on an item in an array?

example:

if (isset($cityWeatherRssUrls[0])

I receive the following warning when doing so.

Warning: get_temperature() [function.get-temperature]: Node no longer exists in C:\xampp\htdocs\Twinz\includes\getWeather.php on line 51

Line 51 begins after the //Pull temperature comment from the function get_temperature(SimpleXMLElement $xml) in my getWeather.php script.

Below contains all the relevant scripts and functions

cityConfig.php – is used for declaring all the cities and corresponding URL’s to yahoo’s weather XML.

// Define arrays // 
$cities = array();
$cityWeatherRssUrls = array(); 

// Feed URL's //
$yahooWeather = 'http://weather.yahooapis.com/forecastrss?p=';

// City 1 //
$city = 'London';
$cityWeatherRssUrl = $yahooWeather . $cityWeatherFeedCode . '&u=c';

array_push($cities, $city);
array_push($cityWeatherRssUrls, $cityWeatherRssUrl); 

getWeather.php – contains functions for parsing XML tag contents and displaying the content

function get_current_weather($weatherRssUrl) {

    // Get XML data from source
    if (isset($weatherRssUrl)) {
        $feed = $weatherRssUrl;
    } else {
        echo 'Feed not found.  Check URL';
    }

    checkFeedExists($feed);
    $xml = new SimpleXmlElement($feed);

    $weather = get_temperature($xml);

return $weather;
}

function get_temperature(SimpleXMLElement $xml) {

    // Pull temperature from XML 
    $weather['temp'] = $xml->channel->item->children('yweather', TRUE)->condition->attributes()->temp;
    echo round($weather['temp']) . "&deg;C" . "<br />";

return $temp;
}

//Display City Content //
function displayCityContent($cityWeatherRssUrls, $columnSubheading) {

    if (isset($cityWeatherRssUrls)) {
        echo get_current_weather($cityWeatherRssUrls);
        echo $columnSubheading;
        echo get_forecast_weather($cityWeatherRssUrls);
        echo '<br />';
    } else {
        content_unavailable();
    }
}

threeColumnContainer.php – is used to display Weather contents inside a html column

<ul class="columns">
    <li class="col1">
        <h3><?php
        if (isset($column1Heading)) {
        echo $column1Heading;
        }
        ?></h3>
            <p>
                <?php
                if (isset($cityWeatherRssUrls[0]) && ($currentPage == 1)) {
                    echo displayCityContent($cityWeatherRssUrls[0], $columnSubheading);

I can confirm that $cityWeatherRssUrls[0] contains the weather url for London because if I increment the array $cityWeatherRssUrls[1] I receive the a message saying that the feed cannot be found.

Any thoughts?

Thanks in advance

Answer 1

There were quite a few key concepts missing from your code, but hopefully the following will help you fix your code…

<?php

function get_feed($feed_url)
{
    $ch = curl_init();

    curl_setopt($ch, CURLOPT_URL, $feed_url);
    curl_setopt($ch, CURLOPT_FRESH_CONNECT, 1);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

    $rss = curl_exec($ch);
    curl_close($ch);

    return $rss;
}

function get_weather_feed_xml($feed_url = null)
{
    $feed = get_feed($feed_url);

    return new SimpleXmlElement($feed);
}

function get_temperature($feed_url)
{
    if(stripos($feed_url, 'yahooapis') !== false)
    {
        return get_temperature_yahoo($feed_url);
    }

    return false;
}

function get_temperature_yahoo($feed_url)
{
    if(($xml = get_weather_feed_xml($feed_url)) !== false)
    {
        return (float)$xml->channel->item->children('yweather', true)->condition->attributes()->temp;
    }

    return false;
}

function get_city_temperature($city_name, $city_WOEID, $feeds)
{
    $results = array();
    foreach($feeds as $feed_name => $feed_url)
    {
        $feed_url = str_replace(array('{WOEID}', '{NAME}'), array($city_WOEID, $city_name), $feed_url);

        $results[$feed_name] = get_temperature($feed_url);
    }

    return $results;
}

function get_cities_temperature($cities, $feeds)
{
    $results = array();
    foreach($cities as $city_name => $city_WOEID)
    {
        $results[$city_name] = get_city_temperature($city_name, $city_WOEID, $feeds);
    }

    return $results;
}


// -------------------------------
$cities = array(
    'London'        => 44418, 
    'Los Angeles'   => 2442047, 
    'Sydney'        => 1105779, 
);
$feeds = array(
    'Yahoo' => 'http://weather.yahooapis.com/forecastrss?u=c&w={WOEID}', 
);

$check = get_cities_temperature($cities, $feeds);

echo '<pre>';
print_r($check);
echo '</pre>';