Google Weather API - parsing and modifying data
This question is no longer up-to-date -- Google shut down the unofficial weather API in 2012
I'd like to put some weather forecast to a friend's web page. When I address for
http://www.google.com/ig/api?weather=koprivnica,croatia&hl=hr
The browser returns the right content I'd like to parse to PHP with this code:
<?php
$xml = simplexml_load_file('http://www.google.com/ig/api?weather=koprivnica,croatia&hl=hr');
$information = $xml->xpath("/xml_api_reply/weather/forecast_information");
$current = $xml->xpath("/xml_api_reply/weather/current_conditions");
$forecast_list = $xml->xpath("/xml_api_reply/weather/forecast_conditions");
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>VREMENSKA PROGNOZA</title>
</head>
<body>
<h1><?= print $information[0]->city['data']; ?></h1>
<h2>Danas</h2>
<div class="weather">
<img src="<?= 'http://www.google.com' . $current[0]->icon['data']?>" alt="weather"?>
<span class="condition">
<?= $current[0]->temp_f['data'] ?>° F,
<?= $current[0]->condition['data'] ?>
</span>
</div>
<h2>Prognoza</h2>
<?php foreach ($forecast_list as $forecast) : ?>
<div class="weather">
<img src="<?= 'http://www.google.com' . $forecast->icon['data']?>" alt="weather"?>
<div><?= $forecast->day_of_week['data']; ?></div>
<span class="condition">
<?= $forecast->low['data'] ?>° F - <?= $forecast->high['data'] ?>° F,
<?= $forecast->condition['data'] ?>
</span>
</div>
<?php endforeach ?>
</body开发者_如何学C>
</html>
But the code above won't work because I used 'hr' instead of 'en' (hr = Croatian language):
$xml = simplexml_load_file('http://www.google.com/ig/api?weather=koprivnica,croatia&hl=en')
is the working syntax but the returned data are in English and the temperature is in Fahrenheit.
I suppose it's matter of a wrong UTF-8 encoding property.
I do not know how to grab the exact Croatian text and convert degrees F into Celsius.
I found afterwards a link to the F-to-C solution and changed line 19:
<?= $current[0]->temp_f['data'] ?>° F,to
<?= $current[0]->temp_c['data'] ?>° C,(I do not use it in the current version because it seems the API handles Celsius.)
To keep the degrees in C while having language set to "en" at the same time you can use
en-gb.
Encoding problem:
For some reason Google returns the XML content without proper encoding declaration. One would expect something like:
<?xml version='1.0' encoding='ISO-8859-2'?>
But they skip the encoding attribute in the header. This makes the simplexml_load_file function assume the default encoding of UTF-8. I would consider this a bug in their API implementation, since the XML spec defines UTF-8 as the fallback default encoding.
To compesate for this, try something like:
<?php
$URL = "http://www.google.com/ig/api?weather=koprivnica,croatia&hl=hr";
$dataInISO = file_get_contents($URL);
$dataInUTF = mb_convert_encoding($dataInISO, "UTF-8", "ISO-8859-2");
$xml = simplexml_load_string($dataInUTF);
...
Which seems to work. The ISO-8859-2 value was a pure guess.
Fahrenheit/Celsius:
I don't see an easy way to request the temperature data to be provided in Celsius instead of Fahrenheit in this API (I couldn't find the official doc, am I blind?). However conversion from F to C shouldn't be hard at all.
Try this formula:
(°F - 32) x 5/9 = °C
which you can find in thousand of places. I took it from http://www.manuelsweb.com/temp.htm
The google xml does return the temperature in Celsius as well look for a temp_c tag inside current_conditons
加载中,请稍侯......
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