使用PHP解析XML网页

Question

How do I use PHP to parse XML on the web?

Here is the example XML . How would you get the value of the first "AskRealtime"?

I am aware of SimpleXML. I am looking for the proper code to open the XML webpage, and work with it using SimpleXML.

This suggested code does not succesfully load the page:

$xml = @simplexml_load_file("http://query.yahooapis.com/v1/public/yql?q=select%20symbol%2C%20AskRealtime%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22A%22%2C%22AA%22)&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys");

$price = $xml->results->quote[0]->AskRealtime;

echo $price;

Answer 1

Step 1 . - load the file in SimpleXML $xml = @simplexml_load_file($fl) or die($errorMsg); where $fl is the file URL and $errorMsg is the error message to display.

Step 2 . - get a content $whatever=$xml->results->quote->AskRealtime[0]; Explained: it goes to the XML, then what is named "results", then what is named "quote", then what is named AskRealtime, but the first (index 0) of it.

And a note : if, for some reason, you'll have to get something which is named whatever-else (so it has a - in the name), then it works only if you make the code $xml->{'whatever-else'}

Answer 2

Have you tried using SimpleXMLElement? It works just like your code but it's constructed differently.

$url = 'http://query.yahooapis.com/v1/public/yql?q=select%20symbol%2C%20AskRealtime%20from%20yahoo.finance.quotes%20where%20symbol%20in%20(%22A%22%2C%22AA%22)&env=store%3A%2F%2Fdatatables.org%2Falltableswithkeys';
$xml = new SimpleXMLElement($url, null, true);
echo $xml->results->quote[0]->AskRealtime;

There are different methods for getting the file contents, even though I doubt it's the problem.

/* cURL */
$curl = curl_init($url);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
$contents = curl_exec($curl);
curl_close($curl);

/* Alternative */
$contents = file_get_contents($url);

Can you tell what is the error you get? Or try var_dump($xml) and see what it returns.

Answer 3

Use can use some HTTP request library to get the file, eg: http://www.php.net/manual/en/function.http-get.php

Then feed the response to SimpleXML.