simplexml error handling php

问题:

I am using the following code:

function GetTwitterAvatar($username){
$xml = simplexml_load_file("http://twitter.com/users/".$username.".xml");
$imgurl = $xml->profile_image_url;
return $imgurl;
}

function GetTwitterAPILimit($username, $password){
$xml = simplexml_load_file("http://$username:$[e-mail]/account/rate_limit_status.xml");
$left = $xml->{"remaining-hits"};
$total = $xml->{"hourly-limit"};
return $left."/".$total;
}

and getting these errors when the stream cannot connect:

Warning: simplexml_load_file(http://twitter.com/users/****.xml) [function.simplexml-load-file]: failed to open stream: HTTP request failed! HTTP/1.0 503 Service Unavailable

Warning: simplexml_load_file() [function.simplexml-load-file]: I/O warning : failed to load external entity "http://twitter.com/users/****.xml" 

Warning: simplexml_load_file(http://[e-mail]/account/rate_limit_status.xml) [function.simplexml-load-file]: failed to open stream: HTTP request failed! HTTP/1.0 503 Service Unavailable

Warning: simplexml_load_file() [function.simplexml-load-file]: I/O warning : failed to load external entity "http://***:***@twitter.com/account/rate_limit_status.xml"

How can I handle these errors so I can display a user friendly message instead of what is shown above?

回答1:

I've found a nice example in the php documentation.

So the code is:

libxml_use_internal_errors(true);
$sxe = simplexml_load_string("<?xml version='1.0'><broken><xml></broken>");
if (false === $sxe) {
    echo "Failed loading XML\n";
    foreach(libxml_get_errors() as $error) {
        echo "\t", $error->message;
    }
}

And the output, as we/I expected:

Failed loading XML

Blank needed here
parsing XML declaration: '?>' expected
Opening and ending tag mismatch: xml line 1 and broken
Premature end of data in tag broken line 1

回答2:

I thinks this is a better way

$use_errors = libxml_use_internal_errors(true);
$xml = simplexml_load_file($url);
if (false === $xml) {
  // throw new Exception("Cannot load xml source.\n");
}
libxml_clear_errors();
libxml_use_internal_errors($use_errors);

more info: http://php.net/manual/en/function.libxml-use-internal-errors.php

回答3:

If you look at the manual, there is an options parameter:

SimpleXMLElement simplexml_load_file ( string $filename [, string $class_name = "SimpleXMLElement" [, int $options = 0 [, string $ns = "" [, bool $is_prefix = false ]]]] )

Options list is available: http://www.php.net/manual/en/libxml.constants.php

This is the correct way to suppress warnings parsing warnings:

$xml = simplexml_load_file('file.xml', 'SimpleXMLElement', LIBXML_NOWARNING);

回答4:

This is an old question, but is still relevant today.

The correct way to handle exceptions when using the oop SimpleXMLElment is like so.

libxml_use_internal_errors(TRUE); // this turns off spitting errors on your screen
try {
  $xml = new SimpleXMLElement($xmlStringOfData);
} catch (Exception $e) {
  // Do something with the exception, or ignore it.
}

回答5:

My little code:

try {
    libxml_use_internal_errors(TRUE);
    $xml = new SimpleXMLElement($xmlString);
    echo '<pre>'.htmlspecialchars($xml->asXML()).'</pre>';
} catch (Exception $e) {
    echo 'Caught exception: ' . $e->getMessage() . chr(10);
    echo 'Failed loading XML: ' . chr(10);
    foreach(libxml_get_errors() as $error) {
        echo '- ' . $error->message;
    }
}

Result example:

Caught exception: String could not be parsed as XML
Failed loading XML: 
- Opening and ending tag mismatch: Body line 3 and Bod-y

回答6:

The documentation says that in the case of an error, simplexml_load_file returns FALSE. So, you can use the "shut-up" operator (@) in combination with a conditional statement:

if (@simplexml_load_file($file))
{
    // continue
}
else 
{
    echo 'Error!';
}

回答7:

if (simplexml_load_file($file) !== false) { // continue } else { echo 'Error!'; }

And Twitter is down, maybe ?