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merged branch jakzal/domcrawler-xpath-namespace-fix (PR #9129)

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This PR was merged into the master branch.

Discussion
----------

[DomCrawler] Fixed an issue with namespace prefix matching being to greedy

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #9121
| License       | MIT
| Doc PR        | -

The regexp matching prefixes is naive and matches most of strings followed by a colon: `/(?P<prefix>[a-z_][a-z_0-9\-\.]*):[^"\/]/i`.

It is also incomplete as it does not match all the supported characters (like the unicode ones). Implementing [the actual specification](http://www.w3.org/TR/2004/REC-xml-names11-20040204/#NT-PrefixedName) would mean creating a very complex expression, especially because we have to ignore strings contained in quotes etc.

This would match any XML tag name (names in quotes not ignored):

```php
$ncNameStartChar = 'a-z_\\xC0-\\xD6\\xD8-\\xF6\\xF8-\\x{2FF}\\x{370}-\\x{37D}\\x{37F}-\\x{1FFF}\\x{200C}-\\x{200D}\\x{2070}-\\x{218F}\\x{2C00}-\\x{2FEF}\\x{3001}-\\x{D7FF}\\x{F900}-\\x{FDCF}\\x{FDF0}-\\x{FFFD}\\x{10000}-\\x{EFFFF}';
$ncNameChar = $ncNameStartChar.'.\\-0-9\\xB7\\x{0300}-\\x{036F}\\x{203F}-\\x{2040}';
$ncName = '['.$ncNameStartChar.']['.$ncNameChar.']*';
$regexp = sprintf('/(?P<prefix>%s):%s/iu', $ncName, $ncName);
```

Therefore, I decided NOT to throw an exception if found prefix is actually not a prefix. If a prefix used in xpath doesn't exist we'll still get a warning when running it (`DOMXPath::query(): Undefined namespace prefix`).

The current implementation is simple and will work in most situations. For edge cases, it's still possible to register prefixes manually.

What do you think?

Commits
-------

3292163 [DomCrawler] Fixed an issue with namespace prefix matching being to greedy.
This commit is contained in:
Fabien Potencier 2013-09-26 08:29:27 +02:00
commit 803d434839
2 changed files with 14 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/Symfony/Component/DomCrawler/Crawler.php
View File

@ -835,7 +835,9 @@ class Crawler extends \SplObjectStorage
foreach ($prefixes as $prefix) {
$namespace = $this->discoverNamespace($domxpath, $prefix);
$domxpath->registerNamespace($prefix, $namespace);
if (null !== $namespace) {
$domxpath->registerNamespace($prefix, $namespace);
}
}
return $domxpath;
@ -861,8 +863,6 @@ class Crawler extends \SplObjectStorage
if ($node = $namespaces->item(0)) {
return $node->nodeValue;
}
throw new \InvalidArgumentException(sprintf('Could not find a namespace for the prefix: "%s"', $prefix));
}
/**
@ -872,7 +872,7 @@ class Crawler extends \SplObjectStorage
*/
private function findNamespacePrefixes($xpath)
{
if (preg_match_all('/(?P<prefix>[a-zA-Z_][a-zA-Z_0-9\-\.]*):[^:]/', $xpath, $matches)) {
if (preg_match_all('/(?P<prefix>[a-z_][a-z_0-9\-\.]*):[^"\/]/i', $xpath, $matches)) {
return array_unique($matches['prefix']);
}

19
src/Symfony/Component/DomCrawler/Tests/CrawlerTest.php
View File

@ -401,15 +401,6 @@ EOF
$this->assertSame('widescreen', $crawler->text());
}
/**
* @expectedException \InvalidArgumentException
* @expectedExceptionMessage Could not find a namespace for the prefix: "foo"
*/
public function testFilterXPathWithAnInvalidNamespace()
{
$this->createTestXmlCrawler()->filterXPath('//media:group/foo:aspectRatio');
}
public function testFilterXPathWithManuallyRegisteredNamespace()
{
$crawler = $this->createTestXmlCrawler();
@ -420,6 +411,15 @@ EOF
$this->assertSame('widescreen', $crawler->text());
}
public function testFilterXPathWithAnUrl()
{
$crawler = $this->createTestXmlCrawler();
$crawler = $crawler->filterXPath('//media:category[@scheme="http://gdata.youtube.com/schemas/2007/categories.cat"]');
$this->assertCount(1, $crawler);
$this->assertSame('Music', $crawler->text());
}
/**
* @covers Symfony\Component\DomCrawler\Crawler::filter
*/
@ -741,6 +741,7 @@ EOF
<media:title type="plain">Chordates - CrashCourse Biology #24</media:title>
<yt:aspectRatio>widescreen</yt:aspectRatio>
</media:group>
<media:category label="Music" scheme="http://gdata.youtube.com/schemas/2007/categories.cat">Music</media:category>
</entry>';
return new Crawler($xml, $uri);