The dom-explorer.php program shown in Example 26-2 provides a shell-like prompt to let you explore an HTML document interactively.
It reads an HTML document from a provided URL, parses it into a DOMDocument, and then gives you a prompt at which you can enter commands to see the node structure and contents of the documents.
Additionally, dom-explorer.php uses the Readline word-completion features to more easily enter node locations.
Enter a few characters and hit Tab to see a list of nodes that match the characters you’ve typed:
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% php dom-explorer.php http://www.php.net /html > ls head body /html > ls head title style[1] comment()[1] style[2] comment()[2] meta link[1] link[2] link[3] ↵ script[1] link[4] script[2] /html > cat head/title PHP: Hypertext Preprocessor /html > cd body /html/body > ls text()[1] div[1] text()[2] div[2] text()[3] div[3] text()[4] div[4] text()[5] ↵ div[5] text()[6] div[6] text()[7] script comment() /html/body > cd div[2] /html/body/div[2] > ls a text()[1] div text()[2] /html/body/div[2] > cat a /html/body/div[2] > cat div downloads | documentation | faq | getting help | mailing lists | licenses | wiki | reporting bugs | php.net sites | conferences | my php.net /html/body/div[2] > exit |
The code for dom-explorer.php is in Example 26-2.
Example 26-2. dom-explorer.php
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/* Need to specify a URL on the commandline */ isset($argv[1]) or die("No URL specified"); /* Load the HTML and start the command loop */ $explorer = new DomExplorer($argv[1]); $explorer->loop(); class DomExplorer { public function __construct($url) { $html = file_get_contents($url); if (false === $html) { throw new Exception("Can't retrieve $url"); } /* Turn the HTML into valid XHTML */ $clean = tidy_repair_string($html, array('output-xhtml' => true)); /* Load it into a DOMDocument, hiding any libxml * warnings */ $this->doc = new DOMDocument(); libxml_use_internal_errors(true); if (false === $this->doc->loadHtml($clean)) { throw new Exception("Can't parse {$url} as HTML"); } libxml_use_internal_errors(false); $this->currentNode = $this->doc->documentElement; $this->x = new DOMXPath($this->doc); } public function loop() { /* The "completion" function will provide tab-completion at the prompt */ readline_completion_function(array($this, 'completion')); while (true) { /* Use the current node as part of the prompt */ $line = readline($this->currentNode->getNodePath() . ' > '); readline_add_history($line); /* The first word typed in is the command, the rest are arguments */ $parts = explode(' ', $line); $cmd = array_shift($parts); /* Each command is a method, so call it if it exists */ $cmd_function_name = "cmd_$cmd"; if (is_callable(array($this, $cmd_function_name))) { try { $this->$cmd_function_name($parts); } catch (Exception $e) { print $e->getMessage() . "\n"; } } else { print "Unknown Command: $line\n"; } } } /** * Command: exit the program */ protected function cmd_exit($args) { exit(); } /** * Command: list all nodes under the current node or * a specified node */ protected function cmd_ls($args) { if (isset($args[0]) && strlen($args[0])) { $node = $this->resolvePath($args[0]); } else { $node = $this->currentNode; } print implode(' ' , $this->getChildNodePaths($node)) . "\n"; } /** * Command: change to a new current node */ protected function cmd_cd($args) { /* If an argument is provided, use it */ if (isset($args[0]) && strlen($args[0])) { $this->currentNode = $this->resolvePath($args[0]); } /* Otherwise go back to the "root" */ else { $this->currentNode = $this->doc->documentElement; } } /** * Command: print the text content of a node */ protected function cmd_cat($args) { if (isset($args[0]) && strlen($args[0])) { $node = $this->resolvePath($args[0]); print $node->textContent . "\n"; } else { throw new Exception("cat requires an argument"); } } /** * Get all the paths of the nodes under the provided * node, trimming off the path of the current node from * the paths of the child nodes */ protected function getChildNodePaths($node) { $children = array(); $curdir = $node->getNodePath(); foreach ($node->childNodes as $node) { $path = $node->getNodePath(); $sub = substr($path, strlen($curdir) + 1); $children[] = $sub; } return $children; } /** * When tab is pressed, return an array of child * node paths as possible completion targets */ protected function completion($str, $index) { return $this->getChildNodePaths($this->currentNode); } /** * Resolve an xpath expression relative to the current * node, and make sure it only matches 1 target node */ protected function resolvePath($arg) { $matches = $this->x->query($arg, $this->currentNode); if ($matches === false) { throw new Exception("Bad expresion: $arg"); } if ($matches->length == 0) { throw new Exception("No match for $arg"); } if ($matches->length > 1) { throw new Exception("{$matches->length} matches for arg"); } return $matches->item(0); } } |
