dataflowkitvsphp-spider
Dataflow kit ("DFK") is a Web Scraping framework for Gophers. It extracts data from web pages, following the specified CSS Selectors. You can use it in many ways for data mining, data processing or archiving.
Web-scraping pipeline consists of 3 general components:
- Downloading an HTML web-page. (Fetch Service)
- Parsing an HTML page and retrieving data we're interested in (Parse Service)
- Encoding parsed data to CSV, MS Excel, JSON, JSON Lines or XML format.
For fetching dataflowkit has several types of page fetchers:
- Base fetcher uses standard golang http client to fetch pages as is. It works faster than Chrome fetcher. But Base fetcher cannot render dynamic javascript driven web pages.
- Chrome fetcher is intended for rendering dynamic javascript based content. It sends requests to Chrome running in headless mode.
For parsing dataflowkit extracts data from downloaded web page following the rules listed in configuration JSON file. Extracted data is returned in CSV, MS Excel, JSON or XML format.
Some dataflowkit features:
- Scraping of JavaScript generated pages;
- Data extraction from paginated websites;
- Processing infinite scrolled pages.
- Sсraping of websites behind login form;
- Cookies and sessions handling;
- Following links and detailed pages processing;
- Managing delays between requests per domain;
- Following robots.txt directives;
- Saving intermediate data in Diskv or Mongodb. Storage interface is flexible enough to add more storage types easily;
- Encode results to CSV, MS Excel, JSON(Lines), XML formats;
- Dataflow kit is fast. It takes about 4-6 seconds to fetch and then parse 50 pages.
- Dataflow kit is suitable to process quite large volumes of data. Our tests show the time needed to parse appr. 4 millions of pages is about 7 hours.
php-spider is a PHP library for web crawling and scraping. It allows developers to easily navigate and extract data from websites by simulating a web browser's behavior.
- supports two traversal algorithms: breadth-first and depth-first
- supports crawl depth limiting, queue size limiting and max downloads limiting
- supports adding custom URI discovery logic, based on XPath, CSS selectors, or plain old PHP
- comes with a useful set of URI filters, such as Domain limiting
- supports custom URI filters, both prefetch (URI) and postfetch (Resource content)
- supports custom request handling logic
- supports Basic, Digest and NTLM HTTP authentication. See example.
- comes with a useful set of persistence handlers (memory, file)
- supports custom persistence handlers
- collects statistics about the crawl for reporting
- dispatches useful events, allowing developers to add even more custom behavior
- supports a politeness policy
This Spider does not support Javascript.
Example Use
Dataflowkit uses JSON configuration like:
which is then ingested through CLI command.
{
"name": "collection",
"request": {
"url": "https://example.com"
},
"fields": [
{
"name": "Title",
"selector": ".product-container a",
"extractor": {
"types": [
"text",
"href"
],
"filters": [
"trim",
"lowerCase"
],
"params": {
"includeIfEmpty": false
}
}
},
{
"name": "Image",
"selector": "#product-container img",
"extractor": {
"types": [
"alt",
"src",
"width",
"height"
],
"filters": [
"trim",
"upperCase"
]
}
},
{
"name": "Buyinfo",
"selector": ".buy-info",
"extractor": {
"types": [
"text"
],
"params": {
"includeIfEmpty": false
}
}
}
],
"paginator": {
"selector": ".next",
"attr": "href",
"maxPages": 3
},
"format": "json",
"fetcherType": "chrome",
"paginateResults": false
}
use Example\StatsHandler;
use VDB\Spider\Discoverer\XPathExpressionDiscoverer;
use Symfony\Contracts\EventDispatcher\Event;
use VDB\Spider\Event\SpiderEvents;
use VDB\Spider\Spider;
require_once('example_complex_bootstrap.php');
// Create Spider
$spider = new Spider('http://dmoztools.net');
// Add a URI discoverer. Without it, the spider does nothing. In this case, we want <a> tags from a certain <div>
$spider->getDiscovererSet()->set(new XPathExpressionDiscoverer("//div[@id='catalogs']//a"));
// Set some sane options for this example. In this case, we only get the first 10 items from the start page.
$spider->getDiscovererSet()->maxDepth = 1;
$spider->getQueueManager()->maxQueueSize = 10;
// Let's add something to enable us to stop the script
$spider->getDispatcher()->addListener(
SpiderEvents::SPIDER_CRAWL_USER_STOPPED,
function (Event $event) {
echo "\nCrawl aborted by user.\n";
exit();
}
);
// Add a listener to collect stats to the Spider and the QueueMananger.
// There are more components that dispatch events you can use.
$statsHandler = new StatsHandler();
$spider->getQueueManager()->getDispatcher()->addSubscriber($statsHandler);
$spider->getDispatcher()->addSubscriber($statsHandler);
// Execute crawl
$spider->crawl();
// Build a report
echo "\n ENQUEUED: " . count($statsHandler->getQueued());
echo "\n SKIPPED: " . count($statsHandler->getFiltered());
echo "\n FAILED: " . count($statsHandler->getFailed());
echo "\n PERSISTED: " . count($statsHandler->getPersisted());
// Finally we could do some processing on the downloaded resources
// In this example, we will echo the title of all resources
echo "\n\nDOWNLOADED RESOURCES: ";
foreach ($spider->getDownloader()->getPersistenceHandler() as $resource) {
echo "\n - " . $resource->getCrawler()->filterXpath('//title')->text();
}