Learn how to scrape data using PHP and Scrapy

As the amount of Internet data increases, how to quickly obtain and process data has become a need for many people. Crawler technology has become a common method to quickly obtain data. This article will introduce how to use PHP and Scrapy to implement data crawling.

1. PHP data crawling

PHP is a very popular server-side scripting language with many powerful data processing functions. Data crawling can be implemented using PHP.

1. Use PHP built-in functions to obtain data

PHP has some built-in functions that can be used to obtain web page content. For example, the file_get_contents() function can obtain the contents of a URL address:

$html = file_get_contents('http://www.example.com/');

2. Use a third-party library to obtain data

In addition to the functions that come with PHP, there are many third-party libraries that can be used retrieve data. For example, cUrl library:

$ch = curl_init();
curl_setopt($ch, CURLOPT_URL, "http://www.example.com/");
curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
$html = curl_exec($ch);
curl_close($ch);

3. Parse HTML content

After obtaining the HTML content, you need to parse it and extract the required data. At this time, you can use PHP's DOMDocument class:

$dom = new DOMDocument();
$dom->loadHTML($html);
$links = $dom->getElementsByTagName('a');
foreach ($links as $link) {
    echo $link->nodeValue;
}

The above code will output all the links in the page.

2. Scrapy data crawling

Scrapy is a powerful Python crawler framework that can be used to quickly build crawlers.

1. Install Scrapy

Scrapy can be installed through the pip install scrapy command. After the installation is complete, you can use the following command to create a new Scrapy project:

scrapy startproject projectname

2. Write Spider

The Spider in Scrapy is used to define how to access and parse data. In Spider, you need to define the link to start crawling and how to parse the data.

import scrapy

class ExampleSpider(scrapy.Spider):
    name = "example"
    start_urls = [
        'http://www.example.com/',
    ]

    def parse(self, response):
        for quote in response.css('div.quote'):
            yield {
                'text': quote.css('span.text::text').get(),
                'author': quote.css('span small::text').get(),
                'tags': quote.css('div.tags a.tag::text').getall(),
            }

3. Run Scrapy

The above code defines how to access and parse the data. Use the following command to run Scrapy:

scrapy crawl example

Scrapy will start crawling data and writing the data to the specified format. You can use the following command to output data to a JSON file:

scrapy crawl example -o items.json

The above is how to use PHP and Scrapy to crawl data. Through these methods, data from the Internet can be quickly obtained and further processed and analyzed.

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