Introduction to crawler framework based on PHP and detailed explanation of application examples

With the explosive growth of Internet information, a large amount of data is stored on websites, which is of important value to many users. Therefore, crawler technology has gradually become a powerful means of utilizing Internet data.

This article introduces a crawler framework based on PHP language: Guzzle and Goutte. Guzzle is an HTTP client developed for PHP that can be used to send HTTP requests and interact with REST resources. Goutte is its complement. It is a web crawler framework based on Guzzle that can easily obtain web content and perform data extraction and analysis.

First, we need to install Guzzle and Goutte in PHP. It can be installed through Composer. The specific command is as follows:

composer require guzzlehttp/guzzle
composer require fabpot/goutte

After the installation is completed, let’s first learn how to use Guzzle. We can send an HTTP GET request and obtain the response content through the following code:

<?php
use GuzzleHttpClient;

$client = new Client();
$response = $client->get('https://www.example.com');
echo $response->getBody();

This code first creates a GuzzleClient object, and then uses the get() method to send a GET request to the specified URL, and The response content was obtained. Call the getBody() method to get the content of the response body.

Goutte is a web crawler framework developed based on Guzzle, and its use is also very simple. The following is a simple example of using Goutte:

<?php
use GoutteClient;

$client = new Client();
$crawler = $client->request('GET', 'https://www.example.com');
$crawler->filter('h1')->each(function ($node) {
    echo $node->text() . "
";
});

This code uses Goutte to create a Client object and sends a GET request to the specified URL, then obtains the response body and parses it into a DOM object . $crawler->filter('h1') is a filter that specifies all h1 tag nodes on the page, and then it calls the each() method. For each h1 tag node, the specified anonymous function will be executed. , where $node is the current node object, and its text() method can obtain the text content of the node.

Let’s look at a more complete example below, which demonstrates how to use Goutte to crawl questions and answers on Zhihu, and save the user name, answer content, number of likes and answer time to In a CSV file:

<?php
use GoutteClient;

$client = new Client();
$crawler = $client->request('GET', 'https://www.zhihu.com/question/21774949');
$fp = fopen('output.csv', 'w');
fputcsv($fp, ['User', 'Content', 'Votes', 'Time']);
$crawler->filter('.List-item')->each(function ($node) use ($fp) {
    $user = $node->filter('.AuthorInfo .Popover')->text();
    $content = $node->filter('.RichText')->text();
    $votes = $node->filter('.Voters')->text();
    $time = $node->filter('.ContentItem-time')->text();
    fputcsv($fp, [$user, $content, $votes, $time]);
});
fclose($fp);

This code first crawls the page with question ID 21774949 on Zhihu, and then uses a file handle to write the CSV header row to the output.csv file. Next, use the filter() method to find all question and answer nodes on the page, and then execute an anonymous function on each node. In the anonymous function, use the filter() method to find each user's name, answer content, number of likes, and answer time, and use the fputcsv() method to write these four fields to the file. Finally close the file handle.

In summary, it is very simple to use Guzzle and Goutte to build a crawler framework, and it has strong flexibility and scalability, and can be applied to a variety of different scenarios, including but not limited to data mining, SEO Optimization and other fields. However, please note that any crawler will need to comply with the website's robots.txt file to avoid placing an undue burden on the target website and infringing on user privacy.

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