Sharing tips on how to capture Zhihu Q&A data using PHP and phpSpider!

Sharing tips on how to use PHP and phpSpider to capture Zhihu Q&A data!

As the largest knowledge sharing platform in China, Zhihu has a massive amount of question and answer data. For many developers and researchers, obtaining and analyzing this data is very valuable. This article will introduce how to use PHP and phpSpider to capture Zhihu Q&A data, and share some tips and practical code examples.

1. Install phpSpider

phpSpider is a crawler framework written in PHP language. It has powerful data capture and processing functions and is very suitable for capturing Zhihu Q&A data. The following are the installation steps for phpSpider:

1. Install Composer: First make sure you have installed Composer. You can check whether it is installed by running the following command:

composer -v

If it works normally If the version number of Composer is displayed, it means the installation has been successful.

2. Create a new project directory: Execute the following command on the command line to create a new phpSpider project:

composer create-project vdb/php-spider my-project

This will create a project called my-project new directory and install phpSpider in it.

2. Write phpSpider code

1. Create a new phpSpider task: Enter the my-project directory and use the following command to create a new phpSpider task:

./phpspider --create mytask

This will create a new directory called mytask in the my-project directory, which contains the necessary files for scraping data.

2. Edit crawling rules: In the mytask directory, open the rules.php file, which is a PHP script used to define crawling rules. You can define in this script the URL of the Zhihu Q&A page you need to crawl, as well as the data fields you want to extract.

The following is a simple crawling rule example:

return array(
    'name' => '知乎问答',
    'tasknum' => 1,
    'domains' => array(
        'www.zhihu.com'
    ),
    'start_urls' => array(
        'https://www.zhihu.com/question/XXXXXXXX'
    ),
    'scan_urls' => array(),
    'list_url_regexes' => array(
        "https://www.zhihu.com/question/XXXXXXXX/page/([0-9]+)"
    ),
    'content_url_regexes' => array(
        "https://www.zhihu.com/question/XXXXXXXX/answer/([0-9]+)"
    ),
    'fields' => array(
        array(
            'name' => "question",
            'selector_type' => 'xpath',
            'selector' => "//h1[@class='QuestionHeader-title']/text()"
        ),
        array(
            'name' => "answer",
            'selector_type' => 'xpath',
            'selector' => "//div[@class='RichContent-inner']/text()"
        )
    )
);

In the above example, we defined a crawling task named Zhihu Q&A, which will crawl Get all the answers to a specific question. It contains the data field name, selector type and selector that need to be extracted.

3. Write a custom callback function: In the mytask directory, open the callback.php file. This is a PHP script used to process and save the captured data.

The following is a simple example of a custom callback function:

function handle_content($url, $content)
{
    $data = array();
    $dom = new DOMDocument();
    @$dom->loadHTML($content);
    
    // 使用XPath选择器提取问题标题
    $xpath = new DOMXPath($dom);
    $question = $xpath->query("//h1[@class='QuestionHeader-title']");
    $data['question'] = $question->item(0)->nodeValue;
    
    // 使用XPath选择器提取答案内容
    $answers = $xpath->query("//div[@class='RichContent-inner']");
    foreach ($answers as $answer) {
        $data['answer'][] = $answer->nodeValue;
    }
    
    // 保存数据到文件或数据库
    // ...
}

In the above example, we defined a callback function named handle_content, which will be fetched is called after the data. In this function, we extracted the question title and answer content using the XPath selector and saved the data in the $data array.

3. Run the phpSpider task

1. Start the phpSpider task: In the my-project directory, use the following command to start the phpSpider task:

./phpspider --daemon mytask

This will Start a phpSpider process in the background and start grabbing Zhihu Q&A data.

2. View the crawling results: The phpSpider task will save the crawled data in the data directory, with the task name as the file name, and each crawling task corresponds to a file.

You can view the crawling results through the following command:

tail -f data/mytask/data.log

This will display the crawling log and results in real time.

4. Summary

This article introduces the techniques of using PHP and phpSpider to capture Zhihu Q&A data. By installing phpSpider, writing crawling rules and custom callback functions, and running phpSpider tasks, we can easily crawl and process Zhihu Q&A data.

Of course, phpSpider has more powerful functions and usages, such as concurrent crawling, proxy settings, UA settings, etc., which can be configured and used according to actual needs. I hope this article will be helpful to developers who are interested in capturing Zhihu Q&A data!

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