google網站 seo优化：搜索引擎优化策略

Data parsing and extraction is the final core component. PHP DOMDocument and DOMXPath are standard, but for more robust extraction, libraries like Symfony DomCrawler or simple__dom are recommended. Each worker should parse the fetched HTML, extract new links (optionally filtering by domain/pattern), and push them back to the queue. The worker also extracts target data (e.g., product prices, article text) and stores it in a database or writes to a file. A typical pattern: after fetching, the worker decodes the response, instantiates a `DomDocument`, and uses XPath queries. Error handling is paramount – try-catch blocks around parsing, and if a page returns an unexpected status code (e.g., 403 or 429), the task should be retried with a different proxy/UA after a delay. The source code must also log every request, response code, and proxy used for debugging and analytics. Combining these components yields a complete PHP spider pool: a master process spawns N workers, each runs an infinite loop pulling tasks, executing requests with proxy rotation, parsing, and re-queuing. The entire pool can be monitored via Redis keys tracking active workers, total requests, and error rates.