使用Scrapy登录网站遇问题，请求代码排查协助

Hey there! Sorry to hear you're hitting a wall with getting your Scrapy spider logged in—let's work through this together. First off, can you share a few key bits of your code and some details about what's happening when you run it? Specifically:

• Your start_requests method (where you initiate the login flow)
• The FormRequest or Request code you're using to send login credentials
• Any relevant settings you’ve tweaked (like USER_AGENT, COOKIES_ENABLED)
• The response you’re getting (status code, or a snippet of the HTML after your login attempt)

In the meantime, here are the most common reasons Scrapy logins fail—let’s check these off first:

• Missing hidden form fields: A ton of sites use hidden fields (like csrfmiddlewaretoken, __VIEWSTATE, or authenticity_token) that you can’t just hardcode. You need to scrape these from the login page’s HTML first, then include them in your POST request. Using FormRequest.from_response() is way more reliable than building form data manually—it auto-extracts these hidden fields for you.
• Wrong request details: Double-check you’re sending a POST request to the correct endpoint (not just the login page URL you see in the browser). Use your browser’s DevTools (Network tab) to watch what happens when you log in manually—copy the exact URL, method, and headers from that real request.
• Cookies not sticking: Scrapy usually handles cookies automatically, but if you’ve messed with COOKIES_ENABLED or are overriding cookies in your requests, that could break things. Also, avoid setting dont_redirect=True unless you have a specific reason—many sites redirect after a successful login, and missing that redirect might make you incorrectly think the login failed.
• Generic User-Agent: Scrapy’s default User-Agent is super easy for sites to flag as a bot. Swap it out for a realistic one in your settings.py, like:

  USER_AGENT = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/118.0.0.0 Safari/537.36'
  

• Anti-bot measures: If the site uses captchas, you’ll need to handle those (manual solving for testing, or a service like 2Captcha for automation). Some sites also require JavaScript to render the login form—if that’s the case, you might need to pair Scrapy with tools like Playwright or Splash to render the page properly.
• Obvious but easy to miss: Double-check that your username and password are actually correct by logging in manually in the same browser you used to inspect the site. Typos happen more often than we’d like to admit!

Once you share those code snippets and details, we can dig deeper into exactly what’s going wrong.

内容的提问来源于stack exchange，提问作者haider