异步代码中URL重定向处理：grequests如何获取最终访问URL？

Absolutely possible! Let me break down how to handle redirects and grab the final URL with grequests—since it’s built on top of requests and gevent, we can reuse a lot of the familiar requests patterns with just a few small adjustments.

Quick Solution: Get the Final URL Directly #

Just like with requests, grequests returns response objects that include a url attribute pointing to the final redirected address. Here’s how it works:

Requests Reference (for context) #

import requests

# Regular requests approach
response = requests.get("http://example.com/redirect-target")
final_url = response.url
print(f"Final URL: {final_url}")

Grequests Equivalent #

import grequests

# Build the async request
req = grequests.get("http://example.com/redirect-target", allow_redirects=True)  # allow_redirects is True by default

# Send the request and get the response
response = grequests.map([req])[0]

# Extract the final URL if the response is valid
if response:
    final_url = response.url
    print(f"Final URL: {final_url}")

Track Full Redirect History #

If you need to see every step of the redirect chain (not just the final URL), you can use the response.history attribute—just like in requests. This gives you a list of all prior response objects from each redirect.

import grequests

def log_redirects(response, *args, **kwargs):
    if response.history:
        print("Redirect chain:")
        for i, redirect in enumerate(response.history):
            next_url = response.history[i+1].url if i+1 < len(response.history) else response.url
            print(f"Step {i+1}: {redirect.url} → {next_url}")

# Add a hook to log redirects (optional but helpful)
req = grequests.get("http://example.com/multi-step-redirect", hooks={"response": log_redirects})
response = grequests.map([req])[0]

# Get the final URL
if response:
    print(f"\nFinal URL: {response.url}")

Batch Requests Example #

For multiple async requests, you can process all responses and extract their final URLs in one go:

import grequests

# List of URLs that might redirect
urls = [
    "http://example.com/redirect-1",
    "http://example.com/redirect-2",
    "http://example.com/no-redirect"
]

# Create async requests for all URLs
requests = [grequests.get(url) for url in urls]

# Send all requests and get responses
responses = grequests.map(requests)

# Iterate through responses to get final URLs
for idx, resp in enumerate(responses):
    if resp:
        print(f"Original URL: {urls[idx]}")
        print(f"Final URL: {resp.url}\n")
    else:
        print(f"Request failed for {urls[idx]}\n")

Key Notes #

• allow_redirects=True is the default in grequests (just like requests), so you don’t need to specify it unless you want to disable redirects.
• The response object from grequests is nearly identical to requests’ Response object—most attributes and methods you’re used to (like url, history, status_code) work the same way.

内容的提问来源于stack exchange，提问作者game0ver