Scenarios for the use of curl's forbidden redirection parameter

Figuring out what curl forbidden redirects mean

When we use the curl command to grab data, we often run into the case of automatic web page jumps. Let's say you use curl to access a certain URL, and the server gives you a"302 Found"If the request is forwarded to a different address, the request will be forwarded directly to the other address. If you add the-Lparameter, the curl will follow the jump honestly. But sometimes ourDon't want the auto-follower featureThis is the time to offer-max-redirs 0This parameter, tells curl, "Don't follow blindly, just stay where you are!"

Redirects must be disabled in these scenarios

Let's start with a real case: last year, I helped a friend debug the login interface, and when I tested it with curl, I found that it always prompted me to say"Session timeout."The test script could not get the critical response header. It was later found that the server automatically jumped to the personal center after logging in, causing the test script to fail to get the critical response header. At this point, I used ipipgo's proxy IP with the-max-redirs 0The problem is solved immediately.

The right posture of matching proxy IP

The focus here is on how to use ipipgo's proxy service. Theirexclusive IP poolIt is particularly suitable for scenarios where precise control of requests is required, for example:

1. Add to the curl command-xparameter specifies the proxy in the formathttp://用户名:密码@ipipgo's proxy IP:port

2. Matching-connect-timeoutSet the timeout period, recommended to be no more than 10 seconds

3. Say what is important three times:Be sure to use the session hold feature! ipipgo's IP lasts for 30 minute sessions, which is so critical for scenarios where cookies need to be handled!

Hands-on Demonstration

Suppose you want to collect price data from an e-commerce site, but the site will detect frequent visits:

Misdemonstration:
curl -L https://xxx.com/product/123

Correct posture:
curl -max-redirs 0 -x http://user:pass@ipipgo-proxy.com:8080 https://xxx.com/product/123

Here with ipipgo'sDynamic Residential IPIn addition, it automatically switches the export IP for each request, which not only prevents blocking but also ensures the accuracy of the data. The collection efficiency can be improved more than 3 times, the key is not to miss the hidden data of the original page.

Frequently Asked Questions QA

Q: What should I do if I return a 30x status code after disabling redirection?
A: This is exactly the effect we want! This is a good time to check the response header for theLocationFields, manual handling of jump logic

Q：How to solve the problem of slow access with proxy IP?
A: Go with ipipgo'sBGP High Speed LineThe delay can be controlled within 200ms. Pay attention to check the proxy setting format, don't miss the username and password!

Q: What if I need to handle multiple jumps?
A: You can set-max-redirs 3Such a parameter, both to control the number of jumps and to avoid infinite loops. Together with ipipgo's IP rotation strategy, it solves the validation problem perfectly!

Guide to avoiding the pit

Recently encountered a typical case: a customer with curl collection always prompted the"Too many redirects", switched to three proxy service providers with no resolution. Later it was found to be:
1. Failure to disable redirects leads to a dead loop
2. The shared proxy IP used has been hacked by the target website.
Switch to ipipgo.Enterprise-level customized agents+-max-redirs 1After the parameters, millions of data were picked up on the same day. This tells us:Parameter settings and agent qualityIt's twins. You can't have one without the other.

One final note: when debugging curl commands, remember to add the-vparameter to see the detailed logs, in conjunction with ipipgo'sRequest Analysis PanelYou can see what's wrong at a glance. Engaged in technology, tools can only be twice as effective with half the effort!