curl POST Request: Form Submission Example

Teach you how to send a POST form request using a proxy IP.

Today we nag with the proxy IP POST request that thing. Many people who do data collection have encountered the situation of website IP blocking, right? This time we have to rely onproxy IPto continue the life. Take our ipipgo proxy service as a chestnut, teach you how to use curl easy to handle form submission.

Why do I need a proxy IP to send a request?

Give a real scene: you want to give a site to submit a bulk registration form, directly with their own IP fierce operation, not half an hour quasi blocked. At this time to hang on the ipipgo dynamic proxy IP, each request for a different export IP, the site simply can not distinguish between a real person operating or robots at work.

curl -x http://username:password@proxy.ipipgo.com:9020
     -d "username=test&password=123456"
     -H "Content-Type: application/x-www-form-urlencoded"
     https://example.com/login

watch carefully-x parameterHere, is the key to specifying a proxy server. ipipgo's proxy address format isUsername:Password@Proxy Address:Port, make no mistake about this.

The Three Pitfalls of Form Submission

I'll list the common mistakes newbies make:
1. Forgetting to addContent-Type headerThe server does not receive the data.
2. Wrong protocol for proxy address (socks5 for http proxy)
3. Loss of login status due to failure to handle cookies

The focus here is on coding. If there is Chinese in the form, remember to do it firstURL encoding。比如”城市=北京”要转成”city=%E5%8C%97%E4%BA%AC”。

Practical case: simulated login

Let's use ipipgo's Beijing node for a demo. Suppose you want to log in to a forum:

curl -x http://vipuser:abcdef@bj-proxy.ipipgo.com:9021
     -d "login=1&username=myaccount&password=mypwd"
     -H "Content-Type: application/x-www-form-urlencoded"
     -c cookies.txt
     https://bbs.example.com/login.php

here are-c parameterSave the cookie to a file and take it with you on subsequent requests-b cookies.txtThen you can stay logged in. With a proxy IP, even frequent logins won't trigger the site's wind control mechanism.

Proxy IP Configuration Tips

A couple of tips that have been tested and are useful:
- Random IP change per request (ipipgo's dynamic package supports this)
- Don't set the timeout for more than 10 seconds.
- Don't fight the CAPTCHA, change your IP and try again.
- IMPORTANT OPERATING USESLong-lasting static IP(like ipipgo's enterprise package)

Frequently Asked Questions QA

Q: What should I do if the proxy IP is invalidated while I am using it?
A: First check if the IP is expired, there is IP expiration date instructions in the package details of ipipgo. If it is a dynamic IP, just get a new IP again.

Q: How can I tell if a proxy is in effect?
A: Add to the request a-v parameterLook at the detailed logs and you should see the "Connected to proxy.ipipgo.com" prompt.

Q: Do HTTPS sites work?
A: Fully supported! ipipgo's proxy server has been configured with an SSL certificate, so you can directly configure it as a http proxy.

As a final rant, you have to look for stability when choosing a proxy IP service. A service like ipipgo provides99.91 TP3T availabilityThe only reliable, don't be greedy and cheap with free agents, by the time they are blocked number cry can't come. There are any problems welcome to leave a message, see will be back!