curlpost-data option: form submission example

Hands-on with curl's -data to play around with form submission

Web developers should have encountered this situation: to send a POST request with data to the server, but the parameters can not pass. Today, let's break it down and talk about it.The -data option of the curl commandEspecially in conjunction with us.Proxy services for ipipgoHow to use it in a smooth way.

The basic posture of form submission

Let's start with the simplest example, sending a login request to a website:

curl -X POST --data "username=Zhang San&password=123456" http://example.com/login

Note three key points here:
1. Must be used-X POSTSpecify the request method
2. -datafollowed by a key-value pair
3. Remember to use special symbols% code，比如空格要转成%20

The right way to open a proxy IP

It is easy to send a request directly and nakedly to be blocked by the IP, and this is the time toProxy services for ipipgoOn the field. Show you a real-world example:

curl -x http://user:pass@proxy.ipipgo.io:8080
--data "city=Beijing&keyword=milk tea"
https://api.example.com/search

It's used here.-x parameterSpecify the proxy server, taking care to replace it with your own account password obtained from ipipgo. Tested with theirDynamic Residential AgentsThe success rate can go up to 98%, which is much more stable than the server room IP.

Uploading files

When you have to transfer files, remember to use the@ symbolSpecifies the file path:

curl --proxy socks5://proxy.ipipgo.io:1080
-F "file=@/path/to/file.zip"
http://upload.example.com

It's changed here.-F parametersDoing a file upload with socks5 proxy enabled. It is recommended to use ipipgo for large file transfers.Enterprise Class Dedicated LineThe speed can be more than 3 times faster.

Guidelines on demining of common problems

Q: Why does it return a 403 error?
A: eighty percent of the IP is recognized as a crawler, hurry to change ipipgo'sHigh Stash Agentstry out

Q: How do I break the request timeout?
A: 1. Check if the proxy address is valid
2. try switching to ipipgoDifferent geographical nodes
3. Increase the value of the -connect-timeout parameter as appropriate.

Q: How do I stay logged in?
A: Save the cookie with the -c parameter and load it with the -b parameter:

curl --proxy http://proxy.ipipgo.io
--c cookies.txt
--data "login=yes"
http://example.com

curl --proxy http://proxy.ipipgo.io
-b cookies.txt
http://example.com/dashboard

Parameter cross-reference quick reference table

One final note to newbies: the testing phase suggests starting with ipipgo'spay-per-use packageThey have a free trial quota every day, so you don't have to spend a lot of money. Encountered difficulties directly to their technical support, the response rate is much faster than peers.