How to urlencode data for curl command?

When sending HTTP requests using the curl command, if the data portion contains URL special characters or non-ASCII characters, URL encoding is required to ensure these characters are transmitted correctly. URL encoding, also known as percent encoding, is a mechanism used to embed special characters in URLs.

Step 1: Understanding When URL Encoding is Needed

When constructing query strings for GET requests or form data for POST requests, if parameter values contain spaces, special characters (such as &, =, ?, +, %, /, #), or non-ASCII text, URL encoding is required.

Step 2: How to Perform URL Encoding

Various tools can be used for URL encoding, including online tools and programming language libraries.

Example 1: Using Online Tools

You can access websites such as urlencoder.org, input the data you need to encode online, and then copy the encoded result.

Example 2: Using Python for URL Encoding

If you are familiar with Python, you can use the urllib.parse module to perform URL encoding:

python
import urllib.parse

# Original data
data = "这是一个测试 & 示例=真的！"
encoded_data = urllib.parse.quote(data)
print(encoded_data)  # Output: 这是一个测试%20%26%20示例%3D真的%EF%BC%81

Step 3: Using URL-Encoded Data in curl Commands

Use the encoded data directly in the curl command. For example, if you are using it in the query parameters of a GET request or in the application/x-www-form-urlencoded format data of a POST request.

Example 3: GET Request

bash
curl "https://api.example.com/data?query=这是一个测试%20%26%20示例%3D真的%EF%BC%81"

Example 4: POST Request

bash
curl -X POST "https://api.example.com/data" \
     -H "Content-Type: application/x-www-form-urlencoded" \
     -d "param=这是一个测试%20%26%20示例%3D真的%EF%BC%81"

These basic steps and examples should help you understand and practice URL encoding when using the curl command.