SoFunction
Updated on 2025-03-03

Detailed explanation of Linux using CURL to send POST requests

What is a POST request

POST requests are mainly used to submit data to the server, which is usually contained in the request body. Unlike GET requests, the data requested by POST is not displayed in the URL, making it more suitable for transferring sensitive information or large amounts of data. POST requests can also carry more data and are not limited by URL length.

Send POST requests using CURL

curl is a file transfer tool that uses URL syntax to work in the command line mode. It supports a variety of protocols, including HTTP, HTTPS, FTP, etc. The basic syntax for sending POST requests using curl is as follows:

curl -X POST -d "data" URL
  • -X POST: Specify the request type as POST.
  • -d "data": Specifies the data to be sent, usually JSON or form data.
  • URL: The address of the target server.

Example Analysis

Next, we will analyze two specificcurlCommand example to understand how to send POST requests in practice.

Example 1: Save the response

The first example shows how to send a POST request and save the response to a variable:

# Send a POST requestresponse=$(curl -s -X POST \
    -H 'Content-Type: application/json' \
    -d "$DATA" \
    "$WEBHOOK_URL")

echo "$response"

In this example:

  • -s:makecurlNo errors and progress information is output while performing an operation.
  • -H 'Content-Type: application/json': Set the request header, specifying that the sent data type is JSON.
  • -d "$DATA": The sent data, variables are used here$DATALet's express it.
  • "$WEBHOOK_URL": Target URL, variables are used here$WEBHOOK_URLLet's express it.
  • response=$(...):WillcurlThe output of the command is assigned to the variableresponse。
  • echo "$response": Print out the response content.

The purpose of this command is to send JSON format data to the specified Webhook URL and print out the server's response.

Example 2: Non-responsive mode

The second example shows how to send a POST request without saving the response:

# Send a POST requestcurl -s -X POST \
    -H 'Content-Type: application/json' \
    -d "$DATA" \
    "$WEBHOOK_URL" > /dev/null

In this example:

  • > /dev/null:WillcurlThe output of the command is redirected to/dev/null, which means no output is saved.

The purpose of this command is to send JSON format data to the specified Webhook URL, but does not care about the server's response and is usually used to perform certain operations without expecting any feedback.

The actual application of POST request

POST requests are very widespread in practical applications. Here are some common scenarios:

  1. Form Submission: In web development, form data filled in by users is usually sent to the server through a POST request.
  2. API calls: Many API interfaces require data submission through POST methods to enable data creation, update or delete.
  3. File upload: Use POST requests to upload files to the server, because GET requests do not support request bodies.
  4. User Authentication: When a user logs in, sensitive information such as username and password are usually sent through a POST request.

Safety considerations

Security is an important consideration when using POST requests. Since the data requested by the POST will not be displayed in the URL, this helps protect sensitive information. However, the sent data may still be intercepted, so it is very important to encrypt data transmission using the HTTPS protocol.

This is the end of this article about the example of Linux using CURL to send POST requests. For more related Linux CURL to send POST content, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!