SoFunction
Updated on 2025-03-03

Tutorial Guide for Flask to handle POST requests

1. Initialize the Flask application

First, you need to import the Flask module and create a Flask application instance. This is the basis for handling any type of request, including POST requests.

from flask import Flask  
  
app = Flask(__name__)

2. Define routing and processing functions

In Flask, the mapping relationship between the URL path and the processing function is defined by a routing decorator (such as @). For POST requests, methods=['POST'] need to be explicitly specified in the router decorator (although in some cases, Flask will also handle POST requests by default if the methods parameter is not specified, explicitly specifying can improve the readability and clarity of the code).

@('/submit', methods=['POST'])  
def submit_data():  
    # The code for processing POST requests will be placed here    pass

3. Obtain POST request data

In the processing function, it can be done by Flask'srequestObject to obtain the data sent by the POST request.requestThe object contains all request information sent by the client, including form data, JSON data, etc.

  • Get form data: If the client sends form data (Content-Type: application/x-www-form-urlencoded or multipart/form-data), it can be used to obtain it. is a dictionary-like object that contains key-value pairs of all fields in the form.
username = ['username']  
password = ['password']
  • Get JSON data: If the client sends data in JSON format (Content-Type: application/json), can be usedCome to get it.The JSON data will be automatically parsed into a Python dictionary.
data =   
# Assume data is a dictionary containing 'name' and 'age' fieldsname = ('name')  
age = ('age')

4. Process request data

After obtaining the data requested by POST, the data can be processed according to business needs. This may include verifying the legitimacy of the data, storing the data to a database, performing certain computing tasks, etc.

5. Return response

After processing the request data, a response needs to be returned to the client. This can be done by simply returning a string, a dictionary (Flask will automatically convert it to JSON format), a file object, or a response object.

  • Return string: Return directly to the text content.
return 'Data received and processed'
  • Return to JSON: If you need to return the data to the client in JSON format, you can usejsonifyfunction.
from flask import jsonify  
return jsonify({'status': 'success', 'message': 'Data received and processed'})

Return to file: If you need to send files to the client, you can usesend_filefunction.

from flask import send_file  
return send_file('path/to/your/file')

Things to note

  • Security: When handling POST requests, be sure to pay attention to security issues, such as preventing SQL injection, cross-site scripting attacks (XSS), etc.
  • Data Verification: Before using the data for further processing, sufficient data verification should be carried out to ensure the legality and accuracy of the data.
    • Error handling: In order to improve the user experience, possible errors should be properly handled and useful error messages should be returned to the client.
    • Logging: In a production environment, detailed log information should be recorded so that problems occur.

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