In web development, redirection is a common technique that allows us to redirect requests from one URL address to another. As a lightweight Python web framework, Flask provides simple and powerful tools to achieve this function. In this article, we will explain how to use Flask to carry headers for strong permanent redirection (301) and temporary redirection (302), and explain the difference between the two.
What are redirects?
Redirect is a common technology in web applications, which allows us to forward user requests from one URL address to another URL address. Redirects are very useful in a variety of scenarios, such as handling page jumps after form submission, handling old URLs to new URLs, etc.
Redirect using Flask
The Flask framework simplifies the redirection process. By using redirect()functions, we can redirect requests to a specified URL address. During this process, we can also add Headers information to implement different types of redirections.
Strong permanent orientation (301)
In the HTTP status code, 301 means Moved Permanently. When the server returns a 301 status code, the client will record the redirect and directly access the new URL address in future requests. This is important for search engine optimization (SEO) and user experience because it tells search engines and browsers that this page has been permanently moved to a new address.
In Flask, we can implement 301 redirection with the following code:
from flask import Flask, redirect
app = Flask(__name__)
@app.route('/old_url')
def old_url():
# 执行一些处理逻辑...
return redirect('/new_url', code=301)
Temporary redirect (302)
Unlike 301, HTTP status code 302 indicates a temporary move (Found or Moved Temporarily). When the server returns a 302 status code, the client will revisit the original URL on each request and will need to find the new URL address in the response headers.
In Flask, we can implement 302 redirection with the following code:
from flask import Flask, redirect
app = Flask(__name__)
@app.route('/old_url')
def old_url():
# 执行一些处理逻辑...
return redirect('/new_url', code=302)
Difference: 301 and 302
The key difference between 301 and 302 is the type of redirect and the client's behavior:
- 301 redirects are permanent. The client will record the new URL after receiving the response and directly access the new URL in future requests. This is great for SEO and long-term redirection.
- 302 redirects are temporary. The client will revisit the original URL with each request and needs to find the new URL address in the response headers. This is appropriate in certain scenarios, such as temporary maintenance pages or AB testing.
Carry Headers Redirection
@app.route('/')
def index():
# 创建一个重定向响应
response = redirect('/new_location')
# 设置自定义 Header
response.headers['X-Custom-Header'] = 'Custom Value'
return responseDemo
Let's say our URL is /old_pagepage, and we want to redirect it to a new page /new_page.
from flask import Flask, redirect
app = Flask(__name__)
@app.route('/old_page')
def old_page():
# 这里可以执行一些处理逻辑...
return redirect('/new_page', code=301)
@app.route('/new_page')
def new_page():
return "这是新页面"
if __name__ == '__main__':
app.run()
After running this sample application, the visit http://127.0.0.1:5000/old_pagewill get a permanent redirect and the visit http://127.0.0.1:5000/new_pagewill display "This is a new page".
in conclusion
Redirects are a common technique in web development and can be easily implemented through the Flask framework. When redirecting, we can use the 301 status code for a strong permanent redirection, or the 302 status code for a temporary redirection.
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