HTTP 301
HTTP response status code
On the World Wide Web, HTTP 301, or 301 Moved Permanently, is the HTTP status code used for permanent redirecting. It means that links or records to this URL should be updated to the destination provided in the Location field of the server response. The 301 redirect is considered a best practice for upgrading users from HTTP to HTTPS.
RFC 2616 states that:
- If a client has link-editing capabilities, it should update all references to the Request URL.
- The response is cacheable unless indicated otherwise.
- Unless the request method was HEAD, the entity should contain a small hypertext note with a hyperlink to the new URL(s).
- If the 301 status code is received in response to a request of any type other than GET or HEAD, the client must ask the user before redirecting.
01Examples
Client request:
GET /index.php HTTP/1.1 Host: www.example.orgServer response:
HTTP/1.1 301 Moved Permanently Location: https://www.example.org/index.aspUsing an .htaccess file
To fix problems with non-existing files or directories using a distributed .htaccess file:
Redirect 301 /calendar.html /calendar/ Redirect 301 /not_found.html /Here is an example using a .htaccess file to redirect a non-secure URL to a secure address without the leading "www":
RewriteEngine On RewriteCond %{HTTPS} off RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC] RewriteRule ^(.*)$ http://%1/$1 [R=301,L] RewriteCond %{HTTPS} on RewriteCond %{HTTP_HOST} ^www\.(.*)$ [NC] RewriteRule ^(.*)$ https://%1/$1 [R=301,L] RewriteEngine On RewriteCond %{SERVER_PORT} 80 RewriteRule ^(.*)$ https://example.com/$1 [R,L]Static HTML
A custom directory redirect, using an index.html file:
<meta http-equiv="refresh" content="0; url=/" /> <p><a href="/">Home</a></p>Using programming languages
Here is an example using Perl CGI.pm:
print redirect("https://example.com/newpage.html");Here is an example using a PHP redirect:
<?php header("Location: https://example.com/newpage.html", true, 301); exit;Here is one way to redirect using Express.js:
app.all("/old/url", (req, res) => { res.redirect(301, "/new/url"); });Caching server
Equivalently simple for an nginx configuration:
location /old/url/ { return 301 /new/url/; }Search engines
Both Bing and Google recommend using a 301 redirect to change the URL of a page as it is shown in search engine results, providing that URL will permanently change and is not due to be changed again any time soon.
Sources and credits
This article is adapted from the Wikipedia article “HTTP 301”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
Images, from Wikimedia Commons:
- HTTP logo.svg by IETF HTTP Working Group (HTTPbis), Public domain
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