The http.Redirect
function in Golang is part of the net/http
package and is used to send an HTTP redirect response to the client. This function allows you to direct the client's browser to a different URL. It is particularly useful when you want to forward a client from one page to another, such as after form submissions, when handling errors, or when implementing URL routing.
Table of Contents
- Introduction
http.Redirect
Function Syntax- Examples
- Basic Usage
- Permanent Redirect (301)
- Temporary Redirect (307)
- Real-World Use Case
- Conclusion
Introduction
The http.Redirect
function sends an HTTP response with a status code indicating a redirect (such as 301, 302, or 307) and a Location
header containing the URL to redirect to. When a client receives this response, it will automatically navigate to the new URL specified in the Location
header.
http.Redirect Function Syntax
The syntax for the http.Redirect
function is as follows:
func Redirect(w http.ResponseWriter, r *http.Request, url string, code int)
Parameters:
w
: Thehttp.ResponseWriter
used to write the HTTP response.r
: The*http.Request
representing the incoming HTTP request.url
: A string specifying the URL to which the client should be redirected.code
: An integer representing the HTTP status code for the redirect. Common codes include 301 (Moved Permanently), 302 (Found), and 307 (Temporary Redirect).
Returns:
- The function does not return any value. It writes the redirect response directly to the HTTP response.
Examples
Basic Usage
This example demonstrates how to use the http.Redirect
function to perform a simple HTTP redirect.
Example
package main
import (
"net/http"
)
func main() {
// Register a handler for the root path "/"
http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
// Redirect the client to "/newpage"
http.Redirect(w, r, "/newpage", http.StatusFound)
})
// Register a handler for the "/newpage" path
http.HandleFunc("/newpage", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("Welcome to the new page!"))
})
// Start the server on port 8080
http.ListenAndServe(":8080", nil)
}
Explanation:
- The code sets up a web server that listens on port 8080.
- When the root path
/
is accessed, the server redirects the client to/newpage
using a 302 status code (http.StatusFound
). - The
/newpage
path then serves a simple message to the client.
Permanent Redirect (301)
This example shows how to perform a permanent redirect using a 301 status code.
Example
package main
import (
"net/http"
)
func main() {
// Register a handler for the old path "/oldpage"
http.HandleFunc("/oldpage", func(w http.ResponseWriter, r *http.Request) {
// Redirect the client to the new path with a 301 status code
http.Redirect(w, r, "/newpage", http.StatusMovedPermanently)
})
// Register a handler for the "/newpage" path
http.HandleFunc("/newpage", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("You have been permanently redirected to the new page!"))
})
// Start the server on port 8080
http.ListenAndServe(":8080", nil)
}
Explanation:
- The server listens for requests to
/oldpage
and permanently redirects clients to/newpage
using a 301 status code (http.StatusMovedPermanently
). - Clients that receive a 301 response will update their bookmarks or caches to use the new URL.
Temporary Redirect (307)
This example demonstrates how to perform a temporary redirect using a 307 status code.
Example
package main
import (
"net/http"
)
func main() {
// Register a handler for the temporary path "/temp"
http.HandleFunc("/temp", func(w http.ResponseWriter, r *http.Request) {
// Redirect the client to the target page with a 307 status code
http.Redirect(w, r, "/target", http.StatusTemporaryRedirect)
})
// Register a handler for the "/target" path
http.HandleFunc("/target", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("You have been temporarily redirected to this target page."))
})
// Start the server on port 8080
http.ListenAndServe(":8080", nil)
}
Explanation:
- The server listens for requests to
/temp
and temporarily redirects clients to/target
using a 307 status code (http.StatusTemporaryRedirect
). - A 307 redirect ensures that the HTTP method and request body are preserved during the redirect, making it suitable for redirecting POST requests.
Real-World Use Case
Redirecting After a Form Submission
In real-world applications, http.Redirect
is commonly used to redirect users after they submit a form. This practice, known as "Post/Redirect/Get" (PRG), prevents the form from being resubmitted if the user refreshes the page.
Example: Post/Redirect/Get Pattern
package main
import (
"fmt"
"net/http"
)
func main() {
// Register a handler for form submissions
http.HandleFunc("/submit", func(w http.ResponseWriter, r *http.Request) {
if r.Method == http.MethodPost {
// Process the form data (omitted for simplicity)
fmt.Println("Form submitted")
// Redirect the client to a confirmation page
http.Redirect(w, r, "/confirmation", http.StatusSeeOther)
return
}
// Serve the form (simple HTML form for demonstration)
w.Write([]byte(`
<form method="POST" action="/submit">
<input type="text" name="name" placeholder="Enter your name">
<input type="submit" value="Submit">
</form>
`))
})
// Register a handler for the confirmation page
http.HandleFunc("/confirmation", func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("Thank you for your submission!"))
})
// Start the server on port 8080
http.ListenAndServe(":8080", nil)
}
Explanation:
- When the form is submitted via POST to
/submit
, the server processes the data and then redirects the client to/confirmation
using a 303 status code (http.StatusSeeOther
). - This pattern prevents duplicate form submissions if the user refreshes the confirmation page.
Conclusion
The http.Redirect
function in Go is used for directing clients to different URLs. Whether you're performing temporary or permanent redirects, implementing the Post/Redirect/Get pattern, or simply rerouting traffic, http.Redirect
provides a straightforward way to manage client navigation. By choosing the appropriate HTTP status code, you can control how clients and search engines handle the redirects, making this function essential for building responsive and user-friendly web applications.
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