How to redirect to a url

Question

I would like to show client another page after data has been collected from previous page. But I have trouble redirect the new URL on the server side. Here is my logic:

submit user input with POST action to server;
server run function saveChoice() to save user input into a database;
After user input is saved, server send a new URL to client;
By the time the client GET the new URL, server reads the database and get saved data out

And I am stuck on step 3 (here is an example of the flow):

type Stuff struct{ List []string } func checkcheck(w http.ResponseWriter, r *http.Request) { sinfo := Stuff{ List: some_slice } t, err := template.New("").Parse(tpl_ds) checkErr(err) err = r.ParseForm() checkErr(err) err = t.Execute(w, sinfo) checkErr(err) if r.Method == "POST" { saveChoice(r.Form["choices"]) /* step 3: make user open another URL */ } }

And here is the template:

<html> <script> $(function () { $('form').on('submit', function (e) { e.preventDefault(); $.ajax({ type: 'post', data: $('form').serialize(), }); }); }); </script> <body> <form method="POST"> {{range .List}} <input type="checkbox" name="choices" value="{{.}}"> <span>{{.}}</span><br> {{end}} <input type="submit" value="Submit"> </form> </body> </html>

May I know how I can redirect to a new page?

p.s. If I put URL on button, then server is not going to run saveChoice()

Actually the effective part is to add if r.Method=="GET" like Aruna said, which prevents the error of redirecting 2 pages — Kyle
– Kyle, Commented Mar 11, 2016 at 17:03

Aruna Herath · Accepted Answer · 2016-03-11 08:52:06Z

The http status 303 is the appropriate response here. So redirect the request with it.

if r.Method == "POST" { saveChoice(r.Form["choices"]) http.Redirect(w, r, newUrl, http.StatusSeeOther) }

And if your newUrl is supposed to return a proper html page to the browser, you don't need to use ajax. Use an html form.

<form action="/postHandler" method="post"> {{range .List}} <input type="checkbox" name="choices" value="{{.}}"> <span>{{.}}</span><br> {{end}} <input type="submit" value="Submit"> </form>

Notice action of the form is defined as /postHandler. Put the name of the endpoint that runs your saveChoice function there.

So to avoid http: multiple response.WriteHeader calls error you get use this code.

 func checkcheck(w http.ResponseWriter, r *http.Request) { if r.Method == "GET" { sinfo := Stuff{ List: some_slice } t, err := template.New("").Parse(tpl_ds) checkErr(err) err = r.ParseForm() checkErr(err) err = t.Execute(w, sinfo) checkErr(err) } if r.Method == "POST" { saveChoice(r.Form["choices"]) http.Redirect(w, r, newUrl, http.StatusSeeOther) } }

Otherwise, the server attempts to render both the form and the redirected url which will result in mutiple calls to the response writer.

At first it shows an error so I have to do preventDefault on the button
Kyle please post the javascript/html code you use with this button as well.
Kyle if the newUrl is supposed to return a proper html page, don't use ajax. Just let the form submit. Then the redirection will work.
I tried without the code and still doesn't work. And if I let the button or form action to redirect before I have data uploaded to server, then saveChoice() won't run. Let me see if I can put more code on so you can take a look at details. Thanks for the helps!
Kyle, what is the url of the post request that runs saveChoice? Could you show the code that defines this endpoint?

Fabian N. · Accepted Answer · 2018-08-30 14:04:11Z

package main import ( "net/http" "html/template" ) type data struct { List string } func main() { http.HandleFunc("/", check) } func check(w http.ResponseWriter, r * http.Request) { if r.Method == "GET" { sinfo: = data { List: "Here is a list of the files Located with in", } var tpl_ds = "index.html" //t, err := template.New("").Parse(tpl_ds) t: = template.Must(template.ParseFiles(tpl_ds)) r.ParseForm() t.Execute(w, sinfo) } if r.Method == "POST" { saveChoice(r.Form["choices"]) http.Redirect(w, r, newUrl, http.StatusSeeOther) } }

This does not answer the entire question but it leads to the answer. I hope this helps.

Collectives™ on Stack Overflow

How to redirect to a url

2 Answers 2

10 Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

10 Comments

1 Comment

Linked

Related