golang http server,can't get post value

Question

func login(rw http.ResponseWriter, req *http.Request) {
    req.ParseForm()

    if req.Method == "GET" {
        fmt.Fprintf(rw, "Error Method")
    } else {
        name := strings.TrimSpace(req.FormValue("userid"))
        fmt.Println("userid:", name)
        fmt.Println("pwd:", req.FormValue("pwd"))
        fmt.Fprintf(rw, "welcome back,%s", req.FormValue("userid"))
    }
}

and i using ASIhttprequst send a from,like this.

[self setRequest:[ASIFormDataRequest requestWithURL:[NSURL URLWithString:@"http://127.0.0.1:8080/login"]]];
[request setPostValue:@"userid" forKey:@"[email protected]"];
[request setPostValue:@"pwd" forKey:@"fdsfdsfdkskfjhds"];
[request setRequestMethod:@"POST"];

i got a null value with req.FormValue("userid")

what happend? and how to fix it?

just a shot in the dark - maybe you just mixed up PostValue and PostKey? — Alex Emelin
– Alex Emelin, Commented Jun 3, 2013 at 13:19

Tarion · Accepted Answer · 2017-03-08 11:30:52Z

10

How about this?

req.ParseForm()
req.Form.Get(key)

edited Mar 8, 2017 at 11:30

Tarion

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answered Mar 11, 2014 at 20:46

rofrol

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2 Comments

Matthew Ratzloff Over a year ago

Yes, but you must precede that with req.ParseForm().

Mauricio Over a year ago

Dont know why your answer wasn't accepted. Straight and to the point

Neo · Accepted Answer · 2013-06-03 12:52:31Z

4

did you already test it with req.PostFormValue instead of req.FormValue ?

answered Jun 3, 2013 at 12:52

Neo

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2 Comments

user1751912 Over a year ago

yes,i try PostFormValue instead of FormValue,but the result is still the same.

Neo Over a year ago

did you also test it with req.ParseMultipartForm() instead of req.ParseForm()?

cnaize · Accepted Answer · 2014-10-08 11:08:56Z

0

I've found solution with calling ParseMultipartForm before ParseForm, it works for me.

edited Oct 8, 2014 at 11:08

answered Oct 8, 2014 at 10:30

cnaize

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Comments

Cem · Accepted Answer · 2015-08-25 22:37:08Z

0

If you make multipart/form-data POST request, ParseForm does not parse request body correctly (this might be a bug). So, use ParseMultipartForm if that is the case.

Or you can call FormValue or PostFormValue directly without calling these parse methods.

answered Aug 25, 2015 at 22:37

Cem

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Comments

davissp14 · Accepted Answer · 2015-09-11 22:04:38Z

0

I had similar issues using ParseForm. I ended up doing something like this:

type UserRequest struct {
  UserId  string `json:"userid"`
  Pwd     string `json:"pwd"`
}

func login(w http.ResponseWriter, r *http.Request) {
   var ur UserRequest
   decode := json.NewDecoder(r.Body)
   decoder.Decode(&ur)

   // Access data via struct
}

Hope that helps!

answered Sep 11, 2015 at 22:04

davissp14

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Comments

Salvador Dali · Accepted Answer · 2016-06-12 05:29:00Z

0

To extract a value from a post request you have to call r.ParseForm() at first. This parses the raw query from the URL and updates r.Form.

For POST or PUT requests, it also parses the request body as a form and put the results into both r.PostForm and r.Form. POST and PUT body parameters take precedence over URL query string values in r.Form.

Now your r.From is a map of all values your client provided. To extract a particular value you can use r.FormValue("<your param name>") or r.Form.Get("<your param name>").

So basically you will have this:

r.ParseForm()
res := r.FormValue("<your param name>")

answered Jun 12, 2016 at 5:29

Salvador Dali

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Comments

Hao · Accepted Answer · 2017-03-24 03:28:33Z

0

    // Form contains the parsed form data, including both the URL
    // field's query parameters and the POST or PUT form data.
    // **This field is only available after ParseForm is called.**
    // The HTTP client ignores Form and uses Body instead.
    Form url.Values

    // PostForm contains the parsed form data from POST, PATCH,
    // or PUT body parameters.
    //
    // **This field is only available after ParseForm is called.**
    // The HTTP client ignores PostForm and uses Body instead.
    PostForm url.Values

answered Mar 24, 2017 at 3:28

Hao

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1 Comment

Hao Over a year ago

This field is only available after ParseForm is called.

noelyahan · Accepted Answer · 2020-09-23 07:47:11Z

0

Make sure the req.Body io.Reader buffer is getting cleared by reading it in some level

ex: ioutil.ReadAll if Body buffer got cleared it will return empty value on FormValue even you ParseForm

answered Sep 23, 2020 at 7:47

noelyahan

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Comments

Zulu · Accepted Answer · 2017-02-20 10:33:25Z

-1

Try this buddy.

hope it will work as it works for me

r.FormValue("userid")

edited Feb 20, 2017 at 10:33

Zulu

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answered Feb 20, 2017 at 10:11

Rajkumar Bijalwan

1

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