Parse input from HTML <form>

Question

I got something running with the Goji framework:

package main

import (
        \"fmt\"
        \"net/http\"

        \"github.com/zenazn/goji\"
        \"gi         


        

Answer 1

In order to read html form values you have to first call r.ParseForm(). The you can get at the form values.

So this code:

func hello(c web.C, w http.ResponseWriter, r *http.Request){
    name := r.PostFormValue("name")
    fmt.Fprintf(w, "Hello, %s!", name)
}

Should be this:

func hello(c web.C, w http.ResponseWriter, r *http.Request){

    //Call to ParseForm makes form fields available.
    err := r.ParseForm()
    if err != nil {
        // Handle error here via logging and then return            
    }

    name := r.PostFormValue("name")
    fmt.Fprintf(w, "Hello, %s!", name)
}

Edit: I should note that this was a point that tripped me up when learning the net/http package

Answer 2

Your form input name, name is the key to be fetched by go program.

<form action="" method="get">
    <input type="text" name="name" />
</form>

You can use FormValue https://golang.org/pkg/net/http/#Request.FormValue

FormValue returns the first value for the named component of the query. POST and PUT body parameters take precedence over URL query string values. FormValue calls ParseMultipartForm and ParseForm if necessary and ignores any errors returned by these functions. If key is not present, FormValue returns the empty string. To access multiple values of the same key, call ParseForm and then inspect Request.Form directly.

func hello(c web.C, w http.ResponseWriter, r *http.Request){
    name := r.FormValue("name")
    fmt.Fprintf(w, "Hello, %s!", name)
}

If FormFile doesn't works, better use ParseMultiForm https://golang.org/pkg/net/http/#Request.ParseMultipartForm

You can use ParseMultipartForm

ParseMultipartForm parses a request body as multipart/form-data. The whole request body is parsed and up to a total of maxMemory bytes of its file parts are stored in memory, with the remainder stored on disk in temporary files. ParseMultipartForm calls ParseForm if necessary. After one call to ParseMultipartForm, subsequent calls have no effect

func hello(c web.C, w http.ResponseWriter, r *http.Request){
    name := r.FormValue("name")
    r.ParseMultipartForm(32 << 20)
    fmt.Fprintf(w, "Hello, %s!", name)
}

Also, a form is useless unless some kind of processing takes place after the form is submitted. So use it accordingly.