CODEWITHSUNDEEP
htmlformshttpgo
as.beaulieu
as.beaulieu

Reputation: 484

Golang, not passing values from HTML

I am trying to build a simple, two-Handler web server. In the first handler, I am pulling values from two fields, a user's first name and last name. In the second handler I am simply stating, "Hello" (first name, last name).

I've put an fmt.Println, and it seems that I'm not correctly pulling the info from the first Handler back into the Go programming. Where is this going wrong?

package main

import (
    "fmt"
    "html/template"
    "log"
    "net/http"
)

type Field struct {
    Firstname  string
    Secondname string
}

func RootHandler(w http.ResponseWriter, r *http.Request) {
    tmpl, err := template.ParseFiles("index.html")
    if err != nil {
        fmt.Println("Index Template Parse Error: ", err)
    }
    err = tmpl.Execute(w, nil)
    if err != nil {
        fmt.Println("Index Template Execution Error: ", err)
    }

}

func main() {
    http.HandleFunc("/", RootHandler) // sets router
    http.HandleFunc("/welcome", WelcomeHandler)
    err := http.ListenAndServe(":4000", nil) // set listen port
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

func WelcomeHandler(w http.ResponseWriter, r *http.Request) {

    Firstname := r.FormValue("Namef")
    Secondname := r.FormValue("Namel")
    fmt.Println(Firstname)

    f := new(Field)
    f.Firstname = Firstname
    f.Secondname = Secondname
    fmt.Println(*f)
    tmpl, err := template.ParseFiles("tmpl/welcome.tmpl")
    if err != nil {
        fmt.Println("Index Template Parse Error: ", err)
    }
    err = tmpl.Execute(w, &f)
    if err != nil {
        fmt.Println("Index Template Execution Error: ", err)
    }

}

And here is the index.html that I'm pulling the two values from:

<!DOCTYPE html>
<html>
<body>

<form action="/welcome" method="post">
<p> Welcome! First I will need your full name: </p>
First Name: <input type="text" id="Namef" name="FirstName"><br>
Last Name:  <input type="text" id="Namel" name="LastName" ><br>
<input type="submit" value="Next">
</form>

<p>Click the "Submit" button and the form-data will be sent to a page on the server called "demo_form.asp".</p>

</body>
</html>

Upvotes: 4

Views: 2257

Answers (1)

icza
icza

Reputation: 418387

The problem is that you try to get the form values using wrong names.

You have to use the values you used as the name attribute in the HTML document, not the id!

Firstname := r.FormValue("FirstName")
Secondname := r.FormValue("LastName")

And this may just be a practice code from your part, but never parse templates in handlers. Parsing templates is a relatively resource-intensive task, you should do that only once, and since templates are safe for concurrent use, you can use a single template.Template value from multiple goroutines (serving concurrent requests). See this question for details: It takes too much time when using "template" package to generate a dynamic web page to client in golang

Upvotes: 6

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