Russtopia/go-cgi-upload.go

## go-cgi-upload.go
// Simple demo of a GO CGI program that takes
// file uploads.
//
// NOTE NOTE DANGER DANGER
// Absolutely No filename/path sanitizing is done,
// don't run this in production unless you want hackers
// to overwrite your server. This is only a demo of
// how to untangle the go stdlib form-related datatypes
// and use them to take file uploads.
//
package main

// upload form with drag and drop using CSS
// Ref: https://codepen.io/TheLukasWeb/pen/qlGDa/

// For a wonderful clarification of the various CGI form
// encodings:
// https://stackoverflow.com/questions/4526273/what-does-enctype-multipart-form-data-mean

import (
        "fmt"
        "io"
        "io/ioutil"
        "net/http"
        "net/http/cgi"
        "os"
)
func main() {
        // First we must get the CGI request info from
        // the server-provided CGI env
        r, err := cgi.Request()
        if err != nil {
                fmt.Fprintf(os.Stderr, err.Error())
                os.Exit(1)
        } else {
                fmt.Fprintf(os.Stderr, "[dbg] got CGI request\n")
        }

        //!// For simple forms... (default form type: application/x-www-form-urlencoded)
        //!if err = r.ParseForm(); err != nil {
        //!     fmt.Fprintf(os.Stderr, err.Error())
        //!     os.Exit(1)
        //!}

        // For multi-part (eg., file upload) forms...
        // (multipart/form-data)
        if err = r.ParseMultipartForm(65536); err != nil {
                fmt.Fprintf(os.Stderr, err.Error())
                os.Exit(1)
        }

        fmt.Printf("Content-type: text/html\n\n")
        fmt.Printf("<!DOCTYPE html>\n")
        fmt.Println("<html><head><title>Test</title></head><body>")
        fmt.Println("<pre>")
        fmt.Printf("1: Request: %+v\n", r)
        fmt.Println("</pre>")
        fmt.Println("<pre>")
        fmt.Printf("2: form.Form (url.Values):%+v\n", r.Form)
        fmt.Println("</pre>")
        fmt.Println("<pre>")
        fmt.Printf("3: multipart.Form.Value[]:%+v\n", r.MultipartForm.Value)
        fmt.Println("</pre>")
        fmt.Println("<pre>")

        // MultipartForm.File[] is a map keyed by form field name (ie., there can be
        // multiple file upload form fields... I guess.)
        for k := range(r.MultipartForm.File) {
                // Individual files are described in each .File[k]
                fhdr := r.MultipartForm.File[k] // []*multipart.FileHeader
                for idx := 0; idx < len(fhdr); idx++ {
                        fmt.Printf("4(%d):%s %d\n", idx, fhdr[idx].Filename, fhdr[idx].Size)
                        fData := make([]byte, fhdr[idx].Size)
                        file, _ := fhdr[idx].Open()
                        file.Read(fData)
                        ioutil.WriteFile(fhdr[idx].Filename, fData, 0755)
                }
        }
        fmt.Println("</pre>")
        fmt.Println("</body></html>")
}

## index.html
<html>
<head>
<link rel="stylesheet" media="all" href="main.css" />
<!-- Ref: https://codepen.io/TheLukasWeb/pen/qlGDa/ -->
</head>

<body>

<form action="../cgi-bin/go-cgi-upload.cgi" method="POST" enctype="multipart/form-data">
  <input type="hidden" id="hidden1" name="hiddenField1" value="none">
  <input type="file" name="uploadFiles" multiple>
  <p>Drag your files here or click in this area.</p>
  <button type="submit">Upload</button>
</form>


<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
<script>
$(document).ready(function(){
  $('form input').change(function () {
    $('form p').text(this.files.length + " file(s) selected");
  });
});
</script>

</body>
</html>
	// Simple demo of a GO CGI program that takes
	// file uploads.
	//
	// NOTE NOTE DANGER DANGER
	// Absolutely No filename/path sanitizing is done,
	// don't run this in production unless you want hackers
	// to overwrite your server. This is only a demo of
	// how to untangle the go stdlib form-related datatypes
	// and use them to take file uploads.
	//
	package main

	// upload form with drag and drop using CSS
	// Ref: https://codepen.io/TheLukasWeb/pen/qlGDa/

	// For a wonderful clarification of the various CGI form
	// encodings:
	// https://stackoverflow.com/questions/4526273/what-does-enctype-multipart-form-data-mean

	import (
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"net/http/cgi"
	"os"
	)
	func main() {
	// First we must get the CGI request info from
	// the server-provided CGI env
	r, err := cgi.Request()
	if err != nil {
	fmt.Fprintf(os.Stderr, err.Error())
	os.Exit(1)
	} else {
	fmt.Fprintf(os.Stderr, "[dbg] got CGI request\n")
	}

	//!// For simple forms... (default form type: application/x-www-form-urlencoded)
	//!if err = r.ParseForm(); err != nil {
	//! fmt.Fprintf(os.Stderr, err.Error())
	//! os.Exit(1)
	//!}

	// For multi-part (eg., file upload) forms...
	// (multipart/form-data)
	if err = r.ParseMultipartForm(65536); err != nil {
	fmt.Fprintf(os.Stderr, err.Error())
	os.Exit(1)
	}

	fmt.Printf("Content-type: text/html\n\n")
	fmt.Printf("<!DOCTYPE html>\n")
	fmt.Println("<html><head><title>Test</title></head><body>")
	fmt.Println("<pre>")
	fmt.Printf("1: Request: %+v\n", r)
	fmt.Println("</pre>")
	fmt.Println("<pre>")
	fmt.Printf("2: form.Form (url.Values):%+v\n", r.Form)
	fmt.Println("</pre>")
	fmt.Println("<pre>")
	fmt.Printf("3: multipart.Form.Value[]:%+v\n", r.MultipartForm.Value)
	fmt.Println("</pre>")
	fmt.Println("<pre>")

	// MultipartForm.File[] is a map keyed by form field name (ie., there can be
	// multiple file upload form fields... I guess.)
	for k := range(r.MultipartForm.File) {
	// Individual files are described in each .File[k]
	fhdr := r.MultipartForm.File[k] // []*multipart.FileHeader
	for idx := 0; idx < len(fhdr); idx++ {
	fmt.Printf("4(%d):%s %d\n", idx, fhdr[idx].Filename, fhdr[idx].Size)
	fData := make([]byte, fhdr[idx].Size)
	file, _ := fhdr[idx].Open()
	file.Read(fData)
	ioutil.WriteFile(fhdr[idx].Filename, fData, 0755)
	}
	}
	fmt.Println("</pre>")
	fmt.Println("</body></html>")
	}
	<html>
	<head>
	<link rel="stylesheet" media="all" href="main.css" />
	<!-- Ref: https://codepen.io/TheLukasWeb/pen/qlGDa/ -->
	</head>

	<body>

	<form action="../cgi-bin/go-cgi-upload.cgi" method="POST" enctype="multipart/form-data">
	<input type="hidden" id="hidden1" name="hiddenField1" value="none">
	<input type="file" name="uploadFiles" multiple>
	<p>Drag your files here or click in this area.</p>
	<button type="submit">Upload</button>
	</form>


	<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/2.1.3/jquery.min.js"></script>
	<script>
	$(document).ready(function(){
	$('form input').change(function () {
	$('form p').text(this.files.length + " file(s) selected");
	});
	});
	</script>

	</body>
	</html>