MichaelCurrie/ Dropzone with Python 3

## Dropzone with Python 3
#Drag-and-drop upload files, via JavaScript, to a simple Python 3 HTTP server

## dropzone.css
body {
    font-family: "Arial", sands-serif;
}

.dropzone {
    width: 300px;
    height: 300px;
    border: 2px dashed #ccc;
    color: #ccc;
    line-height: 300px;
    text-align: center;
}

.dropzone.dragover {
    border-color: #000;
    color: #000;
}

## dropzone.html
<!doctype html>
<html>
    <head>
        <meta charset="utf-8" />
        <title>Drag n' Drop</title>
        <link rel="stylesheet" type="text/css" href="dropzone.css" />
        <script src="dropzone.js"></script>
    </head>
    <body>
        <h1 id="title">Let's try some drag and drop uploading!</h1>

        <div id="dropzone_element" class="dropzone">
            Drop files here to upload
        </div>

        <div id="upload_results_element">
        </div>
    </body>
</html>

## dropzone.js
// Handle drag and drop into a dropzone_element div:
// send the files as a POST request to the server
"use strict";

// Only start once the DOM tree is ready
if(document.readyState === "complete") {
    createDropzoneMethods();
} else {
    document.addEventListener("DOMContentLoaded", createDropzoneMethods);
}

function createDropzoneMethods() {
    let dropzone = document.getElementById("dropzone_element");

    dropzone.ondragover = function() {
        this.className = "dropzone dragover";
        return false;
    }

    dropzone.ondragleave = function() {
        this.className = "dropzone";
        return false;
    }

    dropzone.ondrop = function(e) {
        // Stop browser from simply opening that was just dropped
        e.preventDefault();
        // Restore original dropzone appearance
        this.className = "dropzone";

        upload_files(e.dataTransfer.files)
    }
}

function upload_files(files) {
    let upload_results = document.getElementById("upload_results_element");
    let formData = new FormData(),
        xhr = new XMLHttpRequest();

    console.log("Dropped " + String(files.length) + " files.");
    for(let i=0; i<files.length; i++) {
        formData.append("file", files[i]);
    }

    xhr.onreadystatechange = function() {
        if(xhr.readyState === XMLHttpRequest.DONE) {
            alert(xhr.responseText);
        }

        console.log(xhr.response);
        upload_results.innerHTML = this.response;
    }

    console.log("Let's upload files: ", formData);
    xhr.open('POST', 'upload_handler.py', true); // async = true
    xhr.send(formData);
}

## upload_handler.py
# -*- coding: utf-8 -*-
import re
import sys
import os
import json
from http.server import SimpleHTTPRequestHandler, HTTPServer


class FileUploadHTTPRequestHandler(SimpleHTTPRequestHandler):
    """An HTTP Server that accepts POST requests and saves them as
    files in the same folder as this script.

    """
    protocol_version = "HTTP/1.1"

    def do_POST(self):
        """Handle a POST request."""
        # Save files received in the POST
        wasSuccess, files_uploaded = self.handle_file_uploads()

        # Compose a response to the client
        response_obj = {
            "wasSuccess": wasSuccess,
            "files_uploaded": files_uploaded,
            "client_address": self.client_address
        }

        response_str = json.dumps(response_obj)

        self.log_message(response_str)

        # Send our response code, header, and data
        self.send_response(200)
        self.send_header("Content-type", "Application/json")
        self.send_header("Content-Length", len(response_str))
        self.end_headers()
        self.wfile.write(response_str.encode('utf-8'))

    def read_line(self):
        line_str = self.rfile.readline().decode('utf-8')
        self.char_remaining -= len(line_str)
        return line_str

    def handle_file_uploads(self):
        """
        Take the post request and save any files received to the same folder
        as this script.

        Returns
            wasSuccess: bool: whether the process was a success
            files_uploaded: list of string: files that were created
        """
        self.char_remaining = int(self.headers['content-length'])
        # Find the boundary from content-type, which might look like:
        # 'multipart/form-data; boundary=----WebKitFormBoundaryUI1LY7c2BiEKGfFk'
        boundary = self.headers['content-type'].split("=")[1]

        basepath = self.translate_path(self.path)
        # Strip this script's name from the path so it's just a folder
        basepath = os.path.dirname(basepath)

        # ----WebKitFormBoundaryUI1LY7c2BiEKGfFk
        line_str = self.read_line()
        if not boundary in line_str:
            self.log_message("Content did NOT begin with boundary as " +
                             "it should")
            return False, []

        files_uploaded = []
        while self.char_remaining > 0:
            # Breaking out of this loop on anything except a boundary
            # an end-of-file will be a failure, so let's assume that
            wasSuccess = False

            # Content-Disposition: form-data; name="file"; filename="README.md"
            line_str = self.read_line()
            filename = re.findall('Content-Disposition.*name="file"; ' +
                                  'filename="(.*)"', line_str)
            if not filename:
                self.log_message("Can't find filename " + filename)
                break
            else:
                filename = filename[0]
            filepath = os.path.join(basepath, filename)
            try:
                outfile = open(filepath, 'wb')
            except IOError:
                self.log_message("Can't create file " + str(filepath) +
                                 " to write; do you have permission to write?")
                break

            # Content-Type: application/octet-stream
            line_str = self.read_line()

            # Blank line
            line_str = self.read_line()

            # First real line of code
            preline = self.read_line()
            # Loop through the POST until we find another boundary line,
            # signifying the end of this file and the possible start of another
            while self.char_remaining > 0:
                line_str = self.read_line()

                # ----WebKitFormBoundaryUI1LY7c2BiEKGfFk
                if boundary in line_str:
                    preline = preline[0:-1]
                    if preline.endswith('\r'):
                        preline = preline[0:-1]
                    outfile.write(preline.encode('utf-8'))
                    outfile.close()
                    self.log_message("File '%s' upload success!" % filename)
                    files_uploaded.append(filename)
                    # If this was the last file, the session was a success!
                    wasSuccess = True
                    break
                else:
                    outfile.write(preline.encode('utf-8'))
                    preline = line_str

        return wasSuccess, files_uploaded


if __name__ == "__main__":
    httpd = HTTPServer(("", 8000), FileUploadHTTPRequestHandler)
    sa = httpd.socket.getsockname()
    print("Serving HTTP on", sa[0], "port", sa[1], "...")
    try:
        httpd.serve_forever()
    except KeyboardInterrupt:
        print("\nKeyboard interrupt received, exiting.")
        httpd.server_close()
        sys.exit(0)
	body {
	font-family: "Arial", sands-serif;
	}

	.dropzone {
	width: 300px;
	height: 300px;
	border: 2px dashed #ccc;
	color: #ccc;
	line-height: 300px;
	text-align: center;
	}

	.dropzone.dragover {
	border-color: #000;
	color: #000;
	}
	<!doctype html>
	<html>
	<head>
	<meta charset="utf-8" />
	<title>Drag n' Drop</title>
	<link rel="stylesheet" type="text/css" href="dropzone.css" />
	<script src="dropzone.js"></script>
	</head>
	<body>
	<h1 id="title">Let's try some drag and drop uploading!</h1>

	<div id="dropzone_element" class="dropzone">
	Drop files here to upload
	</div>

	<div id="upload_results_element">
	</div>
	</body>
	</html>
	// Handle drag and drop into a dropzone_element div:
	// send the files as a POST request to the server
	"use strict";

	// Only start once the DOM tree is ready
	if(document.readyState === "complete") {
	createDropzoneMethods();
	} else {
	document.addEventListener("DOMContentLoaded", createDropzoneMethods);
	}

	function createDropzoneMethods() {
	let dropzone = document.getElementById("dropzone_element");

	dropzone.ondragover = function() {
	this.className = "dropzone dragover";
	return false;
	}

	dropzone.ondragleave = function() {
	this.className = "dropzone";
	return false;
	}

	dropzone.ondrop = function(e) {
	// Stop browser from simply opening that was just dropped
	e.preventDefault();
	// Restore original dropzone appearance
	this.className = "dropzone";

	upload_files(e.dataTransfer.files)
	}
	}

	function upload_files(files) {
	let upload_results = document.getElementById("upload_results_element");
	let formData = new FormData(),
	xhr = new XMLHttpRequest();

	console.log("Dropped " + String(files.length) + " files.");
	for(let i=0; i<files.length; i++) {
	formData.append("file", files[i]);
	}

	xhr.onreadystatechange = function() {
	if(xhr.readyState === XMLHttpRequest.DONE) {
	alert(xhr.responseText);
	}

	console.log(xhr.response);
	upload_results.innerHTML = this.response;
	}

	console.log("Let's upload files: ", formData);
	xhr.open('POST', 'upload_handler.py', true); // async = true
	xhr.send(formData);
	}
	# -- coding: utf-8 --
	import re
	import sys
	import os
	import json
	from http.server import SimpleHTTPRequestHandler, HTTPServer


	class FileUploadHTTPRequestHandler(SimpleHTTPRequestHandler):
	"""An HTTP Server that accepts POST requests and saves them as
	files in the same folder as this script.

	"""
	protocol_version = "HTTP/1.1"

	def do_POST(self):
	"""Handle a POST request."""
	# Save files received in the POST
	wasSuccess, files_uploaded = self.handle_file_uploads()

	# Compose a response to the client
	response_obj = {
	"wasSuccess": wasSuccess,
	"files_uploaded": files_uploaded,
	"client_address": self.client_address
	}

	response_str = json.dumps(response_obj)

	self.log_message(response_str)

	# Send our response code, header, and data
	self.send_response(200)
	self.send_header("Content-type", "Application/json")
	self.send_header("Content-Length", len(response_str))
	self.end_headers()
	self.wfile.write(response_str.encode('utf-8'))

	def read_line(self):
	line_str = self.rfile.readline().decode('utf-8')
	self.char_remaining -= len(line_str)
	return line_str

	def handle_file_uploads(self):
	"""
	Take the post request and save any files received to the same folder
	as this script.

	Returns
	wasSuccess: bool: whether the process was a success
	files_uploaded: list of string: files that were created
	"""
	self.char_remaining = int(self.headers['content-length'])
	# Find the boundary from content-type, which might look like:
	# 'multipart/form-data; boundary=----WebKitFormBoundaryUI1LY7c2BiEKGfFk'
	boundary = self.headers['content-type'].split("=")[1]

	basepath = self.translate_path(self.path)
	# Strip this script's name from the path so it's just a folder
	basepath = os.path.dirname(basepath)

	# ----WebKitFormBoundaryUI1LY7c2BiEKGfFk
	line_str = self.read_line()
	if not boundary in line_str:
	self.log_message("Content did NOT begin with boundary as " +
	"it should")
	return False, []

	files_uploaded = []
	while self.char_remaining > 0:
	# Breaking out of this loop on anything except a boundary
	# an end-of-file will be a failure, so let's assume that
	wasSuccess = False

	# Content-Disposition: form-data; name="file"; filename="README.md"
	line_str = self.read_line()
	filename = re.findall('Content-Disposition.*name="file"; ' +
	'filename="(.*)"', line_str)
	if not filename:
	self.log_message("Can't find filename " + filename)
	break
	else:
	filename = filename[0]
	filepath = os.path.join(basepath, filename)
	try:
	outfile = open(filepath, 'wb')
	except IOError:
	self.log_message("Can't create file " + str(filepath) +
	" to write; do you have permission to write?")
	break

	# Content-Type: application/octet-stream
	line_str = self.read_line()

	# Blank line
	line_str = self.read_line()

	# First real line of code
	preline = self.read_line()
	# Loop through the POST until we find another boundary line,
	# signifying the end of this file and the possible start of another
	while self.char_remaining > 0:
	line_str = self.read_line()

	# ----WebKitFormBoundaryUI1LY7c2BiEKGfFk
	if boundary in line_str:
	preline = preline[0:-1]
	if preline.endswith('\r'):
	preline = preline[0:-1]
	outfile.write(preline.encode('utf-8'))
	outfile.close()
	self.log_message("File '%s' upload success!" % filename)
	files_uploaded.append(filename)
	# If this was the last file, the session was a success!
	wasSuccess = True
	break
	else:
	outfile.write(preline.encode('utf-8'))
	preline = line_str

	return wasSuccess, files_uploaded


	if __name__ == "__main__":
	httpd = HTTPServer(("", 8000), FileUploadHTTPRequestHandler)
	sa = httpd.socket.getsockname()
	print("Serving HTTP on", sa[0], "port", sa[1], "...")
	try:
	httpd.serve_forever()
	except KeyboardInterrupt:
	print("\nKeyboard interrupt received, exiting.")
	httpd.server_close()
	sys.exit(0)