A simple Python server superclass

simple_server.py

from http.server import BaseHTTPRequestHandler, HTTPServer
import mimetypes
import urllib.parse
import posixpath
import os
from http import HTTPStatus
import shutil
from io import BytesIO
import json
from urllib.parse import urlparse, parse_qs


class SimpleHTTPRequestHandler(BaseHTTPRequestHandler):
	def do_GET(self):
		"""Serve a GET request."""
		f = self.send_head_if_file()
		print("File check returned {}".format(f))
		if f is None: # Not a file
			s = None
			# try:
			parsed = urlparse(self.path)
			path = parsed.path
			query = parse_qs(parsed.query)
			print("getting json...")
			s = json.dumps(self.get_json(path, query)).encode()
			# except Exception as e:
			# 	s = json.dumps({"error": str(e)}).encode()
			self.send_response(200)
			self.send_header("Content-type", "application/json")
			self.send_header("Content-Length", str(len(s)))
			self.end_headers()
			self.wfile.write(s)
			return
		if f is False: return # Do nothing
		# f is True, continue
		try:
			self.copyfile(f, self.wfile)
		finally:
			f.close()

	def do_POST(self):
		length = self.headers['content-length']
		data = self.rfile.read(int(length))
		s = json.dumps(self.post_json(self.path, data)).encode()

		self.send_response(200)
		self.send_header("Content-type", "application/json")
		self.send_header("Content-Length", str(len(s)))
		self.end_headers()
		self.wfile.write(s)

	def get_json(self, path, query):
		# Override this method and use path, query to return a JSON
		# or raise an Exception.
		raise Exception("Please subclass SimpleHTTPRequestHandler and override get_json")

	def post_json(self, path, data):
		# Override this method and use path, query to return a JSON
		# or raise an Exception.
		raise Exception("Please subclass SimpleHTTPRequestHandler and override post_json")

	def send_head_if_file(self):
		"""Common code for GET and HEAD commands.
		This sends the response code and MIME headers.
		Return value is either a file object (which has to be copied
		to the outputfile by the caller unless the command was HEAD,
		and must be closed by the caller under all circumstances), or
		None, in which case the caller has nothing further to do.
		"""
		path = self.translate_path(self.path)
		print("Checking if {} is file".format(path))
		f = None
		if not os.path.exists(path): return None
		if os.path.isdir(path):
			parts = urllib.parse.urlsplit(self.path)
			if not parts.path.endswith('/'):
				# redirect browser - doing basically what apache does
				self.send_response(HTTPStatus.MOVED_PERMANENTLY)
				new_parts = (parts[0], parts[1], parts[2] + '/',
							parts[3], parts[4])
				new_url = urllib.parse.urlunsplit(new_parts)
				self.send_header("Location", new_url)
				self.end_headers()
				return False
			for index in "index.html", "index.htm":
				index = os.path.join(path, index)
				if os.path.exists(index):
					path = index
					break
			else:
				return self.list_directory(path)
		ctype = self.guess_type(path)
		try:
			_, ext = os.path.splitext(path)
			if ext.lower() not in [".html", ".jpg", ".jpeg", ".png", ".mp4", ".mov"]: return None 
			f = open(path, 'rb')
		except OSError:
			self.send_error(HTTPStatus.NOT_FOUND, "File not found")
			return False
		try:
			self.send_response(HTTPStatus.OK)
			self.send_header("Content-type", ctype)
			fs = os.fstat(f.fileno())
			self.send_header("Content-Length", str(fs[6]))
			self.send_header("Last-Modified", self.date_time_string(fs.st_mtime))
			self.end_headers()
			return f
		except:
			f.close()
			raise

	def list_directory(self, path):
		"""Helper to produce a directory listing (absent index.html).
		Return value is either a file object, or None (indicating an
		error).  In either case, the headers are sent, making the
		interface the same as for send_head().
		"""
		try:
			list = os.listdir(path)
		except OSError:
			self.send_error(
				HTTPStatus.NOT_FOUND,
				"No permission to list directory")
			return None
		list.sort(key=lambda a: a.lower())
		r = []
		try:
			displaypath = urllib.parse.unquote(self.path,
												errors='surrogatepass')
		except UnicodeDecodeError:
			displaypath = urllib.parse.unquote(path)
		displaypath = html.escape(displaypath, quote=False)
		enc = sys.getfilesystemencoding()
		title = 'Directory listing for %s' % displaypath
		r.append('<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" '
				'"http://www.w3.org/TR/html4/strict.dtd">')
		r.append('<html>\n<head>')
		r.append('<meta http-equiv="Content-Type" '
 				'content="text/html; charset=%s">' % enc)
		r.append('<title>%s</title>\n</head>' % title)
		r.append('<body>\n<h1>%s</h1>' % title)
		r.append('<hr>\n<ul>')
		for name in list:
			fullname = os.path.join(path, name)
			displayname = linkname = name
			# Append / for directories or @ for symbolic links
			if os.path.isdir(fullname):
				displayname = name + "/"
				linkname = name + "/"
			if os.path.islink(fullname):
				displayname = name + "@"
				# Note: a link to a directory displays with @ and links with /
			r.append('<li><a href="%s">%s</a></li>'
					% (urllib.parse.quote(linkname,
										errors='surrogatepass'),
					html.escape(displayname, quote=False)))
		r.append('</ul>\n<hr>\n</body>\n</html>\n')
		encoded = '\n'.join(r).encode(enc, 'surrogateescape')
		f = io.BytesIO()
		f.write(encoded)
		f.seek(0)
		self.send_response(HTTPStatus.OK)
		self.send_header("Content-type", "text/html; charset=%s" % enc)
		self.send_header("Content-Length", str(len(encoded)))
		self.end_headers()
		return f

	def translate_path(self, path):
		"""Translate a /-separated PATH to the local filename syntax.
		Components that mean special things to the local file system
		(e.g. drive or directory names) are ignored.  (XXX They should
		probably be diagnosed.)
		"""
		# abandon query parameters
		path = path.split('?',1)[0]
		path = path.split('#',1)[0]
		# Don't forget explicit trailing slash when normalizing. Issue17324
		trailing_slash = path.rstrip().endswith('/')
		try:
			path = urllib.parse.unquote(path, errors='surrogatepass')
		except UnicodeDecodeError:
			path = urllib.parse.unquote(path)
		path = posixpath.normpath(path)
		words = path.split('/')
		words = filter(None, words)
		path = os.getcwd()
		for word in words:
			if os.path.dirname(word) or word in (os.curdir, os.pardir):
				# Ignore components that are not a simple file/directory name
				continue
			path = os.path.join(path, word)
		if trailing_slash:
			path += '/'
		return path

	def copyfile(self, source, outputfile):
		"""Copy all data between two file objects.
		The SOURCE argument is a file object open for reading
		(or anything with a read() method) and the DESTINATION
		argument is a file object open for writing (or
		anything with a write() method).
		The only reason for overriding this would be to change
		the block size or perhaps to replace newlines by CRLF
		-- note however that this the default server uses this
		to copy binary data as well.
		"""
		shutil.copyfileobj(source, outputfile)

	def guess_type(self, path):
		"""Guess the type of a file.
		Argument is a PATH (a filename).
		Return value is a string of the form type/subtype,
		usable for a MIME Content-type header.
		The default implementation looks the file's extension
		up in the table self.extensions_map, using application/octet-stream
		as a default; however it would be permissible (if
		slow) to look inside the data to make a better guess.
		"""

		base, ext = posixpath.splitext(path)
		if ext in self.extensions_map:
			return self.extensions_map[ext]
		ext = ext.lower()
		if ext in self.extensions_map:
			return self.extensions_map[ext]
		else:
			return self.extensions_map['']

	if not mimetypes.inited:
		mimetypes.init() # try to read system mime.types
	extensions_map = mimetypes.types_map.copy()
	extensions_map.update({
	'': 'application/octet-stream', # Default
	'.py': 'text/plain',
	'.c': 'text/plain',
	'.h': 'text/plain',
	})

def runServer(c, port = 8000):
	print('http server is starting...')

	#ip and port of server
	#by default http server port is 80
	server_address = ("", port)
	httpd = HTTPServer(server_address, c)
	print('http server is running...')
	httpd.serve_forever()