pyserv/pyserv.py

from urllib.parse import parse_qs as upunquote
VERSION = "PyServ Beta 0.1"

class Abort404(Exception):
	"""Signals for a 404 error, if listened for"""
	def __init__(self,*args):
		super().__init__(*args)

# Unquotes query strings.
def unquote(*args):
	return upunquote(*args)

# Lazy text sanitizer.
def lazySan(s):
	return s.replace("<","&lt;").replace("&","&amp;")

class HTTPServer:
	"""HTTP Server base class"""
	def __init__(self):
		self.methods = dict()

	"""Registers function to handle requests to a method"""
	def register(self,method,f):
		self.methods[method]=f

	"""Returns whether a function is set to handle the given method"""
	def hasMethod(self,method):
		return method in self.methods.keys()

	"""Returns a list of supported methods."""
	def getMethods(self):
		ret = list(self.methods.keys())
		ret.sort()
		return ret

	"""Formats a response."""
	def formatResponse(self,respcode,headers,content):
		lines = []
		lines.append("HTTP/1.1 {!s} {}".format(respcode,DEFAULT_MSGS[respcode]))
		for h in headers:
			lines.append("{}: {}".format(h,headers[h]))
		lines.append("") # of course
		for line in content:
			lines.append(line)
		return "\n".join(lines)+"\n"

# This function creates a stock error page.
# TODO: Replace DEFAULT_MSGS with maintained database
DEFAULT_MSGS = {100: "Continue",101: "Switching Protocols",102: "Processing",200: "Ok",201: "Created",202: "Accepted",203: "Non Authoritative Information",204: "No Content",205: "Reset Content",206: "Partial Content",207: "Multi Status",208: "Already Reported",226: "Im Used",300: "Multiple Choices",301: "Moved Permanently",302: "Found",303: "See Other",304: "Not Modified",305: "Use Proxy",307: "Temporary Redirect",308: "Permanent Redirect",400: "Bad Request",401: "Unauthorized",402: "Payment Required",403: "Forbidden",404: "Not Found",405: "Method Not Allowed",406: "Not Acceptable",407: "Proxy Authentication Required",408: "Request Timeout",409: "Conflict",410: "Gone",411: "Length Required",412: "Precondition Failed",413: "Request Entity Too Large",414: "Request Uri Too Long",415: "Unsupported Media Type",416: "Requested Range Not Satisfiable",417: "Expectation Failed",418: "I'm A Teapot",422: "Unprocessable Entity",423: "Locked",424: "Failed Dependency",426: "Upgrade Required",428: "Precondition Required",429: "Too Many Requests",431: "Request Header Fields Too Large",500: "Internal Server Error",501: "Not Implemented",502: "Bad Gateway",503: "Service Unavailable",504: "Gateway Timeout",505: "Http Version Not Supported",506: "Variant Also Negotiates",507: "Insufficient Storage",508: "Loop Detected",510: "Not Extended",511: "Network Authentication Required"}
def abort(errorcode,message=None,headers=dict()):
	lines = []
	if message is None:
		message = DEFAULT_MSGS.get(errorcode,"Unknown response code")
	lines.append("HTTP/1.1 {!s} {}".format(errorcode,message))
	headers["Server"] = headers.get("Server",VERSION)
	if errorcode!=204 and "Content-Type" not in headers:
		headers["Content-Type"] = "text/html"
	for h in headers:
		lines.append("{}: {}".format(h,headers[h]))
	if errorcode==204:
		return "\n".join(lines)+"\n" # No content. Duh.
	lines.append("")
	lines.append("<h1>{!s} {}</h1>".format(errorcode, message))
	lines.append("<hr>")
	lines.append("<p>{}</p>".format(headers["Server"]))
	return "\n".join(lines)+"\n"