initial

README.md

@@ -0,0 +1,8 @@
+# serve
+
+My Python port of the webserver Gary Bernhardt built in [this
+screencast](https://www.destroyallsoftware.com/screencasts/catalog/http-server-from-scratch).
+
+It is not spec-compliant, serves files from disk, is vulnerable to directory
+traversal, and if those files are executable, executes them. It’s as terrible
+as it sounds!

serve.py

@@ -0,0 +1,107 @@
+#!/usr/bin/env python3
+
+import os
+import socket
+import subprocess
+
+class Connection():
+    def __init__(self, sock):
+        self.sock = sock
+        self.buffer = ""
+
+    def read_until(self, sep):
+        while sep not in self.buffer:
+            self.buffer += self.sock.recv(4096)
+        res, self.buffer = self.buffer.split(sep, 1)
+        return res
+
+    def read_line(self):
+        return self.read_until("\r\n")
+
+    def read_request(self):
+        request_line = self.read_line()
+        method, path, version = request_line.split(" ", 3)
+
+        headers = {}
+
+        line = self.read_line()
+        while len(line):
+            k, v = line.split(":", 1)
+            headers[k] = v.strip()
+            line = self.read_line()
+
+        # we do not read the body
+
+        return Request(method, path, headers)
+
+
+class Request():
+    def __init__(self, method, path, headers):
+        self.method = method
+        self.path = path
+        self.headers = headers
+
+    def __str__(self):
+        return "Request(method='{}' path='{}' headers='{}')".format(self.method,
+                                                                    self.path,
+                                                                    self.headers)
+
+
+MSGS = {
+    200: "OK",
+    400: "Bad Request",
+    401: "Unauthorized",
+    403: "Forbidden",
+    404: "Not Found",
+    500: "Internal Server Error",
+}
+
+
+def respond(conn, status_code, content):
+    conn.send("HTTP/1.1 {} {}\r\n".format(status_code, MSGS[status_code]), 0)
+    conn.send("Content-Length: {}\r\n".format(len(content)))
+    conn.send("\r\n", 0)
+    conn.send(content, 0)
+
+
+def respond_to(conn, req):
+    content = ""
+    try:
+        path = os.getcwd() + req.path
+        if os.path.exists(path):
+            if os.access(path, os.X_OK):
+                content = subprocess.check_output([path])
+            else:
+                with open(path, 'r') as f:
+                    content = f.read()
+            status_code = 200
+        else:
+            status_code = 404
+    except Exception as e:
+        content = str(e)
+        status_code = 500
+    respond(conn, status_code, content)
+
+
+def accept(s):
+    conn, addr_info = s.accept()
+    connection = Connection(conn)
+    req = connection.read_request()
+    respond_to(conn, req)
+
+
+def accept_loop(s):
+    while True:
+        accept(s)
+
+
+def listen():
+    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+    s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, True)
+    s.bind(('', 8080))
+    s.listen(5)
+
+    accept_loop(s)
+
+if __name__ == '__main__':
+    listen()