Database Server exercise

database_server.py

from http.server import HTTPServer, ThreadingHTTPServer, BaseHTTPRequestHandler

from urllib.parse import urlparse, parse_qs


# Dictionary-db storing user key-value pairs.
#
_db = {}

_database_file = '/tmp/dataserver.txt'
_dbfile = open(_database_file, 'a')

class Handler(BaseHTTPRequestHandler):
    """
    GET handler

    When the server receives a 'set?somekey=somevalue' GET request, store key and value in memory.
    When it receives a 'get?key=somekey' GET request, return the value stored at somekey.
    """
    def __init__(self, *args, **kwargs):
        super(Handler, self).__init__(*args,**kwargs)
        _dbfile_read = open(_database_file, 'r')
        for line in _dbfile_read.readlines():
            k,v = line.strip().split(':')
            # _db.update({bytes(k,'utf-8'):bytes(v,'utf-8')})
            _db.update({k:v})
            print('DB***:',repr(k),repr(v))
            print('DB***:',type(k),type(v))
        # and then you open it up for writing/appending
        #_dbfile = open(_database_file, 'a')

    # def __del__(self):
    #     self._dbfile.close()

    def _get(self):
        o = urlparse(self.path)
        pairs = parse_qs(o.query)
        if o.path == '/set':
            pairs_first = {str(k):str(v[0]) for k,v in pairs.items()}
            for k,v in pairs_first.items():
                print('SET***:',repr(k),repr(v))
                print('SET***:',type(k),type(v))

            _db.update(pairs_first)
            for k,v in pairs_first.items():
                print('{k}:{v}'.format(k=k,v=v), file=_dbfile)
            _dbfile.flush()
            return b'All set!'
        elif o.path == '/get':
            for k,v in _db.items():
                print('GET***:',repr(k),repr(v))
                print('GET***:',type(k),type(v))

            pairs_vals = {k:_db[k]  for p,vs in pairs.items() if p == 'key'
                                    for k in vs if k in _db}
            ans = '\n'.join([F'{k}:{v}' for k,v in pairs_vals.items()])
            return bytes(ans, 'utf-8')
        else:
            return b'Oops: command not found.'

    def do_GET(self):
        ans = self._get()
        if ans:
            print(ans)
        self.send_response(200)
        self.end_headers()
        self.wfile.write(ans)



if __name__ == '__main__':
    host = ''
    port = 4000
    server_address = (host, port)
    httpd = ThreadingHTTPServer(server_address, Handler)
    # httpd = HTTPServer(server_address, Handler)
    print(F"Server running at localhost:{port}...")
    httpd.serve_forever()