Seperate client and server of FTP (#1106)

* added sample file to transfer

* split client and server into separate files

* client and server now work in python2

* server works on python3

* client works on python3

* allow configurable ONE_CONNECTION_ONLY for testing server

* allow testing of ftp server + client

* use f-strings

* removed single letter vars

* fixed bad quote marks

* clearer file handler names

* 'with open() as' syntax

* unicode and emojis in the test data

* s -> sock

* consistent comment spacing

* remove closing formalities

* swap in and out_file

* f-string

* if __name__ == '__main__':

Author: AlexDvorak

Diff for: .travis.yml

@@ -38,7 +38,6 @@ script:
   - mypy --ignore-missing-imports .
   - pytest . --doctest-modules
       --ignore=file_transfer_protocol/ftp_send_receive.py
-      --ignore=file_transfer_protocol/ftp_client_server.py
       --ignore=machine_learning/linear_regression.py
       --ignore=machine_learning/perceptron.py
       --ignore=machine_learning/random_forest_classification/random_forest_classification.py

Diff for: file_transfer_protocol/client.py

@@ -0,0 +1,23 @@
+if __name__ == '__main__':
+    import socket  # Import socket module
+
+    sock = socket.socket()  # Create a socket object
+    host = socket.gethostname()  # Get local machine name
+    port = 12312
+
+    sock.connect((host, port))
+    sock.send(b'Hello server!')
+
+    with open('Received_file', 'wb') as out_file:
+        print('File opened')
+        print('Receiving data...')
+        while True:
+            data = sock.recv(1024)
+            print(f"data={data}")
+            if not data:
+                break
+            out_file.write(data)  # Write data to a file
+
+    print('Successfully got the file')
+    sock.close()
+    print('Connection closed')

Diff for: file_transfer_protocol/ftp_client_server.py

@@ -0,0 +1,6 @@
+Hello
+This is sample data
+«küßî»
+“ЌύБЇ”
+😀😉
+😋

Diff for: file_transfer_protocol/mytext.txt

@@ -0,0 +1,34 @@
+if __name__ == '__main__':
+    import socket  # Import socket module
+
+    ONE_CONNECTION_ONLY = True  # Set this to False if you wish to continuously accept connections
+
+    filename='mytext.txt'
+    port = 12312  # Reserve a port for your service.
+    sock = socket.socket()  # Create a socket object
+    host = socket.gethostname()  # Get local machine name
+    sock.bind((host, port))  # Bind to the port
+    sock.listen(5)  # Now wait for client connection.
+
+    print('Server listening....')
+
+    while True:
+        conn, addr = sock.accept()  # Establish connection with client.
+        print(f"Got connection from {addr}")
+        data = conn.recv(1024)
+        print(f"Server received {data}")
+
+        with open(filename,'rb') as in_file:
+            data = in_file.read(1024)
+            while (data):
+               conn.send(data)
+               print(f"Sent {data!r}")
+               data = in_file.read(1024)
+
+        print('Done sending')
+        conn.close()
+        if ONE_CONNECTION_ONLY:  # This is to make sure that the program doesn't hang while testing
+            break
+
+    sock.shutdown(1)
+    sock.close()