First commands with basic structure.

- Moves DBManager to common.

watchtower-plugin/net/http.py

@@ -0,0 +1,69 @@
+import json
+import requests
+from requests import ConnectionError, ConnectTimeout
+from requests.exceptions import MissingSchema, InvalidSchema, InvalidURL
+
+from common import constants
+from exceptions import TowerConnectionError, TowerResponseError
+
+
+def post_request(data, endpoint):
+    """
+    Sends a post request to the tower.
+
+    Args:
+        data (:obj:`dict`): a dictionary containing the data to be posted.
+        endpoint (:obj:`str`): the endpoint to send the post request.
+
+    Returns:
+        :obj:`dict`: a json-encoded dictionary with the server response if the data can be posted.
+
+    Raises:
+        :obj:`ConnectionError`: if the client cannot connect to the tower.
+    """
+
+    try:
+        return requests.post(url=endpoint, json=data, timeout=5)
+
+    except ConnectTimeout:
+        message = "Can't connect to the Eye of Satoshi at {}. Connection timeout".format(endpoint)
+
+    except ConnectionError:
+        message = "Can't connect to the Eye of Satoshi at {}. Tower cannot be reached".format(endpoint)
+
+    except (InvalidSchema, MissingSchema, InvalidURL):
+        message = "Invalid URL. No schema, or invalid schema, found ({})".format(endpoint)
+
+    raise TowerConnectionError(message)
+
+
+def process_post_response(response):
+    """
+    Processes the server response to a post request.
+
+    Args:
+        response (:obj:`requests.models.Response`): a ``Response`` object obtained from the request.
+
+    Returns:
+        :obj:`dict`: a dictionary containing the tower's response data if the response type is
+        ``HTTP_OK``.
+
+    Raises:
+        :obj:`TowerResponseError <cli.exceptions.TowerResponseError>`: if the tower responded with an error, or the
+        response was invalid.
+    """
+
+    try:
+        response_json = response.json()
+
+    except (json.JSONDecodeError, AttributeError):
+        raise TowerResponseError(
+            "The server returned a non-JSON response", status_code=response.status_code, reason=response.reason
+        )
+
+    if response.status_code not in [constants.HTTP_OK, constants.HTTP_NOT_FOUND]:
+        raise TowerResponseError(
+            "The server returned an error", status_code=response.status_code, reason=response.reason, data=response_json
+        )
+
+    return response_json