Support dsn in connect func.

Author: laodouya

README.rst

@@ -53,7 +53,7 @@ Documentation
 
 Documentation is available online: http://developers.covenantsql.io/
 
-Key file and database_id can get from: http://developers.covenantsql.io/docs/quickstart
+Key file and dsn can get from: http://developers.covenantsql.io/docs/quickstart
 
 For support, please fire a issue at `Github
 <https://github.com/CovenantSQL/CovenantSQL/issues/new>`_.
@@ -76,14 +76,13 @@ The following examples make use of a simple table
 
     import pycovenantsql
 
-    # user key file location
-    key = '/path/to/private.key'
 
-    # Connect to the database
-    connection = pycovenantsql.connect(host='localhost',
+    # Connect to the database with dsn
+    # host and port are your local CovenantSQL Adapter server
+    connection = pycovenantsql.connect(
+                                 dsn='covenantsql://your_database_id',
+                                 host='localhost',
                                  port=11108,
-                                 key=key,
-                                 database='database_id'
                                  )
 
     try:

example.py

@@ -6,8 +6,8 @@
 
 print(pycovenantsql.get_client_info())
 
-conn = pycovenantsql.connect(dsn='covenant://0a10b74439f2376d828c9a70fd538dac4b69e0f4065424feebc0f5dbc8b34872',
-        host="adp00.cn.gridb.io", port=7784, database='0a10b74439f2376d828c9a70fd538dac4b69e0f4065424feebc0f5dbc8b34872')
+conn = pycovenantsql.connect(dsn='covenantsql://0a10b74439f2376d828c9a70fd538dac4b69e0f4065424feebc0f5dbc8b34872',
+        host="adp00.cn.gridb.io", port=7784)
 
 cur = conn.cursor()
 print(cur.description)

pycovenantsql/connections.py

@@ -1,6 +1,7 @@
 import sys
 import os
 import requests
+from urllib.parse import urlparse
 from . import err
 from .cursors import Cursor
 from .optionfile import Parser
@@ -83,6 +84,12 @@ def _config(key, arg):
         self.port = port or 11108
         self.key = key
         self.database = database
+        if self.dsn:
+            u = urlparse(self.dsn)
+            scheme = u.scheme.lower()
+            if scheme == "covenantsql" or scheme == "cql":
+                if u.hostname:
+                    self.database = u.hostname
         if https_pem:
             self._cert = (https_pem, self.key)
         elif self.key: