Support for connecting to Square API endpoints via a proxy

README.md

@@ -394,7 +394,7 @@ Class | Method | HTTP request
 - **Type**: OAuth
 - **Flow**: accessCode
 - **Authorization URL**: `https://connect.squareup.com/oauth2/authorize`
-- **Scopes**: 
+- **Scopes**:
  - **MERCHANT_PROFILE_READ**: GET endpoints related to a merchant's business and location entities. Almost all Connect API applications need this permission in order to obtain a merchant's location IDs
  - **PAYMENTS_READ**: GET endpoints related to transactions and refunds
  - **PAYMENTS_WRITE**: POST, PUT, and DELETE endpoints related to transactions and refunds. E-commerce applications must request this permission
@@ -453,6 +453,33 @@ except ApiException as e:
     print ('Exception when calling V1EmployeesApi->list_employee_roles: %s\n' % e)
 ```
 
+## Using a proxy
+
+You may optionally specify a proxy to be used when connecting to the
+API endpoints.
+
+### Example
+
+```python
+from __future__ import print_function
+
+import squareconnect
+from squareconnect.rest import ApiException
+
+squareconnect.configuration.access_token = 'YOUR_ACCESS_TOKEN'
+squareconnect.configuration.proxy_url = 'http://localhost:3128/'
+
+api = squareconnect.apis.V1LocationsApi()
+
+try:
+    locations = api.list_locations()
+    print('There are {} locations registered in Square.'.format(len(locations)))
+    for location in locations:
+      print('id: {}, name:{}'.format(location.id, location.name))
+except ApiException as e:
+    print ('Exception when calling V1LocationsApi->list_locations: %s\n' % e)
+```  
+
 ## Contributing
 
 Send bug reports, feature requests, and code contributions to the [API

squareconnect/configuration.py

@@ -100,6 +100,9 @@ def __init__(self):
         # client key file
         self.key_file = None
 
+        # Proxy settings
+        self.proxy_url = None
+
     @property
     def logger_file(self):
         """

squareconnect/rest.py

@@ -130,14 +130,23 @@ def __init__(self, pools_size=4):
         key_file = Configuration().key_file
 
         # https pool manager
-        self.pool_manager = urllib3.PoolManager(
+        pool_manager_class = urllib3.PoolManager
+        pool_manager_args = dict(
             num_pools=pools_size,
             cert_reqs=cert_reqs,
             ca_certs=ca_certs,
             cert_file=cert_file,
             key_file=key_file
         )
 
+        # check for proxy
+        proxy_url = Configuration().proxy_url
+        if proxy_url:
+            pool_manager_class = urllib3.ProxyManager
+            pool_manager_args['proxy_url'] = proxy_url
+
+        self.pool_manager = pool_manager_class(**pool_manager_args)
+
     def request(self, method, url, query_params=None, headers=None,
                 body=None, post_params=None):
         """