Implement retry logic.

Author: Rolf Timmermans and Simon Wahlström

CHANGES.md

@@ -0,0 +1,5 @@
+## 1.5.0
+* Retry failed requests by default.
+
+## 1.4.0
+* Added support for HTTP proxies.

test/helper.py

@@ -7,6 +7,11 @@
 import httpretty
 from nose.exc import SkipTest
 
+if sys.version_info < (3, 3):
+    from mock import DEFAULT
+else:
+    from unittest.mock import DEFAULT
+
 if sys.version_info < (2, 7):
     import unittest2 as unittest
 else:
@@ -20,11 +25,16 @@
 import tinify
 
 class RaiseException(object):
-    def __init__(self, exception):
+    def __init__(self, exception, num=None):
         self.exception = exception
+        self.num = num
 
     def __call__(self, *args, **kwargs):
-        raise self.exception
+        if self.num == 0:
+            return DEFAULT
+        else:
+            if self.num: self.num -= 1
+            raise self.exception
 
 class TestHelper(unittest.TestCase):
     def setUp(self):

test/tinify_client_test.py

@@ -15,6 +15,8 @@
 except ImportError:
     from mock import patch
 
+Client.RETRY_DELAY = 10
+
 class TinifyClientRequestWhenValid(TestHelper):
     def setUp(self):
         super(type(self), self).setUp()
@@ -79,7 +81,7 @@ def test_should_issue_request_with_proxy_authorization(self):
 
         self.assertEqual(self.request.headers['proxy-authorization'], 'Basic dXNlcjpwYXNz')
 
-class TinifyClientRequestWithTimeout(TestHelper):
+class TinifyClientRequestWithTimeoutRepeatedly(TestHelper):
     @patch('requests.sessions.Session.request', RaiseException(requests.exceptions.Timeout))
     def test_should_raise_connection_error(self):
         with self.assertRaises(ConnectionError) as context:
@@ -92,7 +94,15 @@ def test_should_raise_connection_error_with_cause(self):
             Client('key').request('GET', '/')
         self.assertIsInstance(context.exception.__cause__, requests.exceptions.Timeout)
 
-class TinifyClientRequestWithConnectionError(TestHelper):
+class TinifyClientRequestWithTimeoutOnce(TestHelper):
+    @patch('requests.sessions.Session.request')
+    def test_should_issue_request(self, mock):
+        mock.side_effect = RaiseException(requests.exceptions.Timeout, num=1)
+        mock.return_value = requests.Response()
+        mock.return_value.status_code = 201
+        self.assertIsInstance(Client('key').request('GET', '/', {}), requests.Response)
+
+class TinifyClientRequestWithConnectionErrorRepeatedly(TestHelper):
     @patch('requests.sessions.Session.request', RaiseException(requests.exceptions.ConnectionError('connection error')))
     def test_should_raise_connection_error(self):
         with self.assertRaises(ConnectionError) as context:
@@ -105,14 +115,30 @@ def test_should_raise_connection_error_with_cause(self):
             Client('key').request('GET', '/')
         self.assertIsInstance(context.exception.__cause__, requests.exceptions.ConnectionError)
 
-class TinifyClientRequestWithSomeError(TestHelper):
+class TinifyClientRequestWithConnectionErrorOnce(TestHelper):
+    @patch('requests.sessions.Session.request')
+    def test_should_issue_request(self, mock):
+        mock.side_effect = RaiseException(requests.exceptions.ConnectionError, num=1)
+        mock.return_value = requests.Response()
+        mock.return_value.status_code = 201
+        self.assertIsInstance(Client('key').request('GET', '/', {}), requests.Response)
+
+class TinifyClientRequestWithSomeErrorRepeatedly(TestHelper):
     @patch('requests.sessions.Session.request', RaiseException(RuntimeError('some error')))
     def test_should_raise_connection_error(self):
         with self.assertRaises(ConnectionError) as context:
             Client('key').request('GET', '/')
         self.assertEqual('Error while connecting: some error', str(context.exception))
 
-class TinifyClientRequestWithServerError(TestHelper):
+class TinifyClientRequestWithSomeErrorOnce(TestHelper):
+    @patch('requests.sessions.Session.request')
+    def test_should_issue_request(self, mock):
+        mock.side_effect = RaiseException(RuntimeError('some error'), num=1)
+        mock.return_value = requests.Response()
+        mock.return_value.status_code = 201
+        self.assertIsInstance(Client('key').request('GET', '/', {}), requests.Response)
+
+class TinifyClientRequestWithServerErrorRepeatedly(TestHelper):
     def test_should_raise_server_error(self):
         httpretty.register_uri(httpretty.GET, 'https://api.tinify.com/', status=584,
             body='{"error":"InternalServerError","message":"Oops!"}')
@@ -121,7 +147,18 @@ def test_should_raise_server_error(self):
             Client('key').request('GET', '/')
         self.assertEqual('Oops! (HTTP 584/InternalServerError)', str(context.exception))
 
-class TinifyClientRequestWithBadServerResponse(TestHelper):
+class TinifyClientRequestWithServerErrorOnce(TestHelper):
+    def test_should_issue_request(self):
+        httpretty.register_uri(httpretty.GET, 'https://api.tinify.com/',
+            responses=[
+                httpretty.Response(body='{"error":"InternalServerError","message":"Oops!"}', status=584),
+                httpretty.Response(body='all good', status=201),
+            ])
+
+        response = Client('key').request('GET', '/')
+        self.assertEqual('201', str(response.status_code))
+
+class TinifyClientRequestWithBadServerResponseRepeatedly(TestHelper):
     def test_should_raise_server_error(self):
         httpretty.register_uri(httpretty.GET, 'https://api.tinify.com/', status=543,
             body='<!-- this is not json -->')
@@ -132,6 +169,17 @@ def test_should_raise_server_error(self):
         msg = r'Error while parsing response: .* \(HTTP 543/ParseError\)'
         self.assertRegexpMatches(str(context.exception), msg)
 
+class TinifyClientRequestWithBadServerResponseOnce(TestHelper):
+    def test_should_issue_request(self):
+        httpretty.register_uri(httpretty.GET, 'https://api.tinify.com/',
+            responses=[
+                httpretty.Response(body='<!-- this is not json -->', status=543),
+                httpretty.Response(body='all good', status=201),
+            ])
+
+        response = Client('key').request('GET', '/')
+        self.assertEqual('201', str(response.status_code))
+
 class TinifyClientRequestWithClientError(TestHelper):
     def test_should_raise_client_error(self):
         httpretty.register_uri(httpretty.GET, 'https://api.tinify.com/', status=492,

tinify/client.py

@@ -8,12 +8,17 @@
 import requests.exceptions
 from requests.compat import json
 import traceback
+import time
 
 import tinify
 from .errors import ConnectionError, Error
 
 class Client(object):
     API_ENDPOINT = 'https://api.tinify.com'
+
+    RETRY_COUNT = 1
+    RETRY_DELAY = 500
+
     USER_AGENT = 'Tinify/{0} Python/{1} ({2})'.format(tinify.__version__, platform.python_version(), platform.python_implementation())
 
     def __init__(self, key, app_identifier=None, proxy=None):
@@ -35,7 +40,7 @@ def __exit__(self, *args):
     def close(self):
         self.session.close()
 
-    def request(self, method, url, body=None, header={}):
+    def request(self, method, url, body=None):
         url = url if url.lower().startswith('https://') else self.API_ENDPOINT + url
         params = {}
         if isinstance(body, dict):
@@ -46,23 +51,29 @@ def request(self, method, url, body=None, header={}):
         elif body:
             params['data'] = body
 
-        try:
-            response = self.session.request(method, url, **params)
-        except requests.exceptions.Timeout as err:
-            raise ConnectionError('Timeout while connecting', cause=err)
-        except Exception as err:
-            raise ConnectionError('Error while connecting: {0}'.format(err), cause=err)
+        for retries in range(self.RETRY_COUNT, -1, -1):
+            if retries < self.RETRY_COUNT: time.sleep(self.RETRY_DELAY / 1000.0)
+
+            try:
+                response = self.session.request(method, url, **params)
+            except requests.exceptions.Timeout as err:
+                if retries > 0: continue
+                raise ConnectionError('Timeout while connecting', cause=err)
+            except Exception as err:
+                if retries > 0: continue
+                raise ConnectionError('Error while connecting: {0}'.format(err), cause=err)
+
+            count = response.headers.get('compression-count')
+            if count:
+                tinify.compression_count = int(count)
 
-        count = response.headers.get('compression-count')
-        if count:
-            tinify.compression_count = int(count)
+            if response.ok:
+                return response
 
-        if response.ok:
-            return response
-        else:
             details = None
             try:
                 details = response.json()
             except Exception as err:
                 details = {'message': 'Error while parsing response: {0}'.format(err), 'error': 'ParseError'}
+            if retries > 0 and response.status_code >= 500: continue
             raise Error.create(details.get('message'), details.get('error'), response.status_code)

tinify/version.py

@@ -1 +1 @@
-__version__ = '1.4.0'
+__version__ = '1.5.0'