From 0af6dc8eea5fcff46fd672a3e2bed8fdcc4ba9cc Mon Sep 17 00:00:00 2001
From: Tomas Groth <second@tgc.dk>
Date: Sun, 23 Nov 2014 20:52:16 +0000
Subject: [PATCH] Always retry on connection failure.

---
 openlp/core/ui/firsttimeform.py | 58 +++++++++++++++++++++------------
 openlp/core/utils/__init__.py   | 34 ++++++++++++++-----
 2 files changed, 62 insertions(+), 30 deletions(-)

diff --git a/openlp/core/ui/firsttimeform.py b/openlp/core/ui/firsttimeform.py
index 0688681a1..7713aa948 100644
--- a/openlp/core/ui/firsttimeform.py
+++ b/openlp/core/ui/firsttimeform.py
@@ -45,7 +45,7 @@ from openlp.core.common import Registry, RegistryProperties, AppLocation, Settin
     translate, clean_button_text, trace_error_handler
 from openlp.core.lib import PluginStatus, build_icon
 from openlp.core.lib.ui import critical_error_message_box
-from openlp.core.utils import get_web_page
+from openlp.core.utils import get_web_page, CONNECTION_RETRIES, CONNECTION_TIMEOUT
 from .firsttimewizard import UiFirstTimeWizard, FirstTimePage
 
 log = logging.getLogger(__name__)
@@ -304,23 +304,30 @@ class FirstTimeForm(QtGui.QWizard, UiFirstTimeWizard, RegistryProperties):
         """
         block_count = 0
         block_size = 4096
-        try:
-            url_file = urllib.request.urlopen(url, timeout=30)
-            filename = open(f_path, "wb")
-            # Download until finished or canceled.
-            while not self.was_download_cancelled:
-                data = url_file.read(block_size)
-                if not data:
-                    break
-                filename.write(data)
-                block_count += 1
-                self._download_progress(block_count, block_size)
-            filename.close()
-        except ConnectionError:
-            trace_error_handler(log)
-            filename.close()
-            os.remove(f_path)
-            return False
+        retries = 0
+        while True:
+            try:
+                url_file = urllib.request.urlopen(url, timeout=CONNECTION_TIMEOUT)
+                filename = open(f_path, "wb")
+                # Download until finished or canceled.
+                while not self.was_download_cancelled:
+                    data = url_file.read(block_size)
+                    if not data:
+                        break
+                    filename.write(data)
+                    block_count += 1
+                    self._download_progress(block_count, block_size)
+                filename.close()
+            except ConnectionError:
+                trace_error_handler(log)
+                filename.close()
+                os.remove(f_path)
+                if retries > CONNECTION_RETRIES:
+                    return False
+                else:
+                    retries += 1
+                    continue
+            break
         # Delete file if cancelled, it may be a partial file.
         if self.was_download_cancelled:
             os.remove(f_path)
@@ -343,9 +350,18 @@ class FirstTimeForm(QtGui.QWizard, UiFirstTimeWizard, RegistryProperties):
 
         :param url: The URL of the file we want to download.
         """
-        site = urllib.request.urlopen(url, timeout=30)
-        meta = site.info()
-        return int(meta.get("Content-Length"))
+        retries = 0
+        while True:
+            try:
+                site = urllib.request.urlopen(url, timeout=CONNECTION_TIMEOUT)
+                meta = site.info()
+                return int(meta.get("Content-Length"))
+            except ConnectionException:
+                if retries > CONNECTION_RETRIES:
+                    raise
+                else:
+                    retries += 1
+                    continue
 
     def _download_progress(self, count, block_size):
         """
diff --git a/openlp/core/utils/__init__.py b/openlp/core/utils/__init__.py
index 8f032cd7d..87dfc48cb 100644
--- a/openlp/core/utils/__init__.py
+++ b/openlp/core/utils/__init__.py
@@ -91,6 +91,8 @@ USER_AGENTS = {
         'Mozilla/5.0 (X11; NetBSD amd64; rv:18.0) Gecko/20130120 Firefox/18.0'
     ]
 }
+CONNECTION_TIMEOUT = 30
+CONNECTION_RETRIES = 2
 
 
 class VersionThread(QtCore.QThread):
@@ -250,10 +252,17 @@ def check_latest_version(current_version):
                 req = urllib.request.Request('http://www.openlp.org/files/version.txt')
         req.add_header('User-Agent', 'OpenLP/%s' % current_version['full'])
         remote_version = None
-        try:
-            remote_version = str(urllib.request.urlopen(req, None).read().decode()).strip()
-        except IOError:
-            log.exception('Failed to download the latest OpenLP version file')
+        retries = 0
+        while True:
+            try:
+                remote_version = str(urllib.request.urlopen(req, None, timeout=CONNECTION_TIMEOUT).read().decode()).strip()
+            except ConnectionException:
+                if retries > CONNECTION_RETRIES:
+                    log.exception('Failed to download the latest OpenLP version file')
+                else:
+                    retries += 1
+                    continue
+            break
         if remote_version:
             version_string = remote_version
     return version_string
@@ -389,11 +398,18 @@ def get_web_page(url, header=None, update_openlp=False):
         req.add_header(header[0], header[1])
     page = None
     log.debug('Downloading URL = %s' % url)
-    try:
-        page = urllib.request.urlopen(req, timeout=30)
-        log.debug('Downloaded URL = %s' % page.geturl())
-    except (urllib.error.URLError, ConnectionError):
-        log.exception('The web page could not be downloaded')
+    retries = 0
+    while True:
+        try:
+            page = urllib.request.urlopen(req, timeout=CONNECTION_TIMEOUT)
+            log.debug('Downloaded URL = %s' % page.geturl())
+        except (urllib.error.URLError, ConnectionError):
+            if retries > CONNECTION_RETRIES:
+                log.exception('The web page could not be downloaded')
+                raise
+            else:
+                continue
+        break
     if not page:
         return None
     if update_openlp: