Support http proxy environment variables

If defined, the variables http_proxy, HTTP_PROXY, https_proxy or
HTTPS_PROXY will be used to create a proxied pool manager.

If the prefix https:// is used by the url, it will try to use
the corresponding proxy variables. If not defined, it will
fallback to http_proxy and HTTP_PROXY.

Signed-off-by: Denis A. Altoé Falqueto <denisfalqueto@gmail.com>

buku.1

@@ -222,6 +222,20 @@ Exit buku.
 .BI BROWSER
 Overrides the default browser. Ref:
 .I http://docs.python.org/library/webbrowser.html
+.TP
+.BR http_proxy ", " HTTP_PROXY ", " https_proxy "  or " HTTPS_PROXY"
+
+If defined, will be used to access http and https resources through the configured proxy. 
+For https requests, if https proxy is not defined but http is, the latter will be used 
+instead. 
+
+They should be in the following format:
+
+    http[s]://proxyhost:proxyport
+
+Buku uses urllib3 for proxy support, but that library doesn't support authenticated
+proxies. So, if that's your need, you should use a local intermediate proxy, such as 
+cntlm, TinyProxy or Polipo.
 .SH EXAMPLES
 .PP
 .IP 1. 4

buku.py

@@ -1492,6 +1492,37 @@ def get_page_title(resp):
         return htmlparser.parsed_title
 
 
+def create_poolmanager(url):
+    '''Creates a pool manager with proxy support, if needed.
+    
+    Checks to see if there are proxy variables defined and creates
+    a ProxyManager. If not, creates a PoolManager.
+    '''
+
+    # Check if http_proxy or HTTP_PROXY is defined
+    http_proxy = os.environ.get('http_proxy')
+    if not http_proxy:
+        http_proxy = os.environ.get('HTTP_PROXY')
+
+    # Check if https_proxy or HTTPS_PROXY is defined
+    https_proxy = os.environ.get('https_proxy')
+    if not https_proxy:
+        https_proxy = os.environ.get('HTTPS_PROXY')
+
+    # If not, falls back to http_proxy, which is more common.
+    if not https_proxy:
+        https_proxy = http_proxy
+
+    # Create a pool manager with or without proxy support as needed.
+    if url.startswith('http://') and http_proxy:
+        manager = urllib3.ProxyManager(http_proxy)
+    elif url.startswith('https://') and https_proxy:
+        manager = urllib3.ProxyManager(https_proxy)
+    else:
+        manager = urllib3.PoolManager()
+    return manager;
+
+
 def network_handler(url):
     '''Handle server connection and redirections
 
@@ -1513,7 +1544,7 @@ def network_handler(url):
 
     if not http_handler:
         urllib3.disable_warnings()
-        http_handler = urllib3.PoolManager()
+        http_handler = create_poolmanager(url)
 
     try:
         while True: