Enable certificate checking (if available)

README.md

@@ -33,3 +33,20 @@ Please note
 * The non HD cameras use a different set of CGI commands and are not covered in this implementation.
 * The behaviour of the camera changes slightly with each new firmware version.  Please include model and firmware version when sending bug reports (run `camtest.py` from the command line).
 
+Certificate checking
+-------------------
+
+Since version 2.7.9 Python is checking certificates used in https connections.
+
+This works fine with most sites on the internet because their certificates are signed by major
+certificate authorities and Python has the means to verify their signatures.
+
+However, most cameras use self-signed certificates which will fail this check and throw an exception. 
+
+The certificate checking is controlled by the parameter `context.` See `camtest.py` for an example.
+This [blog entry](http://tuxpool.blogspot.de/2016/05/accessing-servers-with-self-signed.html) shows how to create a context that fits your camera.
+
+Unfortunately the `context` parameter was first added in Python 3.4.3. Between Python 2.7.9 and 3.4.3 
+you either have to refrain from using https with self-signed certs or you have to tweak your system 
+(i.e. install the camera certificate yourself in the system, change the host file, etc) so that the check is 
+successful without using `context`.    

camtest.py

@@ -4,6 +4,7 @@
 from __future__ import print_function
 
 from foscontrol import Cam
+import sys
 
 try:  # PY3
     from configparser import ConfigParser
@@ -19,15 +20,27 @@
     config = ConfigParser()
 
     # see cam.cfg.example
-    config.readfp(open('cam.cfg'))
+    config.read(['cam.cfg'])
     prot = config.get('general', 'protocol')
     host = config.get('general', 'host')
     port = config.get('general', 'port')
     user = config.get('general', 'user')
     passwd = config.get('general', 'password')
 
+    if sys.hexversion < 0x03040300:
+        # parameter context not available
+        ctx = None
+    else:
+        # disable cert checking
+        # see also http://tuxpool.blogspot.de/2016/05/accessing-servers-with-self-signed.html
+        import ssl
+
+        ctx = ssl.create_default_context()
+        ctx.check_hostname = False
+        ctx.verify_mode = ssl.CERT_NONE
+
     # connection to the camera
-    do = Cam(prot, host, port, user, passwd)
+    do = Cam(prot, host, port, user, passwd, context=ctx)
 
     # display basic camera info
     res = do.getDevInfo()

foscontrol/__init__.py

@@ -23,6 +23,12 @@
 except:
     from urllib.parse import urlencode, unquote
 
+def my_urlopen(url, data=None, context=None):
+    if sys.hexversion < 0x03040300:
+        # context not implemented
+        return urlopen(url, data=data)
+    else:
+        return urlopen(url, data=data, context=context)
 
 def encode_multipart(fields, files, boundary=None):
     """
@@ -371,18 +377,20 @@ class CamBase(object):
     - resultObj param "result" is converted to integer, if possible
     """
 
-    def __init__(self, prot, host, port, user, password):
+    def __init__(self, prot, host, port, user, password, context=None):
         """
         :param prot: protocol used ("http" or "https")
         :param host: hostname (e.g. "www.example.com")
         :param port: port used (e.g. 88 or 443)
         :param user: username of account in camera
         :param password: password of account in camera
+        :param context; context for secure TLS connections
         """
 
         self.base = "%s://%s:%s/cgi-bin/CGIProxy.fcgi" % (prot, host, port)
         self.user = user
         self.password = password
+        self.context = context
 
         self.debugfile = None
         self.consoleDump = False
@@ -491,10 +499,10 @@ def sendcommand(self, cmd, param=None, raw=False, doBool=None, headers=None, dat
         url = self.base + "?" + ps
 
         if headers is None:
-            retdata = urlopen(url, data=data).read()
+            retdata = my_urlopen(url, data=data, context=self.context).read()
         else:
             request = Request(url, data=data, headers=headers)
-            retdata = urlopen(request).read()
+            retdata = my_urlopen(request, context=self.context).read()
 
         if self.consoleDump:
             print("%s\n\n" % retdata)
@@ -798,7 +806,7 @@ def exportConfig(self):
         if w.result == 0:
             link = "/configs/export/%s" % w.fileName
             link2 = urljoin(self.base, link)
-            data = urlopen(link2).read()
+            data = my_urlopen(link2, context=self.context).read()
             return (data, w.fileName)
         else:
             return None
@@ -1169,7 +1177,7 @@ def snapPicture(self):
 
         link2 = urljoin(self.base, link)
 
-        data = urlopen(link2).read()
+        data = my_urlopen(link2, context=self.context).read()
         return (data, fname)
 
     def getPTZSpeed(self):

snapshot.py

@@ -0,0 +1,58 @@
+#!/usr/bin/python3
+# -*- coding: utf-8 -*-
+
+from __future__ import print_function
+
+from foscontrol import Cam
+import sys
+
+try:  # PY3
+    from configparser import ConfigParser
+except ImportError:
+    from ConfigParser import SafeConfigParser as ConfigParser
+
+################################
+# Don't forget to edit cam.cfg #
+# to reflect you setup!        #
+################################
+
+if __name__ == "__main__":
+    config = ConfigParser()
+
+    # see cam.cfg.example
+    config.read(['cam.cfg'])
+    prot = config.get('general', 'protocol')
+    host = config.get('general', 'host')
+    port = config.get('general', 'port')
+    user = config.get('general', 'user')
+    passwd = config.get('general', 'password')
+
+    if sys.hexversion < 0x03040300:
+        # parameter context not available
+        ctx = None
+    else:
+        # disable cert checking
+        # see also http://tuxpool.blogspot.de/2016/05/accessing-servers-with-self-signed.html
+        import ssl
+
+        ctx = ssl.create_default_context()
+        ctx.check_hostname = False
+        ctx.verify_mode = ssl.CERT_NONE
+
+    # connection to the camera
+    do = Cam(prot, host, port, user, passwd, context=ctx)
+
+    (img, fnm) = do.snapPicture()
+    # Possible errors/exceptions:
+    #
+    # urllib.error.URLError (e.g. no route to host)
+    # ssl.CertificateError (e.g. wrong or no ssl certificate)
+    # img == None (e.g. wrong password)
+
+    if img is not None:
+        print('Writing picture')
+        open('/tmp/test.jpg', 'wb').write(img)
+    else:
+        print('No picture')
+
+