added functionality to automatically_authenticate

.gitignore

@@ -7,4 +7,6 @@ README.html
 .fb_access_token
 mark.jpg
 *.egg
-*.egg
+*.egg
+*~
+*.pyc

README.md

@@ -50,6 +50,7 @@ To remove this access token, you can call `logout()`:
 
     fbconsole.logout()
 
+See below for other modes of authentication.
 
 ### Graph API Basics ###
 
@@ -122,6 +123,24 @@ altogether:
 
     fbconsole.ACCESS_TOKEN = '<your-access-token>'
 
+As a means to set the `ACCESS_TOKEN`, fbconsole provides an automatic
+mechanism (python 2.x only) for authenticating server-side apps by
+completing the OAuth process automatically:
+
+    # WARNING: only supported for python 2.x
+    fbconsole.automatically_authenticate(
+        username,     # facebook username for authentication
+        password,     # facebook password for authentication
+        app_secret,   # "app secret" from facebook app settings
+        redirect_uri, # redirect uri specified in facebook app settings
+    )
+
+This method for authentication is particularly helpful, for example,
+for running cron jobs that grab data from the Graph API on a daily
+basis. If you have any trouble using the `automatic_authentication`
+method, be sure to double check that the username, password, app
+secret, and redirect uri are all consistent with your apps
+[facebook settings](https://developers.facebook.com/apps).
 
 ### Other Options ###
 

setup.py

@@ -29,6 +29,7 @@
 else:
     install_requires.extend([
             'poster',
+            'mechanize',
             ])
 
 if sys.version_info[0] == 2 and sys.version_info[1] == 5:

src/fbconsole.py

@@ -74,6 +74,12 @@
     from urllib2 import Request
     from urllib import urlencode
 
+# import mechanize in python 2.x
+if six.PY3:
+    mechanize = None
+else:
+    import mechanize
+
 APP_ID = '179745182062082'
 SERVER_PORT = 8080
 ACCESS_TOKEN = None
@@ -90,6 +96,7 @@
 __all__ = [
     'help',
     'authenticate',
+    'automatically_authenticate',
     'logout',
     'graph_url',
     'oauth_url',
@@ -233,6 +240,17 @@ class UnknownApiException(ApiException):
 class OAuthException(ApiException):
     """Just an oath exception."""
 
+class AutomaticLoginError(Exception):
+    """
+    An error has occurred during login. This can occur for a number
+    of reasons. Make sure you have correctly specified the username,
+    password, client_secret, redirect_uri, and APP_ID for your
+    facebook app:
+
+        https://developers.facebook.com/apps
+    """
+    def __str__(self):
+        return self.__class__.__doc__
 
 def _handle_http_error(e):
     body = e.read()
@@ -263,6 +281,43 @@ def _safe_json_load(*args, **kwargs):
     else:
         return json.loads(f.read())
 
+def _instantiate_browser(debug=False):
+    """Setup the mechanize browser to handle redirects, robots, etc to
+    programmatically complete oauth.
+
+    Helpful resources:
+    * http://stockrt.github.com/p/emulating-a-browser-in-python-with-mechanize/
+    """
+
+    # instantiate the mechanize browser
+    browser = mechanize.Browser()
+
+    # set different settings
+    browser.set_handle_equiv(True)
+    # browser.set_handle_gzip(True) # this is experimental
+    browser.set_handle_redirect(True)
+    browser.set_handle_referer(True)
+    browser.set_handle_robots(False)
+    browser.set_handle_refresh(
+        mechanize._http.HTTPRefreshProcessor(), 
+        max_time=1,
+    )
+
+    # add debug logging
+    if debug:
+        browser.set_debug_http(True)
+        browser.set_debug_redirects(True)
+        browser.set_debug_responses(True)
+
+    # add the cookie jar
+    cj = cookielib.LWPCookieJar()
+    browser.set_cookiejar(cj)
+
+    # setup the headers
+    browser.addheaders = [('User-agent', 'Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.0.1) Gecko/2008071615 Fedora/3.0.1-1.fc9 Firefox/3.0.1')]
+
+    return browser
+
 def help():
     """Print out some helpful information"""
     print '''
@@ -308,6 +363,79 @@ def authenticate():
         while ACCESS_TOKEN is None:
             httpd.handle_request()
 
+def automatically_authenticate(username, password, app_secret, redirect_uri,
+                               debug=False):
+    """Authenticate with facebook automatically so that server-side
+    facebook apps can make api calls that require authorization. A
+    username, password, and app_secret must be specified
+    (http://developers.facebook.com/docs/authentication/server-side/)
+
+    This method automatically sets the ACCESS_TOKEN so that all
+    subsequent calls to facebook are authenticated.
+
+    If you want to request certain permissions, set the AUTH_SCOPE global
+    variable to the list of permissions you want.
+    """
+
+    # use the global APP_ID and AUTH_SCOPE for authentication. this
+    # method sets the ACCESS_TOKEN at the end
+    global APP_ID
+    global AUTH_SCOPE
+    global ACCESS_TOKEN
+
+    # throw an import error as mechanize does not work with python
+    # 3. upset? contribute! https://github.com/jjlee/mechanize
+    if mechanize is None:
+        msg = "automatically_authenticate method is not compatible with "
+        msg += "python 3.x due to mechanize incapatability."
+        raise ImportError(msg)
+
+    # instantiate the browser
+    browser = _instantiate_browser(debug=debug)
+
+    # the state is a random string that is used in subsequent requests
+    chars = "abcdefghijklmnopqrstuvwxyz1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    state = ''.join((random.choice(chars) for i in range(30)))
+
+    # 1. redirect the "user" (a server-side user, in this case) to the
+    # OAuth dialog
+    url = "https://www.facebook.com/dialog/oauth?" + urllib.urlencode({
+        "client_id": APP_ID,
+        "redirect_uri": redirect_uri,
+        "scope": ','.join(AUTH_SCOPE),
+        "state": state,
+    })
+    browser.open(url)
+
+    # 2. "user" is prompted to authorize your application
+    browser.select_form(nr=0)
+    browser.form["email"] = username
+    browser.form["pass"] = password
+    response = browser.submit()
+
+    # 3. Once the user is redirected back to our app, parse out the
+    #    code generated by facebook
+    auth_url = urlparse(response.geturl())
+    oauth = parse_qs(auth_url.query)
+    if "state" not in oauth:
+        raise AutomaticLoginError
+    assert oauth["state"][0] == state, "Inconsistent state: %s != %s" % (
+        oauth["state"][0], state,
+    )
+    code = oauth["code"][0]
+
+    # 4. Exchange the code for a user access token for this user's data
+    url="https://graph.facebook.com/oauth/access_token?"+urllib.urlencode({
+        "client_id": APP_ID,
+        "redirect_uri": redirect_uri,
+        "client_secret": app_secret,
+        "code": code,
+    })
+    browser.open(url)
+    response = browser.response()
+    oauth = parse_qs(response.read())
+    ACCESS_TOKEN = oauth["access_token"][0]
+
 def logout():
     """Logout of facebook.  This just removes the cached access token."""
     if os.path.exists(ACCESS_TOKEN_FILE):