Implement proper two factor authentication

fixes #19, #23

CHANGELOG.md

@@ -4,6 +4,7 @@ Changelog
 **0.13.0 (TBA)**
 
 * Allow passing `--instance` and `--email` to login command
+* Add `login_browser` command for proper two factor authentication through the browser (#19, #23)
 
 **0.12.0 (2016-05-08)**
 

README.rst

@@ -37,8 +37,9 @@ Running ``toot <command> -h`` shows the documentation for the given command.
     toot - a Mastodon CLI client
 
     Authentication:
-      toot login       Log into a Mastodon instance
-      toot login_2fa   Log in using two factor authentication (experimental)
+      toot login           Log into a Mastodon instance, does NOT support two factor authentication
+      toot login_browser   Log in using your browser, supports regular and two factor authentication
+      toot login_2fa       Log in using two factor authentication in the console (hacky, experimental)
       toot logout          Log out, delete stored access keys
       toot auth            Show stored credentials
 
@@ -77,19 +78,23 @@ It is possible to pipe status text into `toot post`, for example:
 Authentication
 --------------
 
-Before tooting, you need to login to a Mastodon instance:
+Before tooting, you need to login to a Mastodon instance.
+
+If you don't use two factor authentication you can log in directly from the command line:
 
 .. code-block::
 
     toot login
 
-**Two factor authentication** is supported experimentally, instead of ``login``, you should instead run ``login_2fa``:
+You will be asked to chose an instance_ and enter your credentials.
+
+If you do use **two factor authentication**, you need to log in through your browser:
 
 .. code-block::
 
-    toot login_2fa
+    toot login_browser
 
-You will be asked to chose an instance_ and enter your credentials.
+You will be redirected to your Mastodon instance to log in and authorize toot to access your account, and will be given an **authorization code** in return which you need to enter to log in.
 
 .. _instance: https://github.com/tootsuite/documentation/blob/master/Using-Mastodon/List-of-Mastodon-instances.md
 

toot/api.py

@@ -4,7 +4,7 @@ import logging
 import re
 import requests
 
-from future.moves.urllib.parse import urlparse
+from future.moves.urllib.parse import urlparse, urlencode
 from requests import Request, Session
 
 from toot import CLIENT_NAME, CLIENT_WEBSITE
@@ -53,11 +53,17 @@ def _process_response(response):
     _log_response(response)
 
     if not response.ok:
-        try:
-            error = response.json()['error']
-        except:
         error = "Unknown error"
 
+        try:
+            data = response.json()
+            if "error_description" in data:
+                error = data['error_description']
+            elif "error" in data:
+                error = data['error']
+        except:
+            pass
+
         if response.status_code == 404:
             raise NotFoundError(error)
 
@@ -131,6 +137,30 @@ def login(app, username, password):
     return _process_response(response).json()
 
 
+def get_browser_login_url(app):
+    """Returns the URL for manual log in via browser"""
+    return "{}/oauth/authorize/?{}".format(app.base_url, urlencode({
+        "response_type": "code",
+        "redirect_uri": "urn:ietf:wg:oauth:2.0:oob",
+        "scope": "read write follow",
+        "client_id": app.client_id,
+    }))
+
+
+def request_access_token(app, authorization_code):
+    url = app.base_url + '/oauth/token'
+
+    response = requests.post(url, {
+        'grant_type': 'authorization_code',
+        'client_id': app.client_id,
+        'client_secret': app.client_secret,
+        'code': authorization_code,
+        'redirect_uri': 'urn:ietf:wg:oauth:2.0:oob',
+    }, allow_redirects=False)
+
+    return _process_response(response).json()
+
+
 def post_status(app, user, status, visibility='public', media_ids=None):
     return _post(app, user, '/api/v1/statuses', {
         'status': status,

toot/commands.py

@@ -4,6 +4,7 @@ from __future__ import print_function
 
 import json
 import requests
+import webbrowser
 
 from bs4 import BeautifulSoup
 from builtins import input
@@ -45,6 +46,15 @@ def create_app_interactive(instance=None):
     return config.load_app(instance) or register_app(instance)
 
 
+def create_user(app, email, access_token):
+    user = User(app.instance, email, access_token)
+    path = config.save_user(user)
+
+    print_out("Access token saved to: <green>{}</green>".format(path))
+
+    return user
+
+
 def login_interactive(app, email=None):
     print_out("Log in to <green>{}</green>".format(app.instance))
 
@@ -62,12 +72,7 @@ def login_interactive(app, email=None):
     except api.ApiError:
         raise ConsoleError("Login failed")
 
-    user = User(app.instance, email, response['access_token'])
-    path = config.save_user(user)
-
-    print_out("Access token saved to: <green>{}</green>".format(path))
-
-    return user
+    return create_user(app, email, response['access_token'])
 
 
 def two_factor_login_interactive(app):
@@ -118,9 +123,7 @@ def two_factor_login_interactive(app):
     data = json.loads(initial_state.get_text())
     access_token = data['meta']['access_token']
 
-    user = User(app.instance, email, access_token)
-    path = config.save_user(user)
-    print_out("Access token saved to: <green>{}</green>".format(path))
+    return create_user(app, email, access_token)
 
 
 def _print_timeline(item):
@@ -222,6 +225,46 @@ def login_2fa(app, user, args):
     print_out("<green>✓ Successfully logged in.</green>")
 
 
+BROWSER_LOGIN_EXPLANATION = """
+This authentication method requires you to log into your Mastodon instance
+in your browser, where you will be asked to authorize <yellow>toot</yellow> to access
+your account. When you do, you will be given an <yellow>authorization code</yellow>
+which you need to paste here.
+"""
+
+
+def login_browser(app, user, args):
+    app = create_app_interactive(instance=args.instance)
+    url = api.get_browser_login_url(app)
+
+    print_out(BROWSER_LOGIN_EXPLANATION)
+
+    print_out("This is the login URL:")
+    print_out(url)
+    print_out("")
+
+    yesno = input("Open link in default browser? [Y/n]")
+    if not yesno or yesno.lower() == 'y':
+        webbrowser.open(url)
+
+    authorization_code = ""
+    while not authorization_code:
+        authorization_code = input("Authorization code: ")
+
+    print_out("\nRequesting access token...")
+    response = api.request_access_token(app, authorization_code)
+
+    # TODO: user email is not available in this workflow, maybe change the User
+    # to store the username instead? Currently set to "unknown" since it's not
+    # used anywhere.
+    email = "unknown"
+
+    create_user(app, email, response['access_token'])
+
+    print_out()
+    print_out("<green>✓ Successfully logged in.</green>")
+
+
 def logout(app, user, args):
     config.delete_user()
 

toot/console.py

@@ -38,26 +38,33 @@ account_arg = (["account"], {
     "help": "account name, e.g. 'Gargron' or 'polymerwitch@toot.cat'",
 })
 
+instance_arg = (["-i", "--instance"], {
+    "type": str,
+    "help": 'mastodon instance to log into e.g. "mastodon.social"',
+})
+
+email_arg = (["-e", "--email"], {
+    "type": str,
+    "help": 'email address to log in with',
+})
+
 
 AUTH_COMMANDS = [
     Command(
         name="login",
-        description="Log into a Mastodon instance",
-        arguments=[
-            (["-i", "--instance"], {
-                "type": str,
-                "help": 'mastodon instance to log into e.g. "mastodon.social"',
-            }),
-            (["-e", "--email"], {
-                "type": str,
-                "help": 'email address to log in with',
-            }),
-        ],
+        description="Log into a Mastodon instance, does NOT support two factor authentication",
+        arguments=[instance_arg, email_arg],
+        require_auth=False,
+    ),
+    Command(
+        name="login_browser",
+        description="Log in using your browser, supports regular and two factor authentication",
+        arguments=[instance_arg, email_arg],
         require_auth=False,
     ),
     Command(
         name="login_2fa",
-        description="Log in using two factor authentication (experimental)",
+        description="Log in using two factor authentication in the console (hacky, experimental)",
         arguments=[],
         require_auth=False,
     ),