Implement OAuth2 provider

.travis.sh

@@ -39,11 +39,11 @@ if [ "$1" == "translation-spelling" ]; then
 	potypo
 fi
 if [ "$1" == "tests" ]; then
-	pip3 install -r src/requirements.txt -Ur src/requirements/dev.txt -r src/requirements/py34.txt
+	pip3 install -r src/requirements.txt -Ur src/requirements/dev.txt -r src/requirements/py34.txt pytest-xdist
 	cd src
 	python manage.py check
 	make all compress
-	py.test --reruns 5 tests
+	py.test --reruns 5 -n 2 tests
 fi
 if [ "$1" == "tests-cov" ]; then
 	pip3 install -r src/requirements.txt -Ur src/requirements/dev.txt -r src/requirements/py34.txt

.travis.yml

@@ -15,7 +15,7 @@ matrix:
     - python: 3.6
       env: JOB=tests PRETIX_CONFIG_FILE=tests/travis_sqlite.cfg
     - python: 3.6
-      env: JOB=tests-cov
+      env: JOB=tests-cov PRETIX_CONFIG_FILE=tests/travis_postgres.cfg
     - python: 3.6
       env: JOB=style
     - python: 3.4

doc/api/fundamentals.rst

@@ -6,27 +6,13 @@ with pretix' REST API, such as authentication, pagination and similar definition
 
 .. _`rest-auth`:
 
-Obtaining an API token
-----------------------
-
-To authenticate your API requests, you need to obtain an API token. You can create a
-token in the pretix web interface on the level of organizer teams. Create a new team
-or choose an existing team that has the level of permissions the token should have and
-create a new token using the form below the list of team members:
-
-.. image:: img/token_form.png
-   :class: screenshot
-
-You can enter a description for the token to distinguish from other tokens later on.
-Once you click "Add", you will be provided with an API token in the success message.
-Copy this token, as you won't be able to retrieve it again.
-
-.. image:: img/token_success.png
-   :class: screenshot
-
 Authentication
 --------------
 
+If you're building an application for end users, we strongly recommend that you use our
+:ref:`OAuth-based authentication progress <rest-oauth>`. However, for simpler needs, you
+can also go with static API tokens that you can create on a per-team basis (see below).
+
 You need to include the API token with every request to pretix' API in the ``Authorization`` header
 like the following:
 
@@ -44,6 +30,24 @@ like the following:
           adding OAuth2 support in the future for user-level authentication. If you want
           to use session authentication, be sure to comply with Django's `CSRF policies`_.
 
+Obtaining an API token
+----------------------
+
+To authenticate your API requests, you need to obtain an API token. You can create a
+token in the pretix web interface on the level of organizer teams. Create a new team
+or choose an existing team that has the level of permissions the token should have and
+create a new token using the form below the list of team members:
+
+.. image:: img/token_form.png
+    :class: screenshot
+
+You can enter a description for the token to distinguish from other tokens later on.
+Once you click "Add", you will be provided with an API token in the success message.
+Copy this token, as you won't be able to retrieve it again.
+
+.. image:: img/token_success.png
+    :class: screenshot
+
 Permissions
 -----------
 

doc/api/index.rst

@@ -14,4 +14,5 @@ in functionality over time.
    :maxdepth: 2
 
    fundamentals
+   oauth
    resources/index

doc/api/oauth.rst

@@ -0,0 +1,171 @@
+.. _`rest-oauth`:
+
+OAuth support / "Connect with pretix"
+=====================================
+
+In addition to static tokens, pretix supports `OAuth2`_-based authentication starting with
+pretix 1.16. This allows you to put a "Connect with pretix" button into your website or tool
+that allows the user to easily set up a connection between the two systems.
+
+If you haven't worked with OAuth before, have a look at the `OAuth2 Simplified`_ tutorial.
+
+Registering an application
+--------------------------
+
+To use OAuth, you need to register your application with the pretix instance you want to connect to.
+In order to do this, log in to your pretix account and go to your user settings. Click on "Authorized applications"
+first and then on "Manage your own apps". From there, you can "Create a new application".
+
+You should fill in a descriptive name of your application that allows users to recognize who you are. You also need to
+give a list of fully-qualified URLs that users will be redirected to after a successful authorization. After you pressed
+"Save", you will be presented with a client ID and a client secret. Please note them down and treat the client secret
+like a password; it should not become available to your users.
+
+Obtaining an authorization grant
+--------------------------------
+
+To authorize a new user, link or redirect them to the ``authorize`` endpoint, passing your client ID as a query
+parameter. Additionally, you can pass a scope (currently either ``read``, ``write``, or ``read write``)
+and an URL the user should be redirected to after successful or failed authorization. You also need to pass the
+``response_type`` parameter with a value of ``code``. Example::
+
+    https://pretix.eu/api/v1/oauth/authorize?client_id=lsLi0hNL0vk53mEdYjNJxHUn1PcO1R6wVg81dLNT&response_type=code&scope=read+write&redirect_uri=https://pretalx.com
+
+To prevent CSRF attacks, you can also optionally pass a ``state`` parameter with a random string. Later, when
+redirecting back to your application, we will pass the same ``state`` parameter back to you, so you can compare if they
+match.
+
+After the user granted or denied access, they will be redirected back either to the ``redirect_url`` you passed in the
+query or to the first redirect URL configured in your application settings.
+
+On successful registration, we will append the query parameter ``code`` to the URL containing an authorization code.
+For example, we might redirect the user to this URL::
+
+    https://pretalx.com/?code=eYBBf8gmeD4E01HLoj0XflqO4Lg3Cw&state=e3KCh9mfx07qxU4bRpXk
+
+You will need this ``code`` parameter to perform the next step.
+
+On a failed registration, a query string like ``?error=access_denied`` will be appended to the redirection URL.
+
+.. note:: In this step, the user is allowed to restrict your access to certain organizer accounts. If you try to
+          re-authenticate the user later, the user might be instantly redirected back to you if authorization is already
+          given and would therefore be unable to review their organizer restriction settings. You can append the
+          ``approval_prompt=force`` query parameter if you want to make sure the user actively needs to confirm the
+          authorization.
+
+Getting an access token
+-----------------------
+
+Using the ``code`` value you obtained above and your client ID, you can now request an access token that actually gives
+access to the API. The ``token`` endpoint expects you to authenticate using `HTTP Basic authentication`_ using your client
+ID as a username and your client secret as a password. You are also required to again supply the same ``redirect_uri``
+parameter that you used for the authorization.
+
+.. http:get:: /api/v1/oauth/token
+
+   Request a new access token
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /api/v1/oauth/token HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Authorization: Basic bHNMaTBoTkwwdms1M21FZFlqTkp4SFVuMVBjTzFSNndWZzgxZExOVDplSmpzZVA0UjJMN0hMcjBiS0p1b3BmbnJtT2cyY3NDeTdYaFVVZ0FoalhUU0NhZHhRTjk3cVNvMkpPaXlWTFpQOEozaTVQd1FVdFIwNUNycG5ac2Z0bXJjdmNTbkZ1SkFmb2ZsUTdZUDRpSjZNTWFYTHIwQ0FpNlhIRFJjV1Awcg==
+
+      grant_type=authorization_code&code=eYBBf8gmeD4E01HLoj0XflqO4Lg3Cw&redirect_uri=https://pretalx.com
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+      {
+        "access_token": "i3ytqTSRWsKp16fqjekHXa4tdM4qNC",
+        "expires_in": 86400,
+        "token_type": "Bearer",
+        "scope": "read write",
+        "refresh_token": "XBK0r8z4A4TTeR9LyMUyU2AM5rqpXp"
+      }
+
+   :statuscode 200: no error
+   :statuscode 401: Authentication failure
+
+
+As you can see, you receive two types of tokens: One "access token", and one "refresh token". The access token is valid
+for a day and can be used to actually access the API. The refresh token does not have an expiration date and can be used
+to obtain a new access_token after a day, so you should make sure to store the access token safely if you need long-term
+access.
+
+Using the API with an access token
+----------------------------------
+
+You can supply a valid access token as a ``Bearer``-type token in the ``Authorization`` header to get API access.
+
+.. sourcecode:: http
+   :emphasize-lines: 3
+
+       GET /api/v1/organizers/ HTTP/1.1
+       Host: pretix.eu
+       Authorization: Bearer i3ytqTSRWsKp16fqjekHXa4tdM4qNC
+
+Refreshing an access token
+--------------------------
+
+You can obtain a new access token using your refresh token any time. This can be done using the same ``token`` endpoint
+used to obtain the first access token above, but with a different set of parameters:
+
+.. sourcecode:: http
+
+  POST /api/v1/oauth/token HTTP/1.1
+  Host: pretix.eu
+  Accept: application/json, text/javascript
+  Authorization: Basic bHNMaTBoTkwwdms1M21FZFlqTkp4SFVuMVBjTzFSNndWZzgxZExOVDplSmpzZVA0UjJMN0hMcjBiS0p1b3BmbnJtT2cyY3NDeTdYaFVVZ0FoalhUU0NhZHhRTjk3cVNvMkpPaXlWTFpQOEozaTVQd1FVdFIwNUNycG5ac2Z0bXJjdmNTbkZ1SkFmb2ZsUTdZUDRpSjZNTWFYTHIwQ0FpNlhIRFJjV1Awcg==
+
+  grant_type=refresh_token&refresh_token=XBK0r8z4A4TTeR9LyMUyU2AM5rqpXp
+
+The previous access token will instantly become invalid.
+
+Revoking a token
+----------------
+
+If you don't need a token any more or if you believe it may have been compromised, you can use the ``revoke_token``
+endpoint to revoke it.
+
+.. http:get:: /api/v1/oauth/revoke_token
+
+   Revoke an access or refresh token. If you revoke an access token, you can still create a new one using the refresh token. If you
+   revoke a refresh token, the connected access token  will also be revoked.
+
+   **Example request**:
+
+   .. sourcecode:: http
+
+      POST /api/v1/oauth/revoke_token HTTP/1.1
+      Host: pretix.eu
+      Accept: application/json, text/javascript
+      Authorization: Basic bHNMaTBoTkwwdms1M21FZFlqTkp4SFVuMVBjTzFSNndWZzgxZExOVDplSmpzZVA0UjJMN0hMcjBiS0p1b3BmbnJtT2cyY3NDeTdYaFVVZ0FoalhUU0NhZHhRTjk3cVNvMkpPaXlWTFpQOEozaTVQd1FVdFIwNUNycG5ac2Z0bXJjdmNTbkZ1SkFmb2ZsUTdZUDRpSjZNTWFYTHIwQ0FpNlhIRFJjV1Awcg==
+
+      token=XBK0r8z4A4TTeR9LyMUyU2AM5rqpXp
+
+   **Example response**:
+
+   .. sourcecode:: http
+
+      HTTP/1.1 200 OK
+      Vary: Accept
+      Content-Type: application/json
+
+   :statuscode 200: no error
+   :statuscode 401: Authentication failure
+
+If you want to revoke your client secret, you can generate a new one in the list of your managed applications in the
+pretix user interface.
+
+.. _OAuth2: https://en.wikipedia.org/wiki/OAuth
+.. _OAuth2 Simplified: https://aaronparecki.com/oauth-2-simplified/
+.. _HTTP Basic authentication: https://en.wikipedia.org/wiki/Basic_access_authentication

src/pretix/api/__init__.py

@@ -0,0 +1,9 @@
+from django.apps import AppConfig
+
+
+class PretixApiConfig(AppConfig):
+    name = 'pretix.api'
+    label = 'pretixapi'
+
+
+default_app_config = 'pretix.api.PretixApiConfig'

src/pretix/api/auth/permission.py

@@ -1,5 +1,6 @@
 from rest_framework.permissions import SAFE_METHODS, BasePermission
 
+from pretix.api.models import OAuthAccessToken
 from pretix.base.models import Event
 from pretix.base.models.organizer import Organizer, TeamAPIToken
 from pretix.helpers.security import (
@@ -55,6 +56,15 @@ def has_permission(self, request, view):
 
             if required_permission and required_permission not in request.orgapermset:
                 return False
+
+        if isinstance(request.auth, OAuthAccessToken):
+            if not request.auth.allow_scopes(['write']) and request.method not in SAFE_METHODS:
+                return False
+            if not request.auth.allow_scopes(['read']) and request.method in SAFE_METHODS:
+                return False
+        if isinstance(request.auth, OAuthAccessToken) and hasattr(request, 'organizer'):
+            if not request.auth.organizers.filter(pk=request.organizer.pk).exists():
+                return False
         return True