API: Add endpoint to expose pretix version

src/pretix/api/urls.py

@@ -7,8 +7,8 @@ from rest_framework import routers
 from pretix.api.views import cart
 
 from .views import (
-    checkin, device, event, item, oauth, order, organizer, user, voucher,
-    waitinglist, webhooks,
+    checkin, device, event, item, oauth, order, organizer, user, version,
+    voucher, waitinglist, webhooks,
 )
 
 router = routers.DefaultRouter()
@@ -83,4 +83,5 @@ urlpatterns = [
     url(r"^device/roll$", device.RollKeyView.as_view(), name="device.roll"),
     url(r"^device/revoke$", device.RevokeKeyView.as_view(), name="device.revoke"),
     url(r"^me$", user.MeView.as_view(), name="user.me"),
+    url(r"^version$", version.VersionView.as_view(), name="version"),
 ]

src/pretix/api/views/version.py

@@ -0,0 +1,56 @@
+from oauth2_provider.contrib.rest_framework import OAuth2Authentication
+from packaging import version
+from rest_framework.authentication import SessionAuthentication
+from rest_framework.response import Response
+from rest_framework.views import APIView
+
+from pretix import __version__
+from pretix.api.auth.device import DeviceTokenAuthentication
+from pretix.api.auth.token import TeamTokenAuthentication
+
+
+def numeric_version(v):
+    # Converts a pretix version to a large int
+    # e.g. 30060001000
+    #      |--------------------- Major version
+    #       |-|------------------ Minor version
+    #          |-|--------------- Patch version
+    #             ||------------- Stage (10 dev, 20 alpha, 30 beta, 40 rc, 50 release, 60 post)
+    #               ||----------- Stage version (number of dev/alpha/beta/rc/post release)
+    v = version.parse(v)
+    phases = {
+        'dev': 10,
+        'a': 20,
+        'b': 30,
+        'rc': 40,
+        'release': 50,
+        'post': 60
+    }
+    vnum = 0
+
+    if v.is_postrelease:
+        vnum += v.post
+        vnum += phases['post'] * 100
+    elif v.dev is not None:
+        vnum += v.dev
+        vnum += phases['dev'] * 100
+    elif v.is_prerelease and v.pre:
+        vnum += v.pre[0]
+        vnum += phases[v.pre[1]] * 100
+    else:
+        vnum += phases['release'] * 100
+    for i, part in enumerate(reversed(v.release)):
+        vnum += part * (1000 ** i) * 10000
+    return vnum
+
+
+class VersionView(APIView):
+    authentication_classes = (
+        SessionAuthentication, OAuth2Authentication, DeviceTokenAuthentication, TeamTokenAuthentication
+    )
+
+    def get(self, request, format=None):
+        return Response({
+            'pretix': __version__,
+            'pretix_numeric': numeric_version(__version__),
+        })