QR code handling (boostorg#1896)

Author: gregjkal

config/urls.py

@@ -33,6 +33,7 @@
     UserGuideTemplateView,
     BoostDevelopmentView,
     ModernizedDocsView,
+    QRCodeView,
 )
 from libraries.api import LibrarySearchView
 from libraries.views import (
@@ -116,6 +117,14 @@
         path("feed/news.rss", RSSNewsFeed(), name="news_feed_rss"),
         path("feed/news.atom", AtomNewsFeed(), name="news_feed_atom"),
         path("LICENSE_1_0.txt", BSLView, name="license"),
+        path(
+            "qrc/<str:campaign_identifier>/", QRCodeView.as_view(), name="qr_code_root"
+        ),  # just in case
+        path(
+            "qrc/<str:campaign_identifier>/<path:main_path>",
+            QRCodeView.as_view(),
+            name="qr_code",
+        ),
         path(
             "accounts/social/signup/",
             CustomSocialSignupViewView.as_view(),

core/tests/test_views.py

@@ -1,3 +1,4 @@
+import logging
 from unittest.mock import patch
 
 import pytest
@@ -268,3 +269,53 @@ def test_docs_libs_gateway_200_html_transformed(rf, tp, mock_get_file_data):
 def test_calendar(rf, tp):
     response = tp.get("calendar")
     tp.response_200(response)
+
+
+def test_qrc_redirect_and_plausible_payload(tp):
+    """XFF present; querystring preserved; payload/headers correct."""
+    with patch("core.views.requests.post", return_value=None) as post_mock:
+        url = "/qrc/pv-01/library/latest/beast/?x=1&y=2"
+        res = tp.get(url)
+
+    tp.response_302(res)
+    assert res["Location"] == "/library/latest/beast/?x=1&y=2"
+
+    # Plausible call
+    (endpoint,), kwargs = post_mock.call_args
+    assert endpoint == "https://plausible.io/api/event"
+
+    # View uses request.path, so no querystring in payload URL
+    assert kwargs["json"] == {
+        "name": "pageview",
+        "domain": "qrc.boost.org",
+        "url": "http://testserver/qrc/pv-01/library/latest/beast/",
+        "referrer": "",  # matches view behavior with no forwarded referer
+    }
+
+    headers = kwargs["headers"]
+    assert headers["Content-Type"] == "application/json"
+    assert kwargs["timeout"] == 2.0
+
+
+def test_qrc_falls_back_to_remote_addr_when_no_xff(tp):
+    """No XFF provided -> uses REMOTE_ADDR (127.0.0.1 in Django test client)."""
+    with patch("core.views.requests.post", return_value=None) as post_mock:
+        res = tp.get("/qrc/camp/library/latest/algorithm/")
+
+    tp.response_302(res)
+    assert res["Location"] == "/library/latest/algorithm/"
+
+    (_, kwargs) = post_mock.call_args
+    headers = kwargs["headers"]
+    assert headers["X-Forwarded-For"] == "127.0.0.1"  # Django test client default
+
+
+def test_qrc_logs_plausible_error_but_still_redirects(tp, caplog):
+    """Plausible post raises -> error logged; redirect not interrupted."""
+    with patch("core.views.requests.post", side_effect=RuntimeError("boom")):
+        with caplog.at_level(logging.ERROR, logger="core.views"):
+            res = tp.get("/qrc/c1/library/", HTTP_USER_AGENT="ua")
+
+    tp.response_302(res)
+    assert res["Location"] == "/library/"
+    assert any("Plausible event post failed" in r.message for r in caplog.records)

core/views.py

@@ -2,6 +2,7 @@
 import re
 from urllib.parse import urljoin
 
+import requests
 import structlog
 from bs4 import BeautifulSoup
 from dateutil.parser import parse
@@ -13,11 +14,14 @@
     HttpResponse,
     HttpResponseNotFound,
     HttpResponseRedirect,
+    HttpRequest,
 )
 from django.shortcuts import redirect
 from django.template.loader import render_to_string
 from django.urls import reverse
+from django.utils.decorators import method_decorator
 from django.views import View
+from django.views.decorators.cache import never_cache
 from django.views.generic import TemplateView
 from requests.compat import chardet
 
@@ -898,3 +902,57 @@ def get(self, request, requested_version):
         if requested_version == "release":
             new_path = "/libraries/"
         return HttpResponseRedirect(new_path)
+
+
+@method_decorator(never_cache, name="dispatch")
+class QRCodeView(View):
+    """Handles QR code urls, sending them to Plausible, then redirecting to the desired url.
+
+    QR code urls are formatted /qrc/<campaign_identifier>/desired/path/to/content/, and will
+    result in a redirect to /desired/path/to/content/.
+
+    E.g. https://www.boost.org/qrc/pv-01/library/latest/beast/ will send this full url to Plausible,
+    then redirect to https://www.boost.org/library/latest/beast/
+    """
+
+    def get(self, request: HttpRequest, campaign_identifier: str, main_path: str = ""):
+        absolute_url = request.build_absolute_uri(request.path)
+        referrer = request.META.get("HTTP_REFERER", "")
+        user_agent = request.META.get("HTTP_USER_AGENT", "")
+
+        plausible_payload = {
+            "name": "pageview",
+            "domain": "qrc.boost.org",
+            "url": absolute_url,
+            "referrer": referrer,
+        }
+
+        headers = {"Content-Type": "application/json", "User-Agent": user_agent}
+
+        client_ip = request.META.get("HTTP_X_FORWARDED_FOR", "").split(",")[0].strip()
+        client_ip = client_ip or request.META.get("REMOTE_ADDR")
+
+        if client_ip:
+            headers["X-Forwarded-For"] = client_ip
+
+        try:
+            requests.post(
+                "https://plausible.io/api/event",
+                json=plausible_payload,
+                headers=headers,
+                timeout=2.0,
+            )
+        except Exception as e:
+            # Don’t interrupt the redirect - just log it
+            logger.error(f"Plausible event post failed: {e}")
+
+        # Now that we've sent the request url to plausible, we can redirect to the main_path
+        # Preserve the original querystring, if any.
+        # Example: /qrc/3/library/latest/algorithm/?x=1  ->  /library/latest/algorithm/?x=1
+        # `main_path` is everything after qrc/<campaign>/ thanks to <path:main_path>.
+        redirect_path = "/" + main_path if main_path else "/"
+        qs = request.META.get("QUERY_STRING")
+        if qs:
+            redirect_path = f"{redirect_path}?{qs}"
+
+        return HttpResponseRedirect(redirect_path)