Merge branch 'browse-pagination'

9 files changed, 235 insertions, 42 deletions

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index a88eb05..1df3995 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -17,6 +17,7 @@ Changed
 - There is now a proper 404 (Not Found) page.
 - There is now a proper 403 (Forbidden) page.
 - The heat map is now preselected on the profile page.
+- The browse page now paginates its results.
 
 Fixed
 ^^^^^
diff --git a/fietsboek/locale/de/LC_MESSAGES/messages.mo b/fietsboek/locale/de/LC_MESSAGES/messages.mo
index 5ddd7f3..6526f6f 100644
--- a/fietsboek/locale/de/LC_MESSAGES/messages.mo
+++ b/fietsboek/locale/de/LC_MESSAGES/messages.mo
diff --git a/fietsboek/locale/de/LC_MESSAGES/messages.po b/fietsboek/locale/de/LC_MESSAGES/messages.po
index 6736e5a..f306a46 100644
--- a/fietsboek/locale/de/LC_MESSAGES/messages.po
+++ b/fietsboek/locale/de/LC_MESSAGES/messages.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2025-05-10 23:36+0200\n"
+"POT-Creation-Date: 2025-06-12 22:39+0200\n"
 "PO-Revision-Date: 2022-07-02 17:35+0200\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: de\n"
@@ -16,7 +16,7 @@ msgstr ""
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=utf-8\n"
 "Content-Transfer-Encoding: 8bit\n"
-"Generated-By: Babel 2.15.0\n"
+"Generated-By: Babel 2.17.0\n"
 
 #: fietsboek/actions.py:278
 msgid "email.verify_mail.subject"
@@ -37,35 +37,35 @@ msgstr "Passwörter stimmen nicht überein"
 msgid "password_constraint.length"
 msgstr "Passwort zu kurz"
 
-#: fietsboek/models/track.py:603
+#: fietsboek/models/track.py:622
 msgid "tooltip.table.length"
 msgstr "Länge"
 
-#: fietsboek/models/track.py:604
+#: fietsboek/models/track.py:623
 msgid "tooltip.table.people"
 msgstr "# Personen"
 
-#: fietsboek/models/track.py:605
+#: fietsboek/models/track.py:624
 msgid "tooltip.table.uphill"
 msgstr "Bergauf"
 
-#: fietsboek/models/track.py:606
+#: fietsboek/models/track.py:625
 msgid "tooltip.table.downhill"
 msgstr "Bergab"
 
-#: fietsboek/models/track.py:607 fietsboek/templates/home.jinja2:7
+#: fietsboek/models/track.py:626 fietsboek/templates/home.jinja2:7
 msgid "tooltip.table.moving_time"
 msgstr "Fahrzeit"
 
-#: fietsboek/models/track.py:608 fietsboek/templates/home.jinja2:8
+#: fietsboek/models/track.py:627 fietsboek/templates/home.jinja2:8
 msgid "tooltip.table.stopped_time"
 msgstr "Haltezeit"
 
-#: fietsboek/models/track.py:610
+#: fietsboek/models/track.py:629
 msgid "tooltip.table.max_speed"
 msgstr "Maximalgeschwindigkeit"
 
-#: fietsboek/models/track.py:614
+#: fietsboek/models/track.py:633
 msgid "tooltip.table.avg_speed"
 msgstr "Durchschnittsgeschwindigkeit"
 
@@ -353,11 +353,19 @@ msgstr "Bilder"
 msgid "page.browse.download_multiple"
 msgstr "ausgewählte Herunterladen"
 
-#: fietsboek/templates/browse.jinja2:218
+#: fietsboek/templates/browse.jinja2:222 fietsboek/templates/browse.jinja2:226
+msgid "pagination.previous"
+msgstr "Vorherige"
+
+#: fietsboek/templates/browse.jinja2:231 fietsboek/templates/browse.jinja2:235
+msgid "pagination.next"
+msgstr "Nächste"
+
+#: fietsboek/templates/browse.jinja2:242
 msgid "page.browse.no_results"
 msgstr "Es wurden keine Strecken gefunden, die den Filtern entsprechen."
 
-#: fietsboek/templates/browse.jinja2:220
+#: fietsboek/templates/browse.jinja2:244
 msgid "page.browse.no_tracks"
 msgstr ""
 "Es wurden keine Strecken gefunden, auf die Du Zugriff hast. Versuche, "
diff --git a/fietsboek/locale/en/LC_MESSAGES/messages.mo b/fietsboek/locale/en/LC_MESSAGES/messages.mo
index 00a8b9c..18f473c 100644
--- a/fietsboek/locale/en/LC_MESSAGES/messages.mo
+++ b/fietsboek/locale/en/LC_MESSAGES/messages.mo
diff --git a/fietsboek/locale/en/LC_MESSAGES/messages.po b/fietsboek/locale/en/LC_MESSAGES/messages.po
index f2f7583..89e183d 100644
--- a/fietsboek/locale/en/LC_MESSAGES/messages.po
+++ b/fietsboek/locale/en/LC_MESSAGES/messages.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2025-05-10 23:36+0200\n"
+"POT-Creation-Date: 2025-06-12 22:39+0200\n"
 "PO-Revision-Date: 2023-04-03 20:42+0200\n"
 "Last-Translator: \n"
 "Language: en\n"
@@ -16,7 +16,7 @@ msgstr ""
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=utf-8\n"
 "Content-Transfer-Encoding: 8bit\n"
-"Generated-By: Babel 2.15.0\n"
+"Generated-By: Babel 2.17.0\n"
 
 #: fietsboek/actions.py:278
 msgid "email.verify_mail.subject"
@@ -37,35 +37,35 @@ msgstr "Passwords don't match"
 msgid "password_constraint.length"
 msgstr "Password not long enough"
 
-#: fietsboek/models/track.py:603
+#: fietsboek/models/track.py:622
 msgid "tooltip.table.length"
 msgstr "Length"
 
-#: fietsboek/models/track.py:604
+#: fietsboek/models/track.py:623
 msgid "tooltip.table.people"
 msgstr "# People"
 
-#: fietsboek/models/track.py:605
+#: fietsboek/models/track.py:624
 msgid "tooltip.table.uphill"
 msgstr "Uphill"
 
-#: fietsboek/models/track.py:606
+#: fietsboek/models/track.py:625
 msgid "tooltip.table.downhill"
 msgstr "Downhill"
 
-#: fietsboek/models/track.py:607 fietsboek/templates/home.jinja2:7
+#: fietsboek/models/track.py:626 fietsboek/templates/home.jinja2:7
 msgid "tooltip.table.moving_time"
 msgstr "Moving Time"
 
-#: fietsboek/models/track.py:608 fietsboek/templates/home.jinja2:8
+#: fietsboek/models/track.py:627 fietsboek/templates/home.jinja2:8
 msgid "tooltip.table.stopped_time"
 msgstr "Stopped Time"
 
-#: fietsboek/models/track.py:610
+#: fietsboek/models/track.py:629
 msgid "tooltip.table.max_speed"
 msgstr "Max Speed"
 
-#: fietsboek/models/track.py:614
+#: fietsboek/models/track.py:633
 msgid "tooltip.table.avg_speed"
 msgstr "Average Speed"
 
@@ -353,11 +353,19 @@ msgstr "Images"
 msgid "page.browse.download_multiple"
 msgstr "Download selected"
 
-#: fietsboek/templates/browse.jinja2:218
+#: fietsboek/templates/browse.jinja2:222 fietsboek/templates/browse.jinja2:226
+msgid "pagination.previous"
+msgstr "Previous"
+
+#: fietsboek/templates/browse.jinja2:231 fietsboek/templates/browse.jinja2:235
+msgid "pagination.next"
+msgstr "Next"
+
+#: fietsboek/templates/browse.jinja2:242
 msgid "page.browse.no_results"
 msgstr "No results matching the filters were found."
 
-#: fietsboek/templates/browse.jinja2:220
+#: fietsboek/templates/browse.jinja2:244
 msgid "page.browse.no_tracks"
 msgstr "You currently do not have access to any tracks. Try logging in."
 
diff --git a/fietsboek/locale/fietslog.pot b/fietsboek/locale/fietslog.pot
index 02fdb37..6383760 100644
--- a/fietsboek/locale/fietslog.pot
+++ b/fietsboek/locale/fietslog.pot
@@ -8,14 +8,14 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PROJECT VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2025-05-10 23:36+0200\n"
+"POT-Creation-Date: 2025-06-12 22:39+0200\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
 "MIME-Version: 1.0\n"
 "Content-Type: text/plain; charset=utf-8\n"
 "Content-Transfer-Encoding: 8bit\n"
-"Generated-By: Babel 2.15.0\n"
+"Generated-By: Babel 2.17.0\n"
 
 #: fietsboek/actions.py:278
 msgid "email.verify_mail.subject"
@@ -33,35 +33,35 @@ msgstr ""
 msgid "password_constraint.length"
 msgstr ""
 
-#: fietsboek/models/track.py:603
+#: fietsboek/models/track.py:622
 msgid "tooltip.table.length"
 msgstr ""
 
-#: fietsboek/models/track.py:604
+#: fietsboek/models/track.py:623
 msgid "tooltip.table.people"
 msgstr ""
 
-#: fietsboek/models/track.py:605
+#: fietsboek/models/track.py:624
 msgid "tooltip.table.uphill"
 msgstr ""
 
-#: fietsboek/models/track.py:606
+#: fietsboek/models/track.py:625
 msgid "tooltip.table.downhill"
 msgstr ""
 
-#: fietsboek/models/track.py:607 fietsboek/templates/home.jinja2:7
+#: fietsboek/models/track.py:626 fietsboek/templates/home.jinja2:7
 msgid "tooltip.table.moving_time"
 msgstr ""
 
-#: fietsboek/models/track.py:608 fietsboek/templates/home.jinja2:8
+#: fietsboek/models/track.py:627 fietsboek/templates/home.jinja2:8
 msgid "tooltip.table.stopped_time"
 msgstr ""
 
-#: fietsboek/models/track.py:610
+#: fietsboek/models/track.py:629
 msgid "tooltip.table.max_speed"
 msgstr ""
 
-#: fietsboek/models/track.py:614
+#: fietsboek/models/track.py:633
 msgid "tooltip.table.avg_speed"
 msgstr ""
 
@@ -347,11 +347,19 @@ msgstr ""
 msgid "page.browse.download_multiple"
 msgstr ""
 
-#: fietsboek/templates/browse.jinja2:218
+#: fietsboek/templates/browse.jinja2:222 fietsboek/templates/browse.jinja2:226
+msgid "pagination.previous"
+msgstr ""
+
+#: fietsboek/templates/browse.jinja2:231 fietsboek/templates/browse.jinja2:235
+msgid "pagination.next"
+msgstr ""
+
+#: fietsboek/templates/browse.jinja2:242
 msgid "page.browse.no_results"
 msgstr ""
 
-#: fietsboek/templates/browse.jinja2:220
+#: fietsboek/templates/browse.jinja2:244
 msgid "page.browse.no_tracks"
 msgstr ""
 
diff --git a/fietsboek/templates/browse.jinja2 b/fietsboek/templates/browse.jinja2
index 6723d19..28693f6 100644
--- a/fietsboek/templates/browse.jinja2
+++ b/fietsboek/templates/browse.jinja2
@@ -214,6 +214,30 @@
   </div>
   {% endfor %}
   <button type="button" class="btn btn-primary ui-element" id="archiveDownloadButton" disabled><i class="bi bi-file-earmark-zip"></i> {{ _("page.browse.download_multiple") }}</button>
+
+  <nav aria-label="Page navigation">
+    <ul class="pagination justify-content-center">
+      {% if page_previous is none %}
+      <li class="page-item disabled">
+        <span class="page-link">{{ _("pagination.previous") }}</span>
+      </li>
+      {% else %}
+      <li class="page-item">
+        <a class="page-link" href="{{ page_previous | safe }}">{{ _("pagination.previous") }}</a>
+      </li>
+      {% endif %}
+      {% if page_next is none %}
+      <li class="page-item disabled">
+        <span class="page-link">{{ _("pagination.next") }}</span>
+      </li>
+      {% else %}
+      <li class="page-item">
+        <a class="page-link" href="{{ page_next | safe }}">{{ _("pagination.next") }}</a>
+      </li>
+      {% endif %}
+    </ul>
+  </nav>
+
   {% elif used_filters %}
   <p>{{ _("page.browse.no_results") }}</p>
   {% else %}
diff --git a/fietsboek/views/browse.py b/fietsboek/views/browse.py
index 97bee35..e8e3edf 100644
--- a/fietsboek/views/browse.py
+++ b/fietsboek/views/browse.py
@@ -1,10 +1,11 @@
 """Views for browsing all tracks."""
 
 import datetime
+import urllib.parse
 from collections.abc import Callable, Iterable
 from enum import Enum
 from io import RawIOBase
-from typing import TypeVar
+from typing import Iterator, TypeVar
 from zipfile import ZIP_DEFLATED, ZipFile
 
 from pyramid.httpexceptions import HTTPBadRequest, HTTPForbidden, HTTPNotFound
@@ -12,12 +13,14 @@ from pyramid.request import Request
 from pyramid.response import Response
 from pyramid.view import view_config
 from sqlalchemy import func, not_, or_, select
-from sqlalchemy.orm import aliased
+from sqlalchemy.orm import Session, aliased
 from sqlalchemy.sql import Select
 
 from .. import models, util
+from ..data import DataManager
 from ..models.track import TrackType, TrackWithMetadata
 
+TRACKS_PER_PAGE = 20
 T = TypeVar("T", bound=Enum)
 
 AliasedTrack = type[models.Track]
@@ -69,6 +72,14 @@ def _get_enum(enum: type[T], value: str) -> T:
         raise HTTPBadRequest(f"Invalid enum value {value!r}") from exc
 
 
+def _with_page(url: str, num: int) -> str:
+    parsed = urllib.parse.urlparse(url)
+    query = urllib.parse.parse_qs(parsed.query)
+    query["page"] = [str(num)]
+    new_qs = urllib.parse.urlencode(query, doseq=True)
+    return urllib.parse.urlunparse(parsed._replace(query=new_qs))
+
+
 class ResultOrder(Enum):
     """Enum representing the different ways in which the tracks can be sorted
     in the result."""
@@ -415,6 +426,49 @@ def apply_order(query: Select, track: AliasedTrack, order: ResultOrder) -> Selec
     return query
 
 
+def paginate(
+    dbsession: Session,
+    data_manager: DataManager,
+    query: Select,
+    filters: Filter,
+    start: int,
+    num: int,
+) -> Iterator[TrackWithMetadata]:
+    """Paginates a query.
+
+    Unlike a simple OFFSET/LIMIT solution, this generator will request more
+    elements if the filters end up throwing tracks out.
+
+    :param dbsession: The current database session.
+    :param data_manager: The current data manager.
+    :param query: The (filtered and ordered) query.
+    :param filters: The filters to apply after retrieving elements from the
+        database.
+    :param track: The aliased ``Track`` class.
+    :param start: The offset from which to start the pagination.
+    :param num: How many items to retrieve at maximum.
+    :return: An iterable over ``num`` tracks (or fewer).
+    """
+    # pylint: disable=too-many-arguments,too-many-positional-arguments
+    num_retrieved = 0
+    offset = start
+    while num_retrieved < num:
+        # Best to try and get all at once
+        num_query = num - num_retrieved
+        this_query = query.offset(offset).limit(num_query)
+        offset += num_query
+
+        tracks = list(dbsession.execute(this_query).scalars())
+        if not tracks:
+            break
+
+        for track in tracks:
+            track = TrackWithMetadata(track, data_manager)
+            if filters.apply(track):
+                num_retrieved += 1
+                yield track
+
+
 @view_config(
     route_name="browse", renderer="fietsboek:templates/browse.jinja2", request_method="GET"
 )
@@ -431,18 +485,34 @@ def browse(request: Request) -> Response:
     query = select(track).join(models.TrackCache, isouter=True)
     query = filters.compile(query, track)
 
+    if "page" in request.params:
+        page = _get_int(request, "page")
+    else:
+        page = 1
+
     order = ResultOrder.DATE_DESC
     if request.params.get("sort"):
         order = _get_enum(ResultOrder, request.params.get("sort"))
     query = apply_order(query, track, order)
 
-    tracks = request.dbsession.execute(query).scalars()
-    tracks = (TrackWithMetadata(track, request.data_manager) for track in tracks)
-    tracks = [track for track in tracks if filters.apply(track)]
+    tracks = list(
+        paginate(
+            request.dbsession,
+            request.data_manager,
+            query,
+            filters,
+            (page - 1) * TRACKS_PER_PAGE,
+            # We request one more so we can tell easily if there is a next page
+            TRACKS_PER_PAGE + 1,
+        )
+    )
+
     return {
-        "tracks": tracks,
+        "tracks": tracks[:TRACKS_PER_PAGE],
         "mps_to_kph": util.mps_to_kph,
         "used_filters": bool(filters),
+        "page_previous": None if page == 1 else _with_page(request.url, page - 1),
+        "page_next": None if len(tracks) <= TRACKS_PER_PAGE else _with_page(request.url, page + 1),
     }
 
 
diff --git a/tests/integration/test_browse.py b/tests/integration/test_browse.py
index 46ec329..83218cc 100644
--- a/tests/integration/test_browse.py
+++ b/tests/integration/test_browse.py
@@ -70,6 +70,55 @@ def added_tracks(tm, dbsession, owner, data_manager):
         tm.doom()
 
 
+@contextmanager
+def a_lot_of_tracks(tm, dbsession, owner, data_manager):
+    """Adds some tracks to the database session.
+
+    This function should be used as a context manager and it ensures that the
+    added tracks are deleted again after the test, to make a clean slate for
+    the next test.
+    """
+    # The normal transaction is "doomed", so we need to abort it, start a fresh
+    # one, and then explicitely commit it, otherwise we will not persist the
+    # objects to the database.
+    tm.abort()
+
+    gpx_data = load_gpx_asset("MyTourbook_1.gpx.gz")
+
+    tracks = []
+    track_ids = []
+    with tm:
+        for index in range(50):
+            track = models.Track(
+                owner=owner,
+                title=f"Traxi {index}",
+                visibility=Visibility.PUBLIC,
+                description="One of many",
+                badges=[],
+                link_secret="foobar",
+                tagged_people=[],
+            )
+            track.date = datetime(2022 - index, 3, 14, 9, 26, 59)
+            dbsession.add(track)
+            dbsession.flush()
+            data_manager.initialize(track.id).compress_gpx(gpx_data)
+            tracks.append(track)
+            track_ids.append(track.id)
+
+    tm.begin()
+    tm.doom()
+
+    try:
+        yield track_ids
+    finally:
+        tm.abort()
+        with tm:
+            for track in tracks:
+                dbsession.delete(track)
+        tm.begin()
+        tm.doom()
+
+
 def test_browse(testapp, dbsession, route_path, logged_in, tm, data_manager):
     # pylint: disable=too-many-positional-arguments
     # Ensure there are some tracks in the database
@@ -81,6 +130,31 @@ def test_browse(testapp, dbsession, route_path, logged_in, tm, data_manager):
         assert "Barfoo" in browse.text
 
 
+def test_browse_paged(testapp, dbsession, route_path, logged_in, tm, data_manager):
+    # pylint: disable=too-many-positional-arguments
+    with a_lot_of_tracks(tm, dbsession, logged_in, data_manager):
+        page_1 = testapp.get(route_path("browse", _query=[("page", 1)]))
+        assert "Traxi 0" in page_1.text
+        assert "Traxi 10" in page_1.text
+        assert "Traxi 20" not in page_1.text
+        assert "Traxi 30" not in page_1.text
+        assert "Traxi 40" not in page_1.text
+
+        page_2 = testapp.get(route_path("browse", _query=[("page", 2)]))
+        assert "Traxi 0" not in page_2.text
+        assert "Traxi 10" not in page_2.text
+        assert "Traxi 20" in page_2.text
+        assert "Traxi 30" in page_2.text
+        assert "Traxi 40" not in page_2.text
+
+        page_3 = testapp.get(route_path("browse", _query=[("page", 3)]))
+        assert "Traxi 0" not in page_3.text
+        assert "Traxi 10" not in page_3.text
+        assert "Traxi 20" not in page_3.text
+        assert "Traxi 30" not in page_3.text
+        assert "Traxi 40" in page_3.text
+
+
 def test_archive(testapp, dbsession, route_path, logged_in, tm, data_manager):
     # pylint: disable=too-many-positional-arguments
     with added_tracks(tm, dbsession, logged_in, data_manager) as tracks: