From b9bbeafafb1f0750e4adaf12462b86094a5cad25 Mon Sep 17 00:00:00 2001
From: Daniel Schadt <kingdread@gmx.de>
Date: Sat, 16 Jul 2022 23:54:06 +0200
Subject: actually implement the multi download button

---
 fietsboek/static/fietsboek.js     | 20 ++++++++++++++++++++
 fietsboek/templates/browse.jinja2 |  6 ++++--
 fietsboek/views/browse.py         | 33 +++++++++++++++++++++++----------
 3 files changed, 47 insertions(+), 12 deletions(-)

diff --git a/fietsboek/static/fietsboek.js b/fietsboek/static/fietsboek.js
index dd5b9bf..d27e21e 100644
--- a/fietsboek/static/fietsboek.js
+++ b/fietsboek/static/fietsboek.js
@@ -130,4 +130,24 @@ document.addEventListener('DOMContentLoaded', function(event) {
     }, false)
   })
 
+  /* Enable the "Download archive" button */
+  var button = $("#archiveDownloadButton");
+  if (button) {
+    button.addEventListener('click', () => {
+      let checked = document.querySelectorAll(".archive-checkbox:checked");
+      let url = new URL("/track/archive", window.location);
+      checked.forEach((c) => {
+        url.searchParams.append("track_id[]", c.value);
+      });
+      window.location.assign(url);
+    });
+  }
+
+  /* Enable checkbox listeners */
+  document.querySelectorAll(".archive-checkbox").forEach((c) => {
+    c.addEventListener("change", () => {
+      let checked = document.querySelectorAll(".archive-checkbox:checked");
+      $("#archiveDownloadButton").disabled = (checked.length == 0);
+    });
+  });
 });
diff --git a/fietsboek/templates/browse.jinja2 b/fietsboek/templates/browse.jinja2
index 1f61bc6..2732984 100644
--- a/fietsboek/templates/browse.jinja2
+++ b/fietsboek/templates/browse.jinja2
@@ -2,10 +2,11 @@
 {% block content %}
 <div class="container">
   <h1>{{ _("page.browse.title") }}</h1>
+  {% if tracks %}
   {% for track in tracks %}
   <div class="card mb-3">
     <h5 class="card-header">
-      <input type="checkbox" class="form-check-input" name="track_id[]" value="{{ track.id }}">
+      <input type="checkbox" class="form-check-input archive-checkbox" name="track_id[]" value="{{ track.id }}">
       <a href="{{ request.route_url('details', track_id=track.id) }}">{{ track.title | default(track.date, true) }}</a>
       {% if track.text_tags() %}
       {% for tag in track.tags %}<span class="badge bg-info text-dark">{{ tag.tag }}</span> {% endfor %}
@@ -56,7 +57,8 @@
     </div>
   </div>
   {% endfor %}
-  {% if not tracks %}
+  <button type="button" class="btn btn-primary" id="archiveDownloadButton" disabled><i class="bi bi-file-earmark-zip"></i> {{ _("page.browse.download_multiple") }}</button>
+  {% else %}
   <p>{{ _("page.browse.no_tracks") }}</p>
   {% endif %}
 </div>
diff --git a/fietsboek/views/browse.py b/fietsboek/views/browse.py
index 24cf082..490c0cf 100644
--- a/fietsboek/views/browse.py
+++ b/fietsboek/views/browse.py
@@ -1,5 +1,6 @@
 """Views for browsing all tracks."""
-from zipfile import ZipFile
+from io import RawIOBase
+from zipfile import ZipFile, ZIP_DEFLATED
 
 from pyramid.view import view_config
 from pyramid.httpexceptions import HTTPForbidden
@@ -10,12 +11,20 @@ from sqlalchemy import select
 from .. import models, util
 
 
-class Stream:
+class Stream(RawIOBase):
+    """A :class:`Stream` represents an in-memory buffered FIFO.
+
+    This is useful for the zipfile module, as it needs a file-like object, but
+    we do not want to create an actual temporary file.
+    """
+
     def __init__(self):
+        super().__init__()
         self.buffer = []
 
     def write(self, b):
         self.buffer.append(b)
+        return len(b)
 
     def readall(self):
         buf = self.buffer
@@ -71,10 +80,11 @@ def archive(request):
     :return: The HTTP response.
     :rtype: pyramid.response.Response
     """
-    from pprint import pformat
+    # We need to create a separate session, otherwise we will get detached instances
+    session = request.registry['dbsession_factory']()
 
     track_ids = set(map(int, request.params.getall("track_id[]")))
-    tracks = request.dbsession.execute(
+    tracks = session.execute(
         select(models.Track).filter(models.Track.id.in_(track_ids))).scalars().fetchall()
 
     for track in tracks:
@@ -82,12 +92,15 @@ def archive(request):
             return HTTPForbidden()
 
     def generate():
-        stream = Stream()
-        with ZipFile(stream, "w") as zipfile:
-            for track in tracks:
-                zipfile.writestr(f"track_{track.id}.gpx", track.gpx_data)
-                yield sream.readall()
-        yield stream.readall()
+        try:
+            stream = Stream()
+            with ZipFile(stream, "w", ZIP_DEFLATED) as zipfile:
+                for track in tracks:
+                    zipfile.writestr(f"track_{track.id}.gpx", track.gpx_data)
+                    yield stream.readall()
+            yield stream.readall()
+        finally:
+            session.close()
 
     return Response(
         app_iter=generate(),
-- 
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