very dodgy prototype

README.md

@@ -4,6 +4,8 @@ An app that uses the [`temp-index`](https://pypi.org/project/temp-index/) python
 
 ## deploy it
 
+[Install `pdfcpu`](https://github.com/pdfcpu/pdfcpu/releases) to `/usr/bin/pdfcpu`.
+
 ```
 sudo apt-get install libtiff5-dev libjpeg-dev libopenjp2-7-dev zlib1g-dev \
 libfreetype6-dev liblcms2-dev libwebp-dev tcl8.6-dev tk8.6-dev python3-tk \

app.py

@@ -1,6 +1,8 @@
 import os
 import random
+import shutil
 import string
+import subprocess
 from pathlib import Path
 
 import petname
@@ -56,6 +58,15 @@ class UploadForm(FlaskForm):
     petname = HiddenField("petname")
 
 
+def impose_cards(fpath):
+    """Impose the cards with pdfcpu."""
+    if shutil.which("pdfcpu"):
+        old_fpath = "{}.old.pdf".format(fpath)
+        shutil.move(fpath, old_fpath)
+        cmd = 'pdfcpu booklet -- "p:A4, border:on" {} 4 {}'.format(fpath, old_fpath)
+        subprocess.run(cmd, shell=True)
+
+
 @app.route("/")
 def home():
     upload_form = UploadForm()
@@ -120,6 +131,8 @@ def upload():
             side_b,
         )
 
+        impose_cards(pdf_path)
+
         gen_msg = (
             "Currently working on {}, click 'generate' to re-generate the same PDF"
         ).format(pdf_name)