commit e6cf1c6b5f0b5b999fd3685b8a712570b3b8b4fe
Author: Julien Palard <julien@palard.fr>
Date:   Sun Apr 16 22:48:49 2023 +0200

    Initial commit

diff --git a/README.md b/README.md
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index 0000000..18fb741
--- /dev/null
+++ b/README.md
@@ -0,0 +1,3 @@
+This is the sapin server to serve as an HackInScience example.
+
+It's hosted on https://sapin.hackinscience.org.
diff --git a/sapin.py b/sapin.py
new file mode 100644
index 0000000..d5e922d
--- /dev/null
+++ b/sapin.py
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+from io import BytesIO
+from zipfile import ZipFile
+import os
+
+from flask import Flask, request
+
+app = Flask(__name__)
+
+expr_zip = BytesIO(
+    # Look ma! An ugly binary blob! Is that how non-free software actually look?
+    b"PK\x03\x04\x14\x00\t\x00\x08\x009\xb3\x90V\xc2U\xacy4\x00\x00\x001\x00"
+    b"\x00\x00\x04\x00\x1c\x00exprUT\t\x00\x03\xceY<d\xceY<dux\x0b\x00\x01"
+    b"\x04\xe8\x03\x00\x00\x04\xe8\x03\x00\x00\x1d'!d\x00kyl8 \x14g\x9dm\x16"
+    b"\xa5\\\xc9\xd6%s\xb6M\xd2H\x8c'J,\tJ_\xe2m\x1e\xf5`\\j\x94gnJ\x8dw\x8e"
+    b"L\x84fL*!PK\x07\x08\xc2U\xacy4\x00\x00\x001\x00\x00\x00PK\x01\x02\x1e\x03"
+    b"\x14\x00\t\x00\x08\x009\xb3\x90V\xc2U\xacy4\x00\x00\x001\x00\x00\x00\x04"
+    b"\x00\x18\x00\x00\x00\x00\x00\x01\x00\x00\x00\xa4\x81\x00\x00\x00\x00"
+    b"exprUT\x05\x00\x03\xceY<dux\x0b\x00\x01\x04\xe8\x03\x00\x00\x04\xe8\x03"
+    b"\x00\x00PK\x05\x06\x00\x00\x00\x00\x01\x00\x01\x00J\x00\x00\x00\x82\x00"
+    b"\x00\x00\x00\x00"
+)
+with ZipFile(expr_zip) as myzip:
+    with myzip.open("expr", pwd=os.environ["SAPIN_KEY"].encode()) as myfile:
+        expr = myfile.read().decode()
+        stage_width = lambda n: eval(expr, globals(), {"n": n})
+
+
+def sapin(fir_width):
+    lines = []
+    draw_width = stage_width(fir_width) + fir_width * 2 + 4
+    for stage in range(1, 1 + fir_width):
+        current_width = stage_width(stage)
+        for i in range(3 + stage):
+            yield f"{'*' * (current_width + i * 2):^{draw_width}}"
+
+    trunk_width = fir_width + 1 - fir_width % 2
+    for i in range(fir_width):
+        yield f"{'|' * trunk_width:^{draw_width}}"
+
+
+@app.route("/")
+def slash():
+    try:
+        fir_width = int(request.args.get("n"))
+    except TypeError:
+        return (
+            "Give an `n` query string as an integer, like <a href='/?n=10'>/?n=10</a>."
+        )
+    return "<pre>" + "\n".join(sapin(fir_width)) + "</pre>"