added a button to download zip sample

app.py

@@ -1,3 +1,5 @@
+import base64
+
 import streamlit as st
 import zipfile
 from utils import *
@@ -6,7 +8,6 @@ import matplotlib.pyplot as plt
 import matplotlib.animation as animation
 import streamlit.components.v1 as components
 from matplotlib import colors
-from huggingface_hub import hf_hub_url
 
 st.set_page_config(layout="wide")
 
@@ -287,19 +288,39 @@ if st.paths is not None:
     anim_src = load_src_images_as_animations(img_full_paths, pred_dates)
     components.html(anim_src.to_jshtml(), height=600)
 
-zip_url = hf_hub_url(repo_id="ARTeLab/DemoCropMapping", filename="demo_data/1509.zip")
+# zip_url = hf_hub_url(repo_id="ARTeLab/DemoCropMapping", filename="demo_data/1509.zip")
+# with open("demo_data/1509.zip", "rb") as f:
+#     bytes = f.read()
+#     b64 = base64.b64encode(bytes).decode()
+#     href = f'<a href="data:file/zip;base64,{b64}" download=\'1509.zip\'>\
+#         Click to download\
+#     </a>'
+# st.sidebar.markdown(href, unsafe_allow_html=True)
+# download_button_str = download_button(s, filename, f'Click here to download {filename}')
+# st.markdown(download_button_str, unsafe_allow_html=True)
+# with open('demo_data/1509.zip') as f:
+#     st.download_button('Download 1509.zip', f, file_name="demo_data/1509.zip")
+
 st.markdown(f""" 
     ## Lombardia Dataset
     You can download other patches from the original dataset created and published on 
     [Kaggle](https://www.kaggle.com/datasets/ignazio/sentinel2-crop-mapping) and used in our paper.
 
     ## How to build an input file for the Demo 
-    You can download this [example zip]({zip_url}) to understand 
-    how to create a new sample to feed as input to the model. A sample is a time series of sentinel-2 images, 
+    You can download the following zip example to better understand how to create a new sample to feed as input to the model. """)
+with open("demo_data/1509.zip", "rb") as fp:
+    btn = st.download_button(
+        label="Download ZIP example",
+        data=fp,
+        file_name="1509.zip",
+        mime="application/octet-stream"
+    )
+st.markdown(f""" 
+    A sample is a time series of sentinel-2 images, 
     i.e. all images acquired by the satellite during a year.    
     A zip file must contain 
     - a geoTiff image of size _9 x 48 x 48_ for each date of the time series; 
     - the name of each geoTif must show the date like this example "20221225.tif" which represents the date 25 December 2022; 
     - each image must contain all sentinel-2 bands as reported in the [paper](https://www.sciencedirect.com/science/article/pii/S0924271622003203); 
-    - all the images inside the zip file must be placed inside a directory (see [example zip](demo_data/1509.zip)) where the name represents the name of the patch (for example "24"). ) 
+    - all the images inside the zip file must be placed inside a directory (see ZIP example) where the name represents the name of the patch (for example "24"). ) 
 """)