utils_dashboard.py

import base64
import os
import json
import pickle
import uuid
import re

import streamlit as st
import pandas as pd

from contextlib import contextmanager, redirect_stdout
from io import StringIO
from time import sleep

@contextmanager
def st_capture(output_func):
    with StringIO() as stdout, redirect_stdout(stdout):
        old_write = stdout.write

        def new_write(string):
            ret = old_write(string)
            output_func(stdout.getvalue())
            return ret
        
        stdout.write = new_write
        yield



def save_uploaded_file(uploaded_file, save_path='static/images'):
    if not os.path.exists(save_path):
        os.makedirs(save_path)
    try:
        save_file_path = os.path.join(save_path,uploaded_file.name)
        with open(os.path.join(save_path,uploaded_file.name),'wb') as f:
            f.write(uploaded_file.getbuffer())
        return save_file_path   
    except:
        return None

def download_button(object_to_download, download_filename, button_text, pickle_it=False):
    """
    Generates a link to download the given object_to_download.
    Params:
    ------
    object_to_download:  The object to be downloaded.
    download_filename (str): filename and extension of file. e.g. mydata.csv,
    some_txt_output.txt download_link_text (str): Text to display for download
    link.
    button_text (str): Text to display on download button (e.g. 'click here to download file')
    pickle_it (bool): If True, pickle file.
    Returns:
    -------
    (str): the anchor tag to download object_to_download
    Examples:
    --------
    download_link(your_df, 'YOUR_DF.csv', 'Click to download data!')
    download_link(your_str, 'YOUR_STRING.txt', 'Click to download text!')
    """
    if pickle_it:
        try:
            object_to_download = pickle.dumps(object_to_download)
        except pickle.PicklingError as e:
            st.write(e)
            return None

    else:
        if isinstance(object_to_download, bytes):
            pass

        elif isinstance(object_to_download, pd.DataFrame):
            object_to_download = object_to_download.to_csv(index=False)

        # Try JSON encode for everything else
        else:
            object_to_download = json.dumps(object_to_download)

    try:
        # some strings <-> bytes conversions necessary here
        b64 = base64.b64encode(object_to_download.encode()).decode()

    except AttributeError as e:
        b64 = base64.b64encode(object_to_download).decode()

    button_uuid = str(uuid.uuid4()).replace('-', '')
    button_id = re.sub('\d+', '', button_uuid)

    custom_css = f""" 
        <style>
            #{button_id} {{
                background-color: rgb(255, 255, 255);
                color: rgb(38, 39, 48);
                padding: 0.25em 0.38em;
                position: relative;
                text-decoration: none;
                border-radius: 4px;
                border-width: 1px;
                border-style: solid;
                border-color: rgb(230, 234, 241);
                border-image: initial;
            }} 
            #{button_id}:hover {{
                border-color: rgb(246, 51, 102);
                color: rgb(246, 51, 102);
            }}
            #{button_id}:active {{
                box-shadow: none;
                background-color: rgb(246, 51, 102);
                color: white;
                }}
        </style> """

    dl_link = custom_css + f'<a download="{download_filename}" id="{button_id}" href="data:file/txt;base64,{b64}">{button_text}</a><br></br>'

    return dl_link