Loan App

Basic Example App

This projects builds a basic business lending shiny app using shinyspring. This is a motivating example to get to build your first shinyspring app. This App demonstrates the following features of of shinyspring

Template based code creation
Menu creation in configuration files
Wiring of Datasets
Reuse of pre-built shiny modules
Writing the Core App

This example does not demonstrate other features like Authentication , job scheduling(targets) and more as they get added.

Application Context

This app is based on Bankruptcy Data of 5000+ companies. the data has been modified slightly so as to enable a rich demo and case for shinyspring. The datasets for the app can be found at link here

Goals and Persona’s

App Goals

Provide a Lending Risk Monitor Dashboard for a portfolio of loans spread across 5 countries.
Based on Bankruptcy default probability show the Value at Risk

Persona Board

Persona	Frequency of Visits	Reason to visit and Use	What is Awesome?	What would suck?

Design

Build Steps

Step 1: Create Skeleton App

in R console run shinyspring::create_new_project()
open the newly created user_script.R . make sure all the dependencies are installed as indicated in user_script
open config.yml

Adjust the following properties in config yml.

Dashboard Look and Feel

# Dashboard UI information : You should customize
  app_title: Credit Dashboard
  footer_left: Built on Shiny Spring
  footer_left_url: http://www.shinyspring.dev
  footer_right: 2021
  sidebar_expand_onhover: FALSE
  dark_theme: FALSE
  header_href: https://www.shinyspring.dev
  header_image: https://storage.googleapis.com/shiny-pics/spring_logo.png
  header_fixed: 'TRUE'
  title_color: primary
  app_title_h3: Lending Monitoer
  side_bar_fixed: TRUE
  side_bar_header: Business Lending
  header_opacity: 0.8

Create Menu Structure

# Menus : You should customize - documentation here $TODO link
# Note: the ui_function and server_function are from sweetmods or your custom modules
  menus: [
    { title: Introduction , name: intro_tab , icon: leanpub  },
    { title: Lending Book , name: core_tab , icon: credit-card  },
    { title: Data Exploration ,  icon: chart-bar ,  parent_menu: true ,
       sub_menu: [
         {first:  true ,submenu_title: Visualize , submenu_name: explore_tab , submenu_icon: circle-thin } ,
         {last_submenu:  true , submenu_title: Correlations , submenu_name: corr_tab , submenu_icon: cubes } ,
       ]
    },
    { title: Credits , name: credits_tab , icon: heart , last_menu: true }
  ]

For now leave the explore_tab and corr_tab the way way the are, we can adjust them later

Run the rest of the commands in user_script.r . You will have a new app.R . You can run the shiny app in Rstudio or call shiny::runApp() which will launch the app.

Step 2 : Wire Datasets

Wire the Dataset to shinyspring with the following update in config.yml

# datsets : This is the approach to pre-load datasets
 ds.portfolio.type: rds
  ds.portfolio.connection: data/portfolio.rds
  ds.portfolio.ds_info_type: google
  ds.portfolio.ds_info_url: https://docs.google.com/spreadsheets/d/17QhXC0b6a0WZGRSFGPA6KBdjq_lalm0TGi33hLBNsFI

Now run the application to see if dataset portolio is loaded correctly. You can check based on
- Check 1: steps 2 to Step 5 in user_script.R should run without error and the Shiny app should get launched :white_check_mark:
- Check 2: When you run the App , you should be able to see the the portfolio dataset in the drop down in Data Explodation \ Visualize Menu . ✅ .

Notes: ds.portfolio.ds_info_type and ds.portfolio.ds_info_url in config.yml are optional. They perform initial data validation and provide an opportunity to clean colnames and provide “pretty_names” to colums that are easily understood. Please refer to Configuring Datasets document here # TODO Link

Step 3: Write Core App

Create your custom shiny module needed for Lending Dashboard with shinyspring::create_module("lending_mod") in R console
open lending_mod.R and browse skeleton code
wire the lending_mod into the menu’s and application with the following changes in config.yml

core_tab.mod_name: lending_mod core_tab.ui_function: lending_mod_ui core_tab.server_function: lending_mod_server core_tab.onload_function: lending_mod_onLoad

the above 4 line items are needed or all modules to talk to shinyspring. For pre-built modules they are defined in package and hence you do not need to wire them explicitly here. Here is the module registry for pre-built modules. Browse these to get an idea how wiring modules to shinyspring. [Link here](https://docs.google.com/spreadsheets/d/15HXspcKqGyDYAM1Jfa7SFjCALHMWTPyTbjrXnWuHY2I/)

Now , let us write the core lending modules. Cut and paste the code from here (TODO) in your lending_mod.R file
Finally , let us make sure that you source the lending_mod.R on app startup. Include the following line source("lending_mod.R") in on_startup.R . on_startup.R was created when you created the project.

shambhu112 / loan_app_basic