Mohammad Khorasani - Web Application Development with Streamlit: Develop and Deploy Secure and Scalable Web Applications to the Cloud Using a Pure Python Framework

Web ApplicationDevelopment withStreamlitDevelop and Deploy Secureand Scalable Web Applicationsto the Cloud Using a PurePython FrameworkMohammad KhorasaniMohamed AbdouJavier Hernndez FernndezWeb Application Development with Streamlit: Develop and Deploy Secureand Scalable Web Applications to the Cloud Using a Pure Python Framework Mohammad Khorasani Mohamed Abdou Doha, Qatar Cambridge, United Kingdom Javier Hernndez Fernndez Doha, Qatar ISBN-13 (pbk): 978-1-4842-8110-9 ISBN-13 (electronic): 978-1-4842-8111-6 https://doi.org/10.1007/978-1-4842-8111-6 Copyright 2022 by Mohammad Khorasani, Mohamed Abdou, Javier Hernndez Fernndez This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Trademarked names, logos, and images may appear in this book. Rather than use a trademark symbol with every occurrence of a trademarked name, logo, or image we use the names, logos, and images only in an editorial fashion and to the benefit of the trademark owner, with no intention of infringement of the trademark. The use in this publication of trade names, trademarks, service marks, and similar terms, even if they are not identified as such, is not to be taken as an expression of opinion as to whether or not they are subject to proprietary rights. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made.

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For more detailed information, please visit http://www.apress.com/ source- code. the Cloud .................................................................................2 1.1.2 A Trend Toward Cloud Computing ...........................................................3 1.1.3 History of Web Frameworks in Python ...................................................5 1.1.4 Flask .......................................................................................................6 1.1.5 Django ....................................................................................................6 1.1.6 Dash .......................................................................................................7 1.1.7 Web2Py ...................................................................................................7 1.1.8 The Need for a Pure Python Web Framework .........................................8 1.1.9 Academic Significance ...........................................................................8 1.2 Firing It Up.......................................................................................................9 1.2.1 Technical Requirements .........................................................................9 1.2.2 Environment Installation with Anaconda ..............................................10 v Table of ConTenTs 1.2.3 Downloading and Installing Streamlit ...................................................15 1.2.4 Streamlit Console Commands ..............................................................17 1.2.5 Running Demo Apps .............................................................................19 1.2.6 Writing and Testing Code with PyCharm ...............................................21 1.3 How Streamlit Works.....................................................................................25 1.3.1 The Streamlit Architecture ....................................................................26 1.3.2 ReactJS in Streamlit .............................................................................29 1.4 Summary.......................................................................................................30 Chapter 2: Streamlit Basics 31 2.1 Creating a Basic Application .........................................................................31 2.1.1 Generating User Input Forms ................................................................32 2.1.2 Introducing Conditional Flow ................................................................34 2.1.3 Managing and Debugging Errors ..........................................................36 2.2 Mutating Dataframes ....................................................................................40 2.2.1 Filter .....................................................................................................41 2.2.2 Select ...................................................................................................42 2.2.3 Arrange .................................................................................................44 2.2.4 Mutate ..................................................................................................46 2.2.5 Group By ...............................................................................................48 2.2.6 Merge ...................................................................................................49 2.3 Rendering Static and Interactive Charts .......................................................52 2.3.1 Static Bar Chart ....................................................................................52 2.3.2 Static Line Chart ...................................................................................53 2.3.3 Interactive Line Chart ...........................................................................55 2.3.4 Interactive Map .....................................................................................57 2.4 Developing the User Interface .......................................................................58 2.5 Summary.......................................................................................................62 vi Table of ConTenTs Chapter 3: Architecting the User Interface 63 3.1 Designing the Application .............................................................................64 3.1.1 Configuring the Page ............................................................................64 3.1.2 Developing Themes and Color schemes ...............................................77 3.1.3 Organizing the Page .............................................................................81 3.2 Displaying Dynamic Content .........................................................................85 3.2.1 Creating a Real-Time Progress Bar ......................................................87 3.3 Provisioning Multipage Applications .............................................................88 3.3.1 Creating Pages .....................................................................................88 3.3.2 Creating Subpages ...............................................................................91 3.4 Modularizing Application Development .........................................................94 3.4.1 Example: Developing a Social Network Application .............................95 3.4.2 Best Practices for Folder Structuring .................................................101 3.5 Summary.....................................................................................................104 Chapter 4: Data Management and Visualization 105 4.1 Data Management .......................................................................................106 4.1.1 Processing Bytes Data ........................................................................106 4.1.2 Caching Big Data ................................................................................108 4.1.3 Mutating Data in Real Time ................................................................111 4.1.4 Advanced and Interactive Data Mutation ............................................113 4.2 Exploring Plotly Data Visualizations ............................................................120 4.2.1 Rendering Plotly in Streamlit ..............................................................120 4.2.2 Basic Charts .......................................................................................121 4.2.3 Statistical Charts ................................................................................125 4.2.4 Time-Series Charts .............................................................................127 4.2.5 Geospatial Charts ...............................................................................128 4.2.6 Animated Visualizations ......................................................................128 4.3 Summary.....................................................................................................131 vii Table of ConTenTs Chapter 5: Database Integration 133 5.1 Relational Databases ..................................................................................133 5.1.1 Introduction to SQL .............................................................................134 5.1.2 Connecting a PostgreSQL Database to Streamlit ...............................136 5.1.3 Displaying Tables in Streamlit ............................................................141 5.2 Nonrelational Databases .............................................................................144 5.2.1 Introduction to MongoDB ....................................................................145 5.2.2 Provisioning a Cloud Database ...........................................................146 5.2.3 Full-Text Indexing ...............................................................................150 5.2.4 Querying the Database .......................................................................152 5.2.5 Displaying Tables in Streamlit ............................................................157 5.3 Summary.....................................................................................................160 Chapter 6: Leveraging Backend Servers 161 6.1 The Need for Backend Servers ...................................................................161 6.2 Frontend-Backend Communication ............................................................162 6.2.1 HTTP Methods ....................................................................................163 6.3 Working with JSON Files .............................................................................164 6.4 Provisioning a Backend Server ...................................................................165 6.4.1 API Building ........................................................................................166 6.4.2 API Testing ..........................................................................................170 6.5 Multithreading and Multiprocessing Requests ...........................................171 6.6 Connecting Streamlit to a Backend Server .................................................174 6.7 Summary.....................................................................................................177 viii Table of ConTenTs Chapter 7: Implementing Session State 179 7.1 Implementing Session State Natively .........................................................179 7.1.1 Building an Application with Session State ........................................182 7.2 Introducing Session IDs ..............................................................................185 7.3 Implementing Session State Persistently ...................................................186 7.4 User Insights ...............................................................................................191 7.4.1 Visualizing User Insights .....................................................................195 7.5 Cookie Management ...................................................................................198 7.6 Summary.....................................................................................................202 Chapter 8: Authentication and Application Security 203 8.1 Developing User Accounts ..........................................................................203 8.1.1 Hashing ..............................................................................................204 8.1.2 Salting ................................................................................................205 8.2 Verifying User Credentials ...........................................................................207 8.3 Secrets Management ..................................................................................224 8.4 Anti-SQL Injection Measures with SQLAlchemy ..........................................225 8.5 Configuring Gitignore Variables ...................................................................226 8.6 Summary.....................................................................................................227 Chapter 9: Deploying Locally and to the Cloud 229 9.1 Exposing Streamlit to the World Wide Web .................................................230 9.1.1 Port Forwarding over a Network Gateway ..........................................230 9.1.2 HTTP Tunneling Using NGROK .............................................................232 9.2 Deployment to Streamlit Cloud ...................................................................235 9.2.1 One-Click Deployment ........................................................................235 9.2.2 Streamlit Secrets ................................................................................238 ix Table of ConTenTs 9.3 Deployment to Linux ...................................................................................240 9.3.1 Native Deployment on a Linux Machine .............................................240 9.3.2 Deployment with Linux Docker Containers .........................................243 9.4 Deployment to Windows Server ..................................................................246 9.4.1 Establishing a Remote Desktop Connection .......................................247 9.4.2 Opening TCP/IP Ports ..........................................................................249 9.4.3 Anaconda Offline Package Installation ...............................................253 9.4.4 Adding Anaconda to System Path .......................................................254 9.4.5 Running Application as an Executable Batch File ...............................256 9.4.6 Running Application As a Persistent Windows Service ......................257 9.5 Summary.....................................................................................................261 Chapter 10: Building Streamlit Components 263 10.1 Introduction to Streamlit Custom Components .........................................263 10.2 Using ReactJS to Create Streamlit Custom Components ..........................264 10.2.1 Making a ReactJS Component .........................................................265 10.2.2 Using a ReactJS Component in Streamlit .........................................268 10.2.3 Sending Data to the Custom Component ..........................................270 10.2.4 Receiving Data from the Custom Component ...................................273 10.3 Publishing Components As Pip Packages .................................................276 10.4 Component in Focus: Extra-Streamlit- Components ..................................280 10.4.1 Stepper Bar ......................................................................................280 10.4.2 Bouncing Image ................................................................................286 10.4.3 Tab Bar ..............................................................................................290 10.4.4 Cookie Manager................................................................................295 10.4.5 Router ...............................................................................................302 10.5 Summary...................................................................................................307 x Table of ConTenTs Chapter 11: Streamlit Use Cases 309 11.1 Dashboards and Real-Time Applications ..................................................309 11.1.1 Temperature Data Recorder Application ...........................................310 11.1.2 Motor Command and Control Application .........................................316 11.2 Time-Series Applications ..........................................................................321 11.2.1 Date-Time Filter Application .............................................................321 11.2.2 Time-Series Heatmap Application ....................................................324 11.2.3 Time Synchronization Application .....................................................328 11.3 Data Management and Machine Learning Applications ............................332 11.3.1 Data Warehouse Application .............................................................332 11.3.2 Advanced Application Development: Machine Learning As a Service ..............................................................................................344 11.4 Summary...................................................................................................361 Chapter 12: Streamlit at Work 363 12.1 Streamlit in Clean Energy: