GaitVision

How to Run the PCA Small Web App Locally

This guide will help you get the PCA Small Web App up and running on your computer, even if you’re new to programming. Just follow these steps carefully!

Step 1: Install Python

Python is the programming language this app is built with. You need to install it first. If you think python may be already installed, skip ahead to step 3 and try to verify the installation.

The docs here use python for Python related commands. On MacOS/Linux devices you’d typically use python3 instead of python for all python related commands

1. Download Python:
   • Go to the official Python website: https://www.python.org/downloads/
   • Look for the latest stable version of Python 3 (e.g., Python 3.10.x, 3.11.x, or 3.12.x). Click on the “Download” button for your operating system (Windows, macOS, or Linux).
2. Install Python:
   • Windows: Double-click the downloaded .exe file. IMPORTANT: Make sure to check the box that says “Add Python X.Y to PATH” during installation. Then, click “Install Now”.
   • macOS: Double-click the downloaded .pkg file and follow the on-screen instructions. Python is often pre-installed on macOS, but it’s good to install the latest version.
   • Linux: Python is usually pre-installed. If you need a newer version, you might use your system’s package manager (e.g., sudo apt-get install python3.x for Ubuntu/Debian or sudo dnf install python3.x for Fedora).
3. Verify Installation:
   • Open your computer’s “Terminal” (on macOS/Linux) or “Command Prompt” / “PowerShell” (on Windows).
   • Type python --version and press Enter. You should see something like Python 3.10.12 (the version number might be different). If you see an error, Python might not be installed correctly or added to your system’s PATH.

Step 2: Open the Terminal and Navigate to the Project Folder

The “Terminal” (or “Command Prompt” / “PowerShell”) is where you’ll type commands to run the app.

1. Open Terminal/Command Prompt:
   • Windows: Search for “Command Prompt” or “PowerShell” in your Start Menu and open it.
   • macOS: Search for “Terminal” in Spotlight (Cmd + Space) and open it.
   • Linux: Look for “Terminal” in your applications menu.
2. Navigate to the Project Folder:
   • This is a crucial step. All of the following commands must be run from inside the correct project folder.
   • It should look something like this (your path will be different):

     cd "/path/to/your/GaitVision-main/PCA Small Web App"
     

     Note for Windows users: Your path will look different, e.g., cd "C:\Users\YourUser\Desktop\GaitVision-main\PCA Small Web App".

   • For this web app, please ensure that the file path is enclosed in quotes.

💡 Pro Tip: How to Copy a File Path

• On macOS: Right-click on a file or folder, hold down the Option key, and select “Copy [item name] as Pathname”.
• On Windows: Hold down the Shift key and right-click on a file or folder, then select “Copy as path”.

You can then paste this path directly into the terminal after typing cd . Ensure you provide quotes around the file path as well.

Step 3: Create and Activate a Virtual Environment (Recommended)

A virtual environment keeps the app’s dependencies separate from other Python projects on your computer. This is good practice.

1. Create the Virtual Environment:
   • In the Terminal, make sure you are in the “PCA Small Web app” folder (from Step 2).
   • Type the following command and press Enter:

     python -m venv venv
     

   • This will create a new folder named venv inside your project folder.

2. Activate the Virtual Environment:

   Now, activate the environment based on your operating system.

   On Windows

   For simplicity, we recommend using Command Prompt for the following steps.

   • In Command Prompt:

     .\venv\Scripts\activate
     

   • In PowerShell:

     .\venv\Scripts\Activate.ps1
     

     Note: If you get an error using PowerShell, you may need to run it as an Administrator and execute the command Set-ExecutionPolicy RemoteSigned. Using Command Prompt is often easier.

   On macOS / Linux

   In your terminal, run:

   source venv/bin/activate
   

   • You’ll know it’s activated because (venv) will appear at the beginning of your Terminal prompt.

Step 4: Install Project Dependencies

Now you need to install all the specific libraries the app needs to run.

1. Install Dependencies:
   • With the virtual environment activated (you see (venv) in your prompt), type the following command and press Enter:

     pip install -r requirements.txt
     

   • This might take a few moments as it downloads and installs several packages.

Step 5: Run the Web Application

Almost there! Now you can start the app.

1. Start the Application:
   • In the same Terminal window (with (venv) activated), type:

     python app.py
     

   • Press Enter.
2. Look for the Link:
   • After running the command, you will see some messages in the Terminal. Look for a line that says something like: ```
     • Running on http://127.0.0.1:5000 ```
   • This is the address where your app is running.

Step 6: Access the App in Your Web Browser

1. Open Your Web Browser: Open Chrome, Firefox, Edge, Safari, or any web browser you prefer.

2. Go to the Address: In the address bar of your web browser, type or paste the address you saw in the Terminal (e.g., http://127.0.0.1:5000) and press Enter.

   • You should now see the PCA Small Web App running in your browser!

When You’re Done

To stop the application, go back to the Terminal window where it’s running and press Ctrl + C (hold down the Control key and press C). To exit the virtual environment, simply type deactivate and press Enter.

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Having Trouble?

• command not found (e.g., python): This usually means Python was not added to your system’s PATH. When installing, make sure to check the box that says “Add Python to PATH”.

• pip install fails:
  • This can be a network issue. Make sure you are connected to the internet.
  • On Windows, if the installation fails with an error mentioning “C++” or “Microsoft Visual C++”, you may need to install Microsoft’s C++ Build Tools. This is an advanced step, but you can find the tools by searching for “Visual Studio Build Tools”.
• Server doesn’t start or crashes:
  • Look for an “Address already in use” error in the terminal. This means another application is using the required port (e.g., 5000). You will need to close that other application or restart your computer.
  • For any other errors, try to read the message in the terminal carefully. It will often give you a clue as to what went wrong.

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