Rolling back to previous UI versions in v0

 
Configuring the Rollback Feature
 

• Create a new file named config.py. This file will determine which UI version is active.
• Insert the following code into config.py. It tells your application to use the previous UI version (v0):

  
  # config.py
  ACTIVE_UI_VERSION = "v0"   # "v0" loads the previous version. Change this value to "current" to load the latest version.
      

 
Creating the Previous UI Module
 

• Create a new file named ui\_v0.py. This file will include the code for your previous UI version.
• Insert the following code into ui\_v0.py. It defines a simple function that renders your UI:

  
  # ui\_v0.py
  def render\_ui():
      # This function represents your previous UI.
      # Add your UI components and layout code here.
      return "UI: Version 0 - Rollback Active"
      

 
Modifying the Main Application
 

• Locate your main application file (for example, app.py).
• Add code at the top of your app.py to import the configuration and the correct UI module based on the active version. Insert the following code into your main file:

  
  # app.py
  import config
  
  if config.ACTIVE_UI_VERSION == "v0":
      import ui_v0 as ui
  else:
      import ui_current as ui  # This assumes you have a file named ui_current.py for your latest UI version
  def main():
      # Call the function from the UI module to render your interface.
      rendered_ui = ui.render_ui()
      print(rendered_ui)  # For demonstration purposes, it prints the UI text to the screen.
  if name == "main":
      main()
      

  
  

 
Setting Up Dependencies
 

• If your application requires additional libraries, you need to ensure they are available since Lovable doesn't have a terminal for installations.
• Add code to check for a dependency and inform you if it is missing. For example, if you need a library called some\_library, add the following snippet in your code (you can place it in your app.py file):

  
  try:
      import some\_library
  except ImportError:
      print("Dependency missing: Please add 'some\_library' to your project files manually.")
      # If you are using a dependency manager provided by Lovable, include the library file(s) in your project.
      

 
Testing Your Rollback Feature
 

• After making all the changes, use Lovable's integrated "Run" or "Preview" feature to start your application.
• Observe the output. It should indicate "UI: Version 0 - Rollback Active" to confirm that the previous UI version is loaded.
• If you wish to switch back to the current UI version at any time, modify the value in config.py to "current" and ensure you have a corresponding ui\_current.py file.

 
Set Up a UI Version Registry File
 

• In your project’s file structure, create a new file named ui\_versions.json. This file will keep track of the different UI versions you have.
• Copy and paste the following code into ui\_versions.json. This code creates a simple list matching version keys to their corresponding UI file names. Adjust the version numbers and file names as needed:

  
  {
    "v1": "index\_v1.html",
    "v0": "index\_v0.html"
  }
      

 
Implement the Rollback Controller Code
 

• Create a new file called rollback.js in your project directory. This file will contain the code to load the desired version of your UI based on the registry.
• Insert the following code into rollback.js. This code defines a function that reads the version registry and then chooses the appropriate HTML file to display:

  
  function loadUI(version) {
    // In a real scenario, you might read the ui\_versions.json file.
    // Since Lovable doesn't have a terminal, we simulate this by hardcoding the object.
    const uiVersions = {
      "v1": "index\_v1.html",
      "v0": "index\_v0.html"
    };
  
    // Check if the desired version exists in our registry
    if (uiVersions[version]) {
      // Here, we set the current UI by changing the 'src' attribute of an iframe or by loading the HTML file.
      // For example, assuming you use an iframe with id 'uiFrame':
      document.getElementById("uiFrame").src = uiVersions[version];
    } else {
      // Fallback option: load a default UI version if the requested version is not found.
      document.getElementById("uiFrame").src = uiVersions["v1"];
      console.error("Requested UI version not found. Loading default version.");
    }
  }
      

  
  


• Because Lovable doesn’t offer a terminal for installing packages, this code uses only simple JavaScript. No extra dependencies need to be installed.

 
Integrate the Rollback Controller into Your Main HTML File
 

• Open your main HTML file (for example, index.html or main.html) where you want the UI to load.
• Ensure that there is an element to display the UI, such as an iframe. Add the following snippet into your HTML file within the <body> section:

  
  <iframe id="uiFrame" width="100%" height="600px" frameborder="0"></iframe>
      

• Include the rollback.js file in your HTML by adding this snippet before the closing </body> tag:

  
  <script src="rollback.js"></script>
      

• After including the script, call the loadUI function with the desired version. You can add this code snippet right after including the script:

  
  <script>
    // Change "v0" to the version you want to roll back to.
    loadUI("v0");
  </script>
      

 
Testing and Troubleshooting the Rollback Process
 

• To see if everything is working correctly, open your main HTML file in Lovable. The iframe should display the UI from the version you specified (in this example, index\_v0.html).
• If the incorrect version shows up or nothing loads, double-check the following:
  • Ensure that the ui\_versions.json file contains the correct mappings and that the version you are calling in loadUI exists.
  • Make sure that the iframe’s ID in your HTML matches the ID used in rollback.js ("uiFrame" in our example).
  • Confirm that your rollback.js is correctly linked to your main HTML file.
• If you encounter any issues, check the code inside rollback.js for typos or small mistakes. This guided rollback mechanism is a best practice to ensure you always have a way to revert to a working UI.