Capabilities for Different Windows and Platforms

This guide will help you customize the capabilities of your Tauri app.

Content of this guide

• Create multiple windows in a Tauri app
• Use different capabilities for different windows
• Use platform-specific capabilities

Prerequisites

This exercise is meant to be read after completing Using Plugin Permissions.

Guide

1. Create Multiple Windows in a Tauri Application

   Here we create an app with two windows labelled first and second. There are multiple ways to create windows in your Tauri application.

   Create Windows with the Tauri Configuration File

   In the Tauri configuration file, usually named tauri.conf.json:

   Show solution

     "productName": "multiwindow",
     ...
     "app": {
       "windows": [
         {
           "label": "first",
           "title": "First",
           "width": 800,
           "height": 600
         },
         {
           "label": "second",
           "title": "Second",
           "width": 800,
           "height": 600
         }
       ],
     },
     ...
   }

   Create Windows Programmatically

   In the Rust code to create a Tauri app:

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   tauri::Builder::default()
       .invoke_handler(tauri::generate_handler![greet])
       .setup(|app| {
           let webview_url = tauri::WebviewUrl::App("index.html".into());
           // First window
           tauri::WebviewWindowBuilder::new(app, "first", webview_url.clone())
               .title("First")
               .build()?;
           // Second window
           tauri::WebviewWindowBuilder::new(app, "second", webview_url)
               .title("Second")
               .build()?;
           Ok(())
       })
       .run(context)
       .expect("error while running tauri application");

2. Apply Different Capabilities to Different Windows

   The windows of a Tauri app can use different features or plugins of the Tauri backend. For better security it is recommended to only give the necessary capabilities to each window. We simulate a scenario where the first windows uses filesystem and dialog functionalities and second only needs dialog functionalities.

   Separate capability files per category

   It is recommended to separate the capability files per category of actions they enable.

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   JSON files in the src-tauri/capabilities will be taken into account for the capability system. Here we separate capabilities related to the filesystem and dialog window into filesystem.json and dialog.json.

   filetree of the Tauri project:

   /src
   /src-tauri
     /capabilities
       filesystem.json
       dialog.json
     tauri.conf.json
   package.json
   README.md

   Give filesystem capabilities to the first window

   We give the first window the capability to have read access to the content of the $HOME directory.

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   Use the windows field in a capability file with one or multiple window labels.

   filesystem.json

   {
     "identifier": "fs-read-home",
     "description": "Allow access file access to home directory",
     "local": true,
     "windows": ["first"],
     "permissions": [
       "fs:allow-home-read",
     ]
   }

   Give dialog capabilities to the first and second window

   We give to first and second windows the capability to create a “Yes/No” dialog

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   Use the windows field in a capability file with one or multiple window labels.

   dialog.json

   {
     "identifier": "dialog",
     "description": "Allow to open a dialog",
     "local": true,
     "windows": ["first", "second"],
     "permissions": ["dialog:allow-ask"]
   }

3. Make Capabilities Platform Dependent

   We now want to customize the capabilities to be active only on certain platforms. We make our filesystem capabilities only active on linux and windows.

   Show solution

   Use the platforms field in a capability file to make it platform-specific.

   filesystem.json

   {
     "identifier": "fs-read-home",
     "description": "Allow access file access to home directory",
     "local": true,
     "windows": ["first"],
     "permissions": [
       "fs:allow-home-read",
     ],
     "platforms": ["linux", "windows"]
   }

   The currently available platforms are linux, windows, macos, android, and ios.

Conclusion and Resources

We have learned how to create multiple windows in a Tauri app and give them specific capabilities. Furthermore these capabilities can also be targeted to certain platforms.

An example application that used window capabilities can be found in the api example of the Tauri Github repository. The fields that can be used in a capability file are listed in the Capability reference.