Custom URL schemes for your app: A guide
A URL scheme is a unique identifier that allows one app to launch another or perform specific tasks. Unlike standard URLs, URL schemes enable direct communication between apps.
Learn about the benefits of using URL schemes and instructions on how to configure them.
Key takeaways
- A URL scheme enables interaction between apps by allowing one app to launch another or perform actions within it, enhancing user experience through direct navigation.
- Implementing custom URL schemes facilitates deep linking, improving user engagement by providing seamless access to specific content in apps, and enabling inter-app communication.
- Proper setup and handling of URL schemes, including registration in settings and managing incoming URLs with delegate methods, are crucial for ensuring functionality and a smooth user experience.
What is a URL scheme?
A URL scheme is a method for one app to launch another or perform specific actions within it.
Instead of using standard URLs like “http://“ or “https://“, URL schemes use a unique identifier string that allows apps to interact and recognize each other.
Custom URL schemes let apps respond to specific URLs, providing direct access to certain content or features within the app.
This enhances user experience by making navigation more seamless — for example, clicking a link in an email that directly opens a specific page in a shopping app.
Custom URLs must start with a unique scheme name and can include optional parameters for additional information or commands.
A link like “myapp://section?name=home” can take users directly to the home section of your app. Developers must handle cases where the corresponding app isn't installed to avoid user errors.
Benefits of using URL schemes
Custom URL schemes boost user engagement by allowing direct navigation within an app. For example, a user can click a link in an email and be taken straight to the app’s sales section screen, making access to in-app content quick and easy.
They enable apps to reference resources internally and facilitate inter-app interactions, where one app can initiate actions or display content from another. This cross-app communication creates interconnected experiences that keep users engaged.
Deep links streamline transitions between apps, making navigation effortless. This is particularly useful for tasks that span multiple apps, like moving from a shopping app to a banking app for payment, ensuring seamless continuity throughout the user journey.
Setting up a custom URL scheme
To establish a custom URL scheme, follow these steps to ensure your app can identify and act upon specific URLs effectively:
- Define the format of your URL:some text
- Choose a unique prefix, typically based on the name of your app.
- Incorporate optional parameters for additional information or commands.
- Example: myapp://section?name=home.
- Register the URL scheme in Xcode:some text
- Navigate to the Info tab in your project's settings.
- Add the URL scheme in the URL Types section.
By completing these steps, you guarantee that your custom URL scheme operates effectively and as intended, facilitating the desired action or navigation within your app.
Defining the URL format
Your app’s custom URL scheme should use a unique prefix, typically based on your app's name. This prefix forms the core of your scheme and can include parameters to specify actions or content in your app.
An example URL could be “myapp:section?name=home,” which directs users to the “home” area of your app. Parameters provide detailed control, allowing direct navigation to specific parts of the app.
To avoid conflicts with other apps, use a reverse DNS style for your URLs.
Registering your URL scheme
To enable an app to open specific URLs, iOS requires apps to specify the URL schemes they support.
This is done in Xcode by registering a custom URL scheme in the project settings’ Info tab, under the URL Types section. By doing this, you inform iOS that your app can handle certain schemes.
Use a reverse DNS string format for your URL scheme identifier to avoid conflicts with other apps.
Include elements from your company’s domain and your app name to ensure the uniqueness of your URL scheme.
Handling incoming URLs
Setting up a custom URL scheme is just the first step. What’s critical next is adeptly managing incoming URLs.
iOS apps use delegate methods to process incoming URLs, ensuring they perform the intended actions or display the correct content.
The URL may include parameters that the app uses to execute specific functions, enabling smooth interaction between different apps.
To handle incoming URLs, there are two primary methods: the application(_:open:options:) method and the scene(_:willConnectTo:options:) method. Each method is relevant depending on whether the app is active when it receives the URL or not.
application(_:open:options:)
When an app is opened by a link from another external application, the method application(_:open:options:) gets called to handle the URL.
This same function is activated when there’s an attempt to open a URL in your app that contains a custom scheme specified for this purpose.
Within the context of the app delegate, incoming URLs are capably processed using the application(_:open:options:) method.
By using NSURLComponents, apps can deconstruct and scrutinize various elements of any received URL to ensure it’s interpreted correctly. Through the options parameter, one can gain insight into how exactly a user initiated the opening of said URL.
scene(_:willConnectTo:options:)
If the app is not active and a URL is accessed, the specifics of that URL are dispatched to the scene(_:willConnectTo:options:) method.
This delegate method serves to convey the URL when the app isn’t in operation, making certain that actions linked to URLs are executed.
When handling incoming URLs while the app is not active, the scene(_:willConnectTo:options:) method is used.
Using user activities by way of options permits developers to administer actions connected with URLs proficiently, thus maintaining an uninterrupted experience for users.
Universal links vs. URL schemes
Universal links and custom URL schemes are two methods for enabling app redirection and inter-app communication.
While both have their own advantages and disadvantages, understanding the key differences can help developers choose the best approach for their needs.
Some of the key differences include:
- Redirection: Universal links provide a fluid redirection to an app when available, or otherwise direct to a website. Custom URL schemes solely launch the application.
- Setup: Universal links require complex steps such as hosting a specific apple-app-site-association file on your server and declaring the associated domain within Xcode. Custom URL schemes involve including the scheme in the app’s manifest file, which is more straightforward.
- Security: Universal links offer superior security by validating domains upon setup, automatically supporting fallbacks to web pages. Security in URL schemes might be compromised due to multiple apps having permission to register identical schemes, potentially leading to hijacking issues.
- Use of URLs: Universal links employ standard web URLs which can open content within an installed app or reroute to a browser if the app isn’t present. Custom URL schemes use a unique format for URLs that apps must register exclusively.
Best practices for implementing URL schemes
Ensure the uniqueness of your app’s URL scheme by adopting a reverse DNS string as its identifier, mirroring your company’s domain.
This practice prevents any overlap with existing schemes and maintains the distinctiveness of your custom URL scheme.
For better association between your app and a specific website, universal links are preferable to custom URL schemes.
They offer not only unique identifiability, but also enable tracking and measurement of deep links, providing insightful data for evaluating the success of marketing initiatives.
Common issues and troubleshooting
To guarantee that an app properly identifies and reacts to specific URL schemes, they must be meticulously set within the Info.plist file.
If this is not done accurately, there’s a risk that the app won’t acknowledge or act on these predetermined schemes.
Here are three common issues and their troubleshooting steps:
- Application not recognizing the URL scheme:some text
- Ensure the URL scheme is correctly defined in the Info.plist file.
- Verify the scheme name is unique and does not conflict with other apps.
- Check the case sensitivity of the URL scheme as it must match exactly.
- Universal links triggering web browser instead of the app:some text
- Confirm the apple-app-site-association file is correctly configured and hosted on your server.
- Make sure the associated domain is declared in Xcode under the Capabilities tab.
- Test the universal link to ensure it redirects to the app when installed and to the website when not.
- Handling invalid URLs:some text
- Implement strong error management to catch and handle invalid URLs gracefully.
- Provide user feedback when an invalid URL is encountered, such as an alert or a fallback action.
- Log errors for further analysis to improve URL handling in future updates.
By following these steps, you can ensure the continuity of a smooth experience while interacting with links.
Summary
URL schemes are unique identifiers that allow apps to communicate and perform specific actions, enhancing user experience through direct navigation and inter-app interactions.
By implementing custom URL schemes and universal links, developers can facilitate seamless access to app content, improve user engagement, and ensure secure and efficient handling of URLs.
Proper setup and management, including registering schemes in Xcode and handling incoming URLs with delegate methods, are crucial.
Adopting best practices, such as using reverse DNS strings for uniqueness and thoroughly testing for potential issues, ensures smooth navigation and interaction within apps.
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Frequently asked questions
What method is called to handle incoming URLs for a custom scheme?
The application(_:open:options:) method in the app delegate is responsible for processing incoming URLs that use a custom scheme. It plays an essential role in handling URL requests that are uniquely tailored to your app.
What additional information can be obtained when handling a URL?
By managing a URL, it is possible to gather extra details including the precise application that launched the URL via the options dictionary supplied by the system.
This improved insight into how the application environment uses the URL.
What method is used if the app has opted into Scenes and isn't running when a URL is opened?
If the app has opted into Scenes and is not running when a URL is opened, the scene(_:willConnectTo:options:) delegate method is used to deliver the URL.
How can a custom URL scheme be registered in an app?
In order to register a custom URL scheme within your application, navigate to the Info tab located in your project settings while using Xcode. Once there, you can add your desired scheme by locating the URL Types section.
By following this procedure, you enable your app to process specific requests made via URLs associated with that custom scheme.
What should the identifier for a custom URL scheme include for uniqueness?
In order to maintain distinctiveness, the method for creating an identifier for a custom URL scheme involves using a reverse DNS string that incorporates both the company’s domain and the name of the app.
Using this approach helps avoid any overlap with other apps by effectively eliminating potential conflicts.
How can URL schemes be used to open a specific location in a maps application?
URL schemes can be used to open a specific location in a maps application by creating a custom URL that includes the coordinates or address of the desired location. For example, using a URL like "maps://?q=1600+Amphitheatre+Parkway,+Mountain+View,+CA" can open the maps app and display the specified address. This allows for direct navigation and enhances the user experience by providing seamless access to map locations from within your app.
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