Navigating to a target URL that contains App Link metadata follows a common protocol that has two key components:
al_applink_data
object that contains context for the navigation.al_applink_data
is meant to be a metadata container that can hold any kind of information that could be held in a JSON
object. Top-level properties of al_applink_data
are meant to contain routing information relevant to the act of navigating to a URL using this protocol.
Deep-linking on iOS and Windows Phone is URL-based, wherein each app can register and define URL schemes (e.g. myapp:// or example:// – note that we strongly recommend that apps choose unique URL schemes to avoid collisions with other apps) that the operating system will route to that app. Performing an App Link navigation on iOS or Windows Phone involves constructing a URL that combines a prefix defined by the app with al_applink_data
.
For iOS, the Bolts SDK for iOS available to help you with the discovery and construction of outbound links.
iOS and Windows Phone are covered later in this document.
Deep-linking on Android is Intent-based, wherein each app can register and define Activities and Intent filters that the operating system will route to that app. Performing an App Link navigation on Android involves constructing an Intent that contains al_applink_data
in its Intent extras.
The Bolts SDK for Android is available to help you with the discovery and construction of outbound links.
Android is covered later in this document.
al_applink_data
ContentsThe first step to supporting outbound links is to construct an al_applink_data
object that will be used on each platform.
al_applink_data
is meant to be a metadata container that can hold any kind of information that could be held in a JSON object. Top-level properties of al_applink_data
are meant to contain routing information relevant to the act of navigating to a URL using this protocol.
The following table lists the properties of al_applink_data
defined by this protocol, but additional properties may be defined by others to extend the protocol:
Property | Example Content | Description | Required (Y/N) |
---|---|---|---|
target_url | https://example.com | A string containing the web URL being navigated to. This is an http or https URL representing some content. | Y |
referer_app_link | {
“target_url”: “http://ex.com/docs”,
“url”: “example://docs”,
“app_name”: “Example App”
} | An object containing a target url as well as app link metadata (as defined in the metadata registry) that can be used to identify the Referer for this navigation. This enables the receiving app to provide a link back to the navigating app, which is especially important on platforms without a built-in back button. | N |
extras | {“myapp_token”: “t0kEn”} | An object containing information from the navigating app. | N |
version | 1.0 | A string containing the version of the protocol – currently “1.0″; defaults to “1.0″. | N |
user_agent | Bolts Android 1.0 | A string containing an identifier for the library that the navigating code is using to navigate. | N |
For example, al_applink_data
for a navigation to http://example.com/docs might look like:
{
"target_url": "http://example.com/docs",
"extras": {
"myapp_token": "t0kEn"
},
"user_agent": "Bolts iOS 1.1",
"version": "1.0"
}
Deep-linking on iOS is URL-based, wherein each app can register and define URL schemes (e.g. myapp:// or example:// – note that we strongly recommend that apps choose unique URL schemes to avoid collisions with other apps) that the operating system will route to that app. Performing an App Link navigation on iOS involves constructing a URL that combines a prefix defined by the app with al_applink_data
as defined above.
To navigate to a target URL on iOS:
For example, if http://example.com/applinks contained the following markup:
<html>
<head>
<meta property="al:ios:url" content="example://applinks" />
<meta property="al:ios:app_store_id" content="12345" />
<meta property="al:ios:app_name" content="Example App" />
<!-- Other headers -->
</head>
<!-- Other HTML content -->
</html>
An navigating app might open the following URL if the app is installed:
example://applinks?al_applink_data=%7B%22user_agent%22%3A%22Bolts%20iOS%201.0.0%22%2C%22target_url%22%3A%22http%3A%5C%2F%5C%2Fexample.com%5C%2Fapplinks%22%2C%22extras%22%3A%7B%22myapp_token%22%3A%22t0kEn%22%7D%7D
Or to the following URL if the app is not installed:
http://example.com/applinks?al_applink_data=%7B%22user_agent%22%3A%22Bolts%20iOS%201.0.0%22%2C%22target_url%22%3A%22http%3A%5C%2F%5C%2Fexample.com%5C%2Fapplinks%22%2C%22extras%22%3A%7B%22myapp_token%22%3A%22t0kEn%22%7D%7D
Deep-linking on Android is Intent-based, wherein each app can register and define Activities and Intent filters that the operating system will route to that app. Performing an App Link navigation on Android involves constructing an Intent that contains al_applink_data
in its Intent extras.
To navigate to a target URL on Android:
VIEW
Intent with the specified class
and package
. If a url
is specified, set this as the data for the Intent. Otherwise, set the target URL as the data for the intent. Finally, check whether the Intent can be opened by calling PackageManager.resolveActivity()
and checking whether any ResolveInfo
is returned.al:web:should_fallback
is false
, the navigation fails. Otherwise, use the value of al:web:url
(or the original target URL if none is specified) to construct an Intent that will launch the default web browser on the device. To this URL, you should add a query parameter named al_applink_data
whose value is al_applink_data
encoded as a JSON string and then URL-encoded.al_applink_data
for the navigation as a Bundle (using nested Bundles, Strings, arrays and numbers as values) and add it to the Intent as an extra named al_applink_data
.For example, if http://example.com/applinks contained the following markup:
<html>
<head>
<meta property="al:android:url" content="example://applinks" />
<meta property="al:android:package" content="com.example" />
<meta property="al:android:app_name" content="Example App" />
<!-- Other headers -->
</head>
<!-- Other HTML content -->
</html>
A navigating app might start the following Intent if the app is installed:
action: android.intent.action.VIEW
data: example://applinks
package: com.example
extras:
al_applink_data:
target_url: "http://example.com/applinks"
user_agent: "Bolts Android 1.0"
version: "1.0"
extras:
myapp_token: "t0kEn"
Or it may start the following Intent if the app is not installed:
action: android.intent.action.VIEW
data: http://example.com/applinks?al_applink_data=%7B%22user_agent%22%3A%22Bolts%20Android%201.0.0%22%2C%22target_url%22%3A%22http%3A%5C%2F%5C%2Fexample.com%5C%2Fapplinks%22%2C%22extras%22%3A%7B%22myapp_token%22%3A%22t0kEn%22%7D%7D
Deep-linking on Windows Phone is URL-based, wherein each app can register and define URL schemes (e.g. myapp:// or example:// – note that we strongly recommend that apps choose unique URL schemes to avoid collisions with other apps) that the operating system will route to that app. Performing an App Link navigation on Windows Phone involves constructing a URL that combines a prefix defined by the app with al_applink_data
as defined above.
To navigate to a target URL on Windows Phone:
windows_phone
in order, construct a URL from the url
and adding a query parameter named al_applink_data
containing the al_applink_data
for this navigation encoded as a JSON string and then URL-encoded. Until a launch succeeds, attempt to launch the URL.al:web:should_fallback
is false
, the navigation fails. Otherwise, use the value of al:web:url
(or the original target URL if none is specified), adding al_applink_data
as above, and attempt to launch this URL.For example, if http://example.com/applinks contained the following markup:
<html>
<head>
<meta property="al:windows_phone:url" content="example://applinks" />
<meta property="al:windows_phone:app_name" content="Example App" />
<!-- Other headers -->
</head>
<!-- Other HTML content -->
</html>
An navigating app might open the following URL if the app is installed:
example://applinks?al_applink_data=%7B%22user_agent%22%3A%22Bolts%20Windows%20Phone%201.0.0%22%2C%22target_url%22%3A%22http%3A%5C%2F%5C%2Fexample.com%5C%2Fapplinks%22%2C%22extras%22%3A%7B%22myapp_token%22%3A%22t0kEn%22%7D%7D
Or to the following URL if the app is not installed:
http://example.com/applinks?al_applink_data=%7B%22user_agent%22%3A%22Bolts%20Windows%20Phone%201.0.0%22%2C%22target_url%22%3A%22http%3A%5C%2F%5C%2Fexample.com%5C%2Fapplinks%22%2C%22extras%22%3A%7B%22myapp_token%22%3A%22t0kEn%22%7D%7D