Create Dynamic Links with C++

You can create short or long Dynamic Links with the Firebase Dynamic Links API. The API takes several optional parameter structures to build links. Short links can also be created from a previously generated long link. Firebase Dynamic Links generates a URL like the following:

https://example.page.link/WXYZ

The C++ SDK works for both Android and iOS, with some additional setup required for each platform.

Before you begin

Before you can use Firebase Dynamic Links, you need to:

• Register your C++ project and configure it to use Firebase.
  If your C++ project already uses Firebase, then it's already registered and configured for Firebase.
• In your project-level build.gradle file, make sure to include Google's Maven repository in both your buildscript and allprojects sections.
• Add the Firebase C++ SDK to your C++ project.

Find detailed instructions for these initial setup tasks in Add Firebase to your C++ project.

Note that adding Firebase to your C++ project involves tasks both in the Firebase console and in your open C++ project (for example, you download Firebase config files from the console, then move them into your C++ project).

AndroidiOS

1. In the Firebase console, open the Dynamic Links section.
2. If you have not already accepted the terms of service and set a URI prefix for your Dynamic Links, do so when prompted.
   If you already have a Dynamic Links URI prefix, take note of it. You need to provide a Dynamic Links URI prefix when you programmatically create Dynamic Links.
   
3. Recommended: Specify the URL patterns allowed in your deep links and fallback links. By doing so, you prevent unauthorized parties from creating Dynamic Links that redirect from your domain to sites you don't control. See Whitelist URL patterns.

Use the Firebase console 

If you want to generate a single Dynamic Link, either for testing purposes, or for your marketing team to easily create a link that can be used in something like a social media post, the simplest way would be to visit the Firebase console and create one manually following the step-by-step form.

Custom domains

You can have greater control over your Dynamic Link's branding by using your own domain instead of a goo.glor page.link subdomain. Follow these instructions to set up a custom domain for your project.

If you are building your project for iOS, you must edit the `Info.plist` file per the [iOS only instructions](https://firebase.google.com/docs/dynamic-links/custom-domains#set_up_a_custom_domain_in_the).

Using the Firebase Dynamic Links API

Create and initialize App

Before you can create Dynamic Links, you'll need to create and initialize a firebase::App object.

You only need to initialize firebase::App once, no matter how many Firebase C++ features you use.

Include the header file for firebase::App:

#include "firebase/app.h"

The next part varies depending on your platform:

AndroidiOS

Create the firebase::App, passing the JNI environment and a jobject reference to the Java Activity as arguments:

app = ::firebase::App::Create(::firebase::AppOptions("APPLICATION NAME"), jni_env, activity);

Initialize Dynamic Links library

Before creating a Dynamic Link, you must first initialize the Dynamic Links library:

::firebase::dynamic_links::Initialize(app, null);

Creating a long Dynamic Link from parameters

To create a Dynamic Link, create a DynamicLinkComponents object, setting any of the optional members for additional configuration, and passing it to dynamic_links::GetShortLink or dynamic_links::GetLongLink.

The following minimal example creates a long Dynamic Link to https://www.example.com/ that opens with your Android app com.example.android.package_name and iOS app com.example.ios:

firebase::dynamic_links::IOSParameters ios_parameters("com.example.ios");

firebase::dynamic_links::AndroidParameters android_parameters(
    "com.example.android.package_name");

firebase::dynamic_links::DynamicLinkComponents components(
    "https://www.example.com/", "example.page.link");
components.android_parameters = &android_parameters;
components.ios_parameters = &ios_parameters;

firebase::dynamic_links::GeneratedDynamicLink long_link =
    firebase::dynamic_links::GetLongLink(components);

Note: Long Links append all of the configuration settings as query arguments to the link and therefore do not require any network calls.

Creating a short Dynamic Link

To create a short Dynamic Link, pass a previously generated long link to GetShortLink or build DynamicLinkComponents the same way as above.

GetShortLink optionally takes an extra DynamicLinkOptions config parameter with PathLength; this allows you to control how the link should be generated. Generating a short link requires a network request to the Firebase backend, so GetShortLink is asynchronous, returning a Future<GeneratedLink>.

For example:

firebase::dynamic_links::DynamicLinkOptions short_link_options;
short_link_options.path_length = firebase::dynamic_links::kPathLengthShort;

firebase::Future<firebase::dynamic_links::GeneratedDynamicLink> result =
    firebase::dynamic_links::GetShortLink(components, short_link_options);

If your program has an update loop that runs regularly (say at 30 or 60 times per second), you can check the results once per update:

if (result.status() == firebase::kFutureStatusComplete) {
  if (result.error() == firebase::dynamic_links::kErrorCodeSuccess) {
    firebase::dynamic_links::GeneratedDynamicLink link = *result.result();
    printf("Create short link succeeded: %s\n", link.url.c_str());
  } else {
    printf("Created short link failed with error '%s'\n",
           result.error_message());
  }
}