node-deeplink

Easily create express endpoint to handle mobile deeplinks in your web server

Takes away the pain of forwarding users to the right app store / mobile app depending on their platform.

Use case

Suppose you have a custom url scheme app:// handled by your mobile apps. You want to create a universal "smart" link that will know where to send the user:

• If the user has the app installed, open the app with the deeplink.
• If the user doesn't have the app installed, send to the app store to download the app (google play / itunes).
• If the user doesn't have a supported phone, send to a fallback url.

Usage

Example:

var express = require('express');
var deeplink = require('node-deeplink')

var app = express();

app.get('/deeplink', deeplink({ 
    fallback: 'https://cupsapp.com',
    android_package_name: 'com.citylifeapps.cups', 
    ios_store_link: 'https://itunes.apple.com/us/app/cups-unlimited-coffee/id556462755?mt=8&uo=4',
}));

This example creates an endpoint GET /deeplink in your web server.

Assuming your server address is https://acme.org, you can use the link https://acme.org/deeplink?url=app://account so when users will open it the app will open with app://account deeplink or the users will be redirected to download the app in case they don't have it.

Note on url encoding: to avoid problems with url parsing libraries, the deep link (app://... part) has to be url encoded. node-deeplink will decode the url correctly. So, in the above example, the link is actually https://acme.org/deeplink?url=app%3A%2F%2Faccount. Here's an example of url encoder/decoder.

Available options

node-deeplink currently only supports Android and IOS.

Options to pass on to node-deeplink are:

• fallback: mandatory. A fallback url in case the user is opening the link via an unsupported platform like desktop / windows phone etc. In such case, the fallback url will be opened in the user's browser like a normal link.
• android_package_name: optional. In case you want to support Android deep links, pass your app's package name.
• ios_store_link: optional. In case you want to support IOS deep links, pass your app's itunes url. You can get it here.
• title: optional. Title for the intermediate html page. Defaults to an empty string.

Query params

When a request comes in, the following query params a re checked:

• url: mandatory. The deeplink url you want the user to be directed to e.g. app://account.
• fallback: optional. If available, will prefer this fallback address over the one from the options.

Behaviour

node-deeplink expects the request to contain a query param url=... so that the deeplink mechanism will work. If no such query is present then node-deeplink ignores the request and calls next() so the request will be handled by the next middleware.

node-deeplink works by first sending the user to an html page with a user-agent sniffing script. After figuring out the user's device, it redirects the to the predefined deeplink. In practice, after clicking the link, the browser will be opened for a very short moment and then the redirect will happen.

TODO

• Better user-agent discovery.
• Enable non-express use.