什么是Universal Links?
在iOS9之前，對于從各種從瀏覽器、Safari中喚醒APP的需求，我們通常只能使用scheme。但是這種方式需要提前判斷系統(tǒng)中是否安裝了能夠響應此scheme的app。
Universal Links是iOS9推出的一項功能，你的應用如果iOS設備上已經(jīng)安裝了你的app可以通過傳統(tǒng)的HTTP鏈接來啟動APP，iOS設備上沒有安裝你的app來打開網(wǎng)頁。
官方的說明文檔 怎么使用Universal Links。
1.先決條件：你必須有一個域名,且這個域名需要支持https。
2.需要在開發(fā)者中心做配置：找到對應的App ID，在Application Services列表里有Associated Domains一條，把它變?yōu)镋nabled就可以了。
3.打開工程配置中的Associated Domains，在其中的Domains中填入你想支持的域名，必須以applinks:為前綴。
**4.創(chuàng)建一個內(nèi)容為json格式的文件，app安裝后，app從我們在項目中填入的域名請求這個文件。這個文件名必須為apple-app-site-association，沒有后綴名，文件內(nèi)容大概是這樣子：
ios 12及其以前**
{
"applinks": {
"apps": [],
"details": [
{
"appID": "ABCDE12345.com.example.app",
"paths": [ "/buy/*", "NOT /help/website/*", "/help/*" ]
}
{
"appID": "ABCDE12345.com.example.app2",
"paths": [ "/buy/*", "NOT /help/website/*", "/help/*" ]
}
]
},
"webcredentials": {
"apps": [ "ABCDE12345.com.example.app" ]
}
}
ios13開始變了（有點坑）
{
"applinks": {
"details": [
{
"appIDs": [ "ABCDE12345.com.example.app", "ABCDE12345.com.example.app2" ],
"components": [
{
"#": "no_universal_links",
"exclude": true,
"comment": "Matches any URL whose fragment equals no_universal_links and instructs the system not to open it as a universal link"
},
{
"/": "/buy/*",
"comment": "Matches any URL whose path starts with /buy/"
},
{
"/": "/help/website/*",
"exclude": true,
"comment": "Matches any URL whose path starts with /help/website/ and instructs the system not to open it as a universal link"
}
{
"/": "/help/*",
"?": { "articleNumber": "????" },
"comment": "Matches any URL whose path starts with /help/ and which has a query item with name 'articleNumber' and a value of exactly 4 characters"
}
]
}
]
},
"webcredentials": {
"apps": [ "ABCDE12345.com.example.app" ]
}
}
- appID：組成方式是 teamId.yourapp’s bundle identifier。如上面的 9JA89QQLNQ就是teamId。登陸開發(fā)者中心，在Account - Membership里面可以找到Team ID
-paths：設定你的app支持的路徑列表，只有這些指定的路徑的鏈接，才能被app所處理。星號的寫法代表了可識別域名下所有鏈接
5. 上傳該文件到你的域名所對應的根目錄或者.well-known目錄下，這是為了蘋果能獲取到你上傳的文件。上傳完后,自己先訪問一下,看看是否能夠獲取到，當你在瀏覽器中輸入這個文件鏈接后，應該是直接下載apple-app-site-association文件。
在safari中輸入一下兩個鏈接能下載到上述的json文件
(https://你的域名/.well-known/apple-app-site-association)
(https://你的域名/apple-app-site-association)
6.如果能夠下載成功了，為了能夠分享到微信和QQ，你還需要到微信開發(fā)者中心中和QQ互聯(lián)中填寫Universal Links并且需要驗證
#7.在此強調(diào)一個重要的信息，第3步中的域名一旦填寫，還有json文件一旦填寫升級app既生效，如果想修改json中的信息，只能等app下次升級才能起作用(或者卸載app重裝)（大坑，大坑）。一旦你的rul鏈接中有第3步中的域名，那么他們會微信和safari中直接調(diào)起app，所以，第3步中的域名要使用平時你們的分享以及業(yè)務不用到的域名。
相關(guān)文檔
* The `apple-app-site-association` file is cached *once* when the app is first installed.
* If this initial scrape fails, in almost all situations it will not be reattempted. The only exception to this is if the initial return is a 5xx error, in which case a limited number of retries may occur. This is not well-documented, and is not covered in Universal Links documentation at all. You can find a mention in the [Shared Web Credentials docs](https://developer.apple.com/reference/security/1654440-shared_web_credentials).
* The file is *not* checked at all when a Universal Link is opened. This is why you are able to get Universal Links behavior in airplane mode.
* The file does not expire. Once it is cached, it sticks permanently for as long as the app is installed.
* The file will be re-checked when installing an app update.
* The file must be accessible via a valid SSL connection at either `https://example.com/apple-app-site-association` or `https://example.com/.well-known/apple-app-site-association`. If there are redirects of any kind, this will fail.
* It is theoretically possible to MITM the request if you are able to install a new SSL certificate directly on the device in question. [Charles Proxy](https://www.charlesproxy.com) for example uses this approach for debugging. I have never seen or heard of this being exploited, and the damage would be quite limited because the domain still has to be specified inside the app itself.
