prewarm URLs in onPressIn

modules/url-prewarm/expo-module.config.json

@@ -0,0 +1,6 @@
+{
+  "platforms": ["ios"],
+  "ios": {
+    "modules": ["UrlPrewarmModule"]
+  }
+}

modules/url-prewarm/index.ts

@@ -0,0 +1 @@
+export * from './src/UrlPrewarmModule'

modules/url-prewarm/ios/UrlPrewarm.podspec

@@ -0,0 +1,25 @@
+Pod::Spec.new do |s|
+  s.name           = 'UrlPrewarm'
+  s.version        = '1.0.0'
+  s.summary        = 'A sample project summary'
+  s.description    = 'A sample project description'
+  s.author         = ''
+  s.homepage       = 'https://docs.expo.dev/modules/'
+  s.platforms      = {
+    :ios => '15.1',
+    :tvos => '15.1'
+  }
+  s.source         = { git: '' }
+  s.static_framework = true
+
+  s.dependency 'ExpoModulesCore'
+
+  # Swift/Objective-C compatibility
+  s.pod_target_xcconfig = {
+    'DEFINES_MODULE' => 'YES',
+  }
+
+  s.frameworks = 'SafariServices'
+
+  s.source_files = "**/*.{h,m,mm,swift,hpp,cpp}"
+end

modules/url-prewarm/ios/UrlPrewarmModule.swift

@@ -0,0 +1,13 @@
+import ExpoModulesCore
+import SafariServices
+
+public class UrlPrewarmModule: Module {
+  public func definition() -> ModuleDefinition {
+    Name("UrlPrewarm")
+
+    AsyncFunction("prewarmUrlsAsync") { (urls: [String]) in
+      let validUrls = urls.compactMap { URL(string: $0) }
+      SFSafariViewController.prewarmConnections(to: validUrls)
+    }
+  }
+}

modules/url-prewarm/src/UrlPrewarmModule.ios.ts

@@ -0,0 +1,7 @@
+import {requireNativeModule} from 'expo'
+
+const NativeModule = requireNativeModule('UrlPrewarm')
+
+export function prewarmUrlsAsync(urls: string[]): Promise<void> {
+  return NativeModule.prewarmUrlsAsync(urls)
+}

modules/url-prewarm/src/UrlPrewarmModule.ts

@@ -0,0 +1,5 @@
+export function prewarmUrlsAsync(_urls: string[]): Promise<void> {
+  throw new Error(
+    '[Not available] prewarmUrlsAsync is not available on this platform',
+  )
+}

src/components/Post/Embed/ExternalEmbed/index.tsx

@@ -7,6 +7,7 @@ import {useLingui} from '@lingui/react'
 
 import {parseAltFromGIFDescription} from '#/lib/gif-alt-text'
 import {useHaptics} from '#/lib/haptics'
+import {prewarmUrl} from '#/lib/hooks/useOpenLink'
 import {shareUrl} from '#/lib/sharing'
 import {parseEmbedPlayerFromUrl} from '#/lib/strings/embed-player'
 import {toNiceDomain} from '#/lib/strings/url-helpers'
@@ -79,6 +80,7 @@ export const ExternalEmbed = ({
       label={link.title || _(msg`Open link to ${niceUrl}`)}
       to={link.uri}
       shouldProxy={true}
+      onPressIn={() => prewarmUrl(link.uri)}
       onPress={onPress}
       onLongPress={onShareExternal}>
       {({hovered}) => (

src/components/RichText.tsx

@@ -2,6 +2,7 @@ import React from 'react'
 import {type StyleProp, type TextStyle} from 'react-native'
 import {AppBskyRichtextFacet, RichText as RichTextAPI} from '@atproto/api'
 
+import {prewarmUrl} from '#/lib/hooks/useOpenLink'
 import {toShortUrl} from '#/lib/strings/url-helpers'
 import {atoms as a, flatten, type TextStyleProp} from '#/alf'
 import {isOnlyEmoji} from '#/alf/typography'
@@ -108,7 +109,7 @@ export function RichText({
             style={interactiveStyles}
             // @ts-ignore TODO
             dataSet={WORD_WRAP}
-            shouldProxy={shouldProxyLinks}
+            shouldProxy={false}
             onPress={onLinkPress}>
             {segment.text}
           </InlineLinkText>
@@ -128,6 +129,7 @@ export function RichText({
             dataSet={WORD_WRAP}
             shareOnLongPress
             shouldProxy={shouldProxyLinks}
+            onPressIn={() => prewarmUrl(link.uri, shouldProxyLinks)}
             onPress={onLinkPress}
             emoji>
             {toShortUrl(segment.text)}

src/lib/hooks/useOpenLink.ts

@@ -12,12 +12,13 @@ import {
   toNiceDomain,
 } from '#/lib/strings/url-helpers'
 import {logger} from '#/logger'
-import {isNative} from '#/platform/detection'
+import {isIOS, isNative} from '#/platform/detection'
 import {useInAppBrowser} from '#/state/preferences/in-app-browser'
 import {useTheme} from '#/alf'
 import {useDialogContext} from '#/components/Dialog'
 import {useSheetWrapper} from '#/components/Dialog/sheet-wrapper'
 import {useGlobalDialogsControlContext} from '#/components/dialogs/Context'
+import * as UrlPrewarm from '../../../modules/url-prewarm'
 
 export function useOpenLink() {
   const enabled = useInAppBrowser()
@@ -81,3 +82,15 @@ export function useOpenLink() {
 
   return openLink
 }
+
+export async function prewarmUrl(url: string, shouldProxy: boolean = true) {
+  if (!isIOS) return
+
+  if (!isBskyAppUrl(url)) {
+    const urls = [url]
+    if (shouldProxy) {
+      urls.push(createProxiedUrl(url))
+    }
+    await UrlPrewarm.prewarmUrlsAsync(urls)
+  }
+}