✅ Fix "Download CAR file" on mobile (#3816)

* download CAR file using AtpAgent instead of building URL

* add loader icon on download car button

* actually save to disk on android

* style nits

* bottom margin nit

* localize toast

* remove fallback so back button works correctly

* keep throwing an error if mime type isn't used

* be more explicit with toasts

* send errors to sentry when encountered

---------

Co-authored-by: Hailey <me@haileyok.com>

4 files changed, 144 insertions, 47 deletions

diff --git a/src/lib/api/api-polyfill.ts b/src/lib/api/api-polyfill.ts
index ea1d97598..e3aec7631 100644
--- a/src/lib/api/api-polyfill.ts
+++ b/src/lib/api/api-polyfill.ts
@@ -1,5 +1,5 @@
-import {BskyAgent, stringifyLex, jsonToLex} from '@atproto/api'
 import RNFS from 'react-native-fs'
+import {BskyAgent, jsonToLex, stringifyLex} from '@atproto/api'
 
 const GET_TIMEOUT = 15e3 // 15s
 const POST_TIMEOUT = 60e3 // 60s
@@ -68,8 +68,10 @@ async function fetchHandler(
       resBody = jsonToLex(await res.json())
     } else if (resMimeType.startsWith('text/')) {
       resBody = await res.text()
+    } else if (resMimeType === 'application/vnd.ipld.car') {
+      resBody = await res.arrayBuffer()
     } else {
-      throw new Error('TODO: non-textual response body')
+      throw new Error('Non-supported mime type')
     }
   }
 
diff --git a/src/lib/media/manip.ts b/src/lib/media/manip.ts
index 9cd4abc62..71d5c701f 100644
--- a/src/lib/media/manip.ts
+++ b/src/lib/media/manip.ts
@@ -1,12 +1,23 @@
 import {Image as RNImage, Share as RNShare} from 'react-native'
 import {Image} from 'react-native-image-crop-picker'
 import uuid from 'react-native-uuid'
-import {cacheDirectory, copyAsync, deleteAsync} from 'expo-file-system'
+import {
+  cacheDirectory,
+  copyAsync,
+  deleteAsync,
+  documentDirectory,
+  EncodingType,
+  makeDirectoryAsync,
+  StorageAccessFramework,
+  writeAsStringAsync,
+} from 'expo-file-system'
 import * as MediaLibrary from 'expo-media-library'
 import * as Sharing from 'expo-sharing'
 import ImageResizer from '@bam.tech/react-native-image-resizer'
+import {Buffer} from 'buffer'
 import RNFetchBlob from 'rn-fetch-blob'
 
+import {logger} from '#/logger'
 import {isAndroid, isIOS} from 'platform/detection'
 import {Dimensions} from './types'
 
@@ -240,3 +251,64 @@ function normalizePath(str: string, allPlatforms = false): string {
   }
   return str
 }
+
+export async function saveBytesToDisk(
+  filename: string,
+  bytes: Uint8Array,
+  type: string,
+) {
+  const encoded = Buffer.from(bytes).toString('base64')
+  return await saveToDevice(filename, encoded, type)
+}
+
+export async function saveToDevice(
+  filename: string,
+  encoded: string,
+  type: string,
+) {
+  try {
+    if (isIOS) {
+      const tmpFileUrl = await withTempFile(filename, encoded)
+      await Sharing.shareAsync(tmpFileUrl, {UTI: type})
+      safeDeleteAsync(tmpFileUrl)
+      return true
+    } else {
+      const permissions =
+        await StorageAccessFramework.requestDirectoryPermissionsAsync()
+
+      if (!permissions.granted) {
+        return false
+      }
+
+      const fileUrl = await StorageAccessFramework.createFileAsync(
+        permissions.directoryUri,
+        filename,
+        type,
+      )
+
+      await writeAsStringAsync(fileUrl, encoded, {
+        encoding: EncodingType.Base64,
+      })
+      return true
+    }
+  } catch (e) {
+    logger.error('Error occurred while saving file', {message: e})
+    return false
+  }
+}
+
+async function withTempFile(
+  filename: string,
+  encoded: string,
+): Promise<string> {
+  // Using a directory so that the file name is not a random string
+  // documentDirectory will always be available on native, so we assert as a string.
+  const tmpDirUri = joinPath(documentDirectory as string, String(uuid.v4()))
+  await makeDirectoryAsync(tmpDirUri, {intermediates: true})
+
+  const tmpFileUrl = joinPath(tmpDirUri, filename)
+  await writeAsStringAsync(tmpFileUrl, encoded, {
+    encoding: EncodingType.Base64,
+  })
+  return tmpFileUrl
+}
diff --git a/src/lib/media/manip.web.ts b/src/lib/media/manip.web.ts
index 522aa2e51..25315ebbd 100644
--- a/src/lib/media/manip.web.ts
+++ b/src/lib/media/manip.web.ts
@@ -1,6 +1,7 @@
-import {Dimensions} from './types'
 import {Image as RNImage} from 'react-native-image-crop-picker'
-import {getDataUriSize, blobToDataUri} from './util'
+
+import {Dimensions} from './types'
+import {blobToDataUri, getDataUriSize} from './util'
 
 export async function compressIfNeeded(
   img: RNImage,
@@ -138,3 +139,23 @@ function createResizedImage(
     img.src = dataUri
   })
 }
+
+export async function saveBytesToDisk(
+  filename: string,
+  bytes: Uint8Array,
+  type: string,
+) {
+  const blob = new Blob([bytes], {type})
+  const url = URL.createObjectURL(blob)
+  await downloadUrl(url, filename)
+  // Firefox requires a small delay
+  setTimeout(() => URL.revokeObjectURL(url), 100)
+  return true
+}
+
+async function downloadUrl(href: string, filename: string) {
+  const a = document.createElement('a')
+  a.href = href
+  a.download = filename
+  a.click()
+}
diff --git a/src/view/screens/Settings/ExportCarDialog.tsx b/src/view/screens/Settings/ExportCarDialog.tsx
index 1b8d430b2..af835cb62 100644
--- a/src/view/screens/Settings/ExportCarDialog.tsx
+++ b/src/view/screens/Settings/ExportCarDialog.tsx
@@ -3,12 +3,16 @@ import {View} from 'react-native'
 import {msg, Trans} from '@lingui/macro'
 import {useLingui} from '@lingui/react'
 
-import {useAgent, useSession} from '#/state/session'
-import {atoms as a, useBreakpoints, useTheme} from '#/alf'
-import {Button, ButtonText} from '#/components/Button'
+import {saveBytesToDisk} from '#/lib/media/manip'
+import {logger} from '#/logger'
+import {useAgent} from '#/state/session'
+import * as Toast from '#/view/com/util/Toast'
+import {atoms as a, useTheme} from '#/alf'
+import {Button, ButtonIcon, ButtonText} from '#/components/Button'
 import * as Dialog from '#/components/Dialog'
-import {InlineLinkText, Link} from '#/components/Link'
-import {P, Text} from '#/components/Typography'
+import {InlineLinkText} from '#/components/Link'
+import {Loader} from '#/components/Loader'
+import {Text} from '#/components/Typography'
 
 export function ExportCarDialog({
   control,
@@ -17,21 +21,35 @@ export function ExportCarDialog({
 }) {
   const {_} = useLingui()
   const t = useTheme()
-  const {gtMobile} = useBreakpoints()
-  const {currentAccount} = useSession()
   const {getAgent} = useAgent()
+  const [loading, setLoading] = React.useState(false)
 
-  const downloadUrl = React.useMemo(() => {
+  const download = React.useCallback(async () => {
     const agent = getAgent()
-    if (!currentAccount || !agent.session) {
-      return '' // shouldnt ever happen
+    if (!agent.session) {
+      return // shouldnt ever happen
     }
-    // eg: https://bsky.social/xrpc/com.atproto.sync.getRepo?did=did:plc:ewvi7nxzyoun6zhxrhs64oiz
-    const url = new URL(agent.pdsUrl || agent.service)
-    url.pathname = '/xrpc/com.atproto.sync.getRepo'
-    url.searchParams.set('did', agent.session.did)
-    return url.toString()
-  }, [currentAccount, getAgent])
+    try {
+      setLoading(true)
+      const did = agent.session.did
+      const downloadRes = await agent.com.atproto.sync.getRepo({did})
+      const saveRes = await saveBytesToDisk(
+        'repo.car',
+        downloadRes.data,
+        downloadRes.headers['content-type'],
+      )
+
+      if (saveRes) {
+        Toast.show(_(msg`File saved successfully!`))
+      }
+    } catch (e) {
+      logger.error('Error occurred while downloading CAR file', {message: e})
+      Toast.show(_(msg`Error occurred while saving file`))
+    } finally {
+      setLoading(false)
+      control.close()
+    }
+  }, [_, control, getAgent])
 
   return (
     <Dialog.Outer control={control}>
@@ -40,34 +58,34 @@ export function ExportCarDialog({
       <Dialog.ScrollableInner
         accessibilityDescribedBy="dialog-description"
         accessibilityLabelledBy="dialog-title">
-        <View style={[a.relative, a.gap_md, a.w_full]}>
+        <View style={[a.relative, a.gap_lg, a.w_full]}>
           <Text nativeID="dialog-title" style={[a.text_2xl, a.font_bold]}>
             <Trans>Export My Data</Trans>
           </Text>
-          <P nativeID="dialog-description" style={[a.text_sm]}>
+          <Text nativeID="dialog-description" style={[a.text_sm]}>
             <Trans>
               Your account repository, containing all public data records, can
               be downloaded as a "CAR" file. This file does not include media
               embeds, such as images, or your private data, which must be
               fetched separately.
             </Trans>
-          </P>
+          </Text>
 
-          <Link
+          <Button
             variant="solid"
             color="primary"
             size="large"
             label={_(msg`Download CAR file`)}
-            to={downloadUrl}
-            download="repo.car">
+            disabled={loading}
+            onPress={download}>
             <ButtonText>
               <Trans>Download CAR file</Trans>
             </ButtonText>
-          </Link>
+            {loading && <ButtonIcon icon={Loader} />}
+          </Button>
 
-          <P
+          <Text
             style={[
-              a.py_xs,
               t.atoms.text_contrast_medium,
               a.text_sm,
               a.leading_snug,
@@ -83,23 +101,7 @@ export function ExportCarDialog({
               </InlineLinkText>
               .
             </Trans>
-          </P>
-
-          <View style={gtMobile && [a.flex_row, a.justify_end]}>
-            <Button
-              testID="doneBtn"
-              variant="outline"
-              color="primary"
-              size={gtMobile ? 'small' : 'large'}
-              onPress={() => control.close()}
-              label={_(msg`Done`)}>
-              <ButtonText>
-                <Trans>Done</Trans>
-              </ButtonText>
-            </Button>
-          </View>
-
-          {!gtMobile && <View style={{height: 40}} />}
+          </Text>
         </View>
       </Dialog.ScrollableInner>
     </Dialog.Outer>