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jaredsburrowsjaredsburrows
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improve caching with database (#1096)
1 parent 313b5db commit 38a1aea

23 files changed

+826
-273
lines changed

‎app/build.gradle.kts‎

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@@ -230,6 +230,12 @@ dependencies {
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implementation(libs.androidx.compose.uitooling)
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androidTestImplementation(libs.androidx.compose.junit)
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// Room Database
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implementation(libs.androidx.room.runtime)
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implementation(libs.androidx.room)
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implementation(libs.androidx.room.paging)
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ksp(libs.androidx.room.compiler)
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// Glide
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implementation(libs.landscapist.animation)
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implementation(libs.landscapist.glide)

‎app/src/main/java/com/burrowsapps/gif/search/data/db/AppDatabase.kt‎

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package com.burrowsapps.gif.search.data.db
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import androidx.room.Database
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import androidx.room.RoomDatabase
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import com.burrowsapps.gif.search.data.db.dao.GifDao
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import com.burrowsapps.gif.search.data.db.dao.QueryResultDao
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import com.burrowsapps.gif.search.data.db.dao.RemoteKeysDao
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import com.burrowsapps.gif.search.data.db.entity.GifEntity
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import com.burrowsapps.gif.search.data.db.entity.QueryResultEntity
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import com.burrowsapps.gif.search.data.db.entity.RemoteKeysEntity
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@Database(
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entities = [GifEntity::class, QueryResultEntity::class, RemoteKeysEntity::class],
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version = 1,
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exportSchema = false,
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)
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internal abstract class AppDatabase : RoomDatabase() {
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abstract fun gifDao(): GifDao
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abstract fun queryResultDao(): QueryResultDao
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abstract fun remoteKeysDao(): RemoteKeysDao
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}

‎app/src/main/java/com/burrowsapps/gif/search/data/db/dao/GifDao.kt‎

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package com.burrowsapps.gif.search.data.db.dao
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import androidx.room.Dao
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import androidx.room.Insert
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import androidx.room.OnConflictStrategy
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import androidx.room.Query
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import com.burrowsapps.gif.search.data.db.entity.GifEntity
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@Dao
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internal interface GifDao {
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@Insert(onConflict = OnConflictStrategy.REPLACE)
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suspend fun upsertAll(items: List<GifEntity>)
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@Query("DELETE FROM gifs")
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suspend fun clearAll()
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@Query("SELECT COUNT(*) FROM gifs")
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suspend fun count(): Int
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@Query("SELECT * FROM gifs WHERE tinyGifUrl = :id LIMIT 1")
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suspend fun getById(id: String): GifEntity?
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}

‎app/src/main/java/com/burrowsapps/gif/search/data/db/dao/QueryResultDao.kt‎

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package com.burrowsapps.gif.search.data.db.dao
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import androidx.paging.PagingSource
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import androidx.room.Dao
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import androidx.room.Insert
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import androidx.room.OnConflictStrategy
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import androidx.room.Query
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import androidx.room.RewriteQueriesToDropUnusedColumns
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import com.burrowsapps.gif.search.data.db.entity.QueryResultEntity
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import com.burrowsapps.gif.search.ui.giflist.GifImageInfo
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@Dao
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internal interface QueryResultDao {
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// Keep first-seen ordering stable by ignoring duplicates
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@Insert(onConflict = OnConflictStrategy.IGNORE)
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suspend fun insertAll(items: List<QueryResultEntity>)
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@Query("DELETE FROM query_results WHERE searchKey = :searchKey")
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suspend fun clearQuery(searchKey: String)
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@Query("SELECT COALESCE(MAX(position) + 1, 0) FROM query_results WHERE searchKey = :searchKey")
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suspend fun nextPositionForQuery(searchKey: String): Long
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@RewriteQueriesToDropUnusedColumns
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@Query(
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"""
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SELECT g.tinyGifUrl AS tinyGifUrl,
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g.tinyGifPreviewUrl AS tinyGifPreviewUrl,
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g.gifUrl AS gifUrl,
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g.gifPreviewUrl AS gifPreviewUrl
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FROM query_results qr
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INNER JOIN gifs g ON g.tinyGifUrl = qr.gifId
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WHERE qr.searchKey = :searchKey
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ORDER BY qr.position ASC
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""",
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)
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fun pagingSource(searchKey: String): PagingSource<Int, GifImageInfo>
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@RewriteQueriesToDropUnusedColumns
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@Query(
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"""
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SELECT g.tinyGifUrl AS tinyGifUrl,
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g.tinyGifPreviewUrl AS tinyGifPreviewUrl,
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g.gifUrl AS gifUrl,
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g.gifPreviewUrl AS gifPreviewUrl
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FROM query_results qr
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INNER JOIN gifs g ON g.tinyGifUrl = qr.gifId
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WHERE qr.searchKey = :searchKey
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ORDER BY qr.position ASC
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""",
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)
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suspend fun allForQuery(searchKey: String): List<GifImageInfo>
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}

‎app/src/main/java/com/burrowsapps/gif/search/data/db/dao/RemoteKeysDao.kt‎

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package com.burrowsapps.gif.search.data.db.dao
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import androidx.room.Dao
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import androidx.room.Insert
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import androidx.room.OnConflictStrategy
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import androidx.room.Query
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import com.burrowsapps.gif.search.data.db.entity.RemoteKeysEntity
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@Dao
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internal interface RemoteKeysDao {
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@Query("SELECT * FROM remote_keys WHERE searchKey = :searchKey LIMIT 1")
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suspend fun remoteKeys(searchKey: String): RemoteKeysEntity?
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@Insert(onConflict = OnConflictStrategy.REPLACE)
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suspend fun upsert(keys: RemoteKeysEntity)
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@Query("DELETE FROM remote_keys WHERE searchKey = :searchKey")
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suspend fun clearQuery(searchKey: String)
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}

‎app/src/main/java/com/burrowsapps/gif/search/data/db/entity/GifEntity.kt‎

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package com.burrowsapps.gif.search.data.db.entity
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import androidx.room.Entity
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import androidx.room.PrimaryKey
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@Entity(tableName = "gifs")
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internal data class GifEntity(
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@PrimaryKey val tinyGifUrl: String,
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val tinyGifPreviewUrl: String,
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val gifUrl: String,
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val gifPreviewUrl: String,
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)

‎app/src/main/java/com/burrowsapps/gif/search/data/db/entity/QueryResultEntity.kt‎

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package com.burrowsapps.gif.search.data.db.entity
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import androidx.room.Entity
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import androidx.room.ForeignKey
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import androidx.room.Index
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import com.burrowsapps.gif.search.data.db.entity.GifEntity
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@Entity(
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tableName = "query_results",
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primaryKeys = ["searchKey", "gifId"],
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indices = [
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Index(value = ["searchKey", "position"], unique = true),
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Index(value = ["gifId"]),
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],
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foreignKeys = [
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ForeignKey(
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entity = GifEntity::class,
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parentColumns = ["tinyGifUrl"],
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childColumns = ["gifId"],
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onDelete = ForeignKey.CASCADE,
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onUpdate = ForeignKey.CASCADE,
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),
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],
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)
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internal data class QueryResultEntity(
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val searchKey: String,
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val gifId: String, // references GifEntity.tinyGifUrl
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val position: Long,
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)

‎app/src/main/java/com/burrowsapps/gif/search/data/db/entity/RemoteKeysEntity.kt‎

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package com.burrowsapps.gif.search.data.db.entity
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import androidx.room.Entity
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import androidx.room.PrimaryKey
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@Entity(tableName = "remote_keys")
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internal data class RemoteKeysEntity(
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@PrimaryKey val searchKey: String,
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val nextKey: String?,
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)

‎app/src/main/java/com/burrowsapps/gif/search/data/repository/GifRemoteMediator.kt‎

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package com.burrowsapps.gif.search.data.repository
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import androidx.paging.ExperimentalPagingApi
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import androidx.paging.LoadType
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import androidx.paging.PagingState
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import androidx.paging.RemoteMediator
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import androidx.room.withTransaction
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import com.burrowsapps.gif.search.data.api.model.GifResponseDto
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import com.burrowsapps.gif.search.data.api.model.NetworkResult
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import com.burrowsapps.gif.search.data.db.AppDatabase
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import com.burrowsapps.gif.search.data.db.entity.GifEntity
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import com.burrowsapps.gif.search.data.db.entity.QueryResultEntity
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import com.burrowsapps.gif.search.data.db.entity.RemoteKeysEntity
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import com.burrowsapps.gif.search.ui.giflist.GifImageInfo
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import kotlinx.coroutines.CoroutineDispatcher
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import kotlinx.coroutines.withContext
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@OptIn(ExperimentalPagingApi::class)
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internal class GifRemoteMediator(
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private val queryKey: String,
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private val repository: GifRepository,
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private val database: AppDatabase,
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private val dispatcher: CoroutineDispatcher,
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) : RemoteMediator<Int, GifImageInfo>() {
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override suspend fun load(
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loadType: LoadType,
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state: PagingState<Int, GifImageInfo>,
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): MediatorResult {
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val remoteKeysDao = database.remoteKeysDao()
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val gifDao = database.gifDao()
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val queryResultsDao = database.queryResultDao()
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val currentKey =
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when (loadType) {
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LoadType.REFRESH -> null
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LoadType.PREPEND -> return MediatorResult.Success(endOfPaginationReached = true)
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LoadType.APPEND -> remoteKeysDao.remoteKeys(queryKey)?.nextKey
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}
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val result: NetworkResult<GifResponseDto> =
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withContext(dispatcher) {
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if (queryKey.isBlank()) {
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repository.getTrendingResults(currentKey)
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} else {
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repository.getSearchResults(queryKey, currentKey)
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}
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}
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return when (result) {
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is NetworkResult.Error -> MediatorResult.Error(Exception(result.message))
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is NetworkResult.Loading -> MediatorResult.Error(IllegalStateException("Unexpected Loading"))
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is NetworkResult.Empty -> MediatorResult.Success(endOfPaginationReached = true)
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is NetworkResult.Success -> {
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val response = result.data
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val items = buildGifList(response)
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database.withTransaction {
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if (loadType == LoadType.REFRESH) {
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queryResultsDao.clearQuery(queryKey)
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remoteKeysDao.clearQuery(queryKey)
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}
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// upsert gifs
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val gifEntities =
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items.map { info ->
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GifEntity(
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tinyGifUrl = info.tinyGifUrl,
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tinyGifPreviewUrl = info.tinyGifPreviewUrl,
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gifUrl = info.gifUrl,
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gifPreviewUrl = info.gifPreviewUrl,
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)
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}
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gifDao.upsertAll(gifEntities)
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// compute start position
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val startPos = if (loadType == LoadType.APPEND) queryResultsDao.nextPositionForQuery(queryKey) else 0L
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val mappings =
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items.mapIndexed { index, item ->
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QueryResultEntity(searchKey = queryKey, gifId = item.tinyGifUrl, position = startPos + index)
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}
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queryResultsDao.insertAll(mappings)
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// update remote keys
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val nextKey = response?.next?.takeUnless { it == currentKey }
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remoteKeysDao.upsert(RemoteKeysEntity(searchKey = queryKey, nextKey = nextKey))
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}
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MediatorResult.Success(endOfPaginationReached = items.isEmpty())
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}
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}
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}
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private fun buildGifList(response: GifResponseDto?): List<GifImageInfo> =
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response
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?.results
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?.map { result ->
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val media = result.media.firstOrNull()
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val gifUrl = media?.gif?.url.orEmpty()
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val gifPreviewUrl = media?.gif?.preview.orEmpty()
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val tinyUrl = media?.tinyGif?.url.orEmpty()
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val tinyPreview = media?.tinyGif?.preview.orEmpty()
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GifImageInfo(
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gifUrl = gifUrl,
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gifPreviewUrl = gifPreviewUrl,
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tinyGifUrl = tinyUrl,
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tinyGifPreviewUrl = tinyPreview,
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)
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}.orEmpty()
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}

‎app/src/main/java/com/burrowsapps/gif/search/di/DatabaseModule.kt‎

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package com.burrowsapps.gif.search.di
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import android.content.Context
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import androidx.room.Room
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import androidx.room.RoomDatabase
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import com.burrowsapps.gif.search.data.db.AppDatabase
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import com.burrowsapps.gif.search.data.db.dao.GifDao
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import com.burrowsapps.gif.search.data.db.dao.QueryResultDao
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import com.burrowsapps.gif.search.data.db.dao.RemoteKeysDao
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import dagger.Module
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import dagger.Provides
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import dagger.hilt.InstallIn
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import dagger.hilt.android.qualifiers.ApplicationContext
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import dagger.hilt.components.SingletonComponent
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import javax.inject.Singleton
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@Module
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@InstallIn(SingletonComponent::class)
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internal class DatabaseModule {
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@Provides
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@Singleton
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fun provideDatabase(
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@ApplicationContext context: Context,
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): AppDatabase =
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Room
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.databaseBuilder(context, AppDatabase::class.java, "gif-db")
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.setJournalMode(RoomDatabase.JournalMode.WRITE_AHEAD_LOGGING)
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.fallbackToDestructiveMigration(false)
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.build()
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@Provides
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@Singleton
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fun provideGifDao(db: AppDatabase): GifDao = db.gifDao()
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@Provides
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@Singleton
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fun provideQueryResultDao(db: AppDatabase): QueryResultDao = db.queryResultDao()
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@Provides
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@Singleton
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fun provideRemoteKeysDao(db: AppDatabase): RemoteKeysDao = db.remoteKeysDao()
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}

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