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# Caching
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HTTP response caching to improve performance and reduce network usage.
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## Cache
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Stores HTTP responses for reuse to avoid redundant network requests.
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```kotlin { .api }
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class Cache(directory: File, maxSize: Long) : Closeable, Flushable {
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    val directory: File
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    val directoryPath: Path
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    fun delete()
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    fun evictAll()
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    fun urls(): MutableIterator<String>
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    fun size(): Long
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    fun maxSize(): Long
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    fun flush()
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    fun close()
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    fun writeAbortCount(): Int
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    fun writeSuccessCount(): Int
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    fun networkCount(): Int
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    fun hitCount(): Int
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    fun requestCount(): Int
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}
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```
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### Cache Usage
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```kotlin
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// Create cache directory
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val cacheDirectory = File(context.cacheDir, "http_cache")
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val cacheSize = 10L * 1024 * 1024 // 10 MiB
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// Configure client with cache
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val client = OkHttpClient.Builder()
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    .cache(Cache(cacheDirectory, cacheSize))
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    .build()
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```
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## CacheControl
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Directives that control HTTP caching behavior.
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```kotlin { .api }
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class CacheControl private constructor() {
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    val noCache: Boolean
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    val noStore: Boolean
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    val maxAgeSeconds: Int
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    val sMaxAgeSeconds: Int
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    val isPrivate: Boolean
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    val isPublic: Boolean
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    val mustRevalidate: Boolean
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    val maxStaleSeconds: Int
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    val minFreshSeconds: Int
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    val onlyIfCached: Boolean
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    val noTransform: Boolean
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    val immutable: Boolean
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    override fun toString(): String
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    companion object {
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        val FORCE_NETWORK: CacheControl
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        val FORCE_CACHE: CacheControl
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        fun parse(headers: Headers): CacheControl
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    }
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}
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```
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### CacheControl Builder
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```kotlin { .api }
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class CacheControl.Builder {
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    fun noCache(): Builder
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    fun noStore(): Builder
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    fun maxAge(maxAge: Int, timeUnit: TimeUnit): Builder
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    fun maxAge(maxAge: Duration): Builder
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    fun maxStale(maxStale: Int, timeUnit: TimeUnit): Builder
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    fun maxStale(maxStale: Duration): Builder
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    fun minFresh(minFresh: Int, timeUnit: TimeUnit): Builder
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    fun minFresh(minFresh: Duration): Builder
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    fun onlyIfCached(): Builder
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    fun noTransform(): Builder
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    fun immutable(): Builder
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    fun build(): CacheControl
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}
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```
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### Cache Control Examples
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```kotlin
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// Force network request (skip cache)
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val request = Request.Builder()
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    .url("https://api.example.com/data")
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    .cacheControl(CacheControl.FORCE_NETWORK)
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    .build()
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// Only use cached response (don't make network request)
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val cachedRequest = Request.Builder()
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    .url("https://api.example.com/data")
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    .cacheControl(CacheControl.FORCE_CACHE)
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    .build()
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// Custom cache control
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val cacheControl = CacheControl.Builder()
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    .maxAge(5, TimeUnit.MINUTES)
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    .maxStale(1, TimeUnit.HOURS)
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    .build()
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val request = Request.Builder()
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    .url("https://api.example.com/data")
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    .cacheControl(cacheControl)
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    .build()
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```