Matt Bruce
9a9889b8a0
Summary: - Sources: Audit, Helpers, Services - Tests: StorageCatalogTests.swift - Docs: Design, Migration, Testing - Added symbols: struct MyNewKey, func setupSession, func handleReceivedContext, class SessionDelegateProxy, func session, func sessionDidBecomeInactive (+2 more) Stats: - 10 files changed, 181 insertions(+), 1 deletion(-)
36 lines
1.2 KiB
Markdown
36 lines
1.2 KiB
Markdown
# LocalData Migration Guide
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## Overview
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`LocalData` provides built-in support for migrating data from legacy storage locations or keys to modern `StorageKey` definitions.
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## Automatic Migration
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When calling `get(_:)` on a key, the `StorageRouter` automatically:
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1. Checks the primary location.
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2. If not found, iterates through `migrationSources` defined on the key.
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3. If data is found in a source:
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- Unsecures it using the source's old policy.
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- Re-secures it using the new key's policy.
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- Stores it in the new location.
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- Deletes the legacy data.
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- Returns the value.
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## Proactive Migration (Sweep)
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You can trigger a sweep of all registered keys at app launch:
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```swift
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try await StorageRouter.shared.registerCatalog(MyCatalog.self, migrateImmediately: true)
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```
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This iterates through all keys in the catalog and calls `migrate(for:)` on each, ensuring all legacy data is consolidated.
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## Defining Migration Sources
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When defining a `StorageKey`, add legacy descriptors to the `migrationSources` array:
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```swift
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struct MyNewKey: StorageKey {
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// ...
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var migrationSources: [AnyStorageKey] {
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[
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.key(LegacyKey(name: "old_key_name", domain: .userDefaults(suite: nil)))
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]
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}
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}
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```
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