Requirements AzureData

Offline Persistence

Phase 1: Simple Data Persistence

• Offline persistence is enabled by default (for all resources)
• User has option to disable offline persistence (for all resources)
• Data is written remotely before caching locally
• Only READING is supported while device is offline, WRITE throws a (useful) error
• Add fromCache to response object when returning data from cache (device offline)

Phase 2: Offline Write

• Add WRITE support when offline
• Automatically push any local changes as soon as device comes back online

Phase 3

• User has option to disable offline persistence for collections only (documents would respect parent collection option persistence)

Phase 4

• Add Time-To-Live (TTL) functionality to improve GET performance for non-volatile data

Initial Notes

• Cosmos DB DocumentDB/SQL API Coverage
• Well-defined auth model (TokenProvider)
• Support multiple Collections (thus multiple tokens)
• Offline caching
• Querying resources
  • Support for "raw" SQL queries (validation?)
  • Query type and custom syntax language for chaining together conditions
• Save tokens to Keychain (AzureCore)
• Validate Resource IDs
  • Resource IDs must not exceed 255 characters
• Instantiate using both database name (auto adding .document.azure) or full URL for instances using custom domains
  • Configure override that takes database name
  • Configure override that takes database URL
• Date format options & defaults
• API for direct access to resources (database name, collection name, etc.) & extensions on instances
• Document type to use as a superclass of custom model objects
• DictionaryDocument type to support subscript syntax
• Overrides for partition keys
• Paging support for List
• Optimistic concurrency
  • If-None-Match on GET
  • If-Match on PUT and DELETE
  • If-Modified-Since on GET (ignored when If-None-Match is specified)
• Offline support
  • Cache everything by default
    • Disk (maybe memory in the future)
    • API for:
      • Opt per document/collection
      • Purge
    • Cache size limit/expiration
      • Options
  • Syncing/Concurrency Options
    • Latest wins (silent)
    • Mine wins (silent)
    • Manual (callback)
  • Get cached docs
  • Queue changes
  • Flag for transparent sync (agressive, 10 seconds, etc.)
• Document user/master token differences (e.g. create DB, read vs write, etc.)
• For Phase 2/future:
  • Start identifying libs for compatability support
  • Caching (HTTP cache + disk?)
  • Transaction support?
  • Realtime DB (websocket-based connection to support real time push/pull a la Firebase)