indexeddb

README

IndexedDB

Bindings for Go to IndexedDB for WebAssembly and GopherJS.

Getting Started

Check out the example.

Sample:

  key := []byte("key")
  val := []byte("test")

  err := objStore.Set(key, val)
  err = objStore.Commit()

  data, found, err := objStore.Get(key)
  if err == nil && !found {
    err = errors.New("key not found after setting it")
  }
  // data contains same data as "val"

  prefix := []byte("ke")
  err = objStore.ScanPrefix(prefix, func(key, val []byte) error {
    fmt.Printf("got key/value pair: %v => %v\n", key, val)
    return nil
  })

Transactions expiring

In IndexedDB, transactions will expire if inactive for a short period of time, or if the Go code goes inactive (such as when waiting for a select statement). After the transaction expires, all requests will panic / return an error - "transaction is not active."

This unfortunately happens quite frequently with the Go implementation of the IndexedDB client in this library, because the Go wasm and/or GopherJS implementations frequently unwind the stack to the event loop when switching goroutines. The code will also sometimes panic if the Js code throws any errors.

The IndexedDB code in this library tries to be as minimal of a wrapper around the underlying JavaScript implementations as possible. As such, the fix for these issues is implemented in an additional wrapper. After constructing a Database, call NewDurableTransaction(db, scope, mode) instead of Transaction. If the transaction "goes inactive," it will will re-start the transaction. It will also handle any panics from the calls.

Unfortunately, a transaction "going inactive" will also commit the transaction. The "abort" call will "roll-back" the changes made by the transaction. This is a fairly weak transaction mechanism and should not be relied upon like a traditional transaction system (in BoltDB or similar).

The "Kvtx" implementation has a easy to use get/set API using []byte slices. It also implements "ScanPrefix" and "ScanPrefixKeys" for iterating over the db.

Reference: https://developer.mozilla.org/en-US/docs/Web/API/IndexedDB_API/Using_IndexedDB

License

MIT

Documentation

Index

• Variables

Variables

var (
	// ErrEmptyKey is returned if the key was empty.
	ErrEmptyKey = errors.New("key cannot be empty")
)