kv-toolbox

A set of tools for working with Deno KV.

Toolbox

The default export of the library is the encapsulation of major functionality of the library into classes which enhance the capabilities of working with a Deno KV store, which are also available as individual named exports of the the library.

There are to variants of the toolbox: KvToolbox and CryptoKvToolbox. These provide all the APIs of a Deno.Kv and the additional APIs offered by the rest of the library. The CryptoKvToolbox also attempts to encrypt and decrypt blob values.

Opening a toolbox is similar to opening a Deno.Kv store:

import { openKvToolbox } from "jsr:@kitsonk/kv-toolbox";

const kv = await openKvToolbox();

If an encryption key is passed as an option, a CryptoKvToolbox instance will be returned, where when storing and retrieving blobs in the store, they will be encrypted and decrypted by default:

import { generateKey, openKvToolbox } from "jsr:@kitsonk/kv-toolbox";

const encryptWith = generateKey();
const kv = await openKvToolbox({ encryptWith });

Batched Atomic

A set of APIs for dealing with the limitation of atomic commit sizes in Deno KV. Deno KV limits the number of checks and mutations as well as the overall byte size of each commit and the byte size of the keys.

These limits are currently high for most workloads, but if you are dealing with large transactions where if you need to perform more than 100 checks, 1000 mutations, using over 80k of key sizes or have an overall payload of over 800k, then batchedAtomic() will avoid the transaction throwing by breaking up the transaction into as many separate commits as necessary.

batchedAtomic()

Similar to Deno.Kv#atomic(), but will batch individual transactions across as many atomic operations as necessary.

There are three additional methods supported on batched atomics not supported by Deno KV atomic transactions:

• .checkBlob({ key, versionstamp }) - Allows performing checks on blob entries previously set with blob’s set() function or via .setBlob() as part of a transaction.

• .setBlob(key, value, options?) - Allows setting of arbitrarily size blob values as part of an atomic transaction. The values can be a byte ReadableStream, array buffer like, a Blob or a File. It will work around the constraints of Deno KV value sizes by splitting the value across multiple keys.

• .deleteBlob(key) - Allows deletion of all parts of a blob value as part of an atomic transaction.

The commit() method will return a promise which resolves with an array of results based on how many batches the operations was broken up into.

Blob

A set of APIs for storing arbitrarily sized blobs in Deno KV. Currently Deno KV has a limit of key values being 64k. The set() function breaks down a blob into chunks and manages sub-keys to store the complete value. The get(), getAsBlob() and getAsStream() functions reverse that process, and remove() will delete the key, sub-keys and values.

set()

Similar to Deno.Kv.prototype.set(), in that it stores a blob value with an associated key. In order to deal with the size limitations of values, set() will transparently chunk up the blob into parts that can be handled by Deno KV.

The blob can be a byte ReadableStream, array buffer like, a Blob or a File.

When the value is being set is a Blob or File the meta data will also be preserved (like the type property).

The resolved Deno.KvCommitResult will contain the versionstamp of the blob’s meta data, which can be used for consistency checks.

get()

Similar to Deno.Kv.prototype.get(), in that it retrieves a blob entry based on the provided key. If a previous blob value has been set with set(), it will be retrieved.

By default the value of the entry is resolved as a Uint8Array but if the option stream is set to true, then a byte ReadableStream is provided to read out the blob. If the option blob is set to true, then a Blob or File will be the value of the entry. If the value originally set was a File or Blob the resolved value instance will be that of the original value including restoring the additional properties, like type. If the value wasn’t a Blob or File originally, the function will resolve to a Blob with an empty type.

getAsBlob()

Retrieves a blob value based on the provided key and resolves with a Blob or File. If the value originally set was a File or Blob the resolved instance will be that of the original value including restoring the additional properties, like type. If the value wasn’t a Blob or File originally, the function will resolve to a Blob with an empty type.

getAsJSON()

Retrieve a blob value based on the provided key and resolve with its JSON representation.

getAsResponse()

Retrieve a blob entry as a Response which will stream the value from the store to a client. If the entry does not exist, the response will be a 404 Not Found. There are several options to configure how the response is set.

getAsStream()

Retrieves a blob value based on the provided key and returns a byte ReadableStream which the binary data can be read from. If there is no value present, the stream will be empty.

getMeta()

Retrieves the meta data entry of a blob value based on the key provided. The entries versionstamp is considered the version of the blob.

remove()

Similar to Deno.Kv.prototype.delete(), in that it deletes a blob key and value form the data store. If a blob value isn’t stored for the given key, it resolves in a noop.

toBlob()

A convenience function which takes a string value, and optional media type, and converts it into a Blob which then can be stored via set().

toJSON()

Convert an array buffer, typed array, Blob or File to a format which can be stringified into a JSON string.

toValue()

Convert a JSON representation of a blob back into a value. Depending on what kind of value the JSON represents, either a Uint8Array, Blob or File is returned.

Crypto

APIs which allow you to encrypt and decrypt values within a Deno KV datastore.

generateKey()

Generate a random crypto key which can be used with CryptoKv. The value returned will be a hex encoded string. It defaults to 256 bits long. A value of 128, 192, 256 bits can be supplied as an argument to the function to change the key length.

openCryptoKv()

Like Deno.openKv() but returns an instance of CryptoKv. encryptWith argument needs to be supplied, which is either a hex encoded string or Uint8Array that is 128, 192, 256 bits in length or an object which conforms to the Encryptor interface. The path option works just like path option for Deno.openKv().

CryptoKv

A class which currently provides the ability to set, get and delete encrypted blob values. If created directly, an instance of Deno.Kv needs to be passed to the constructor along with a value for encryptWith.

When a key is supplied,

Encryptor

An interface which specifies two methods of encrypt() and decrypt() which will be used for encrypting and decrypting values. This can be used to provide alternative

NDJSON

New line delimitated JSON (NDJSON) is a standard for supporting JSON string encoding of data where each record of data is delimitated by a new line. This particular format is the most straight- forward way of supporting JSON encoding and streaming.

The toolbox includes the capabilities to export entries from a KV store to NDJSON, transform a byte stream of NDJSON into individual JSON KV entry representations, and be able to import KV entries from NDJSON encoded data.

exportEntries()

Like Deno.Kv.prototype.list(), but entries are returned as a stream of bytes or strings encoded as NDJSON.

exportToResponse()

Like Deno.Kv.prototype.list(), but a Response is returned with the selected entries encoded as NDJSON as the body of the response, suitable for sending to a client as a response to a query.

LineTransformStream()

A transform stream which takes a byte stream, like from a Request body, of NDJSON encoded entry data and transforms it into individual chunks of JSON strings which can be used with JSON.parse().

importEntries()

Takes NDJSON encoded data and imports it into a Deno KV store.

Keys

APIs for dealing with Deno KV keys.

equals()

Compares the equality of two Deno.KvKeys, returning true if they are equal and false if they are not. This is more specialized than other forms of deeply equal comparison.

partEquals()

Compares the equality of two Deno.KvKeyParts, returning true if they are equal and false if they are not. This is more specialized than other forms of equality comparison.

startsWith()

Determines if the key starts with the prefix provided, returning true if it does, otherwise false.

keys()

Similar to Deno.Kv.prototype.list(), in that is takes a selector, but instead of returning an async iterator of matched values, it resolves with an array of matching keys.

tree()

This resolves with the key parts in an tree like structure, where each branch of the tree contains the children indexed by key part. The interface of the resolved value is:

interface KeyTreeNode {
  part: Deno.KvKeyPart;
  children?: KeyTreeNode[];
}

interface KeyTree {
  prefix: Deno.KvKey;
  children?: KeyTreeNode[];
}

unique()

Resolves with an array of unique sub keys/prefixes for the provided prefix.

This is useful when storing keys and values in a hierarchical/tree view, where you are retrieving a list and you want to know all the unique descendants of a key in order to be able to enumerate them.

uniqueCount()

Resolves with an array of values which contain the unique sub keys/prefixes for the provided prefix along with a count of how many keys there are.

This is useful when storing keys and values in a hierarchical/tree view, where you are retrieving a list and you want to know all the unique descendants of a key (and the count of keys that match that prefix) in order to be able to enumerate them or provide information about them.

Copyright 2023 - 2024 Kitson P. Kelly - All rights reserved.

MIT License.