Class ApiReponseCache<V>

Persistent API response cache based on level-db.

Type Parameters

Hierarchy

ApiReponseCache

Index

Constructors

constructor

new ApiReponseCache<V>(options): ApiReponseCache<V>
Create a new instance.
Type Parameters
- V
Parameters
- options: IApiResponseCacheOptions
  
  Options for creating a new instance.
Returns ApiReponseCache<V>

Emits
options - the options used to create the instance.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:49

Properties

`Readonly` db

db: Level<string, string>

Level database instance

`Readonly` events

events: EventEmitter = ...

Event emitter for cache events

`Readonly` maxAgeMs

maxAgeMs: number

Max age of cached data in milliseconds. Defaults to 0 (no max age).

`Static` `Readonly` optionsDefaults

optionsDefaults: {
    dirpath: string;
    maxAgeMs: number;
    name: string;
} = ...

Default options for creating new instances

Type declaration

dirpath: string
maxAgeMs: number
name: string

Accessors

eventNames

get eventNames(): string[]
All emitted event names.

Returns string[]
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:26

Methods

delete

delete(hash): Promise<void>
Delete a given value for a given hash key if it exists.
Parameters
- hash: string
  
  The hash key.
Returns Promise<void>

Remarks
No error is thrown if no value exists for the given hash.

Emits
error - if deletion fails.

Emits
delete - if deletion succeeds.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:155

deleteEverything

deleteEverything(): Promise<void>
Delete all cached API responses.

Returns Promise<void>

Emits
delete - if deletion succeeds.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:176

deleteExpired

deleteExpired(): Promise<ApiReponseCache<V>>
Delete all expired data.

Returns Promise<ApiReponseCache<V>>
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:165

`Protected` emit

emit<T>(eventName, arg): T
Emit an event but this automatically adds 'this' as an extra argument.
Type Parameters
- T
Parameters
- eventName: string
  
  The event name.
- arg: T
Returns T
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:306

`Protected` ensureNotExpired

ensureNotExpired(hash, serialized): Promise<void>
Deletes a value from the cache if it is expired.
Parameters
- hash: string
  
  The hash key.
- serialized: string
  
  The serialized value.
Returns Promise<void>

Emits
expired - if the value is expired.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:246

entries

entries(): AsyncIterableIterator<[string, V]>
Iterate over all [key, value] pairs in the cache.

Returns AsyncIterableIterator<[string, V]>

Remarks
This data entries are expired, they are deleted and not yielded.

Emits
error - if iteration encounters an error.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:188

get

get(hash): Promise<V>
Get a value for a given hash key.
Parameters
- hash: string
  
  The hash key.
Returns Promise<V>

Emits
error - if the value does not exist for the give hash.

Emits
get - if the value exists for the given hash.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:94

getOrElse

getOrElse(hash, apiRequest): Promise<V>
Get a value for a given hash key if it exists. If the does not exist, returns a value from the api by invoking the provided function and then stores that value in the cache.
Parameters
- hash: string
  
  The hash key.
- apiRequest: (() => V | Promise<V>)
  
  function that returns a new value for a given key if it doesn't exist in the cache.
  - - (): V | Promise<V>
    - Returns V | Promise<V>
Returns Promise<V>

Emits
hit - if the value exists in the cache.

Emits
miss - if the value does not exist in the cache.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:76

getSafe

getSafe(hash): Promise<undefined | V>
Get a value for a given hash key or undefined if it does not exist or an error occurs.
Parameters
- hash: string
  
  The hash key.
Returns Promise<undefined | V>

Emits
get - if the value exists for the given hash.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:108

has

has(hash): Promise<boolean>
Returns whether a value exists for a given key.
Parameters
- hash: string
  
  The hash key.
Returns Promise<boolean>
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:123

hashKey

hashKey(key): string
Hash any type of key to a base64 string, using the SHA1 algorithm.
Parameters
- key: any
  
  The key to hash.
Returns string
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:64

`Protected` isExpired

isExpired(serialized): boolean
Check if a still raw serialized value string is expired.
Parameters
- serialized: string
  
  The serialized value.
Returns boolean
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:258

keys

keys(): AsyncIterableIterator<string>
Iterate over all keys in the cache.

Returns AsyncIterableIterator<string>

Emits
error - if iteration encounters an error.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:205

`Protected` orThrow

orThrow<T>(fn): T | Promise<T>
Shorthand for try/catch block with error-handling. Wrap a function call in a try catch block and emit an error event if an error occurs.
Type Parameters
- T
Parameters
- fn: (() => T | Promise<T>)
  
  The function to wrap.
  - - (): T | Promise<T>
    - Returns T | Promise<T>
Returns T | Promise<T>
The return value of the provided function.

Emits
error - if the provided function throws an error.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:294

`Protected` parseSerializedTimestamp

parseSerializedTimestamp(serialized): number
Parse the timestamp part of a raw serialized value string from the database.
Parameters
- serialized: string
  
  The serialized value.
Returns number
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:275

`Protected` parseSerializedValue

parseSerializedValue(serialized): V
Parse the json part of a raw serialized value string from the database.
Parameters
- serialized: string
  
  The serialized value.
Returns V
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:283

put

put(hash, value): Promise<V>
Set a given value for a given hash key.
Parameters
- hash: string
  
  The hash key.
- value: V
  
  The value to store.
Returns Promise<V>

Emits
put - if insertion succeeds.

Emits
error - if insertion fails.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:139

`Protected` serializeValue

serializeValue(value): string
Custom JSON stringify function that prepends a timestamp to the stringified object.
Parameters
- value: V
  
  The value to serialize.
Returns string
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:267

size

size(): Promise<number>
Get the number of entries in the cache.

Returns Promise<number>
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:232

values

values(): AsyncIterableIterator<V>
Iterate over all values in the cache.

Returns AsyncIterableIterator<V>

Emits
error - if iteration encounters an error.
- Defined in packages/api-util/src/lib/ApiReponseCache.ts:219

Class ApiReponseCache<V>

Type Parameters

V

Hierarchy

Index

Constructors

Properties

Accessors

Methods

Constructors

constructor

Type Parameters

V

Parameters

options: IApiResponseCacheOptions

Returns ApiReponseCache<V>

Emits

Properties

Readonly db

Readonly events

Readonly maxAgeMs

Static Readonly optionsDefaults

Type declaration

dirpath: string

maxAgeMs: number

name: string

Accessors

eventNames

Returns string[]

Methods

delete

Parameters

hash: string

Returns Promise<void>

Remarks

Emits

Emits

deleteEverything

Returns Promise<void>

Emits

deleteExpired

Returns Promise<ApiReponseCache<V>>

Protected emit

Type Parameters

T

Parameters

eventName: string

arg: T

Returns T

Protected ensureNotExpired

Parameters

hash: string

serialized: string

Returns Promise<void>

Emits

entries

Returns AsyncIterableIterator<[string, V]>

Remarks

Emits

get

Parameters

hash: string

Returns Promise<V>

Emits

Emits

getOrElse

Parameters

hash: string

apiRequest: (() => V | Promise<V>)

Returns V | Promise<V>

Returns Promise<V>

Emits

Emits

getSafe

Parameters

hash: string

Returns Promise<undefined | V>

Emits

has

Parameters

`Readonly` db

`Readonly` events

`Readonly` maxAgeMs

`Static` `Readonly` optionsDefaults

`Protected` emit

`Protected` ensureNotExpired

`Protected` isExpired

`Protected` orThrow

`Protected` parseSerializedTimestamp

`Protected` parseSerializedValue

`Protected` serializeValue