axios-retryer/dist/plugins/CachingPlugin.d.ts

TypeScript-first Axios retry library with concurrency limits, request priority, token refresh, response caching, and circuit breaker plugins.

import { Method, AxiosRequestConfig, AxiosError, AxiosInstance, AxiosResponse } from 'axios';

type AxiosRetryerHttpMethod = Method;
declare const AXIOS_RETRYER_REQUEST_PRIORITIES: {
    readonly CRITICAL: 4;
    readonly HIGHEST: 3;
    readonly HIGH: 2;
    readonly MEDIUM: 1;
    readonly LOW: 0;
};
type AxiosRetryerRequestPriority = (typeof AXIOS_RETRYER_REQUEST_PRIORITIES)[keyof typeof AXIOS_RETRYER_REQUEST_PRIORITIES];

type RetryEventArgs<TEvents extends object, K extends keyof TEvents> = NonNullable<TEvents[K]> extends (...args: infer TArgs) => unknown ? TArgs : never;
type RetryEventListener<TEvents extends object, K extends keyof TEvents> = (...args: RetryEventArgs<TEvents, K>) => void;
/**
 * Terminal request error payload emitted by `onRequestError`.
 */
interface AxiosRetryerRequestErrorEvent {
    /** Final Axios error object that caused request failure. */
    error: AxiosError;
    /** Final Axios request config that failed. */
    config: AxiosRequestConfig;
    /** HTTP status if available, otherwise `null` for network-level failures. */
    status: number | null;
    /** Request identifier if available. */
    requestId?: string;
    /** Total attempts performed including the initial attempt. */
    attempts: number;
    /** Whether the final error shape is considered retryable by the active strategy. */
    retryable: boolean;
}
/**
 * Queue-entry payload emitted by `onRequestQueued`.
 */
interface AxiosRetryerRequestQueuedEvent {
    /** Request identifier generated or assigned by RetryManager. */
    requestId: string;
    /** Request config entering the queue. */
    config: AxiosRequestConfig;
    /** Resolved priority used for queue ordering. */
    priority: AxiosRetryerRequestPriority;
    /** Queue size immediately after this request was enqueued. */
    queueSize: number;
}
/**
 * Queue-dispatch payload emitted by `onRequestDispatched`.
 */
interface AxiosRetryerRequestDispatchedEvent {
    /** Request identifier generated or assigned by RetryManager. */
    requestId: string;
    /** Request config dispatched from the queue. */
    config: AxiosRequestConfig;
    /** Resolved priority used for queue ordering. */
    priority: AxiosRetryerRequestPriority;
    /** Time spent waiting in the queue before dispatch (milliseconds). */
    queuedForMs: number;
}
/**
 * Success payload emitted by `onRequestSucceeded`.
 */
interface AxiosRetryerRequestSucceededEvent {
    /** Request identifier generated or assigned by RetryManager. */
    requestId?: string;
    /** Final request config that succeeded. */
    config: AxiosRequestConfig;
    /** Final HTTP status code. */
    status: number;
    /** Total attempts performed including the initial attempt. */
    attempts: number;
}
/**
 * Core events exposed by RetryManager without any plugins attached.
 */
interface CoreRetryEvents {
    /**
     * Triggered when the retry process begins.
     */
    onRetryProcessStarted?: () => void;
    /**
     * Triggered before each retry attempt.
     * @param config The Axios request configuration being retried.
     */
    beforeRetry?: (config: AxiosRequestConfig) => void;
    /**
     * Triggered after a retry attempt.
     * @param config The Axios request configuration being retried.
     * @param success Whether the retry was successful.
     * @param error If the retry failed, the error that caused the failure.
     */
    afterRetry?: (config: AxiosRequestConfig, success: boolean, error?: AxiosError) => void;
    /**
     * Triggered when a retry is scheduled and waiting for the specified delay.
     * @param delayMs The delay in milliseconds.
     * @param config The Axios request configuration.
     */
    onRetryScheduled?: (delayMs: number, config: AxiosRequestConfig) => void;
    /**
     * Triggered for each failed retry attempt.
     * @param config The failed Axios request configuration.
     */
    onFailure?: (config: AxiosRequestConfig) => void;
    /**
     * Triggered when a request enters the queue.
     *
     * @param payload Queue entry metadata for this request.
     */
    onRequestQueued?: (payload: AxiosRetryerRequestQueuedEvent) => void;
    /**
     * Triggered when a queued request is dispatched from the queue to the network layer.
     *
     * @param payload Dispatch metadata including queue wait duration.
     */
    onRequestDispatched?: (payload: AxiosRetryerRequestDispatchedEvent) => void;
    /**
     * Triggered when a request succeeds (initial attempt or after retries).
     *
     * @param payload Success metadata for this request.
     */
    onRequestSucceeded?: (payload: AxiosRetryerRequestSucceededEvent) => void;
    /**
     * Triggered once when a request fails terminally (all retries exhausted or no-retry terminal path).
     * Unlike `onFailure`, this event is emitted only for the final failure.
     *
     * @param payload Terminal error context for application-level handling.
     */
    onRequestError?: (payload: AxiosRetryerRequestErrorEvent) => void;
    /**
     * Triggered when all retries are completed.
     */
    onRetryProcessFinished?: () => void;
    /**
     * Triggered when an in-flight retry delay timer is cancelled — either because
     * the user aborted the request (`source: 'user'`) or because the system shut
     * the request down (`source: 'system'`, e.g. plugin destroy, queue clear).
     */
    onRetryTimerCancelled?: (payload: {
        requestId: string;
        source: 'user' | 'system';
    }) => void;
    /**
     * Triggered when a request cancelled.
     * @param requestId Id of the cancelled request.
     */
    onRequestCancelled?: (requestId: string) => void;
    /**
     * Called when a request fails due to network or connection issues, meaning
     * no valid server response was received (e.g., user is offline).
     *
     * @param request - The Axios request config that encountered a connection error.
     */
    onInternetConnectionError?: (request: AxiosRequestConfig) => void;
    /**
     * Triggered when a blocking request (at or above `blockingPriorityThreshold`) fails terminally.
     * Only fires when `blockingPriorityThreshold` is configured.
     *
     * @param config The Axios request config of the failed blocking request.
     */
    onBlockingRequestFailed?: (config: AxiosRequestConfig) => void;
    /**
     * Triggered when every in-flight blocking request (at or above `blockingPriorityThreshold`)
     * has **succeeded** (terminal success) and none remain in the internal blocker set.
     * Not emitted when a blocker fails (`onBlockingRequestFailed`) or is cancelled.
     * Only fires when `blockingPriorityThreshold` is configured.
     */
    onAllBlockingRequestsResolved?: () => void;
}
type RetryManagerEvents<TPluginEvents extends object = Record<never, never>> = {
    [K in keyof CoreRetryEvents | keyof TPluginEvents]: K extends keyof TPluginEvents ? K extends keyof CoreRetryEvents ? CoreRetryEvents[K] & TPluginEvents[K] : TPluginEvents[K] : K extends keyof CoreRetryEvents ? CoreRetryEvents[K] : never;
};

/**
 * Represents the distribution of different error types encountered
 */
interface ErrorTypesDistribution {
    /** Number of network-related errors (e.g., connection failures) */
    network: number;
    /** Number of 5xx server errors */
    server5xx: number;
    /** Number of 4xx client errors */
    client4xx: number;
    /** Number of canceled requests */
    cancelled: number;
}
/**
 * Represents metrics for a specific request priority level
 */
interface PriorityMetrics {
    /** The priority level (higher numbers indicate higher priority) */
    priority: number;
    /** Total number of retry attempts for this priority */
    total: number;
    /** Number of successful retries for this priority */
    successes: number;
    /** Number of failed retries for this priority */
    failures: number;
    /** Success rate percentage for this priority (0-100) */
    successRate: number;
    /** Failure rate percentage for this priority (0-100) */
    failureRate: number;
}
/**
 * AxiosRetryer detailed metrics
 * */
interface AxiosRetryerDetailedMetrics {
    /** Total number of requests made through the retryer */
    totalRequests: number;
    /** Number of successfully completed retries */
    successfulRetries: number;
    /** Number of failed retry attempts */
    failedRetries: number;
    /** Requests that failed all retry attempts */
    completelyFailedRequests: number;
    /** Requests canceled before completion */
    canceledRequests: number;
    /** Critical priority requests that failed all retries */
    completelyFailedCriticalRequests: number;
    /** Distribution of error types encountered */
    errorTypesDistribution: ErrorTypesDistribution;
    /** Distribution of retry attempts across all requests */
    retryAttemptsDistribution: Record<number, number>;
    /** Count of requests by priority level */
    requestCountsByPriority: Record<number, number>;
    /** Average time spent in queue (seconds) */
    avgQueueWait: number;
    /** Average delay between retry attempts (seconds) */
    avgRetryDelay: number;
    /** Detailed metrics grouped by request priority */
    priorityMetrics: PriorityMetrics[];
    /** Timer health and accumulation metrics */
    timerHealth: {
        /** Number of active internal timers */
        activeTimers: number;
        /** Number of active retry timers */
        activeRetryTimers: number;
        /** Health score (0 = excellent, 100+ = potential issues) */
        healthScore: number;
    };
}
/**
 * Interface for pluggable metrics recording.
 * The core library ships with no-op metrics by default.
 * Use MetricsPlugin for full metrics collection.
 */
interface MetricsRecorder {
    reset(): void;
    buildDetailedMetrics(timerStats: {
        activeTimers: number;
        activeRetryTimers: number;
    }): AxiosRetryerDetailedMetrics;
    emitMetricsUpdated?(): void;
}

/**
 * Logger interface used by RetryManager and its collaborators.
 * Supply a custom implementation via {@link RetryManagerOptions.logger}
 * to redirect or suppress log output.
 */
interface Logger {
    log(message: string, data?: unknown): void;
    error(message: string, error?: unknown): void;
    warn(message: string, data?: unknown): void;
    debug(message: string, meta?: unknown): void;
}
/**
 * Context object passed to plugins during initialization and teardown.
 * Provides the plugin-facing view of RetryManager capabilities including
 * plugin-only wiring hooks that are not part of the public manager API.
 */
interface PluginContext<TPluginEvents extends object = Record<never, never>> {
    /** The Axios instance managed by RetryManager. */
    readonly axiosInstance: AxiosInstance;
    /** Returns the configured logger. */
    getLogger(): Logger;
    /** Subscribe to a manager or plugin event. */
    on<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, listener: RetryEventListener<RetryManagerEvents<TPluginEvents>, K>): void;
    /** Unsubscribe from a manager or plugin event. */
    off<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, listener: RetryEventListener<RetryManagerEvents<TPluginEvents>, K>): boolean;
    /** Fire all listeners registered for this event. */
    emit<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, ...args: RetryEventArgs<RetryManagerEvents<TPluginEvents>, K>): void;
    /**
     * Identical to `emit` — fires all listeners registered for this event.
     *
     * Kept for backward compatibility with existing plugins. There is no semantic
     * distinction from `emit`: prefer `emit` in new code.
     */
    triggerAndEmit<K extends keyof RetryManagerEvents<TPluginEvents>>(event: K, ...args: RetryEventArgs<RetryManagerEvents<TPluginEvents>, K>): void;
    /** Cancel a specific in-flight or queued request by its ID. */
    cancelRequest(requestId: string): void;
    /** Cancel all active and queued requests. */
    cancelAllRequests(): void;
    /** Cancel only requests currently waiting in the queue. */
    cancelQueuedRequests(): void;
    /**
     * Register a queue gate that must approve each request before it is dispatched.
     * Used by plugins that need to block request processing under certain conditions.
     */
    registerQueueGate(name: string, canProcess: (request: AxiosRequestConfig) => boolean): void;
    /** Remove a previously registered queue gate. */
    unregisterQueueGate(name: string): boolean;
    /** Trigger a queue drain pass. Useful after a gate condition changes. */
    refreshQueue(): void;
    /**
     * Register or unregister a metrics recorder.
     * Pass `null` to detach. Used by MetricsPlugin to expose metric data to the RetryManager's getMetrics() method.
     */
    registerMetricsRecorder(recorder: MetricsRecorder | null): void;
    /**
     * Return active timer counts.
     * Used by MetricsPlugin to populate the timerHealth section of detailed metrics.
     */
    getTimerStats(): {
        activeTimers: number;
        activeRetryTimers: number;
    };
    /**
     * Release lifecycle tracking for a request config and mark its queue slot complete.
     * Used by TokenRefreshPlugin when a tracked request is intercepted for token refresh.
     */
    releaseRequestTracking(config: AxiosRequestConfig): void;
}
/**
 * AxiosRetryer plugin interface that can be attached with {@link RetryManager.use} and removed with {@link RetryManager.unuse}
 * */
interface RetryPlugin<TPluginEvents extends object = Record<never, never>> {
    /**
     * Plugin name. Should be unique
     * */
    name: string;
    /**
     * Plugin version (e.g. 1.0.0)
     * */
    version: string;
    /**
     * Phantom covariant marker for TypeScript to infer `TPluginEvents` at call sites
     * such as `manager.use(plugin)`. Never set this at runtime; implementations may
     * simply omit it (it is always `undefined`).
     * */
    readonly _events?: Readonly<TPluginEvents>;
    /**
     * Called when the plugin is attached and initialized.
     * @param context Plugin context providing manager capabilities and plugin-only wiring hooks.
     * */
    initialize: (context: PluginContext<TPluginEvents>) => void;
    /**
     * Called before the plugin is removed.
     * @param context Plugin context providing manager capabilities and plugin-only wiring hooks.
     * */
    onBeforeDestroyed?: (context: PluginContext<TPluginEvents>) => void;
}

type MaybePromise<T> = T | Promise<T>;
/**
 * Represents a cached item containing the AxiosResponse and the timestamp it was cached.
 */
interface CachedItem {
    response: AxiosResponse<unknown>;
    timestamp: number;
    ttr?: number;
    lastAccessedAt?: number;
}
interface CacheStorageEntry {
    readonly key: string;
    readonly value: CachedItem;
}
interface CacheStorage {
    get(key: string): MaybePromise<CachedItem | undefined>;
    set(key: string, value: CachedItem): MaybePromise<void>;
    delete(key: string): MaybePromise<void>;
    clear(): MaybePromise<void>;
    /**
     * Returns the adapter's full cache index.
     * Cleanup and non-exact invalidation operate on this index.
     */
    entries(): MaybePromise<readonly CacheStorageEntry[]>;
}
/**
 * Options for the CachingPlugin.
 */
interface CachingPluginOptions {
    /**
     * Response header names that are stripped before a response is written to the cache.
     * This prevents sensitive per-user or session-establishing headers (e.g. `Set-Cookie`)
     * from being replayed to different callers who receive a cached response.
     *
     * Matching is case-insensitive.
     *
     * @default ['set-cookie']
     */
    sensitiveResponseHeaders?: readonly string[];
    /**
     * If true, include the entire headers object in the cache key.
     * @default false
     */
    compareHeaders?: boolean;
    /**
     * Duration (in milliseconds) a cached entry is considered fresh.
     * If 0, the cache never expires.
     * @default 0
     */
    timeToRevalidate?: number;
    /**
     * HTTP methods to cache. By default, only GET requests are cached.
     * @default [AXIOS_RETRYER_HTTP_METHODS.GET]
     */
    cacheMethods?: readonly AxiosRetryerHttpMethod[];
    /**
     * Interval in milliseconds to run cache cleanup.
     * If 0, periodic cleanup is disabled.
     * @default 0
     */
    cleanupInterval?: number;
    /**
     * Maximum age in milliseconds for cached items.
     * Items older than this will be removed during cleanup.
     * If 0, items don't expire based on age.
     * @default 0
     */
    maxAge?: number;
    /**
     * Maximum number of items to keep in cache.
     * If exceeded, oldest items will be removed first.
     * If 0, no limit is applied.
     * @default 1000
     */
    maxItems?: number;
    /**
     * If true, only requests that are retried will be cached.
     * Requests that are not retried will not be cached even if they are cacheable.
     * @default false
     */
    cacheOnlyRetriedRequests?: boolean;
    /**
     * Indexed storage backend used for cache entries.
     * Custom adapters must implement `entries()` so cleanup and invalidation can
     * operate on the adapter's source of truth after restart or across processes.
     * Defaults to the built-in in-memory storage.
     */
    storage?: CacheStorage;
    /**
     * If true, concurrent identical cacheable requests share the same in-flight response.
     * @default true
     */
    dedupeConcurrentRequests?: boolean;
    /**
     * Allows custom cache key composition from canonical request parts.
     * The default builder uses normalized method, URL, params, body, and optional headers.
     */
    cacheKeyBuilder?: CacheKeyBuilder;
    /**
     * When true, requests carrying authentication headers (Authorization, Cookie,
     * Proxy-Authorization, X-Auth-Token, X-API-Key) are excluded from caching.
     * This prevents cross-principal cache collisions on shared retryer instances.
     *
     * Set to `false` only for legitimate shared-cache use cases where all
     * principals should receive the same cached response.
     *
     * @default true
     */
    skipWhenAuthPresent?: boolean;
    /**
     * Header names whose values are folded into the cache key, binding each
     * cache entry to the identity or context carried by those headers.
     *
     * Use this instead of (or together with) `skipWhenAuthPresent: false`
     * when you need per-principal caching rather than skipping the cache entirely.
     *
     * Header name matching is case-insensitive.
     *
     * @default []
     *
     * @example
     * ```ts
     * // Cache responses per-user based on their Authorization header:
     * new CachingPlugin({ skipWhenAuthPresent: false, varyHeaders: ['Authorization'] });
     * ```
     */
    varyHeaders?: readonly string[];
    /**
     * Maximum byte size of a response body (measured via `JSON.stringify` length) that
     * will be written to the cache. Responses whose serialized body exceeds this limit
     * are served normally but not stored.
     *
     * Use this to prevent a single large response from consuming excessive memory.
     * Set to `0` to disable the check (no limit).
     *
     * @default 0
     */
    maxEntrySize?: number;
}
interface CachingRequestOptions {
    cache?: boolean;
    ttr?: number;
}
interface CacheKeyBuilderContext {
    readonly config: AxiosRequestConfig;
    readonly method: string;
    readonly normalizedUrl: string;
    readonly normalizedParams: string;
    readonly normalizedData: string;
    readonly normalizedHeaders: string;
}
type CacheKeyBuilder = (context: CacheKeyBuilderContext) => string;
interface CachingPluginEvents {
    onCacheHit?: (payload: {
        keyFingerprint: string;
        config: AxiosRequestConfig;
        ageMs: number;
    }) => void;
    onCacheMiss?: (payload: {
        keyFingerprint: string;
        config: AxiosRequestConfig;
        reason: 'empty' | 'stale';
    }) => void;
    onCacheInvalidated?: (payload: {
        count: number;
        matcher: 'all' | 'custom';
    }) => void;
}
type CacheInvalidationMatcher = string | RegExp | {
    exact: string;
} | {
    prefix: string;
};

declare class InMemoryCacheStorage implements CacheStorage {
    private readonly storage;
    get(key: string): CachedItem | undefined;
    set(key: string, value: CachedItem): void;
    delete(key: string): void;
    clear(): void;
    entries(): readonly CacheStorageEntry[];
}

declare class CachingPlugin implements RetryPlugin<CachingPluginEvents> {
    name: string;
    version: string;
    readonly _events?: Readonly<CachingPluginEvents>;
    private context;
    private interceptorIdReq;
    private interceptorIdRes;
    private static readonly CACHE_CLEANUP_TIMEOUT_MS;
    private static readonly CACHE_CLEANUP_DISABLE_AFTER;
    private readonly cache;
    private readonly inflight;
    private readonly cleanup;
    private readonly options;
    private readonly storage;
    constructor(options?: CachingPluginOptions);
    initialize(context: PluginContext<CachingPluginEvents>): void;
    onBeforeDestroyed(): void;
    private getCacheKeyFingerprint;
    /**
     * Checks if there is a fresh cached response and handles the request accordingly.
     */
    private handleRequest;
    /**
     * Handles successful responses by caching them when appropriate.
     */
    private handleResponseSuccess;
    private handleResponseError;
    /**
     * Generates a unique cache key based on the request configuration.
     */
    buildCacheKey(config: AxiosRequestConfig): string;
    private runCacheCleanup;
    /**
     * Manually clears all cache entries.
     */
    clearCache(): void | Promise<void>;
    /**
     * Invalidates cache entries using explicit exact-key, prefix, or RegExp matching.
     *
     * Plain string input is treated as an exact-key match.
     *
     * @param matcher The exact key, prefix matcher, or RegExp to match for invalidation
     * @returns The number of invalidated cache entries
     */
    invalidateCache(matcher: CacheInvalidationMatcher): number | Promise<number>;
    /**
     * Returns current cache statistics.
     */
    getCacheStats(): {
        size: number;
        oldestItemAge: number;
        newestItemAge: number;
        averageAge: number;
    };
    private upsertCacheEntry;
    private touchCacheEntry;
    private deleteCacheEntry;
    private getRequestCachingOptions;
    private readCacheEntriesForScan;
    private syncLocalCache;
    private enforceMaxItemsBeforeUpsert;
    private persistCacheTouchIfNeeded;
    private invalidateCacheEntries;
    private buildCacheKeyContext;
}

declare class InvalidCacheKeyError extends Error {
    constructor();
}

declare module 'axios' {
    interface AxiosRequestConfig {
        __cachingOptions?: CachingRequestOptions;
    }
}
/**
 * Creates a CachingPlugin instance.
 * Functional alternative to using the `new CachingPlugin()` constructor.
 *
 * The caching plugin stores responses from successful requests and returns them
 * for identical requests, reducing network traffic and improving performance.
 *
 * @param options Configuration options for the CachingPlugin
 * @returns A configured CachingPlugin instance
 *
 * @example
 * ```typescript
 * import { AXIOS_RETRYER_HTTP_METHODS } from 'axios-retryer';
 *
 * const cachePlugin = createCachePlugin({
 *   timeToRevalidate: 60000,  // Cache responses for 60 seconds
 *   cacheMethods: [AXIOS_RETRYER_HTTP_METHODS.GET], // Only cache GET requests
 *   cleanupInterval: 300000,  // Run cleanup every 5 minutes
 *   maxItems: 100,            // Store at most 100 responses
 *   compareHeaders: false     // Don't include headers in cache key
 * });
 *
 * manager.use(cachePlugin);
 * ```
 */
declare function createCachePlugin(options?: CachingPluginOptions): CachingPlugin;

export { CachingPlugin, InMemoryCacheStorage, InvalidCacheKeyError, createCachePlugin };
export type { CacheInvalidationMatcher, CacheKeyBuilder, CacheKeyBuilderContext, CacheStorage, CacheStorageEntry, CachedItem, CachingPluginEvents, CachingPluginOptions, CachingRequestOptions };