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Class: ProxyFetchDO

Defined in: src/ProxyFetchDurableObject.ts:50

ProxyFetchDO - Durable Object that queues and processes external fetch requests

This DO provides a centralized service for executing external fetch() calls on behalf of other Durable Objects. By offloading fetch operations to this dedicated DO, other DOs avoid wall-clock billing while fetch requests are in flight.

Architecture:

  • Single named instance ('proxy-fetch-global') handles all proxy fetch operations
  • ULID-based FIFO queue ensures requests are processed in order
  • In-flight tracking prevents duplicate processing
  • Automatic retry with exponential backoff for transient failures
  • Callback delivery to origin DO when complete
  • Fire-and-forget mode supported (no callback)

Usage:

// From within another DO:
const reqId = await proxyFetchDO(
  this,                    // DO instance
  'https://api.example.com/data',
  'MY_DO',                 // DO binding name
  'handleApiResponse',     // Handler method name
  { timeout: 10000 }
);

// Handler receives response:
async handleApiResponse(item: ProxyFetchHandlerItem) {
  if (item.error) {
    console.error('Fetch failed:', item.error);
  } else {
  *     const response = decodeResponse(item.response);
    const data = await response.json();
    // Process data...
  }
}

See​

https://lumenize.com/docs/proxy-fetch/durable-object

Extends​

  • DurableObject

Constructors​

Constructor​

new ProxyFetchDO(ctx, env): ProxyFetchDO

Defined in: src/ProxyFetchDurableObject.ts:51

Parameters​

ctx​

DurableObjectState

env​

any

Returns​

ProxyFetchDO

Overrides​

DurableObject.constructor

Properties​

__DURABLE_OBJECT_BRAND​

__DURABLE_OBJECT_BRAND: never

Defined in: test/do/worker-configuration.d.ts:7767

Inherited from​

DurableObject.__DURABLE_OBJECT_BRAND

ctx​

protected ctx: DurableObjectState<{ }>

Defined in: test/do/worker-configuration.d.ts:7768

Inherited from​

DurableObject.ctx

env​

protected env: Env

Defined in: test/do/worker-configuration.d.ts:7769

Inherited from​

DurableObject.env

Methods​

alarm()​

alarm(): Promise<void>

Defined in: src/ProxyFetchDurableObject.ts:83

Process the queue via alarm

Alarm is triggered automatically by Cloudflare when scheduled. Calls the shared queue processing logic.

Returns​

Promise<void>

Overrides​

DurableObject.alarm

enqueue()​

enqueue(request): Promise<void>

Defined in: src/ProxyFetchDurableObject.ts:66

Enqueue a request for async processing

Called by proxyFetchDO() client function to add a request to the queue. Generates a monotonic ULID for FIFO ordering and immediately processes the queue.

Parameters​

request​

ProxyFetchQueueMessage

Serialized request with metadata

Returns​

Promise<void>

fetch()?​

optional fetch(request): Response | Promise<Response>

Defined in: test/do/worker-configuration.d.ts:7771

Parameters​

request​

Request

Returns​

Response | Promise<Response>

Inherited from​

DurableObject.fetch

triggerRecovery()​

triggerRecovery(): Promise<void>

Defined in: src/ProxyFetchDurableObject.ts:93

TEST ONLY: Manually trigger orphaned request recovery

This method exists solely for testing. In production, recovery happens automatically in the constructor when a DO is evicted and reinstantiated.

Returns​

Promise<void>

webSocketClose()?​

optional webSocketClose(ws, code, reason, wasClean): void | Promise<void>

Defined in: test/do/worker-configuration.d.ts:7774

Parameters​

ws​

WebSocket

code​

number

reason​

string

wasClean​

boolean

Returns​

void | Promise<void>

Inherited from​

DurableObject.webSocketClose

webSocketError()?​

optional webSocketError(ws, error): void | Promise<void>

Defined in: test/do/worker-configuration.d.ts:7775

Parameters​

ws​

WebSocket

error​

unknown

Returns​

void | Promise<void>

Inherited from​

DurableObject.webSocketError

webSocketMessage()?​

optional webSocketMessage(ws, message): void | Promise<void>

Defined in: test/do/worker-configuration.d.ts:7773

Parameters​

ws​

WebSocket

message​

string | ArrayBuffer

Returns​

void | Promise<void>

Inherited from​

DurableObject.webSocketMessage