base-handler.ts•3.75 kB
/**
* Base trigger handler - abstract class for all trigger handlers
*/
import { z } from 'zod';
import { Workflow } from '../../types/n8n-api';
import { InstanceContext } from '../../types/instance-context';
import { N8nApiClient } from '../../services/n8n-api-client';
import { getN8nApiConfig } from '../../config/n8n-api';
import {
TriggerType,
TriggerResponse,
TriggerHandlerCapabilities,
DetectedTrigger,
BaseTriggerInput,
} from '../types';
/**
* Constructor type for trigger handlers
*/
export type TriggerHandlerConstructor = new (
client: N8nApiClient,
context?: InstanceContext
) => BaseTriggerHandler;
/**
* Abstract base class for all trigger handlers
*
* Each handler implements:
* - Input validation via Zod schema
* - Capability declaration (active workflow required, etc.)
* - Execution logic specific to the trigger type
*/
export abstract class BaseTriggerHandler<T extends BaseTriggerInput = BaseTriggerInput> {
protected client: N8nApiClient;
protected context?: InstanceContext;
/** The trigger type this handler supports */
abstract readonly triggerType: TriggerType;
/** Handler capabilities */
abstract readonly capabilities: TriggerHandlerCapabilities;
/** Zod schema for input validation */
abstract readonly inputSchema: z.ZodSchema<T>;
constructor(client: N8nApiClient, context?: InstanceContext) {
this.client = client;
this.context = context;
}
/**
* Validate input against schema
* @throws ZodError if validation fails
*/
validate(input: unknown): T {
return this.inputSchema.parse(input);
}
/**
* Execute the trigger
*
* @param input - Validated trigger input
* @param workflow - The workflow being triggered
* @param triggerInfo - Detected trigger information (may be undefined for 'execute' type)
*/
abstract execute(
input: T,
workflow: Workflow,
triggerInfo?: DetectedTrigger
): Promise<TriggerResponse>;
/**
* Get the n8n instance base URL from context or environment config
*/
protected getBaseUrl(): string | undefined {
// First try context (for multi-tenant scenarios)
if (this.context?.n8nApiUrl) {
return this.context.n8nApiUrl.replace(/\/api\/v1\/?$/, '');
}
// Fallback to environment config
const config = getN8nApiConfig();
if (config?.baseUrl) {
return config.baseUrl.replace(/\/api\/v1\/?$/, '');
}
return undefined;
}
/**
* Get the n8n API key from context or environment config
*/
protected getApiKey(): string | undefined {
// First try context (for multi-tenant scenarios)
if (this.context?.n8nApiKey) {
return this.context.n8nApiKey;
}
// Fallback to environment config
const config = getN8nApiConfig();
return config?.apiKey;
}
/**
* Normalize response to unified format
*/
protected normalizeResponse(
result: unknown,
input: T,
startTime: number,
extra?: Partial<TriggerResponse>
): TriggerResponse {
const endTime = Date.now();
const duration = endTime - startTime;
return {
success: true,
triggerType: this.triggerType,
workflowId: input.workflowId,
data: result,
metadata: {
duration,
},
...extra,
};
}
/**
* Create error response
*/
protected errorResponse(
input: BaseTriggerInput,
error: string,
startTime: number,
extra?: Partial<TriggerResponse>
): TriggerResponse {
const endTime = Date.now();
const duration = endTime - startTime;
return {
success: false,
triggerType: this.triggerType,
workflowId: input.workflowId,
error,
metadata: {
duration,
},
...extra,
};
}
}