Class RouterBlockHandler

apps/sim/executor/handlers/router/router-handler.ts:31–424

 * Supports both legacy router (block-based) and router_v2 (port-based).
 */
export class RouterBlockHandler implements BlockHandler {
  constructor(private pathTracker?: any) {}

  canHandle(block: SerializedBlock): boolean {
    return block.metadata?.id === BlockType.ROUTER || block.metadata?.id === BlockType.ROUTER_V2
  }

  async execute(
    ctx: ExecutionContext,
    block: SerializedBlock,
    inputs: Record<string, any>
  ): Promise<BlockOutput> {
    const isV2 = isRouterV2BlockType(block.metadata?.id)

    if (isV2) {
      return this.executeV2(ctx, block, inputs)
    }

    return this.executeLegacy(ctx, block, inputs)
  }

  /**
   * Execute legacy router (block-based routing).
   */
  private async executeLegacy(
    ctx: ExecutionContext,
    block: SerializedBlock,
    inputs: Record<string, any>
  ): Promise<BlockOutput> {
    const targetBlocks = this.getTargetBlocks(ctx, block)

    const routerConfig = {
      prompt: inputs.prompt,
      model: inputs.model || ROUTER.DEFAULT_MODEL,
      apiKey: inputs.apiKey,
      vertexProject: inputs.vertexProject,
      vertexLocation: inputs.vertexLocation,
      vertexCredential: inputs.vertexCredential,
      bedrockAccessKeyId: inputs.bedrockAccessKeyId,
      bedrockSecretKey: inputs.bedrockSecretKey,
      bedrockRegion: inputs.bedrockRegion,
    }

    await validateModelProvider(ctx.userId, ctx.workspaceId, routerConfig.model, ctx)

    const providerId = getProviderFromModel(routerConfig.model)

    try {
      const url = new URL('/api/providers', getInternalApiBaseUrl())
      if (ctx.userId) url.searchParams.set('userId', ctx.userId)

      const messages = [{ role: 'user', content: routerConfig.prompt }]
      const systemPrompt = generateRouterPrompt(routerConfig.prompt, targetBlocks)

      let finalApiKey: string | undefined = routerConfig.apiKey
      if (providerId === 'vertex' && routerConfig.vertexCredential) {
        finalApiKey = await resolveVertexCredential(
          routerConfig.vertexCredential,