feat: add support for lambda streaming (#225)

src/Nextjs.ts

@@ -100,6 +100,11 @@ export interface NextjsProps {
    * could be important for some users.
    */
   readonly skipFullInvalidation?: boolean;
+  /**
+   * Streaming allows you to send data to the client as it's generated
+   * instead of waiting for the entire response to be generated.
+   */
+  readonly streaming?: boolean;
 }
 
 /**
@@ -160,6 +165,7 @@ export class Nextjs extends Construct {
       environment: props.environment,
       quiet: props.quiet,
       skipBuild: props.skipBuild,
+      streaming: props.streaming,
       ...props.overrides?.nextjs?.nextjsBuildProps,
     });
 
@@ -205,6 +211,7 @@ export class Nextjs extends Construct {
       nextjsPath: props.nextjsPath,
       basePath: props.basePath,
       distribution: props.distribution,
+      streaming: props.streaming,
       staticAssetsBucket: this.staticAssets.bucket,
       nextBuild: this.nextBuild,
       nextDomain: this.domain,

src/NextjsBuild.ts

@@ -41,6 +41,10 @@ export interface NextjsBuildProps {
    * @see {@link NextjsProps.skipBuild}
    */
   readonly skipBuild?: NextjsProps['skipBuild'];
+  /**
+   * @see {@link NextjsProps.streaming}
+   */
+  readonly streaming?: NextjsProps['streaming'];
 }
 
 /**
@@ -142,7 +146,8 @@ export class NextjsBuild extends Construct {
 
   private build() {
     const buildPath = this.props.buildPath ?? this.props.nextjsPath;
-    const buildCommand = this.props.buildCommand ?? 'npx open-next@^2 build';
+    const defaultBuildCommand = `npx open-next@^2 build ${this.props.streaming ? '--streaming' : ''}`;
+    const buildCommand = this.props.buildCommand ?? defaultBuildCommand;
     // run build
     if (!this.props.quiet) {
       console.debug(`Running "${buildCommand}" in`, buildPath);

src/NextjsDistribution.ts

@@ -13,7 +13,7 @@ import * as origins from 'aws-cdk-lib/aws-cloudfront-origins';
 import { HttpOriginProps } from 'aws-cdk-lib/aws-cloudfront-origins';
 import { PolicyStatement, ServicePrincipal } from 'aws-cdk-lib/aws-iam';
 import * as lambda from 'aws-cdk-lib/aws-lambda';
-import { Runtime } from 'aws-cdk-lib/aws-lambda';
+import { Runtime, InvokeMode } from 'aws-cdk-lib/aws-lambda';
 import * as s3 from 'aws-cdk-lib/aws-s3';
 import { Construct } from 'constructs';
 import { NEXTJS_BUILD_DIR, NEXTJS_STATIC_DIR } from './constants';
@@ -89,6 +89,10 @@ export interface NextjsDistributionProps {
    * Must be provided if you want to serve static files.
    */
   readonly staticAssetsBucket: s3.IBucket;
+  /**
+   * @see {@link NextjsProps.streaming}
+   */
+  readonly streaming?: boolean;
 }
 
 /**
@@ -256,7 +260,10 @@ export class NextjsDistribution extends Construct {
   }
 
   private createServerBehaviorOptions(): cloudfront.BehaviorOptions {
-    const fnUrl = this.props.serverFunction.addFunctionUrl({ authType: this.fnUrlAuthType });
+    const fnUrl = this.props.serverFunction.addFunctionUrl({
+      authType: this.fnUrlAuthType,
+      invokeMode: this.props.streaming ? InvokeMode.RESPONSE_STREAM : InvokeMode.BUFFERED,
+    });
     const origin = new origins.HttpOrigin(Fn.parseDomainName(fnUrl.url), this.props.overrides?.serverHttpOriginProps);
     const serverBehaviorOptions = this.props.overrides?.serverBehaviorOptions;