feat: enable C# emitter in playground with backend server

cspell.yaml

@@ -49,6 +49,7 @@ words:
   - CORGE
   - createsorreplacesresource
   - createsorupdatesresource
+  - Creds
   - CRUDL
   - ctxt
   - dbaeumer
@@ -270,6 +271,7 @@ words:
   - tspwebsitepr
   - tsvs
   - typespec
+  - typespecacr
   - typespecvs
   - tzname
   - Uhoh

eng/emitters/pipelines/templates/stages/emitter-stages.yml

@@ -87,6 +87,24 @@ parameters:
     type: boolean
     default: false
 
+  # The npm script to run to build the emitter for playground bundling.
+  # Default is "build". C# uses "build:emitter" to skip the .NET generator build.
+  - name: PlaygroundBundleBuildScript
+    type: string
+    default: "build"
+
+  # Path to a Dockerfile (relative to PackagePath) for the playground server.
+  # When set alongside UploadPlaygroundBundle, the server container is built and
+  # deployed to Azure App Service after publishing.
+  - name: PlaygroundServerDockerfile
+    type: string
+    default: ""
+
+  # Azure App Service name for the playground server.
+  - name: PlaygroundServerAppName
+    type: string
+    default: ""
+
 stages:
   # Build stage
   # Responsible for building the autorest generator and typespec emitter packages
@@ -353,10 +371,30 @@ stages:
                   LanguageShortName: ${{ parameters.LanguageShortName }}
 
               - ${{ if parameters.UploadPlaygroundBundle }}:
+                  - task: NodeTool@0
+                    displayName: Use Node 22.x for playground bundle
+                    inputs:
+                      versionSpec: "22.x"
                   - script: npm ci
                     displayName: Install emitter dependencies for playground bundle
                     workingDirectory: $(Build.SourcesDirectory)/${{ parameters.PackagePath }}
-                  - script: npm run build
+                  - ${{ if parameters.BuildPrereleaseVersion }}:
+                      - script: |
+                          CURRENT_VERSION=$(node -p "require('./package.json').version")
+                          NEW_VERSION="${CURRENT_VERSION}-alpha.${BUILD_BUILDNUMBER}"
+                          echo "Setting version to $NEW_VERSION"
+                          npm version "$NEW_VERSION" --no-git-tag-version
+                        displayName: Stamp build version for playground bundle
+                        workingDirectory: $(Build.SourcesDirectory)/${{ parameters.PackagePath }}
+                  - ${{ else }}:
+                      - script: |
+                          CURRENT_VERSION=$(node -p "require('./package.json').version")
+                          NEW_VERSION="${CURRENT_VERSION}-beta.${BUILD_BUILDNUMBER}"
+                          echo "Setting version to $NEW_VERSION"
+                          npm version "$NEW_VERSION" --no-git-tag-version
+                        displayName: Stamp build version for playground bundle
+                        workingDirectory: $(Build.SourcesDirectory)/${{ parameters.PackagePath }}
+                  - script: npm run ${{ parameters.PlaygroundBundleBuildScript }}
                     displayName: Build emitter for playground bundle
                     workingDirectory: $(Build.SourcesDirectory)/${{ parameters.PackagePath }}
                   - script: npm install -g pnpm
@@ -375,6 +413,38 @@ stages:
                       inlineScript: node ./eng/emitters/scripts/upload-bundled-emitter.js ${{ parameters.PackagePath }}
                       workingDirectory: $(Build.SourcesDirectory)
 
+              - ${{ if and(parameters.PlaygroundServerDockerfile, parameters.PlaygroundServerAppName) }}:
+                  - task: AzureCLI@1
+                    displayName: Build and deploy playground server
+                    inputs:
+                      azureSubscription: "Azure SDK Engineering System"
+                      scriptLocation: inlineScript
+                      inlineScript: |
+                        set -e
+                        REGISTRY="typespecacr"
+                        RESOURCE_GROUP="typespec"
+                        APP_NAME="${{ parameters.PlaygroundServerAppName }}"
+                        IMAGE="$REGISTRY.azurecr.io/$APP_NAME:$(Build.BuildId)"
+
+                        # Build and push Docker image to ACR
+                        echo "Building Docker image: $IMAGE"
+                        CONTEXT="$(Build.SourcesDirectory)/${{ parameters.PackagePath }}"
+                        az acr build \
+                          --registry "$REGISTRY" \
+                          --image "$APP_NAME:$(Build.BuildId)" \
+                          --file "$CONTEXT/${{ parameters.PlaygroundServerDockerfile }}" \
+                          "$CONTEXT"
+
+                        # Update App Service container image
+                        az webapp config container set \
+                          --name "$APP_NAME" \
+                          --resource-group "$RESOURCE_GROUP" \
+                          --container-image-name "$IMAGE" \
+                          --container-registry-url "https://$REGISTRY.azurecr.io"
+
+                        echo "Deployed to https://$APP_NAME.azurewebsites.net"
+                      workingDirectory: $(Build.SourcesDirectory)
+
             templateContext:
               outputs:
                 - output: pipelineArtifact

packages/http-client-csharp/.dockerignore

@@ -0,0 +1,8 @@
+node_modules/
+dist/
+emitter/
+.tspd/
+**/artifacts/
+*.md
+*.tsp
+package-lock.json

packages/http-client-csharp/emitter/src/code-model-writer.ts

@@ -8,6 +8,16 @@ import { CSharpEmitterContext } from "./sdk-context.js";
 import { CodeModel } from "./type/code-model.js";
 import { Configuration } from "./type/configuration.js";
 
+/**
+ * Serializes the code model to a JSON string with reference tracking.
+ * @param context - The CSharp emitter context
+ * @param codeModel - The code model to serialize
+ * @beta
+ */
+export function serializeCodeModel(context: CSharpEmitterContext, codeModel: CodeModel): string {
+  return prettierOutput(JSON.stringify(buildJson(context, codeModel), transformJSONProperties, 2));
+}
+
 /**
  * Writes the code model to the output folder. Should only be used by autorest.csharp.
  * @param context - The CSharp emitter context
@@ -22,7 +32,7 @@ export async function writeCodeModel(
 ) {
   await context.program.host.writeFile(
     resolvePath(outputFolder, tspOutputFileName),
-    prettierOutput(JSON.stringify(buildJson(context, codeModel), transformJSONProperties, 2)),
+    serializeCodeModel(context, codeModel),
   );
 }
 

packages/http-client-csharp/emitter/src/emit-generate.browser.ts

@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft Corporation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+// Browser implementation: sends code model to a playground server for generation.
+
+import { resolvePath } from "@typespec/compiler";
+import type { GenerateOptions } from "./emit-generate.js";
+import { CSharpEmitterContext } from "./sdk-context.js";
+
+const SERVER_URL = "https://csharp-playground-server.azurewebsites.net";
+const MAX_RESPONSE_SIZE = 10 * 1024 * 1024; // 10 MB
+
+export async function generate(
+  sdkContext: CSharpEmitterContext,
+  codeModelJson: string,
+  configJson: string,
+  options: GenerateOptions,
+): Promise<void> {
+  const response = await fetch(`${SERVER_URL}/generate`, {
+    method: "POST",
+    headers: { "Content-Type": "application/json" },
+    body: JSON.stringify({
+      codeModel: codeModelJson,
+      configuration: configJson,
+      generatorName: options.generatorName,
+    }),
+  });
+
+  if (!response.ok) {
+    const errorText = await response.text();
+    throw new Error(`Playground server error (${response.status}): ${errorText}`);
+  }
+
+  const contentType = response.headers.get("content-type");
+  if (!contentType?.includes("application/json")) {
+    throw new Error(`Unexpected response content-type: ${contentType}`);
+  }
+
+  const contentLength = response.headers.get("content-length");
+  if (contentLength && parseInt(contentLength, 10) > MAX_RESPONSE_SIZE) {
+    throw new Error(
+      `Response too large: ${contentLength} bytes exceeds ${MAX_RESPONSE_SIZE} byte limit`,
+    );
+  }
+
+  const result = await response.json();
+
+  if (!result || !Array.isArray(result.files)) {
+    throw new Error("Invalid response: expected { files: [...] }");
+  }
+
+  for (const file of result.files) {
+    if (typeof file.path !== "string" || typeof file.content !== "string") {
+      throw new Error(`Invalid file entry: expected { path: string, content: string }`);
+    }
+    await sdkContext.program.host.writeFile(
+      resolvePath(options.outputFolder, file.path),
+      file.content,
+    );
+  }
+}