[Azure App Configuration] - Normalize the query parameters in request url (#35962)

### Packages impacted by this PR
@azure/app-configuration 

### Issues associated with this PR


### Describe the problem that is addressed by this PR

Adds a new pipeline to update the query params to make sure they are all
lowercase and in alphabetical order. This is required for support of
Azure Front Door as a CDN.

### What are the possible designs available to address the problem? If
there are more than one possible design, why was the one in this PR
chosen?


### Are there test cases added in this PR? _(If not, why?)_

Yes

### Provide a list of related PRs _(if any)_


### Command used to generate this PR:**_(Applicable only to SDK release
request PRs)_

### Checklists
- [x] Added impacted package name to the issue description
- [ ] Does this PR needs any fixes in the SDK Generator?** _(If so,
create an Issue in the
[Autorest/typescript](https://github.com/Azure/autorest.typescript)
repository and link it here)_
- [x] Added a changelog (if necessary)

Author: zhiyuanliang-ms

sdk/appconfiguration/app-configuration/CHANGELOG.md

@@ -4,6 +4,8 @@
 
 ### Features Added
 
+- Added internal pipeline policy to normalize (case-insensitive alphabetical) ordering of query parameters for deterministic request URLs.
+
 - Support snapshot reference.
   - New type for SnapshotReference - `ConfigurationSetting<SnapshotReferenceValue>`
   - Upon using `getConfigurationSetting`(or add/update), use `parseSnapshotReference` methods to access the properties (to translate `ConfigurationSetting` into the type above).
@@ -18,8 +20,9 @@
 ## 1.9.0 (2025-04-08)
 
 ### Features Added
- - Include all the changes from 1.9.0-beta.1 version
- 
+
+- Include all the changes from 1.9.0-beta.1 version
+
 ### Other Changes
 
 - Update README with a link to [*`@azure/app-configuration-provider`*](https://www.npmjs.com/package/@azure/app-configuration-provider). [#33152](https://github.com/Azure/azure-sdk-for-js/pull/33152)
@@ -149,7 +152,6 @@ See [`listConfigurationSettings.ts`](https://github.com/Azure/azure-sdk-for-js/t
 ### Other Changes
 
 - Updated our `@azure/core-tracing` dependency to the latest version (1.0.0).
-
   - Notable changes include Removal of `@opentelemetry/api` as a transitive dependency and ensuring that the active context is properly propagated.
   - Customers who would like to continue using OpenTelemetry driven tracing should visit our [OpenTelemetry Instrumentation](https://www.npmjs.com/package/@azure/opentelemetry-instrumentation-azure-sdk) package for instructions.
 
@@ -186,7 +188,6 @@ See [`listConfigurationSettings.ts`](https://github.com/Azure/azure-sdk-for-js/t
 ### Features Added
 
 - Special configuration settings - feature flag and secret reference are now supported. 🎉
-
   - For types, use `ConfigurationSetting<FeatureFlagValue>` and `ConfigurationSetting<SecretReferenceValue>`.
   - Use `parseFeatureFlag` and `parseSecretReference` methods to parse the configuration settings into feature flag and secret reference respectively.
 

sdk/appconfiguration/app-configuration/assets.json

@@ -2,5 +2,5 @@
   "AssetsRepo": "Azure/azure-sdk-assets",
   "AssetsRepoPrefixPath": "js",
   "TagPrefix": "js/appconfiguration/app-configuration",
-  "Tag": "js/appconfiguration/app-configuration_257c4f0dd5"
+  "Tag": "js/appconfiguration/app-configuration_e47e6a8bab"
 }

sdk/appconfiguration/app-configuration/src/appConfigurationClient.ts

@@ -56,7 +56,8 @@ import type { PagedAsyncIterableIterator, PagedResult } from "@azure/core-paging
 import { getPagedAsyncIterator } from "@azure/core-paging";
 import type { PipelinePolicy, RestError } from "@azure/core-rest-pipeline";
 import { bearerTokenAuthenticationPolicy } from "@azure/core-rest-pipeline";
-import { SyncTokens, syncTokenPolicy } from "./internal/synctokenpolicy.js";
+import { SyncTokens, syncTokenPolicy } from "./internal/syncTokenPolicy.js";
+import { queryParamPolicy } from "./internal/queryParamPolicy.js";
 import type { TokenCredential } from "@azure/core-auth";
 import { isTokenCredential } from "@azure/core-auth";
 import type {
@@ -196,6 +197,7 @@ export class AppConfigurationClient {
       internalClientPipelineOptions,
     );
     this.client.pipeline.addPolicy(authPolicy, { phase: "Sign" });
+    this.client.pipeline.addPolicy(queryParamPolicy());
     this.client.pipeline.addPolicy(syncTokenPolicy(this._syncTokens), { afterPhase: "Retry" });
   }
 

sdk/appconfiguration/app-configuration/src/generated/src/models/parameters.ts

@@ -0,0 +1,72 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import type {
+  PipelinePolicy,
+  PipelineRequest,
+  PipelineResponse,
+  SendRequest,
+} from "@azure/core-rest-pipeline";
+
+/**
+ * Creates a PipelinePolicy that normalizes query parameters:
+ *  - Lowercase names
+ *  - Sort by lowercase name
+ *  - Preserve the relative order of duplicates
+ */
+export function queryParamPolicy(): PipelinePolicy {
+  return {
+    name: "queryParamPolicy",
+    async sendRequest(request: PipelineRequest, next: SendRequest): Promise<PipelineResponse> {
+      try {
+        const originalUrl: string = request.url;
+        const url = new URL(originalUrl);
+
+        if (url.search === "") {
+          return next(request);
+        }
+
+        const params: ParamEntry[] = [];
+        for (const entry of url.search.substring(1).split("&")) {
+          if (entry === "") {
+            continue;
+          }
+          const equalIndex = entry.indexOf("=");
+          const name = equalIndex === -1 ? entry : entry.substring(0, equalIndex);
+          const value = equalIndex === -1 ? "" : entry.substring(equalIndex + 1);
+          params.push({ lowercaseName: name.toLowerCase(), value });
+        }
+
+        // Modern JavaScript Array.prototype.sort is stable
+        // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/sort#sort_stability
+        params.sort((a, b) => {
+          if (a.lowercaseName < b.lowercaseName) {
+            return -1;
+          } else if (a.lowercaseName > b.lowercaseName) {
+            return 1;
+          }
+          return 0;
+        });
+
+        const newSearchParams: string = params
+          .map(({ lowercaseName, value }) => `${lowercaseName}=${value}`)
+          .join("&");
+
+        const newUrl = url.origin + url.pathname + "?" + newSearchParams + url.hash;
+        if (newUrl !== originalUrl) {
+          request.url = newUrl;
+        }
+      } catch {
+        // If anything goes wrong, fall back to sending the original request.
+        console.log("Failed to normalize query parameters.");
+      }
+
+      return next(request);
+    },
+  };
+}
+
+interface ParamEntry {
+  lowercaseName: string;
+  value: string;
+}

sdk/appconfiguration/app-configuration/src/internal/queryParamPolicy.ts

@@ -1,7 +1,7 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT License.
 
-import { SyncTokens, parseSyncToken } from "../../../src/internal/synctokenpolicy.js";
+import { SyncTokens, parseSyncToken } from "../../../src/internal/syncTokenPolicy.js";
 import {
   assertThrowsRestError,
   createAppConfigurationClientForTests,

sdk/appconfiguration/app-configuration/src/internal/synctokenpolicy.ts renamed to sdk/appconfiguration/app-configuration/src/internal/syncTokenPolicy.ts

@@ -0,0 +1,83 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT License.
+
+import { describe, it, expect } from "vitest";
+import { queryParamPolicy } from "../../src/internal/queryParamPolicy.js";
+import { createPipelineRequest, createHttpHeaders } from "@azure/core-rest-pipeline";
+import type { PipelineRequest, PipelineResponse } from "@azure/core-rest-pipeline";
+
+function mockNext(returnStatus: number = 200) {
+  return async (request: PipelineRequest): Promise<PipelineResponse> => {
+    return {
+      request,
+      headers: createHttpHeaders({ "url-lookup": request.url }),
+      status: returnStatus,
+    } as PipelineResponse;
+  };
+}
+
+describe("urlQueryParamsNormalizationPolicy", () => {
+  it("normalizes query parameters", async () => {
+    const policy = queryParamPolicy();
+    const request = createPipelineRequest({
+      url: "https://example.azconfig.io/kv?api-version=2023-11-01&After=abcdefg&tags=tag3%3Dvalue3&key=*&label=dev&$Select=key&tags=tag2%3Dvalue2&tags=tag1%3Dvalue1",
+    });
+    const response = await policy.sendRequest(request, mockNext());
+    const finalUrl = response.headers.get("url-lookup")!;
+    expect(
+      finalUrl.endsWith(
+        "?$select=key&after=abcdefg&api-version=2023-11-01&key=*&label=dev&tags=tag3%3Dvalue3&tags=tag2%3Dvalue2&tags=tag1%3Dvalue1",
+      ),
+    ).toBe(true);
+  });
+
+  it("keeps original encoded parameter value", async () => {
+    const policy = queryParamPolicy();
+    const request = createPipelineRequest({
+      url: "https://example.azconfig.io/kv?key=%25%20%2B&label=%00",
+    });
+    const response = await policy.sendRequest(request, mockNext());
+    const finalUrl = response.headers.get("url-lookup")!;
+    expect(finalUrl.endsWith("?key=%25%20%2B&label=%00")).toBe(true);
+  });
+
+  it("keeps original order of query parameters", async () => {
+    const policy = queryParamPolicy();
+    const request = createPipelineRequest({
+      url: "https://example.azconfig.io/kv?tags=tag2&api-version=2023-11-01&tags=tag1",
+    });
+    const response = await policy.sendRequest(request, mockNext());
+    const finalUrl = response.headers.get("url-lookup")!;
+    expect(finalUrl.endsWith("?api-version=2023-11-01&tags=tag2&tags=tag1")).toBe(true);
+  });
+
+  it("keeps empty parameter value", async () => {
+    const policy = queryParamPolicy();
+    const request = createPipelineRequest({
+      url: "https://example.azconfig.io/kv?key=&api-version=2023-11-01&key1&=",
+    });
+    const response = await policy.sendRequest(request, mockNext());
+    const finalUrl = response.headers.get("url-lookup")!;
+    expect(finalUrl.endsWith("?=&api-version=2023-11-01&key=&key1=")).toBe(true);
+  });
+
+  it("removes redundant &", async () => {
+    const policy = queryParamPolicy();
+    const request = createPipelineRequest({
+      url: "https://example.azconfig.io/kv?b=2&&a=1",
+    });
+    const response = await policy.sendRequest(request, mockNext());
+    const finalUrl = response.headers.get("url-lookup")!;
+    expect(finalUrl.endsWith("?a=1&b=2")).toBe(true);
+  });
+
+  it("skips when no query parameter is present", async () => {
+    const policy = queryParamPolicy();
+    const request = createPipelineRequest({
+      url: "https://example.azconfig.io/kv?",
+    });
+    const response = await policy.sendRequest(request, mockNext());
+    const finalUrl = response.headers.get("url-lookup")!;
+    expect(finalUrl.endsWith("/kv?")).toBe(true);
+  });
+});