Add public SSRC methods (#2458)

Add public SSRC methods

---------

Co-authored-by: Xin Wei <[email protected]>
Co-authored-by: jen_h <[email protected]>

etc/firebase-admin.remote-config.api.md

@@ -46,8 +46,10 @@ export class RemoteConfig {
     // (undocumented)
     readonly app: App;
     createTemplateFromJSON(json: string): RemoteConfigTemplate;
+    getServerTemplate(options?: RemoteConfigServerTemplateOptions): Promise<RemoteConfigServerTemplate>;
     getTemplate(): Promise<RemoteConfigTemplate>;
     getTemplateAtVersion(versionNumber: number | string): Promise<RemoteConfigTemplate>;
+    initServerTemplate(options?: RemoteConfigServerTemplateOptions): RemoteConfigServerTemplate;
     listVersions(options?: ListVersionsOptions): Promise<ListVersionsResult>;
     publishTemplate(template: RemoteConfigTemplate, options?: {
         force: boolean;
@@ -84,6 +86,41 @@ export interface RemoteConfigParameterGroup {
 // @public
 export type RemoteConfigParameterValue = ExplicitParameterValue | InAppDefaultValue;
 
+// @public
+export interface RemoteConfigServerCondition {
+    expression: string;
+    name: string;
+}
+
+// @public
+export type RemoteConfigServerConfig = {
+    [key: string]: string | boolean | number;
+};
+
+// @public
+export interface RemoteConfigServerTemplate {
+    cache: RemoteConfigServerTemplateData;
+    defaultConfig: RemoteConfigServerConfig;
+    evaluate(): RemoteConfigServerConfig;
+    load(): Promise<void>;
+}
+
+// @public
+export interface RemoteConfigServerTemplateData {
+    conditions: RemoteConfigServerCondition[];
+    readonly etag: string;
+    parameters: {
+        [key: string]: RemoteConfigParameter;
+    };
+    version?: Version;
+}
+
+// @public
+export interface RemoteConfigServerTemplateOptions {
+    defaultConfig?: RemoteConfigServerConfig;
+    template?: RemoteConfigServerTemplateData;
+}
+
 // @public
 export interface RemoteConfigTemplate {
     conditions: RemoteConfigCondition[];

src/remote-config/index.ts

@@ -35,6 +35,11 @@ export {
   RemoteConfigParameterGroup,
   RemoteConfigParameterValue,
   RemoteConfigTemplate,
+  RemoteConfigServerCondition,
+  RemoteConfigServerConfig,
+  RemoteConfigServerTemplate,
+  RemoteConfigServerTemplateData,
+  RemoteConfigServerTemplateOptions,
   RemoteConfigUser,
   TagColor,
   Version,

src/remote-config/remote-config-api.ts

@@ -213,6 +213,27 @@ export interface RemoteConfigServerTemplateData {
   version?: Version;
 }
 
+/**
+ * Represents optional arguments that can be used when instantiating {@link RemoteConfigServerTemplate}.
+ */
+export interface RemoteConfigServerTemplateOptions {
+
+  /**
+   * Defines in-app default parameter values, so that your app behaves as
+   * intended before it connects to the Remote Config backend, and so that
+   * default values are available if none are set on the backend.
+   */
+  defaultConfig?: RemoteConfigServerConfig,
+
+  /**
+   * Enables integrations to use template data loaded independently. For
+   * example, customers can reduce initialization latency by pre-fetching and
+   * caching template data and then using this option to initialize the SDK with
+   * that data.
+   */
+  template?: RemoteConfigServerTemplateData,
+}
+
 /**
  * Represents a stateful abstraction for a Remote Config server template.
  */

src/remote-config/remote-config.ts

@@ -23,9 +23,16 @@ import {
   RemoteConfigCondition,
   RemoteConfigParameter,
   RemoteConfigParameterGroup,
+  RemoteConfigServerTemplate,
   RemoteConfigTemplate,
   RemoteConfigUser,
   Version,
+  ExplicitParameterValue,
+  InAppDefaultValue,
+  ParameterValueType,
+  RemoteConfigServerConfig,
+  RemoteConfigServerTemplateData,
+  RemoteConfigServerTemplateOptions,
 } from './remote-config-api';
 
 /**
@@ -168,6 +175,27 @@ export class RemoteConfig {
 
     return new RemoteConfigTemplateImpl(template);
   }
+
+  /**
+   * Instantiates {@link RemoteConfigServerTemplate} and then fetches and caches the latest
+   * template version of the project.
+   */
+  public async getServerTemplate(options?: RemoteConfigServerTemplateOptions): Promise<RemoteConfigServerTemplate> {
+    const template = this.initServerTemplate(options);
+    await template.load();
+    return template;
+  }
+
+  /**
+   * Synchronously instantiates {@link RemoteConfigServerTemplate}.
+   */
+  public initServerTemplate(options?: RemoteConfigServerTemplateOptions): RemoteConfigServerTemplate {
+    const template = new RemoteConfigServerTemplateImpl(this.client, options?.defaultConfig);
+    if (options?.template) {
+      template.cache = options?.template;
+    }
+    return template;
+  }
 }
 
 /**
@@ -254,6 +282,143 @@ class RemoteConfigTemplateImpl implements RemoteConfigTemplate {
   }
 }
 
+/**
+ * Remote Config dataplane template data implementation.
+ */
+class RemoteConfigServerTemplateImpl implements RemoteConfigServerTemplate {
+  public cache: RemoteConfigServerTemplateData;
+
+  constructor(
+    private readonly apiClient: RemoteConfigApiClient,
+    public readonly defaultConfig: RemoteConfigServerConfig = {}
+  ) { }
+
+  /**
+   * Fetches and caches the current active version of the project's {@link RemoteConfigServerTemplate}.
+   */
+  public load(): Promise<void> {
+    return this.apiClient.getServerTemplate()
+      .then((template) => {
+        this.cache = new RemoteConfigServerTemplateDataImpl(template);
+      });
+  }
+
+  /**
+   * Evaluates the current template in cache to produce a {@link RemoteConfigServerConfig}.
+   */
+  public evaluate(): RemoteConfigServerConfig {
+    if (!this.cache) {
+      throw new FirebaseRemoteConfigError(
+        'failed-precondition',
+        'No Remote Config Server template in cache. Call load() before calling evaluate().');
+    }
+
+    const evaluatedConfig: RemoteConfigServerConfig = {};
+
+    for (const [key, parameter] of Object.entries(this.cache.parameters)) {
+      const { defaultValue, valueType } = parameter;
+
+      if (!defaultValue) {
+        // TODO: add logging once we have a wrapped logger.
+        continue;
+      }
+
+      if ((defaultValue as InAppDefaultValue).useInAppDefault) {
+        // TODO: add logging once we have a wrapped logger.
+        continue;
+      }
+
+      const parameterDefaultValue = (defaultValue as ExplicitParameterValue).value;
+
+      evaluatedConfig[key] = this.parseRemoteConfigParameterValue(valueType, parameterDefaultValue);
+    }
+
+    // Merges rendered config over default config.
+    const mergedConfig = Object.assign(this.defaultConfig, evaluatedConfig);
+
+    // Enables config to be a convenient object, but with the ability to perform additional
+    // functionality when a value is retrieved.
+    const proxyHandler = {
+      get(target: RemoteConfigServerConfig, prop: string) {
+        return target[prop];
+      }
+    };
+
+    return new Proxy(mergedConfig, proxyHandler);
+  }
+
+  /**
+   * Private helper method that processes and parses a parameter value based on {@link ParameterValueType}.
+   */
+  private parseRemoteConfigParameterValue(parameterType: ParameterValueType | undefined,
+    parameterDefaultValue: string): string | number | boolean {
+    const BOOLEAN_TRUTHY_VALUES = ['1', 'true', 't', 'yes', 'y', 'on'];
+    const DEFAULT_VALUE_FOR_NUMBER = 0;
+    const DEFAULT_VALUE_FOR_STRING = '';
+
+    if (parameterType === 'BOOLEAN') {
+      return BOOLEAN_TRUTHY_VALUES.indexOf(parameterDefaultValue) >= 0;
+    } else if (parameterType === 'NUMBER') {
+      const num = Number(parameterDefaultValue);
+      if (isNaN(num)) {
+        return DEFAULT_VALUE_FOR_NUMBER;
+      }
+      return num;
+    } else {
+      // Treat everything else as string
+      return parameterDefaultValue || DEFAULT_VALUE_FOR_STRING;
+    }
+  }
+}
+
+/**
+ * Remote Config dataplane template data implementation.
+ */
+class RemoteConfigServerTemplateDataImpl implements RemoteConfigServerTemplateData {
+  public parameters: { [key: string]: RemoteConfigParameter };
+  public parameterGroups: { [key: string]: RemoteConfigParameterGroup };
+  public conditions: RemoteConfigCondition[];
+  public readonly etag: string;
+  public version?: Version;
+
+  constructor(template: RemoteConfigServerTemplateData) {
+    if (!validator.isNonNullObject(template) ||
+      !validator.isNonEmptyString(template.etag)) {
+      throw new FirebaseRemoteConfigError(
+        'invalid-argument',
+        `Invalid Remote Config template: ${JSON.stringify(template)}`);
+    }
+
+    this.etag = template.etag;
+
+    if (typeof template.parameters !== 'undefined') {
+      if (!validator.isNonNullObject(template.parameters)) {
+        throw new FirebaseRemoteConfigError(
+          'invalid-argument',
+          'Remote Config parameters must be a non-null object');
+      }
+      this.parameters = template.parameters;
+    } else {
+      this.parameters = {};
+    }
+
+    if (typeof template.conditions !== 'undefined') {
+      if (!validator.isArray(template.conditions)) {
+        throw new FirebaseRemoteConfigError(
+          'invalid-argument',
+          'Remote Config conditions must be an array');
+      }
+      this.conditions = template.conditions;
+    } else {
+      this.conditions = [];
+    }
+
+    if (typeof template.version !== 'undefined') {
+      this.version = new VersionImpl(template.version);
+    }
+  }
+}
+
 /**
 * Remote Config Version internal implementation.
 */