feat: DynamoDBProvider

aws-powertools · Dec 29, 2022 · 0aa6b56 · 0aa6b56
1 parent 7af3fee
commit 0aa6b56
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Showing 3 changed files with 405 additions and 26 deletions.
diff --git a/packages/parameters/src/DynamoDBProvider.ts b/packages/parameters/src/DynamoDBProvider.ts
@@ -27,15 +27,22 @@ class DynamoDBProvider extends BaseProvider {
     if (config.valueAttr) this.valueAttr = config.valueAttr;
   }
 
+  public async get(name: string, options?: DynamoDBGetOptionsInterface): Promise<undefined | string | Record<string, unknown>> {
+    return super.get(name, options);
+  }
+
+  public async getMultiple(path: string, options?: DynamoDBGetMultipleOptionsInterface): Promise<undefined | Record<string, unknown>> {
+    return super.getMultiple(path, options);
+  }
+
   protected async _get(name: string, options?: DynamoDBGetOptionsInterface): Promise<string | undefined> {
     const sdkOptions: GetItemCommandInput = {
       TableName: this.tableName,
       Key: marshall({ [this.keyAttr]: name }),
+      ProjectionExpression: this.valueAttr,
     };
-    if (options && options.hasOwnProperty('sdkOptions')) {
-      // Explicit arguments passed to the constructor will take precedence over ones passed to the method
-      delete options.sdkOptions?.Key;
-      // TODO: check if TableName is overridable
+    if (options && options.sdkOptions) {
+      this.removeNonOverridableOptions(options.sdkOptions as GetItemCommandInput);
       Object.assign(sdkOptions, options.sdkOptions);
     }
     const result = await this.client.send(new GetItemCommand(sdkOptions));
@@ -48,14 +55,13 @@ class DynamoDBProvider extends BaseProvider {
       TableName: this.tableName,
       KeyConditionExpression: `${this.keyAttr} = :key`,
       ExpressionAttributeValues: marshall({ ':key': path }),
+      ProjectionExpression: `${this.sortAttr}, ${this.valueAttr}`,
     };
     const paginationOptions: PaginationConfiguration = {
       client: this.client,
     };
-    if (options && options.hasOwnProperty('sdkOptions')) {
-      // Explicit arguments passed to the constructor will take precedence over ones passed to the method
-      delete options.sdkOptions?.KeyConditionExpression;
-      delete options.sdkOptions?.ExpressionAttributeValues;
+    if (options && options.sdkOptions) {
+      this.removeNonOverridableOptions(options.sdkOptions as QueryCommandInput);
       if (options.sdkOptions?.hasOwnProperty('Limit')) {
         paginationOptions.pageSize = options.sdkOptions.Limit;
       }
@@ -66,12 +72,43 @@ class DynamoDBProvider extends BaseProvider {
     for await (const page of paginateQuery(paginationOptions, sdkOptions)) {
       for (const item of page.Items || []) {
         const unmarshalledItem = unmarshall(item);
-        parameters[unmarshalledItem[this.keyAttr]] = unmarshalledItem[this.valueAttr];
+        parameters[unmarshalledItem[this.sortAttr]] = unmarshalledItem[this.valueAttr];
       }
     }
 
     return parameters;
   }
+
+  /**
+   * This method is used as a type guard to narrow down the type of the options object.
+   */
+  protected isGetItemCommandInput(options: GetItemCommandInput | QueryCommandInput): options is GetItemCommandInput {
+    return (options as GetItemCommandInput).Key !== undefined;
+  }
+
+  /**
+   * Explicit arguments passed to the constructor will take precedence over ones passed to the method.
+   * For users who consume the library with TypeScript, this will be enforced by the type system. However,
+   * for JavaScript users, we need to manually delete the properties that are not allowed to be overridden.
+   */
+  protected removeNonOverridableOptions(options: GetItemCommandInput | QueryCommandInput): void {
+    if (options.hasOwnProperty('TableName')) {
+      delete options.TableName;
+    }
+    if (options.hasOwnProperty('ProjectionExpression')) {
+      delete options.ProjectionExpression;
+    }
+    if (options.hasOwnProperty('Key') && this.isGetItemCommandInput(options)) {
+      delete options.Key;
+    } else if (options.hasOwnProperty('KeyConditionExpression') && !this.isGetItemCommandInput(options)) {
+      if (options.hasOwnProperty('KeyConditionExpression')) {
+        delete options.KeyConditionExpression;
+      }
+      if (options.hasOwnProperty('ExpressionAttributeValues')) {
+        delete options.ExpressionAttributeValues;
+      }
+    }
+  }
 }
 
 export {

diff --git a/packages/parameters/src/types/DynamoDBProvider.ts b/packages/parameters/src/types/DynamoDBProvider.ts
@@ -22,12 +22,16 @@ interface DynamoDBProviderOptions {
   clientConfig?: DynamoDBClientConfig
 }
 
-interface DynamoDBGetOptionsInterface {
-  maxAge?: number
-  forceFetch?: boolean
-  decrypt?: boolean
-  transform?: TransformOptions
-  sdkOptions?: Partial<GetItemCommandInput>
+/**
+ * Options for the DynamoDBProvider get method.
+ * 
+ * @interface DynamoDBGetOptionsInterface
+ * @extends {GetOptionsInterface}
+ * @property {boolean} decrypt - If true, the parameter will be decrypted.
+ * @property {Partial<GetItemCommandInput>} sdkOptions - Options for the AWS SDK.
+ */
+interface DynamoDBGetOptionsInterface extends GetBaseOptionsInterface {
+  sdkOptions?: Omit<Partial<GetItemCommandInput>, 'Key' | 'TableName' | 'ProjectionExpression'>
 }
 
 interface DynamoDBGetMultipleOptionsInterface extends GetMultipleBaseOptionsInterface {