Now we are going to add an API that returns a list of all the notes a user has.

Add the Function

Create a new file called list.js with the following.

import handler from "./libs/handler-lib";
import dynamoDb from "./libs/dynamodb-lib";

export const main = handler(async (event, context) => {
  const params = {
    TableName: process.env.tableName,
    // 'KeyConditionExpression' defines the condition for the query
    // - 'userId = :userId': only return items with matching 'userId'
    //   partition key
    KeyConditionExpression: "userId = :userId",
    // 'ExpressionAttributeValues' defines the value in the condition
    // - ':userId': defines 'userId' to be the id of the author
    ExpressionAttributeValues: {
      ":userId": "123",
    },
  };

  const result = await dynamoDb.query(params);

  // Return the matching list of items in response body
  return result.Items;
});

This is pretty much the same as our get.js except we use a condition to only return the items that have the same userId as the one we are passing in. In our case, it’s still hardcoded to 123.

Configure the API Endpoint

Open the serverless.yml file and append the following.

  list:
    # Defines an HTTP API endpoint that calls the main function in list.js
    # - path: url path is /notes
    # - method: GET request
    handler: list.main
    events:
      - http:
          path: notes
          cors: true
          method: get

This defines the /notes endpoint that takes a GET request.

Test

Create a mocks/list-event.json file and add the following.

{}

We are still adding an empty mock event because we are going to replace this later on in the guide.

And invoke our function from the root directory of the project.

$ serverless invoke local --function list --path mocks/list-event.json

The response should look similar to this.

{
    "statusCode": 200,
    "body": "[{\"attachment\":\"hello.jpg\",\"content\":\"hello world\",\"createdAt\":1602891322039,\"noteId\":\"42244c70-1008-11eb-8be9-4b88616c4b39\",\"userId\":\"123\"}]"
}

Note that this API returns an array of note objects as opposed to the get.js function that returns just a single note object.

Next we are going to add an API to update a note.