Skip to main content

One post tagged with "typescript"

View All Tags

· 3 min read
Yuncheng Yang

This article demonstrates how to use the Snowflake REST API to retrieve data for a web application using TypeScript, in this case we are using keypair authentication with Snowflake.

Overview

Snowflake’s SQL API allows you to access snowflake objects using SQL via a REST API request, this allows for easy integration with your applications and deployment pipelines. You can use the API to execute most DDL and DML statements.

There are some limitations you need to be aware of however, for example interactions with stages (using PUT and GET aren’t supported via the Snowflake API) or stored procedure operations (using CALL), you can read more on this here.

Endpoints

There are three endpoints provided:

  • /api/v2/statements/
  • /api/v2/statement/<statementHandle>
  • /api/v2/statements/<statementHandle/cancel

We will be looking at the first two in this article.

Authentication Methods

There are two types of Authentication methods for the API, OAuth and Key Pair. For OAuth method, you can choose to use X-Snowflake-Authorization-Token-Type header, if this header is not present, Snowflake assumes that the token in the Authorization header is an OAuth token. For Key Pair method, the JWT token will be in the Authorization header as Bearer <your token>.

Let’s walk through how to generate and use the JWT.

Generating the JWT

Here's whats needed:

Snowflake JWT

the Code

Request Body

Now we need a request body:

Submitting the Request

We will need to include the region and account identifier, for instance if your account identifier includes a region (e.g. xy12345.us-east2.aws.snowflakecomputing.com).

Response Handling

When making a SELECT query, there are three things worth noting:

  1. rowType fields in the resultSetMetaData represent the columns
  2. data without column names is in the format of string[][]
  3. partitionInfo is an array of object representing different partitions

For more information see Handling Responses from the SQL API - Snowflake Documentation.

Parsing data

Here is a Typescript code snippet demonstrating parsing return data:

Handling multiple partitions

Large result sets are paginated into partitions, each partition is a set of rows.

note

Note that the pages (referred to as partitions) are NOT based on row count, instead they are based on the compressed batch size, so they will not be uniform in terms of the number of rows.

To get a partition, send a GET request with Url https://<accountIdentifier>.snowflakecomputing.com/api/v2/statements/?partition=<partitionId>.

Thanks!