StarSnow Request

HTTP Client for Snowflake database (HTTP get/post from SQL)

The idea is simple: invoke HTTP/HTTPS web servers directly from Snowflake Database SQL statements using pre-deployed, generic external functions. Built on top of Axios.

Detailed blog post on usage: https://medium.com/starschema-blog/starsnow-http-client-for-snowflake-sql-e1b329293fc6

Examples

Simple HTTP get. varchar input (URL), varchar return (content of the site):

select STARSNOW_REQUEST_GET('https://google.com/') as google_content;

Get Snowflake system status. Select value from the result variant:

select STARSNOW_REQUEST('https://status.snowflake.com/api/v2/status.json', NULL):data:status:description as snowflake_status;

Get Snowflake historical stock values:

select key, value:"4. close"::float
from TABLE (FLATTEN(
        input => STARSNOW_REQUEST('https://www.alphavantage.co/query',
                                  object_construct('method', 'get',
                                                   'params', object_construct(
                                                           'function', 'TIME_SERIES_DAILY_ADJUSTED',
                                                           'symbol', 'SNOW',
                                                           'apikey', '<your_alphavantage_key>'))
            ): data:"Time Series (Daily)"));

StarSnow Request API

The package contains two functions: STARSNOW_REQUEST_GET and STARSNOW_REQUEST.

varchar STARSNOW_REQUEST_GET(url VARCHAR)

The function takes one string argument (url) and returns with the content of that web address. It supports only get method and no custom headers.

variant STARSNOW_REQUEST(url VARCHAR, params OBJECT)

The function takes and url and an parameters object that passed as an axios configuration to request. The following configuration properties are supported:

-- params object:

object_construct(
  -- `url` is the server URL that will be used for the request
  'url', '/user',

  -- `method` is the request method to be used when making the request
  'method', 'get', -- default

  -- `headers` are custom headers to be sent
  'headers', object_construct('X-Requested-With', 'XMLHttpRequest'),

  -- `params` are the URL parameters to be sent with the request
  -- Must be a plain object 
  'params', object_construct(
    'ID', 12345
  ),

  -- `data` is the data to be sent as the request body
  -- Only applicable for request methods 'PUT', 'POST', 'DELETE , and 'PATCH'
  'data', object_construct(
    'firstName', 'Fred'
  ),
  
  -- syntax alternative to send data into the body
  -- method post
  -- only the value is sent, not the key
  'data', 'Country=Brasil&City=Belo Horizonte',

  -- `timeout` specifies the number of milliseconds before the request times out.
  -- If the request takes longer than `timeout`, the request will be aborted.
  'timeout', 1000, -- default is `0` (no timeout)

  -- `auth` indicates that HTTP Basic auth should be used, and supplies credentials.
  -- This will set an `Authorization` header, overwriting any existing
  -- `Authorization` custom headers you have set using `headers`.
  -- Please note that only HTTP Basic auth is configurable through this parameter.
  -- For Bearer tokens and such, use `Authorization` custom headers instead.
  'auth', object_construct(
    'username', 'janedoe',
    'password', 's00pers3cret'
  ),

  -- `responseType` indicates the type of data that the server will respond with
  -- options are: 'arraybuffer', 'document', 'json', 'text', 
  'responseType', 'json', -- default

  -- `responseEncoding` indicates encoding to use for decoding responses
  'responseEncoding', 'utf8', -- default

  -- `maxContentLength` defines the max size of the http response content in bytes allowed in node.js
  'maxContentLength', 2000,

  -- `maxBodyLength` defines the max size of the http request content in bytes allowed
  'maxBodyLength', 2000,

  -- `maxRedirects` defines the maximum number of redirects to follow in node.js.
  -- If set to 0, no redirects will be followed.
  'maxRedirects', 5, -- default

  -- `proxy` defines the hostname, port, and protocol of the proxy server.
  -- You can also define your proxy using the conventional `http_proxy` and
  -- `https_proxy` environment variables. If you are using environment variables
  -- for your proxy configuration, you can also define a `no_proxy` environment
  -- variable as a comma-separated list of domains that should not be proxied.
  -- Use `false` to disable proxies, ignoring environment variables.
  -- `auth` indicates that HTTP Basic auth should be used to connect to the proxy, and
  -- supplies credentials.
  -- This will set an `Proxy-Authorization` header, overwriting any existing
  -- `Proxy-Authorization` custom headers you have set using `headers`.
  -- If the proxy server uses HTTPS, then you must set the protocol to `https`. 
  'proxy', object_construct(
    'protocol', 'https',
    'host', '127.0.0.1',
    'port', 9000,
    'auth', object_construct(
      'username', 'mikeymike',
      'password', 'rapunz3l'
    ),
  ),


  -- `decompress` indicates whether or not the response body should be decompressed 
  -- automatically. If set to `true` will also remove the 'content-encoding' header 
  -- from the responses objects of all decompressed responses
  'decompress', true -- default
)

See examples on how to construct snowflake objects from SQL statements.

On successful execution, the status code, headers and data are returned in single variant.

Deploying

To deploy, clone the repo, then:

$ npm install -g serverless
$ npm install
$ vim serverless.yml # edit your snowflake account details
$ sls deploy

Then, the functions should be available in your snowflake account.

License, Copyright

BSD License, Starschema Inc, 2020