You may want to take a look at the authentication options present in the REST connector to see if you can authenticate to this endpoint with any of the available authentication methods, but if you’ve already implement a script to get your SAS token, what you might want to do is use a little cache table to store your SAS token with a timestamp, and look up the stored token against the table first.

If you find a token that’s less than a week old, use that - otherwise, run through your code and update the table. I’ve attached a simple example that uses a SQLite database here: 

In your script, you can query the table first, and use the value that’s there if it’s not too old before running through your script: 

<arc:set attr="db.driver" value="System.Data.SQLite" />
<arc:set attr="db.conn" value="DataSource=C:\\Program Files\\CData Arc 23.4.8801\\SASKeyState.db" />
<arc:set attr="db.query">SELECT SASKey FROM SASKey WHERE CreationDate > 'e_ | now | dateadd("day", -7)]'</arc:set>

<arc:call op="dbQuery" item="db">
  <arc:set attr="tmp.SASKey" value="pdb.SASKey]" />
</arc:call>

<!-- did we get a key -->
<arc:check attr="tmp.SASKey">
  <!-- yes, use it -->
  <arc:set attr="output.filepath" value="ffilepath]"/>
  <arc:set attr="output.header:SASKey" value="rtmp.SASKey]" />
  <arc:push item="output" />
  <!-- no, make it and update the table -->
  <arc:else>
    <!-- simple GUID for this example -->
    <arc:set attr="tmp.SASKey" value="pguid(true)]" />
    <arc:set attr="db.query" value="UPDATE `SASKey` SET `SASKey`= '`tmp.SASKey]', `CreationDate` = 'C_ | now]' WHERE `ID` = 1" />
    <arc:call op="dbNonQuery" item="db" />

    <arc:set attr="output.filepath" value="ffilepath]"/>
    <arc:set attr="output.header:SASKey" value="rtmp.SASKey]" />
    <arc:push item="output" />

  </arc:else>
</arc:check>

The attached zip has the connector and the SQLite table; would something like this work for you?