Need to update audit in table while clicking a!safelink

It is not possible to download and write to audit in single click. You can however have a process with start form. User can click on the download link in the start form and close the form using submit button. In process you can use pp!initiator to write the data in audit. 

Since a!safeLink doesn't support saveInto, we implement a two-step download process - first click logs the audit, second click downloads the file.

Have a look at sample code for your reference:

a!localVariables(
  /* Track whether the initial link has been clicked */
  local!linkClicked: false,
  local!presignedUrl: "www.google.com",
  {
    a!linkField(
      links: {
        /* STEP 1: Initial link that triggers audit logging */
        a!dynamicLink(
          label: "Click to Download",
          value: true,
          saveInto: {
            /* Set flag to show the actual download link */
            local!linkClicked,
            /* Write audit record using a!writeRecords */
            /*a!writeRecords(records: {}, onSuccess: {}, onError: {})*/
          },
          showWhen: not(local!linkClicked)
        ),
        /* STEP 2: Actual download link shown after audit is logged */
        a!safeLink(
          label: "Download Now",
          uri: local!presignedUrl,
          /* Only show after the first link is clicked and audit is logged */
          showWhen: local!linkClicked,
          openLinkIn: "NEW_TAB"
        )
      }
    )
  }
)

Thanks [mention:65b14048184a4eb5aff3a76c87b97431:e9ed411860ed4f2ba0265705b8793d05] [mention:9861aef97eb2483a8b76175d9eda1e37:e9ed411860ed4f2ba0265705b8793d05]  for your response. But since solution I wanted is with single click and I have already implemented this with two clicks. Will look forward for Appian to introduce this feature since this is a valid Use case.

This is how SafeLink works, and has always worked.

The best supported solution will simply involve 2 user clicks, in a large variety of possibilities. One click will persist whatever data you want to the DB, and the other click will be the user opening their link.  I would suggest that you require the user to first click a button (for instance) to "generate link" or "show link" where it both un-hides the existing link but then also persists your log data (and anything else you like).

Hi Anvesh, Not sure if you are still looking for a solution. I had a similar requirement, and this is how I got it done. 

Step 1: Create a Web API (POST Method) that creates audit history either using startProcess or writeRecords logic. 

Step 2: Create an integration to make a call to this Web API. We need these 2 objects since we cannot call POST Web API as part of a safe link.

Step 3: Create a Web API (GET Method) which will redirect the user to the appropriate link as show in the inserted code.

Step 4: Provide the URL of the Web API created at Step 3 as safe link.

Hope this helps.

a!httpResponse(
  statusCode: 301,
  headers: {
    a!httpHeader(
      name: "Location",
      value: http!request.queryParameters.uri  
      /*This is the URL to which the user should be navigated*/
    )
  },
  body: rule!PREFIX_POST_AuditHistory(
    .......
  )
  /*this is the integration call to write audit history*/
)