Grant limited access to Dataverse files using shared access signatures

This static GetFileSasUrl method uses the GetFileSasUrlRequest and GetFileSasUrlResponse classes. The GetFileSasUrlResponse.Result property returns a FileSasUrlResponse class instance with information needed to anonymously download a file.

/// <summary>
/// Generates a link for anonymous access to a file.
/// </summary>
/// <param name="service">The authenticated IOrganizationService instance.</param>
/// <param name="target">The record that has the file data.</param>
/// <param name="fileAttributeName">Optional name of the file or image column</param>
/// <param name="dataSource">Optional source of the data when retained or deleted.</param>
/// <returns>Information to download a file</returns>
static FileSasUrlResponse GetFileSasUrl(IOrganizationService service, 
    EntityReference target, 
    string? fileAttributeName = null, 
    string? dataSource = null) { 

    var request = new GetFileSasUrlRequest() { 
        Target = target
    };

    if (target.LogicalName == "annotation" ||
        target.LogicalName == "activitymimeattachment"){

        //FileAttributeName is required
        request.FileAttributeName = string.Empty;

    }
    else
    {

        if (!string.IsNullOrEmpty(fileAttributeName))
        {
            request.FileAttributeName = fileAttributeName;
        }
        else
        {

            string message = "fileAttributeName is required ";
            message += "when the target isn't annotation ";
            message += "or activitymimeattachment";

            throw new Exception(message);
        }
    }
    
    if (!string.IsNullOrEmpty(dataSource)) {
        //dataSource should be 'retained' or 'bin'
        request.DataSource = dataSource;
    }

   var response = (GetFileSasUrlResponse)service.Execute(request);

    return response.Result;        
}

Use the SDK for .NET

This Get-FileSasUrl PowerShell function uses the GetFileSasUrl function which returns a GetFileSasUrlResponse complex type. The GetFileSasUrlResponse.Result property is a FileSasUrlResponse complex type instance with information needed to anonymously download a file.

This function depends on the $baseURI and $baseHeaders global variables set by the Connect function described in Use PowerShell and Visual Studio Code with the Dataverse Web API

function Get-FileSasUrl {
   param (
      [Parameter(Mandatory)] 
      [string] 
      $setName,
      [Parameter(Mandatory)] 
      [guid] 
      $id,
      [string] 
      $columnName,
      [string] 
      $dataSource
   )

   $uri = $baseURI + "GetFileSasUrl(Target=@t,FileAttributeName=@f"

   $query = "?@t={'@odata.id':'$setName($id)'}&@f="

   if ($setName -eq 'annotations' -or $setName -eq 'activitymimeattachments') {

      $query += "''" # empty string
   }
   else {
      if ($null -ne $columnName) {

         $query += "'$columnName'"
      }
      else {

         $message = "columnName is required "
         $message += "when the setName isn't annotations "
         $message += "or activitymimeattachments"

         throw $message
         
      }
   }

   if("" -ne $dataSource) {
      $uri += ",DataSource=@d"
      # $dataSource should be 'retained' or 'bin'
      $query += "&@d='$dataSource'"
   }

   $GetFileSasUrlRequest = @{
      Uri     = $uri + ')' + $query
      Method  = 'Get'
      Headers = $baseHeaders
   }

   Invoke-RestMethod @GetFileSasUrlRequest | Select-Object -ExpandProperty Result
}

The following examples demonstrate the rules for setting the FileAttributeName parameter. It's a required parameter, but it can contain an empty string for annotations and activitymimeattachments entity sets.

GET [Organization URI]/api/data/v9.2/GetFileSasUrl(Target=@p1,FileAttributeName='')?@p1={'@odata.id':'annotations(<annotationid>)'}

GET [Organization URI]/api/data/v9.2/GetFileSasUrl(Target=@p1,FileAttributeName='')?@p1={'@odata.id':'activitymimeattachments(<activitymimeattachmentid>)'}

GET [Organization URI]/api/data/v9.2/GetFileSasUrl(Target=@p1,FileAttributeName='myattachment')?@p1={'@odata.id':'myfiles(<myfileid>)'}

Use the Microsoft Dataverse Web API