Reading a deployed application's data

Summary#

osy query reads the app on your computer. osyrin app query reads the deployed one.

$ osyrin app query "Job.Where(j => !j.Done).Count()" --app billing-acme
2

$ osyrin app query "Job.OrderBy(j => j.Position)" --app billing-acme --as [email protected]
[
  { "Title": "re-plaster the hall", "Position": 10 }
]

Signature#

osyrin app query "<expression>" --app <slug>                      // read as ANONYMOUS
osyrin app query "<expression>" --app <slug> --as [email protected] // read as one of the app's users
osyrin app query "<expression>" --app <slug> --json               // the whole answer, for a script

Description#

The same verb as osy query#

The expression goes through the same compiler your source goes through, and the answer has the same shapes: rows, a number, a list of values, one row. See Reading your data for what an expression may say and what each shape looks like.

Who may run it#

Whoever may deploy the application may query it: a platform operator, an owner or admin of its organization, or a member of the application. The platform's Admin checks that, then signs a short-lived grant for this one operation, and the command sends the grant to the zone that serves the application. Your sign-in never goes to the zone.

What it can read#

⛔ It reads, it never writes. An expression that creates, updates or deletes is refused before it runs:

$ osyrin app query "new Job { Title = \"sneaky\" }" --app billing-acme
✗ `query` READS — this expression writes data, so it is refused here. …

The read runs under the application's own security { }. With no --as it reads what a signed-out visitor sees, often nothing. With --as <login> it reads what that user sees, and no more. --as takes no password, because the expression has been checked as a read. Changing a user's data stays behind their own password, with osyrin app run.

A zone on an older release#

A zone running platform release 0.17.0 or older does not accept a query grant. The command then says which release the zone needs and that your sign-in is fine. Until the zone is upgraded, restore a backup into a copy (osyrin app restore) and read its rows with osyrin app restore-download.

See also#

• Reading your data — the same verb on your computer, and what an expression may say
• Running a function — making the app do something
• Downloading your daily backups — a copy of the whole database
• The security model — the rules --as shows you