Posting multiple items at once

📚 Official Books Server Side Swift with Vapor
1

Hello!

I’m following the book and there is the post method where I can post an acronym at a time. But, is there a way to create a method to post many at one? How would be this method?

Thank you.

2

@0xtim Can you please help with this when you get a chance? Thank you - much appreciated! :]

3

@macbieoo you can set the incoming type to [Acronym].self and you’ll get an array of acronyms. For saving - I can’t remember if the convenience function exists yet for a batch save, otherwise you’ll need to loop through and save each one

1 Like
4

I’m not sure this is the best solution but worked for me.

Inside the boot method in the controller: acronyms.post[[Acronym].self, use: createHandler]

And the createHandler method:

func createHandler(_ req: Request, acronyms: [Acronym]) throws -> Future<HTTPStatus> {
var arr: [EventLoopFuture< Acronym >] = []
for i in acronyms {
arr.append(i.save(on: req])
}
return arr.flatten(on: req).transform(to: .created]
}

5

I would have done it this way too. But I wonder if, in the event one of the Futures fails and throws, would all transactions be rolled back…

6

No, if one future fails, any futures that have succeeded up to that point won’t be cancelled or rolled back. You can wrap the block in a transaction if you need that

7

@0xtim I suppose this is how you can wrap the database inserts in a transaction that can be rolled back in the event one of the futures fails and throws. The code below assumes a PostgreSQL database and a response of HTTPStatus type:

struct AcronymsController: RouteCollection {
  func boot(router: Router) throws {
    ...
    let tokenAuthMiddleware = User.tokenAuthMiddleware()
    let guardAuthMiddleware = User.guardAuthMiddleware()
    let tokenAuthGroup = acronymsRoutes.grouped(tokenAuthMiddleware, guardAuthMiddleware)
    tokenAuthGroup.post(AcronymCreateData.self, use: createHandler)
    tokenAuthGroup.post([AcronymCreateData].self, use: createAcronymsHandler)
    ...
  }

  func createAcronymsHandler(_ req: Request, acronymsData: [AcronymCreateData]) throws -> Future<HTTPStatus> {
    let user = try req.requireAuthenticated(User.self)
    var acronymSaveResults: [Future<Acronym>] = []
    return req.transaction(on: .psql) { conn in
      for acronymData in acronymsData {
        let acronym = try Acronym(short: acronymData.short, long: acronymData.long, userID: user.requireID())
        acronymSaveResults.append(acronym.save(on: conn))
      }
      return acronymSaveResults.flatten(on: conn)
        .transform(to: .created)
    }
  }

  ...
}

struct AcronymCreateData: Content {
  let short: String
  let long: String
}
1 Like
8

@michaeltansg Thank you for sharing this - much appreciated! :]