Swift Siesta edit fetched entity

Question

I'm building an API client using Siesta and Swift 3 on Xcode 8. I want to be able to fetch an entity using a Siesta resource, then update some of the data and do a patch to the API.

The issue is that having an entity, if I save the JSON arrays in my entity fields I can't send them back to the server, I get the following error:

▿ Siesta.RequestError
  - userMessage: "Cannot send request"
  - httpStatusCode: nil
  - entity: nil
  ▿ cause: Optional(Siesta.RequestError.Cause.InvalidJSONObject())
    - some: Siesta.RequestError.Cause.InvalidJSONObject
  - timestamp: 502652734.40489101

My entity is:

import SwiftyJSON
import Foundation
struct Order {
    let id: String?
    let sessionId: String?
    let userId: Int?
    let status: String?
    let comment: String?
    let price: Float?
    let products: Array<JSON>? 

    init(json: JSON) throws {
        id          = json["id"].string
        sessionId      = json["sessionId"].string
        userId      = json["userId"].int
        status        = json["status"].string
        comment        = json["comment"].string
        price       = json["price"].float
        products   = json["products"].arrayValue

    }

    /**
     * Helper method to return data as a Dictionary to be able to modify it and do a patch
     **/
    public func toDictionary() -> Dictionary<String, Any> {
        var dictionary: [String:Any] = [
            "id": id ?? "",
            "sessionId": sessionId ?? "",
            "userId": userId ?? 0,
            "status": status ?? "",
            "comment": comment ?? ""
        ]
        dictionary["products"] = products ?? []

        return dictionary
    }
}

What I'm doing is:

 MyAPI.sessionOrders(sessionId: sessionId).request(.post, json: ["products": [["product": productId, "amount": 2]], "comment": "get Swifty"]).onSuccess() { response in
    let createdObject : Order? =  response.typedContent()
    expect(createdObject?.sessionId).to(equal(sessionId))
    expect(createdObject?.comment).to(equal("get Swifty"))
    expect(createdObject?.products).to(haveCount(1))
    expect(createdObject?.price).to(equal(product.price! * 2))

    if let createdId = createdObject?.id {
        var data = createdObject?.toDictionary()
        data?["comment"] = "edited Swifty" // can set paid because the user is the business owner
        MyAPI.order(id: createdId).request(.patch, json: data!).onSuccess() { response in
            result = true

        }.onFailure() { response in
                dump(response) //error is here
        }
    }
}

Resources:

func sessionOrders( sessionId: String ) -> Resource {
    return self
        .resource("/sessions")
        .child(sessionId)
        .child("orders")
}
func order( id: String ) -> Resource {
    return self
        .resource("/orders")
        .child(id)
}

Transformers:

    self.configureTransformer("/sessions/*/orders", requestMethods: [.post, .put]) {
        try Order(json: ($0.content as JSON)["data"])
    }

    self.configureTransformer("/orders/*") {
        try Order(json: ($0.content as JSON)["data"])
    }

I've managed to circle this by creating dictionary structures like:

let products: Array<Dictionary<String, Any>>?

    products   = json["products"].arrayValue.map({
        ["product": $0.dictionaryValue["product"]!.stringValue, "amount": $0.dictionaryValue["amount"]!.intValue]
    })

But I live in a hell of downcasts if I need to modify anything:

var data = createdObject?.toDictionary()
data?["comment"] = "edited Swifty" 
//if I want to modify the products...
var products = data?["products"] as! Array<Dictionary<String, Any>>
products[0]["amount"] = 4
data?["products"] = products

How can I send those original JSON arrays with Siesta? They're really easy to modify and read! I've browsed the siesta docs and github issues with no success...

score 2 · Accepted Answer · answered Dec 06 '16 at 01:57

Your problem is a mismatch between SwiftyJSON and Foundation’s JSONSerialization; Siesta just happens to be in the middle of it.

InvalidJSONObject is Siesta telling you that Foundation doesn’t understand the thing you gave it — which would be the value returned by your toDictionary() method. Most of the things in that dictionary look fine: strings, ints, a float. (Careful about using float for money, BTW.)

The culprit is that products array: it’s [JSON], where JSON is a SwiftyJSON type that Foundation doesn’t know what to do with. You should be in the clear if you turn the JSON values back into simple dictionaries:

dictionary["products"] = (products ?? []).map { $0.dictionaryObject }

If that doesn’t do it, or if you need to diagnose a similar error in the future, remove all the values from the offending dictionary and then add them back in one at a time to see which one is tripping up JSONSerialization.

Awesome! To edit products array I still have to cast it right? If I don't I get a "has no subscript members" error. I read on the Siesta docs that's not a good idea to modify you entity attributes... is that right? — SkarXa, Dec 06 '16 at 08:37
It is just fine to modify an entity’s content if the content is a `struct`. (That includes dictionaries and arrays.) Because structs have value semantics, you are really creating a new value, not modifying the existing value the Resource already holds. The concern is if the content is a mutable object, you can change it in place without the observers being notified. — Paul Cantrell, Dec 06 '16 at 20:11

Swift Siesta edit fetched entity

1 Answers1