How can I parse out get request parameters in spray-routing?

Question

This is what the section of code looks like

    get{
      respondWithMediaType(MediaTypes.`application/json`){
          entity(as[HttpRequest]){
            obj => complete{


                println(obj)
                "ok"
            }
          }
      }
    }~

I can map the request to a spray.http.HttpRequest object and I can extract the uri from this object but I imagine there is an easier way to parse out the parameters in a get request than doing it manually.

For example if my get request is

 http://localhost:8080/url?id=23434&age=24

I want to be able to get id and age out of this request

Naphthalene

Answer 1

Actually you can do this much much better. In routing there are two directives: parameter and parameters, I guess the difference is clear, you can also use some modifiers: ! and ?. In case of !, it means that this parameter must be provided or the request is going to be rejected and ? returns an option, so you can provide a default parameter in this case. Example:

val route: Route = {
  (path("search") & get) {
    parameter("q"!) { query =>
      ....
    }
  }
}

val route: Route = {
  (path("search") & get) {
    parameters("q"!, "filter" ? "all") { (query, filter) => 
      ...
    }
  }
}

Spindlelegs

Thanks, this is cleaner. – Naphthalene

Note that on Spray 1.2 it would be parameters('q, 'filter ? "all") – Selena

@SamyDindane it doesn't matter, NameReplacable defined for strings as well as for symbols – Spindlelegs

What's the purpose of "filter" ? "all"? Could you please give an example? Thanks – Comyns

@KevinMeredith Read it like getOrElse for the Option type. If there's no filter parameter in the request, the value for it will be all – Spindlelegs

Thanks. Also, you don't need to specify the query parameters' types? In your example, are the query parameters, q and filter assumed to be of type String since you did not specify a type? – Comyns

using the latest akka 2.4.3 I get error when typing this code: too many arguments for method parameters. What has changed? Are the docs outdated? – Chaplain

@Chaplain nothing, just checked and works fine, I bet you've missed some imports or the types are wrong – Spindlelegs

@Spindlelegs missed what imports? Could the code sample in your solution please explicitly define the necessary imports? I have a get request working perfectly, so if there are other implicit imports I need that is news to me and not discussed at all in the docs. Thanks for the quick response. – Chaplain

@Chaplain In fact you are right, this sample is wrong in that you need to provide a required value for !, like 'q ! "default", which is required. I believe this is your problem – Spindlelegs