run.fsx

#r "System.Net.Http"
#r "Newtonsoft.Json"

open System.Net
open System.Net.Http
open Newtonsoft.Json

type Airport = {
    iata: string;
    country: string;
    city: string;
    lat: float;
    lon: float;
}

let Run(req: HttpRequestMessage, log: TraceWriter) =
    async {
        let airports =
            [
                {iata="CPH"; country="Denmark"; city="Copenhagen"; lat=55.618056; lon=12.656111}
                {iata="GDN"; country="Poland"; city="Gdansk"; lat=54.3775; lon=18.466111}
                {iata="LHR"; country="United Kingdom"; city="London"; lat=51.4775; lon= -0.461389} 
                {iata="ARN"; country="Sweden"; city="Stockholm"; lat=59.651944; lon=17.918611}  
            ]

        log.Info(sprintf 
            "F# HTTP trigger function processed a request.")

        // Set name to query string
        let iata =
            req.GetQueryNameValuePairs()
            |> Seq.tryFind (fun q -> q.Key = "iataCode")

        match iata with
        | Some a ->
            let query = airports |> List.filter(fun x -> x.iata = a.Value )
            match query with
            | [] -> 
                return req.CreateResponse(HttpStatusCode.NotFound, "No data on the airport");
            | _ ->
                let airport = query |> List.head
                return req.CreateResponse(HttpStatusCode.OK, airport, "application/json");
        | None ->
            return req.CreateResponse(HttpStatusCode.BadRequest, "Specify iata code!", "application/json");

    } |> Async.RunSynchronously