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.netsoapf#wsdltype-providers

F# TypeProvider cannot load type

I am trying to write a simple SOAP client using an F# type provider. The complete program is:

open System
open System.Runtime.Serialization
open System.ServiceModel
open Microsoft.FSharp.Data.TypeProviders

type EntrezService = WsdlService<"http://eutils.ncbi.nlm.nih.gov/soap/v2.0/eutils.wsdl">

[<EntryPoint>]
let main argv =
    let client = EntrezService.GeteUtilsServiceSoap()
    try
        let req = EntrezService.ServiceTypes.eSearchRequest()
        let res = client.run_eSearch req
        printfn "%A" res
    with
        | ex ->
            let rec inner (ex : Exception) =
                if ex.InnerException <> null then
                    inner ex.InnerException
                printfn "%s" ex.Message
            inner ex
    0

Unfortunately, it looks like the app crashes before it can even make the SOAP call, with the following TypeLoadException:

Could not load type 'UrlTypeLNG' from assembly 'EntrezGeneAdaptor, Version=0.0.0.0, Culture=neutral, PublicKeyToken=null '.

This type is defined in the WSDL. I don't why .NET would try to load it from my assembly.

Stack trace indicates that the exception is thrown from System.Xml.Serialization.XmlReflectionImporter.ImportMembersMapping.

What's going on here, and is there an easy fix? The equivalent program works fine in C#, so is this a problem with the F# type provider?

Solution

  • It looks like the problem was caused by the WSDL. The service defines a complex type called "UrlType", which contains an attribute called "LNG". Somehow, this was getting combined incorrectly into "UrlTypeLNG". I manually edited the WSDL to use a plain string instead of the complex type, and it seems to be working now.