How to Work with Web Service in Fore/Fore.NET?

Description

PP.SOM service is mostly used to develop web application based systems. Somehow it may be required to address the web service from desktop application based assemblies, forms or units. The Fore language does not contain classes required to work with web services that is why the work can be organized only via the combination Fore.NET-Fore. The HttpWebRequest/HttpWebResponse (.NET Framework, System.NET namespaces) are used to send queries and get responses from web service. Below is the example of static function in Fore.NET that enables the user to send JSON requests and get web service responses.

Fore.NET Example

Public Class SampleWebClient
    Public Shared Function JsonHttpRequest(urlString: string; jsonContent: string): string;
    Var
        response: String;
        wRequest: HttpWebRequest;
        wResponse: HttpWebResponse;
        enc: Encoding;
        bytes: Array Of Byte;
        requestStream, responseStream: Stream;
        reader: StreamReader;
    Begin
        //Create an object for sending web service request and getting response
        wRequest := HttpWebRequest.CreateHttp(urlString);
        Try
            bytes := System.Text.Encoding.ASCII.GetBytes(jsonContent);
            //Setting parameters
            wRequest.Method := "POST";
            wRequest.ContentLength := bytes.Length;
            wRequest.ContentType := "application/json;charset=UTF-8";
            //Record request
            requestStream := wRequest.GetRequestStream();
            requestStream.Write(bytes, 0, bytes.Length);
            requestStream.Close();
            //Send request and get response
            wResponse := wRequest.GetResponse() As HttpWebResponse;
            //If request is executed successfully, read response
            If wResponse.StatusCode = HttpStatusCode.OK Then
                responseStream := wResponse.GetResponseStream();
                reader := New StreamReader(responseStream);
                response := reader.ReadToEnd();
            End If;
            //Close object and free resources
            wResponse.Close();
        Except On we: WebException Do
            Begin
                System.Diagnostics.Debug.WriteLine(we.Message)
            End;
        On ex: Exception Do
            Begin
                System.Diagnostics.Debug.WriteLine(ex.Message)
            End;
        Finally
            wResponse.Close();
        End Try;
        Return response;
    End Function;
End Class;

The following code sends a JSON request for connecting to repository and displays web service response in the development environment console:

Public Shared Sub Main(Params: StartParams);
Var
    request: string;
    response: string;
Begin
    request := "{ ""OpenMetabase"": { ""tDef"": { ""id"": ""PPREPOSITORY"" } , ""tCreds"": { ""user"": { ""id"": ""pprepository"" } , ""pass"": ""pprepository"" } } }";
    response := JsonHttpRequest("http://localhost:9090/axis2/services/PP.SOM.Som", request);
    System.Diagnostics.Debug.WriteLine(response);
End Sub;

Fore Example

To send a JSON request from the code in the Fore, use resources of the ForeNet assembly:

Sub TestJsonRequest;
Var
    MB: IMetabase;
    Run: IForeNETRuntime;
    Asm: IForeNETRuntimeAssembly;
    Typ: IForeNETRuntimeType;
    response: Variant;
    url, request: String;
Begin
    url := "http://localhost:9090/axis2/services/PP.SOM.Som";
    request := "{ ""OpenMetabase"": { ""tDef"": { ""id"": ""PPREPOSITORY"" } , ""tCreds"": { ""user"": { ""id"": ""pprepository"" } , ""pass"": ""pprepository"" } } }";
    MB := MetabaseClass.Active;
    Run := ForeNETAssemblyClass.Runtime;
    Asm := Run.Assembly(MB.ItemById("SampleAssembly").Bind As IForeNETAssembly);
    Typ := Asm.Type("SampleAssembly.SampleWebClient");
    response := Typ.InvokeMethod("JsonHttpRequest", Null, url, request);
    Debug.WriteLine(response);
End Sub TestJsonRequest;