How to use reflection inside a static method - reflection

Ive got a logging method:
public static void WriteSimpleDebugTrace(string logFilePathArg, string messageArg)
{
StreamWriter writer;
//Environment.ExpandEnvironmentVariables("%SystemDrive%") [will get to the c drive]
if (EnumsAndConstants.EnableApplicationLogging)
{
writer = new StreamWriter(logFilePathArg, true);
writer.Write("Time: " + DateTime.Now.ToString() + " Message: " + messageArg);
writer.Write(Environment.NewLine);
writer.Flush();
writer.Close();
}
}
And I am trying to access this.GetType().Name inside it but im not allowed to. Is there anyway around this? I want to easily get the calling class name when this method is called without having to rewrite all calls to this method...

As it's static there is no this instance. You'd usually pass the actual instance into to method to provide method data. I have a logging class which accepts a Reflection.MethodInfo instance to output. As you don't want to change the method signature, perhaps you'd have better luck using the StackTrace diagnostics class:
http://msdn.microsoft.com/en-us/library/system.diagnostics.stacktrace%28VS.71%29.aspx
Get the previous Frame, then recover the calling method. The example pretty much says it all.

You can use stackTrace.GetFrame(1).GetMethod() to retrieve the calling method and from there the associated class name

Related

AutoFixture/AutoMoq: Unable to Create Instance (`BadImageFormatException`)

Below is a minimal example of the problem I am currently encountering:
using System.Net.WebSockets;
using AutoFixture;
using AutoFixture.AutoMoq;
using FluentAssertions;
using Xunit;
...
[Fact]
public void Test1()
{
var fixture = new Fixture().Customize(new AutoMoqCustomization() { ConfigureMembers = true });
var sut = fixture.Create<WebSocket>();
sut.Should().NotBeNull();
}
[Fact]
public void Test2()
{
var fixture = new Fixture().Customize(new AutoMoqCustomization() { ConfigureMembers = true });
var sut = new Mock<WebSocket>().Object;
fixture.Inject(sut);
sut.Should().NotBeNull();
}
...
When I run the first test, I get the following exception:
AutoFixture.ObjectCreationExceptionWithPath : AutoFixture was unable to create an instance from Moq.Mock`1[System.IO.Stream] because creation unexpectedly failed with exception. Please refer to the inner exception to investigate the root cause of the failure.
Inner exception messages:
System.BadImageFormatException: An attempt was made to load a program with an incorrect format. (Exception from HRESULT: 0x8007000B)
The second test succeeds.
I would like to be able to create an instance of a class using AutoFixture which takes a WebSocket as a constructor parameter, without the need to inject a mock object first (ultimately, so that I can use an AutoMoqData attribute, and get rid of some boilerplate). Have I got any misusage or misunderstanding going on here, or would this be better placed as a GitHub issue? In the interim, is there anything I can do to work around this issue?
You observe this issue because of the AutoFixture's factory discovery strategy. When you try to create an object of an abstract type, AutoFixture still inspects the type to find a static factory method to activate the object. In your particular case, the WebSocket type contains such methods, so some of them is used. It looks like it doesn't work well with auto-generated input values, so fails with an exception.
You can customize AutoFixture, to always mock the WebSocket type:
fixture.Register((Mock<WebSocket> m) => m.Object);
Just tested with the latest versions of products (AutoFixture 4.5.0, Moq 4.10.0) and it works like a charm.

How do QueryString parameters get bound to Action method parameters?

I have a webforms project, and am attempting to run some code that allows me to make a call to an MVC route and then render the result within the body of the web forms page.
There are a couple of HttpResponse/Request/Context wrappers which I use to execute a call to an MVC route, e.g.:
private static string RenderInternal(string path)
{
var responseWriter = new StringWriter();
var mvcResponse = new MvcPlayerHttpResponseWrapper(responseWriter, PageRenderer.CurrentPageId);
var mvcRequest = new MvcPlayerHttpRequestWrapper(Request, path);
var mvcContext = new MvcPlayerHttpContextWrapper(Context, mvcResponse, mvcRequest);
lock (HttpContext.Current)
{
new MvcHttpHandlerWrapper().PublicProcessRequest(mvcContext);
}
...
The code works fine for executing simple MVC routes, for e.g. "/Home/Index". But I can't specify any query string parameters (e.g. "/Home/Index?foo=bar") as they simply get ignored. I have tried to set the QueryString directly within the RequestWrapper instance, like so:
public class MvcPlayerHttpRequestWrapper : HttpRequestWrapper
{
private readonly string _path;
private readonly NameValueCollection query = new NameValueCollection();
public MvcPlayerHttpRequestWrapper(HttpRequest httpRequest, string path)
: base(httpRequest)
{
var parts = path.Split('?');
if (parts.Length > 1)
{
query = ExtractQueryString(parts[1]);
}
_path = parts[0];
}
public override string Path
{
get
{
return _path;
}
}
public override NameValueCollection QueryString
{
get
{
return query;
}
}
...
When debugging I can see the correct values are in the "request.QueryString", but the values never get bound to the method parameter.
Does anyone know how QueryString values are used and bound from an http request to an MVC controller action?
It seems like the handling of the QueryString value is more complex than I anticipated. I have a limited knowledge of the internals of the MVC Request pipeline.
I have been trying to research the internals myself and will continue to do so. If I find anything I will update this post appropriately.
I have also created a very simple web forms project containing only the code needed to produce this problem and have shared it via dropbox: https://www.dropbox.com/s/vi6erzw24813zq1/StackMvcGetQuestion.zip
The project simply contains one Default.aspx page, a Controller, and the MvcWrapper class used to render out the result of an MVC path. If you look at the Default.aspx.cs you will see a route path containing a querystring parameter is passed in, but it never binds against the parameter on the action.
As a quick reference, here are some extracts from that web project.
The controller:
public class HomeController : Controller
{
public ActionResult Index(string foo)
{
return Content(string.Format("<p>foo = {0}</p>", foo));
}
}
The Default.aspx page:
protected void Page_Load(object sender, EventArgs e)
{
string path = "/Home/Index?foo=baz";
divMvcOutput.InnerHtml = MvcWrapper.MvcPlayerFunctions.Render(path);
}
I have been struggling with this for quite a while now, so would appreciate any advice in any form. :)
MVC framework will try to fill the values of the parameters of the action method from the query string (and other available data such as posted form fields, etc.), that part you got right. The part you missed is that it does so by matching the name of the parameter with the value names passed in. So if you have a method MyMethod in Controller MyController with the signature:
public ActionResult MyMethod(string Path)
{
//Some code goes here
}
The query string (or one of the other sources of variables) must contain a variable named "Path" for the framework to be able to detect it. The query string should be /MyController/MyMethod?Path=Baz
Ok. This was a long debugging session :) and this will be a long response, so bear with me :)
First how MVC works. When you call an action method with input parameters, the framework will call a class called "DefaultModelBinder" that will try and provide a value for each basic type (int, long, etc.) and instance of complex types (objects). This model binder will depend on something called the ValueProvider collection to look for variable names in query string, submitted forms, etc. One of the ValueProviders that interests us the most is the QueryStringValueProvider. As you can guess, it gets the variables defined in the query string. Deep inside the framework, this class calls HttpContext.Current to retrieve the values of the query string instead of relying on the ones being passed to it. In your setup this is causing it to see the original request with localhost:xxxx/Default.aspx as the underlying request causing it to see an empty query string. In fact inside the Action method (Bar in your case) you can get the value this.QueryString["variable"] and it will have the right value.
I modified the Player.cs file to use a web client to make a call to an MVC application running in a separate copy of VS and it worked perfectly. So I suggest you run your mvc application separately and call into it and it should work fine.

Windows Azure access POST data

Ok, so I can't seem to find decent Windows Azure examples. I have a simple hello world application that's based on this tutorial. I want to have custom output instead of JSON or XML. So I created my interface like:
[ServiceContract]
public interface IService
{
[OperationContract]
[WebInvoke(UriTemplate = "session/create", Method = "POST")]
string createSession();
}
public class MyService : IService
{
public string createSession()
{
// get access to POST data here: user, pass
string sessionid = Session.Create(user, pass);
return "sessionid=" + sessionid;
}
}
For the life of me, I can't seem to figure out how to access the POST data. Please help. Thanks!
If you have an HttpContext there may be a Request object that would have the form data. I'm basing part of this off the ASP.Net tag on this question, so if that is incorrect then there may be the need to handle this another way but it looks a lot like a web service to my mind.
EDIT: HttpRequest is the class that has the Form property that should be where the POST data is stored if this is an HTTP request. This is part of System.Web so it should be ready to be used pretty easily, as I recall.
Sample code showing the Request.Form property:
int loop1;
NameValueCollection coll;
//Load Form variables into NameValueCollection variable.
coll=Request.Form;
// Get names of all forms into a string array.
String[] arr1 = coll.AllKeys;
for (loop1 = 0; loop1 < arr1.Length; loop1++)
{
Response.Write("Form: " + arr1[loop1] + "<br>");
}
This presumed there was an HttpRequest instance around.
WCF Simplified Part 4: Comparing the Request/Reply and One-Way Patterns passes in a parameter so that your "createSession" method would have to take in those strings it would appear. I'm used to the ASP.Net world where there are some built-in objects like Request, Response, Server, Application and Session.
Yes, if you did try changing the method signature as there are ways to pass in parameters in that last example I linked though I don't know if that would work in your case or not.

TypeError: Error #1034: Type Coercion failed: cannot convert Object#1456c7b9 to mx.messaging.messages.IMessage

Im trying to connect a Flash client to BlazeDS. There has been some success with this from others using the vanilla BlazeDS setup. However I'm using the new Spring BlazeDS Integration from springsource and running aground.
The flash client actually seems to be working in that I can see the correct data in the body of the returned object, but for some reason unknown it fails casting as an IMessage. It fails in PollingChannel.as on this line with the subject line error
var messageList:Array = msg.body as Array;
for each (var message:IMessage in messageList) <--
On application load I register a whole bunch of classes like so
registerClassAlias( "flex.messaging.messages.RemotingMessage", RemotingMessage );
registerClassAlias("mx.messaging.messages.IMessage", IMessage);
etc..
my code is basically
var channelSet:mx.messaging.ChannelSet = new mx.messaging.ChannelSet();
var channel:mx.messaging.channels.AMFChannel = new AMFChannel("my-amf", "http://localhost:8400/SpringA/messagebroker/amf");
channelSet.addChannel(channel);
var consumer:mx.messaging.Consumer = new Consumer();
consumer.channelSet = channelSet;
consumer.destination = "simple-feed";
consumer.subscribe();
consumer.addEventListener(MessageEvent.MESSAGE, test);
private function test(event:IMessage)
{
trace("msg..");
// breakpoint never makes it here
}
I have a flex client which works 100% with same destination/channel.
The error in the title means that you, for some reason, got an object that is not implementing or extending the IMessage interface, therefore the loop can not cast it in this part:
for each (var message:IMessage in messageList){
Either you should somehow make sure that you don't add anything that is not extending or implementing IMessage, or check if the variable IS actually ext./imp. it. Also - if you want to do that, you will have to change the for each like this:
for each (var obj in messageList){
if (obj is IMessage){
var message:IMessage = obj as IMessage;
// DO STUFF HERE
}
}
Add this Object mapping:
registerClassAlias("flex.messaging.io.ObjectProxy", ObjectProxy);
If on your Java VO objects you have overridden the hashcode() method, this situation could happen.
Remove the hashcode() override (if you are able to).
See my blog for the backstory on how I discovered this. http://squaredi.blogspot.com/2013/12/remoting-landmine-without-stack-trace.html
I had the same error when trying to send an actionscript object to the backend. My problem was that my c# equivalent object was missing an public parameterless constructor.

best way to store / lookup name value pairs

I have a list of error codes I need to reference, kinda like this:
Code / Error Message
A01 = whatever error
U01 = another error
U02 = yet another error type
I get the Code returned to me via a web service call and I need to display or get the readable error. So I need a function when passed a Code that returns the readable description. I was just going to do a select case but thought their might be a better way. What is the best way / most effieient way to do this?
Use a Dictionary, (in C#, but the concept and classes are the same):
// Initialize this once, and store it in the ASP.NET Cache.
Dictionary<String,String> errorCodes = new Dictionary<String,String>();
errorCodes.Add("A01", "Whatever Error");
errorCodes.Add("U01", "Another Error");
// And to get your error code:
string ErrCode = errorCodes[ErrorCodeFromWS];
You would use a dictionary. A dictionary uses a hashmap internally for performance, so it is good in that regard. Also, because you want this to go as quickly as possible by the sounds of it, I would statically initialize it in its own class instead of, for example, in an XML file or slimier. You would probably want something like:
public static class ErrorCodes
{
private static Dictonary<string, string> s_codes = new Dicontary<string, string>();
static ErrorCodes()
{
s_codes["code"] = "Description";
s_codes["code2"] = "Description2";
}
public static string GetDesc(string code)
{
return s_codes[code];
}
}
That way, if you wanted to move the back end to a file instead of being static, then you could.

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