Understanding compiler-generated type in dotPeek decompiled code
Hei. I was reading Digi Traffic Accelerator's decompiled source (I think it is the best way to learn), until I got some non-understandable code! Please take a look:
internal class ProxyFarm
{
private static Random rand = new Random();
private static Regex UserPassAtHostPort = new Regex("\r\n ^\r\n (?<user>[^:]+?) : (?<pass>[^@]+?)\r\n @\r\n (?<host>[^:]+? (?: : \\d+)? )\r\n $", RegexOptions.IgnorePatternWhitespace);
private static Regex HostPortUserPass = new Regex("\r\n ^\r\n (?<host>[^:]+? : \\d+) : (?<user>[^:]+?) : (?<pass>.+?)\r\n $", RegexOptions.IgnorePatternWhitespace);
public const string NEW = "new";
public const string ACTIVE = "active";
public const string BLOCKED_BY_GOOGLE = "blocked by Google";
public const string INACTIVE = "inactive";
public const string CHECKING = "Checking...";
static ProxyFarm()
{
}
public static StorageDataSet.ProxiesRow GetRandomProxy(bool WillUseRecaptcha = true)
{
// some normal code
}
public static WebProxy MakeWebProxy(StorageDataSet.ProxiesRow row)
{
// some normal code
}
public static void CheckProxy(StorageDataSet.ProxiesRow proxy)
{
// ISSUE: object of a compiler-generated type is created
// ISSUE: variable of a compiler-generated type
ProxyFarm.\u003C\u003Ec__DisplayClass5 cDisplayClass5 = new ProxyFarm.\u003C\u003Ec__DisplayClass5();
// ISSUE: reference to a compiler-generated field
cDisplayClass5.proxy = proxy;
// ISSUE: reference to a compiler-generated field
if (cDisplayClass5.proxy == null)
return;
// ISSUE: reference to a compiler-generated field
cDisplayClass5.logger = LogManager.GetLogger("Program");
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated field
cDisplayClass5.state = new ProxyFarm.CallbackState()
{
Proxy = cDisplayClass5.proxy,
Google = ProxyFarm.CheckStatus.NotChecked,
Post = ProxyFarm.CheckStatus.NotChecked
};
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r = (HttpWebRequest) WebRequest.Create("http://www.digitrafficgenerator.com/post_test.php");
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.Method = "POST";
try
{
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.Proxy = (IWebProxy) ProxyFarm.MakeWebProxy(cDisplayClass5.proxy);
}
catch (Exception ex)
{
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated field
cDisplayClass5.logger.Warn((object) ("Invalid proxy entered: " + cDisplayClass5.proxy.Address), ex);
// ISSUE: reference to a compiler-generated field
ProxyFarm.ChangeStatus(cDisplayClass5.proxy, "inactive");
return;
}
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.ConnectionGroupName = Guid.NewGuid().ToString();
// ISSUE: reference to a compiler-generated field
cDisplayClass5.byteArray = Encoding.UTF8.GetBytes("q=test");
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.ContentLength = (long) cDisplayClass5.byteArray.Length;
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.ContentType = "application/x-www-form-urlencoded";
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.Referer = "http://www.digitrafficgenerator.com/post_test.php";
// ISSUE: reference to a compiler-generated field
cDisplayClass5.r.Timeout = 20000;
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated method
IAsyncResult res = cDisplayClass5.r.BeginGetRequestStream(new AsyncCallback(cDisplayClass5.\u003CCheckProxy\u003Eb__1), (object) null);
// ISSUE: reference to a compiler-generated field
WebObject.AbortRequestAfterTimeout(res, cDisplayClass5.r);
try
{
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated method
// ISSUE: reference to a compiler-generated field
res = cDisplayClass5.r.BeginGetResponse(new AsyncCallback(cDisplayClass5.\u003CCheckProxy\u003Eb__2), (object) cDisplayClass5.r);
}
catch (Exception ex)
{
// ISSUE: reference to a compiler-generated field
// ISSUE: reference to a compiler-generated field
cDisplayClass5.logger.Info((object) ("Got an exception using " + cDisplayClass5.proxy.Address), ex);
}
// ISSUE: reference to a compiler-generated field
WebObject.AbortRequestAfterTimeout(res, cDisplayClass5.r);
HttpWebRequest request = (HttpWebRequest) WebRequest.Create("http://www.google.com/recaptcha/api/js/recaptcha.js");
request.Method = "GET";
// ISSUE: reference to a compiler-generated field
request.Proxy = (IWebProxy) ProxyFarm.MakeWebProxy(cDisplayClass5.proxy);
request.Timeout = 20000;
request.ConnectionGroupName = Guid.NewGuid().ToString();
// ISSUE: reference to a compiler-generated method
WebObject.AbortRequestAfterTimeout(request.BeginGetResponse(new AsyncCallback(cDisplayClass5.\u003CCheckProxy\u003Eb__3), (object) request), request);
}
protected static void ProxyChecked(IAsyncResult result, HttpWebRequest req, ProxyFarm.CallbackState state)
{
ILog logger = LogManager.GetLogger("Program");
ProxyFarm.CheckStatus checkStatus = ProxyFarm.CheckStatus.NotOk;
try
{
HttpWebResponse httpWebResponse = (HttpWebResponse) req.EndGetResponse(result);
if (req.RequestUri == httpWebResponse.ResponseUri)
{
if (httpWebResponse.StatusCode == HttpStatusCode.OK)
checkStatus = ProxyFarm.CheckStatus.Ok;
}
}
catch (Exception ex)
{
}
lock (state)
{
if (req.RequestUri.Authority.Contains("google.com"))
state.Google = checkStatus;
else
state.Post = checkStatus;
if (state.Post == ProxyFarm.CheckStatus.NotOk)
{
ProxyFarm.ChangeStatus(state.Proxy, "inactive");
logger.Info((object) ("Marking " + state.Proxy.Address + " as inactive as it cannot POST"));
}
else if (state.Google == ProxyFarm.CheckStatus.NotOk)
{
ProxyFarm.ChangeStatus(state.Proxy, "inactive");
logger.Info((object) ("Marking " + state.Proxy.Address + " as inactive as it is blocked by google"));
}
else
{
if (state.Google != ProxyFarm.CheckStatus.Ok || state.Post != ProxyFarm.CheckStatus.Ok)
return;
ProxyFarm.ChangeStatus(state.Proxy, "active");
}
}
}
public static void ReportBrokenProxy(StorageDataSet.ProxiesRow proxy, bool recaptcha_fail = false)
{
// some normal code
}
private static void ChangeStatus(StorageDataSet.ProxiesRow Proxy, string status)
{
// some normal code
}
public enum CheckStatus
{
NotChecked,
Ok,
NotOk,
}
protected class CallbackState
{
public StorageDataSet.ProxiesRow Proxy { get; set; }
public ProxyFarm.CheckStatus Post { get; set; }
public ProxyFarm.CheckStatus Google { get; set; }
}
}
As you can see, it seems in CheckProxy method, the compiler generated a new type! Do you have any idea what is really happening in this method? How can I understand the code?
Answer
\u003C and \u003E are the unicode representations of < and > respectively.
Those characters are valid in IL.. so the compiler will generate variables with names like that to avoid collisions.
Your decompiler just didn't know how to convert it to <> and didn't remove the temporary variables.