We Keep Coding

Is there a way of writing a FindElement call by passing in a string value for type

I am currently writing a Selenium UI test for our new transactional website however whilst setting up the solution I am trying to find a more efficient way of creating a method to find my element without duplicate of code.
Ideally I want to create something akin to this:
public void SearchForElement(IWebDriver driver, string elementType, string elementReference)
{
driver.FindElement(By.Id(elementReference));
}
Where 'Id' is the variable value 'elementType'
In previous solutions I have done the following:
if (elementType == "Id")
{
returnElement = driver.FindElement(By.Id(elementReference));
}
else if (elementType == "Name")
{
returnElement = driver.FindElement(By.Name(elementReference));
}
else if (elementType == "CssSelector")
{
returnElement = driver.FindElement(By.CssSelector(elementReference));
}
else if (elementType == "XPath")
{
returnElement = driver.FindElement(By.XPath(elementReference));
}
else if (elementType == "ClassName")
{
returnElement = driver.FindElement(By.ClassName(elementReference));
}
However as you can see the latter is in effect the same line of code that is only differentiated by the type.
Any help/advice would be much appreciated.

As the UI tests are being written in parallel to the development of our transactional site (Not ideal I know) I find it easier to maintain an array of the elements that I am using
There is nothing wrong with writing automated tests in parallel to development. In fact, this is the ideal way to do it. You actually have a much bigger problem than the question you ask. Your problem can be addressed with a different architecture for your tests. Encapsulating automation behavior in a Selenium Page Object Model allows you to partially create classes that other testers can use, but defer things like defining locators until you have a user interface to deal with.
As an example, imagine you are automating the UI for a todo list app. The UI isn't built yet, but that doesn't stop you from writing a test:
todoList = new TodoListPageModel(driver);
todoList.Add("Pay the electric bill");
CollectionAssert.Contains(todoList.GetItems().ToList(), "Pay the electric bill");
Your page model would look like:
public class TodoListPageModel
{
private readonly IWebDriver driver;
private IWebElement AddButton => throw new NotImplementedException();
private IWebElement TodoTextField => throw new NotImplementedException();
private IEnumerable<IWebElement> Items => throw new NotImplementedException();
public TodoListPageModel(IWebDriver driver)
{
this.driver = driver;
}
public void Add(string todo)
{
TodoTextField.SendKeys(todo);
AddButton.Click();
}
public IEnumerable<string> GetItems()
{
return Items.Select(item => item.Text.Trim());
}
}
Properties that refer to elements or collections of elements can throw a NotImplementedException until you have a user interface. Then you can implement those properties using the correct locator, and run the tests.
Depending on who gets done first, you could inform the developer that the tests are written, and they just need to fill in the locators. After that the developer has tests to run during development, which is pretty nice.

Collection stacking ConcurrentQueue with multithreading

Quite a few questions/answers on this topic (only listing a couple that I found. There were many more).
C# Parallel - Adding items to the collection being iterated over, or equivalent?
ConcurrentQueue with multithreading
Thanks to many of them I've come up with what I'm hoping is a possible solution for my problem. I may also be overthinking it. I have an api that needs to write to a text file for logging purposes. Now the api is called N+ times and during each call, it needs to log the request. What I don't want to do is to stop the request from having to wait on the log to be recorded before returning the requested data. Now, the logs cannot just be dropped so it must also stack up on each request if the file is currently in use, using ReaderWriterLock for this. Then when the file isn't locked, I want to write the stacked logs.
I have come up with this in the hopes that it would satisfy the requirements but I think it will still cause a wait.
var wid = WindowsIdentity.GetCurrent().Token;
//add new log items
logs.Enqueue(helpers.createNewLog(requests));
string op;
while (logs.TryDequeue(out op))
{
using (WindowsIdentity.Impersonate(wid))
{
//write to text file, location on shared drive
var wrote = writers.WriteLog(op);
//item cannot be written since file locked, add back to queue to try again
if (!wrote)
{
logs.Enqueue(op);
}
}
}
Logs is a global like so
private static ConcurrentQueue<string> logs = new ConcurrentQueue<string>();
I feel like something isn't right but I'm struggling with what it is and which would be the best way in order for the requirements to be meet and still work in a web farm.

In my opinion, you should use a BlockingCollection instead of the ConcurrentQueue, here is an example of how you can use it as a Producer-Consumer is the same thing you are trying to do.
Now with ASP.Net you can insert modules to intercept every request, if you want to save a log, I suggest you register a module instead of going with your approach. On your Global.asax.cs you have a Register method
public class MvcApplication : System.Web.HttpApplication
{
public static void Register()
{
//registering an HttpModule
HttpApplication.RegisterModule(typeof(LogModule));
}
....
}
public class LogModule: IHttpModule
{
public void Dispose()
{
}
public void Init(HttpApplication context)
{
context.LogRequest += LogEvent;
}
private void LogEvent(object src, EventArgs args)
{
if (HttpContext.Current.CurrentNotification == RequestNotification.LogRequest)
{
if ((MvcHandler)HttpContext.Current.Handler != null)
{
Debug.WriteLine("This was logged!");
//Save the information to your file
}
}
}
}
Hope this helps

Custom keyword coloring in Visual Studio 2010+

I'm trying to add custom coloring for only certain keywords in my Visual Studio editor for C# code. I want to be able to color any type that implements IDisposable as a different color. Ideally I'd like to create a simple list of classes/interfaces that derive from IDisposable in some sort of configuration that I can edit. (Although if you said there was a method/plugin that would automatically find all disposable types and color them independently that would be the Holy Grail).
I've done a ton of research and it looks like an "editor classifier" extension might do the trick. However I created one that merely tries to color the word "Stream" and although it does hit my code that attempts to highlight that word, it does not end up highlighted in the editor.
I have added my VS extension to Github here
This really seems like this should be fairly straightforward but I have gone down many alleys on this one only to find dead-ends. Is there a simpler way to do this, or is my extension broken?
Update
Very strange. I just ran my extension again and although it does not highlight the text in the editor it highlights all instances of "Stream" in the popup text when you hover over a type/variable! Is there any way to get it to apply to the editor?

Depending on wether you are using Jetbrains Resharper or not you may write a plugin for that. That way you are able not only to add visual notification of IDisposable on a variable but also provide quickfixes if, and only if, it is not beeing called, which is what i am assuming you want to catch. Mind you that i can imagine that there's already a R# plugin for that. I know i've considered this too, but i was too lazy to write a plugin for that.
Don't get me wrong btw - If you're not using r# yet you should consider trying it out.
Among others you'd be working with this: API-QuickFix
There are also ways to define custom keywords, as resharper does, given by a custom markup and apply quickfixes to that.
PS: No i don't work at jetbrains. it's just that good :)
UPDATE:
potential VS Extension fix?
check this one out: MSDN Link Highlighting Text
I tried opening your github project but couldn't so i thought i'll just check msdn instead. it seems you are deriving from the wrong class to fulfill your needs?
MSDN keyword "Editors - Extending the Editor - Walkthrough: Highlighting Text"
I know SO wants code on the site, but msdn links going down is rather unlikely and with the given information the content can be found easily enough :)

I'm a bit late to the party, but hey, why not throw my 2 cents in.
As you've explained in your question, your project has two basic parts:
Finding the classes that implement IDisposable
Highlighting them
The first is by far the hardest, though not impossible. A word-list based approach is probably the simplest, though it should be possible with Roslyn to figure out on the fly which classes inherit IDisposible.
You could also always resort to loading the project's compiled .exe/.dll in the background after a build and figuring out what the types are there, but you'd still have to write some magic glue code to figure out what short class names in the code referred to what actual full-name classes in the assembly.
The second part, highlighting, is quite easy once you know how to do it (it helps that I've spent the last several months working full-time on extending VS). Of course, with Visual Studio, nothing is as simple as it looks (despite the efforts of Microsoft to try to make it user-friendly). So, I've built a sample extension that highlights just classes named "Stream" within C# files to get you started.
The relevant code is below, and the full project source is on GitHub). It starts with a classification-tagger provider:
[Export(typeof(ITaggerProvider))]
[ContentType("CSharp")]
[TagType(typeof(ClassificationTag))]
[Name("HighlightDisposableTagger")]
public class HighlightDisposableTaggerProvider : ITaggerProvider
{
[Import]
private IClassificationTypeRegistryService _classificationRegistry = null;
[Import]
private IClassifierAggregatorService _classifierAggregator = null;
private bool _reentrant;
public ITagger<T> CreateTagger<T>(ITextBuffer buffer) where T : ITag
{
if (_reentrant)
return null;
try {
_reentrant = true;
var classifier = _classifierAggregator.GetClassifier(buffer);
return new HighlightDisposableTagger(buffer, _classificationRegistry, classifier) as ITagger<T>;
}
finally {
_reentrant = false;
}
}
}
Then the tagger itself:
public class HighlightDisposableTagger : ITagger<ClassificationTag>
{
private const string DisposableFormatName = "HighlightDisposableFormat";
[Export]
[Name(DisposableFormatName)]
public static ClassificationTypeDefinition DisposableFormatType = null;
[Export(typeof(EditorFormatDefinition))]
[Name(DisposableFormatName)]
[ClassificationType(ClassificationTypeNames = DisposableFormatName)]
[UserVisible(true)]
public class DisposableFormatDefinition : ClassificationFormatDefinition
{
public DisposableFormatDefinition()
{
DisplayName = "Disposable Format";
ForegroundColor = Color.FromRgb(0xFF, 0x00, 0x00);
}
}
public event EventHandler<SnapshotSpanEventArgs> TagsChanged = delegate { };
private ITextBuffer _subjectBuffer;
private ClassificationTag _tag;
private IClassifier _classifier;
private bool _reentrant;
public HighlightDisposableTagger(ITextBuffer subjectBuffer, IClassificationTypeRegistryService typeService, IClassifier classifier)
{
_subjectBuffer = subjectBuffer;
var classificationType = typeService.GetClassificationType(DisposableFormatName);
_tag = new ClassificationTag(classificationType);
_classifier = classifier;
}
public IEnumerable<ITagSpan<ClassificationTag>> GetTags(NormalizedSnapshotSpanCollection spans)
{
if (_reentrant) {
return Enumerable.Empty<ITagSpan<ClassificationTag>>();
}
var tags = new List<ITagSpan<ClassificationTag>>();
try {
_reentrant = true;
foreach (var span in spans) {
if (span.IsEmpty)
continue;
foreach (var token in _classifier.GetClassificationSpans(span)) {
if (token.ClassificationType.IsOfType(/*PredefinedClassificationTypeNames.Identifier*/ "User Types")) {
// TODO: Somehow figure out if this refers to a class which implements IDisposable
if (token.Span.GetText() == "Stream") {
tags.Add(new TagSpan<ClassificationTag>(token.Span, _tag));
}
}
}
}
return tags;
}
finally {
_reentrant = false;
}
}
}
I've only tested this on VS2010, but it should work for VS2013 too (the only thing that might be different is the class classification name, but that's easy to discover with a well-placed breakpoint). I've never written an extension for VS2012, so I can't comment on that, but I know it's quite close to VS2013 in most respects.

So, one possible solution(I believe this one works):
1) Create your own content type which inherits from csharp.
2) Create new TextViewCreationListener which will swap out all "csharp" content types with your own one, thus potentially "disarming" all the other classifiers.
3) Register your classifier to handle your own content type.
Here is some of the code:
[Export(typeof(IVsTextViewCreationListener))]
[ContentType("csharp")]
[TextViewRole(PredefinedTextViewRoles.Editable)]
class TextViewCreationListener : IVsTextViewCreationListener {
internal readonly IVsEditorAdaptersFactoryService _adaptersFactory;
[Import] internal IContentTypeRegistryService ContentTypeRegistryService = null;
[ImportingConstructor]
public TextViewCreationListener(IVsEditorAdaptersFactoryService adaptersFactory) {
_adaptersFactory = adaptersFactory;
}
#region IVsTextViewCreationListener Members
public void VsTextViewCreated(VisualStudio.TextManager.Interop.IVsTextView textViewAdapter) {
var textView = _adaptersFactory.GetWpfTextView(textViewAdapter);
var myContent = ContentTypeRegistryService.GetContentType(MyContentType);
if(myContent == null)
{
ContentTypeRegistryService.AddContentType(MyContentType, new[] {"csharp"});
myContent = ContentTypeRegistryService.GetContentType(MyContentType);
}
// some kind of check if the content type is not already MyContentType.
textView.TextBuffer.ChangeContentType(myContent, null);
}
#endregion
}
And now, just modify your IClassifierProvider to register with your own content type, as such: [ContentType(MyContentType)]
Iin your own IClassifier, you can basically do your own calculation and once you think you can't handle the stuff, you could pass the control to other classifiers.
If you use MEF and import IClassifierAggregatorService, you can get a "MASTER-classifier" which will run all the logic for you. I haven't implemented it yet, but I've suggestes something similiar in the past, and it seemed to work. Alternatively you could maybe use [ImportMany] with List<IClassifier> and filter out the csharp ones?!

What is the Behavior of a Dynamic Attribute in a Static (Extension) Class in C# (MVC3)

I am new to developing in .NET and C#, but have been a long-time developer, working with C, C++, Java, PHP, etc.
I have an MVC3 extension class for my data models that refers to the database. It is set as "private static" in the class, but I think that it is not keeping up with database changes. In other words, when I change data in the controllers, those changes aren't "noticed" in the db because it is static. Currently, I am creating and disposing of the variable for each use, to compensate.
My questions are:
Am I correct that a static db variable could behave that way?
Is it necessary to dispose of the dynamic variable in the static class, or will garbage collection still take care of it automatically?
Here is a relevant snippet of the class:
namespace PBA.Models {
using System;
using System.Text.RegularExpressions;
using PBA.Models;
using PBA.Controllers;
public static class Extensions {
private static PbaDbEntities db = null;
public static PbaDbEntities GetDb() {
// TODO: find out about static memory/disposal, etc.
//
if (db != null) {
db.Dispose();
}
db = new PbaDbEntities();
return db;
}
public static string GetCheckpointState(this Activity activity, long memberProjectId) {
GetDb(); // TODO: Do I need to do this each time, or will a one-time setting work?
string state = CheckpointController.CHECKPOINT_STATUS_NOT_STARTED;
try {
var sub = db.ActivitySubmissions.
Where(s => s.activityId == activity.activityId).
Where(s => s.memberProjectId == memberProjectId).
OrderByDescending(s => s.submitted).
First();
if (sub != null) {
state = sub.checkpointStatusId;
}
}
catch (Exception e) {
// omitted for brevity
}
return state;
}
}
}

Your code will fail horribly in production.
DataContexts are not thread-safe; you must not share a context between requests.
Never put mutable objects in static fields in multi-threaded applications.

Ignoring exceptions that way is a terrible idea, if you don't want to handle exceptions just don't try/catch, or catch & rethrow. Think about it like this, after you've buried the exception, your program is in an invalid state, b/c something you have no control over error'd out. Now, b/c you've buried the exception, your program can continue to operate but it's in a bad state.
If your code makes it to production, 3.5 yrs from now some jr. programmer is going to get involved in some middle of the night firestorm because all of a sudden the website is broken, even though it used to work. It will be completely impossible to track down where the exception is happening so, this poor guy is going to spend 48 straight hours adding logging code all over the place to track down the problem. He will find that some DBA somewhere decided to rename the column MemberProjectId to MemberProjectIdentifier, which caused your linq to blow up.
Think of the children, handle exceptions, don't bury them.
btw - yes, i have been that guy that has to figure out these types of mistakes.

It seems like you need to read about mvc3 and entity framework before writing coding and asking in here for help on something that's coded full of bad practices.
Answering your questions:
1- no
2- makes no sense as the answer to 1
Do it right, here are some useful documentation: http://msdn.microsoft.com/en-us/library/ie/gg416514(v=vs.98).aspx
EDIT: Adding some explicit fix
You could access your dbcontext from an static class, something like this:
var context = DbProvider.CurrentDb;
The idea is to access your db from here always: from your extension methods and from your controller actions.
Then, the implementation of the DbProvider.CurrentDb will be something like this:
public static classDbProvider {
public static void Initialize(){
HttpContext.Current.ApplicationInstance.BeginRequest += CreateDb;
HttpConetxt.Current.ApplicationInstance.EndRequest += DisposeDb;
}
private static void CreateDb(object sender, EventArgs e) {
HttpContext.Items.Add("CurrentDb", new PbaDbEntities(););
}
private static void DisposeDb(object sender, EventArgs e)
{
Current.Dispose();
HttpContext.Items.Remove("CurrentDb");
}
public static PbaDbEntities CurrentDb{
get {
return (PbaDbEntities)HttpContext.Current.Items["CurrentDb"];
}
}
}
As you can see, it will create a new Db per each request and it will be available ONLY in that request. In that way, your db will be disposed at the end of each request. This pattern is called Open-Session-in-View.
Finally, you need to initialize the DbProvider calling the method
Initialize() in your Global.asax file, in the event Application_start.
Hope it helps.

I don't have any idea of the context here-- if db is simply a connection-like object or not, but it appears you are throwing away and recreating whatever it is unnecessarily.
Best to create a property (for whatever your doing) so to be consistent.
private static Thing _thing;
private static Thing thing{
get{
if(_thing==null){
_thing=new Thing();
}
return _thing;
}
}

Caching attribute for method?

Maybe this is dreaming, but is it possible to create an attribute that caches the output of a function (say, in HttpRuntime.Cache) and returns the value from the cache instead of actually executing the function when the parameters to the function are the same?
When I say function, I'm talking about any function, whether it fetches data from a DB, whether it adds two integers, or whether it spits out the content of a file. Any function.

Your best bet is Postsharp. I have no idea if they have what you need, but that's certainly worth checking. By the way, make sure to publish the answer here if you find one.
EDIT: also, googling "postsharp caching" gives some links, like this one: Caching with C#, AOP and PostSharp
UPDATE: I recently stumbled upon this article: Introducing Attribute Based Caching. It describes a postsharp-based library on http://cache.codeplex.com/ if you are still looking for a solution.

I have just the same problem - I have multiply expensive methods in my app and it is necessary for me to cache those results. Some time ago I just copy-pasted similar code but then I decided to factor this logic out of my domain.
This is how I did it before:
static List<News> _topNews = null;
static DateTime _topNewsLastUpdateTime = DateTime.MinValue;
const int CacheTime = 5; // In minutes
public IList<News> GetTopNews()
{
if (_topNewsLastUpdateTime.AddMinutes(CacheTime) < DateTime.Now)
{
_topNews = GetList(TopNewsCount);
}
return _topNews;
}
And that is how I can write it now:
public IList<News> GetTopNews()
{
return Cacher.GetFromCache(() => GetList(TopNewsCount));
}
Cacher - is a simple helper class, here it is:
public static class Cacher
{
const int CacheTime = 5; // In minutes
static Dictionary<long, CacheItem> _cachedResults = new Dictionary<long, CacheItem>();
public static T GetFromCache<T>(Func<T> action)
{
long code = action.GetHashCode();
if (!_cachedResults.ContainsKey(code))
{
lock (_cachedResults)
{
if (!_cachedResults.ContainsKey(code))
{
_cachedResults.Add(code, new CacheItem { LastUpdateTime = DateTime.MinValue });
}
}
}
CacheItem item = _cachedResults[code];
if (item.LastUpdateTime.AddMinutes(CacheTime) >= DateTime.Now)
{
return (T)item.Result;
}
T result = action();
_cachedResults[code] = new CacheItem
{
LastUpdateTime = DateTime.Now,
Result = result
};
return result;
}
}
class CacheItem
{
public DateTime LastUpdateTime { get; set; }
public object Result { get; set; }
}
A few words about Cacher. You might notice that I don't use Monitor.Enter() ( lock(...) ) while computing results. It's because copying CacheItem pointer ( return (T)_cachedResults[code].Result; line) is thread safe operation - it is performed by only one stroke. Also it is ok if more than one thread will change this pointer at the same time - they all will be valid.

You could add a dictionary to your class using a comma separated string including the function name as the key, and the result as the value. Then when your functions can check the dictionary for the existence of that value. Save the dictionary in the cache so that it exists for all users.

PostSharp is your one stop shop for this if you want to create a [Cache] attribute (or similar) that you can stick on any method anywhere. Previously when I used PostSharp I could never get past how slow it made my builds (this was back in 2007ish, so this might not be relevant anymore).
An alternate solution is to look into using Render.Partial with ASP.NET MVC in combination with OutputCaching. This is a great solution for serving html for widgets / page regions.
Another solution that would be with MVC would be to implement your [Cache] attribute as an ActionFilterAttribute. This would allow you to take a controller method and tag it to be cached. It would only work for controller methods since the AOP magic only can occur with the ActionFilterAttributes during the MVC pipeline.
Implementing AOP through ActionFilterAttribute has evolved to be the goto solution for my shop.

AFAIK, frankly, no.
But this would be quite an undertaking to implement within the framework in order for it to work generically for everybody in all circumstances, anyway - you could, however, tailor something quite sufficient to needs by simply (where simplicity is relative to needs, obviously) using abstraction, inheritance and the existing ASP.NET Cache.

If you don't need attribute configuration but accept code configuration, maybe MbCache is what you're looking for?