In my DAL, I'm currently using this in a base class:
protected static MyCMSEntities MyCMSDb
{
get { return new MyCMSEntities(ConfigurationManager.ConnectionStrings["MyCMSEntities"].ConnectionString); }
}
and calling like this from a subclass:
public static bool Add(ContentFAQ newContent)
{
MyCMSEntities db = MyCMSDb;
newContent.DateModified = DateTime.Now;
newContent.OwnerUserId = LoginManager.CurrentUser.Id;
db.ContentFAQ.AddObject(newContent);
return db.SaveChanges() > 0;
}
I understand the method to get the context is static, but as it creates a new intance of the context, this is not static, i.e. it is new for each call to the Add method.
Am I correct and more importantly, ok for a web application?
Thanks.
You are correct in using a new context for every web call - but why this obfuscation? I would recommend removing this indirection with the static property (makes the code harder to understand) and also using a using block since the context is disposable:
public static bool Add(ContentFAQ newContent)
{
using(var db = new MyCMSEntities())
{
newContent.DateModified = DateTime.Now;
newContent.OwnerUserId = LoginManager.CurrentUser.Id;
db.ContentFAQ.AddObject(newContent);
return db.SaveChanges() > 0;
}
}
Also the default constructor of the context should use the default connection string, which is the right one if you didn't change it in your configuration (otherwise just add it back in).
Related
I'm trying to implement a web application using ASP.NET MVC and the Microsoft Unity DI framework. The application needs to support multiple user sessions at the same time, each of them with their own connection to a separate database (but all users using the same DbContext; the database schemas are identical, it's just the data that is different).
Upon a user's log-in, I register the necessary type mappings to the application's Unity container, using a session-based lifetime manager that I found in another question here.
My container is initialized like this:
// Global.asax.cs
public static UnityContainer CurrentUnityContainer { get; set; }
protected void Application_Start()
{
// ...other code...
CurrentUnityContainer = UnityConfig.Initialize();
// misc services - nothing data access related, apart from the fact that they all depend on IRepository<ClientContext>
UnityConfig.RegisterComponents(CurrentUnityContainer);
}
// UnityConfig.cs
public static UnityContainer Initialize()
{
UnityContainer container = new UnityContainer();
DependencyResolver.SetResolver(new UnityDependencyResolver(container));
GlobalConfiguration.Configuration.DependencyResolver = new Unity.WebApi.UnityDependencyResolver(container);
return container;
}
This is the code that's called upon logging in:
// UserController.cs
UnityConfig.RegisterUserDataAccess(MvcApplication.CurrentUnityContainer, UserData.Get(model.AzureUID).CurrentDatabase);
// UnityConfig.cs
public static void RegisterUserDataAccess(IUnityContainer container, string databaseName)
{
container.AddExtension(new DataAccessDependencies(databaseName));
}
// DataAccessDependencies.cs
public class DataAccessDependencies : UnityContainerExtension
{
private readonly string _databaseName;
public DataAccessDependencies(string databaseName)
{
_databaseName = databaseName;
}
protected override void Initialize()
{
IConfigurationBuilder configurationBuilder = Container.Resolve<IConfigurationBuilder>();
Container.RegisterType<ClientContext>(new SessionLifetimeManager(), new InjectionConstructor(configurationBuilder.GetConnectionString(_databaseName)));
Container.RegisterType<IRepository<ClientContext>, RepositoryService<ClientContext>>(new SessionLifetimeManager());
}
}
// SessionLifetimeManager.cs
public class SessionLifetimeManager : LifetimeManager
{
private readonly string _key = Guid.NewGuid().ToString();
public override void RemoveValue(ILifetimeContainer container = null)
{
HttpContext.Current.Session.Remove(_key);
}
public override void SetValue(object newValue, ILifetimeContainer container = null)
{
HttpContext.Current.Session[_key] = newValue;
}
public override object GetValue(ILifetimeContainer container = null)
{
return HttpContext.Current.Session[_key];
}
protected override LifetimeManager OnCreateLifetimeManager()
{
return new SessionLifetimeManager();
}
}
This works fine as long as only one user is logged in at a time. The data is fetched properly, the dashboards work as expected, and everything's just peachy keen.
Then, as soon as a second user logs in, disaster strikes.
The last user to have prompted a call to RegisterUserDataAccess seems to always have "priority"; their data is displayed on the dashboard, and nothing else. Whether this is initiated by a log-in, or through a database access selection in my web application that calls the same method to re-route the user's connection to another database they have permission to access, the last one to draw always imposes their data on all other users of the web application. If I understand correctly, this is a problem the SessionLifetimeManager was supposed to solve - unfortunately, I really can't seem to get it to work.
I sincerely doubt that a simple and common use-case like this - multiple users logged into an MVC application who each are supposed to access their own, separate data - is beyond the abilities of Unity, so obviously, I must be doing something very wrong here. Having spent most of my day searching through depths of the internet I wasn't even sure truly existed, I must, unfortunately, now realize that I am at a total and utter loss here.
Has anyone dealt with this issue before? Has anyone dealt with this use-case before, and if yes, can anyone tell me how to change my approach to make this a little less headache-inducing? I am utterly desperate at this point and am considering rewriting my entire data access methodology just to make it work - not the healthiest mindset for clean and maintainable code.
Many thanks.
the issue seems to originate from your registration call, when registering the same type multiple times with unity, the last registration call wins, in this case, that will be data access object for whoever user logs-in last. Unity will take that as the default registration, and will create instances that have the connection to that user's database.
The SessionLifetimeManager is there to make sure you get only one instance of the objects you resolve under one session.
One option to solve this is to use named registration syntax to register the data-access types under a key that maps to the logged-in user (could be the database name), and on the resolve side, retrieve this user key, and use it resolve the corresponding data access implementation for the user
Thank you, Mohammed. Your answer has put me on the right track - I ended up finally solving this using a RepositoryFactory which is instantiated in an InjectionFactory during registration and returns a repository that always wraps around a ClientContext pointing to the currently logged on user's currently selected database.
// DataAccessDependencies.cs
protected override void Initialize()
{
IConfigurationBuilder configurationBuilder = Container.Resolve<IConfigurationBuilder>();
Container.RegisterType<IRepository<ClientContext>>(new InjectionFactory(c => {
ClientRepositoryFactory repositoryFactory = new ClientRepositoryFactory(configurationBuilder);
return repositoryFactory.GetRepository();
}));
}
// ClientRepositoryFactory.cs
public class ClientRepositoryFactory : IRepositoryFactory<RepositoryService<ClientContext>>
{
private readonly IConfigurationBuilder _configurationBuilder;
public ClientRepositoryFactory(IConfigurationBuilder configurationBuilder)
{
_configurationBuilder = configurationBuilder;
}
public RepositoryService<ClientContext> GetRepository()
{
var connectionString = _configurationBuilder.GetConnectionString(UserData.Current.CurrentPermission);
ClientContext ctx = new ClientContext(connectionString);
RepositoryService<ClientContext> repository = new RepositoryService<ClientContext>(ctx);
return repository;
}
}
// UserData.cs (multiton-singleton-hybrid)
public static UserData Current
{
get
{
var currentAADUID = (string)(HttpContext.Current.Session["currentAADUID"]);
return Get(currentAADUID);
}
}
public static UserData Get(string AADUID)
{
UserData instance;
lock(_instances)
{
if(!_instances.TryGetValue(AADUID, out instance))
{
throw new UserDataNotInitializedException();
}
}
return instance;
}
public static UserData Current
{
get
{
var currentAADUID = (string)(HttpContext.Current.Session["currentAADUID"]);
return Get(currentAADUID);
}
}
public static UserData Get(string AADUID)
{
UserData instance;
lock(_instances)
{
if(!_instances.TryGetValue(AADUID, out instance))
{
throw new UserDataNotInitializedException();
}
}
return instance;
}
My application can connect with multiple data bases (every data base have the same schema), I store the current DB, selected by user, in Session and encapsule access using a static property like:
public class DataBase
{
public static string CurrentDB
{
get
{
return HttpContext.Current.Session["CurrentDB"].ToString();
}
set
{
HttpContext.Current.Session["CurrentDB"] = value;
}
}
}
Other pieces of code access the static CurrentDB to determine what DB use.
Some actions start background process in a thread and it need access the CurrentDB to do some stuff. I'm thinking using something like this:
[ThreadStatic]
private static string _threadSafeCurrentDB;
public static string CurrentDB
{
get
{
if (HttpContext.Current == null)
return _threadSafeCurrentDB;
return HttpContext.Current.Session["CurrentDB"].ToString();
}
set
{
if (HttpContext.Current == null)
_threadSafeCurrentDB = value;
else
HttpContext.Current.Session["CurrentDB"] = value;
}
}
And start thread like:
public class MyThread
{
private string _currentDB;
private thread _thread;
public MyThread (string currentDB)
{
_currentDB = currentDB;
_thread = new Thread(DoWork);
}
public DoWork ()
{
DataBase.CurrentDB = _currentDB;
... //Do the work
}
}
This is a bad practice?
Actually, I think you should be able to determine which thread uses which database, so I would create a class inherited from Thread, but aware of the database it uses. It should have a getDB() method, so, if you need a new Thread which will use the same database as used in another specific Thread, you can use it. You should be able to setDB(db) of a Thread as well.
In the session you are using a current DB approach, which assumes that there is a single current DB. If this assumption describes the truth, then you can leave it as it is and update it whenever a new current DB is being used. If you have to use several databases in the same time, then you might want to have a Dictionary of databases, where the Value would be the DB and the Key would be some kind of code which would have a sematic meaning which you could use to be able to determine which instance is needed where.
I'm using WebAPI 2.2 and Microsoft.AspNet.OData 5.7.0 to create an OData service that supports paging.
When hosted in the production environment, the WebAPI lives on a server that is not exposed externally, hence the various links returned in the OData response such as the #odata.context and #odata.nextLink point to the internal IP address e.g. http://192.168.X.X/<AccountName>/api/... etc.
I've been able to modify the Request.ODataProperties().NextLink by implementing some logic in each and every ODataController method to replace the internal URL with an external URL like https://account-name.domain.com/api/..., but this is very inconvenient and it only fixes the NextLinks.
Is there some way to set an external host name at configuration time of the OData service? I've seen a property Request.ODataProperties().Path and wonder if it's possible to set a base path at the config.MapODataServiceRoute("odata", "odata", GetModel()); call, or in the GetModel() implementation using for instance the ODataConventionModelBuilder?
UPDATE: The best solution I've come up with so far, is to create a BaseODataController that overrides the Initialize method and checks whether the Request.RequestUri.Host.StartsWith("beginning-of-known-internal-IP-address") and then do a RequestUri rewrite like so:
var externalAddress = ConfigClient.Get().ExternalAddress; // e.g. https://account-name.domain.com
var account = ConfigClient.Get().Id; // e.g. AccountName
var uriToReplace = new Uri(new Uri("http://" + Request.RequestUri.Host), account);
string originalUri = Request.RequestUri.AbsoluteUri;
Request.RequestUri = new Uri(Request.RequestUri.AbsoluteUri.Replace(uriToReplace.AbsoluteUri, externalAddress));
string newUri = Request.RequestUri.AbsoluteUri;
this.GetLogger().Info($"Request URI was rewritten from {originalUri} to {newUri}");
This perfectly fixes the #odata.nextLink URLs for all controllers, but for some reason the #odata.context URLs still get the AccountName part (e.g. https://account-name.domain.com/AccountName/api/odata/$metadata#ControllerName) so they still don't work.
Rewriting the RequestUri is sufficient to affect #odata.nextLink values because the code that computes the next link depends on the RequestUri directly. The other #odata.xxx links are computed via a UrlHelper, which is somehow referencing the path from the original request URI. (Hence the AccountName you see in your #odata.context link. I've seen this behavior in my code, but I haven't been able to track down the source of the cached URI path.)
Rather than rewrite the RequestUri, we can solve the problem by creating a CustomUrlHelper class to rewrite OData links on the fly. The new GetNextPageLink method will handle #odata.nextLink rewrites, and the Link method override will handle all other rewrites.
public class CustomUrlHelper : System.Web.Http.Routing.UrlHelper
{
public CustomUrlHelper(HttpRequestMessage request) : base(request)
{ }
// Change these strings to suit your specific needs.
private static readonly string ODataRouteName = "ODataRoute"; // Must be the same as used in api config
private static readonly string TargetPrefix = "http://localhost:8080/somePathPrefix";
private static readonly int TargetPrefixLength = TargetPrefix.Length;
private static readonly string ReplacementPrefix = "http://www.contoso.com"; // Do not end with slash
// Helper method.
protected string ReplaceTargetPrefix(string link)
{
if (link.StartsWith(TargetPrefix))
{
if (link.Length == TargetPrefixLength)
{
link = ReplacementPrefix;
}
else if (link[TargetPrefixLength] == '/')
{
link = ReplacementPrefix + link.Substring(TargetPrefixLength);
}
}
return link;
}
public override string Link(string routeName, IDictionary<string, object> routeValues)
{
var link = base.Link(routeName, routeValues);
if (routeName == ODataRouteName)
{
link = this.ReplaceTargetPrefix(link);
}
return link;
}
public Uri GetNextPageLink(int pageSize)
{
return new Uri(this.ReplaceTargetPrefix(this.Request.GetNextPageLink(pageSize).ToString()));
}
}
Wire-up the CustomUrlHelper in the Initialize method of a base controller class.
public abstract class BaseODataController : ODataController
{
protected abstract int DefaultPageSize { get; }
protected override void Initialize(System.Web.Http.Controllers.HttpControllerContext controllerContext)
{
base.Initialize(controllerContext);
var helper = new CustomUrlHelper(controllerContext.Request);
controllerContext.RequestContext.Url = helper;
controllerContext.Request.ODataProperties().NextLink = helper.GetNextPageLink(this.DefaultPageSize);
}
Note in the above that the page size will be the same for all actions in a given controller class. You can work around this limitation by moving the assignment of ODataProperties().NextLink to the body of a specific action method as follows:
var helper = this.RequestContext.Url as CustomUrlHelper;
this.Request.ODataProperties().NextLink = helper.GetNextPageLink(otherPageSize);
The answer by lencharest is promising, but I found an improvement on his method. Rather than using the UrlHelper, I created a class derived from System.Net.Http.DelegatingHandler. This class is inserted (first) into the message handling pipeline and thus has a crack at altering the incoming HttpRequestMessage. It's an improvement over the above solution because in addition to altering the controller-specific URLs (as the UrlHelper does, e,g, https://data.contoso.com/odata/MyController), it also alters the url that appears as the xml:base in the OData service document (e.g., https://data.contoso.com/odata).
My particular application was to host an OData service behind a proxy server, and I wanted all the URLs presented by the server to be the externally-visible URLs, not the internally-visible ones. And, I didn't want to have to rely on annotations for this; I wanted it to be fully automatic.
The message handler looks like this:
public class BehindProxyMessageHandler : DelegatingHandler
{
protected async override Task<HttpResponseMessage> SendAsync(
HttpRequestMessage request, CancellationToken cancellationToken)
{
var builder = new UriBuilder(request.RequestUri);
var visibleHost = builder.Host;
var visibleScheme = builder.Scheme;
var visiblePort = builder.Port;
if (request.Headers.Contains("X-Forwarded-Host"))
{
string[] forwardedHosts = request.Headers.GetValues("X-Forwarded-Host").First().Split(new char[] { ',' });
visibleHost = forwardedHosts[0].Trim();
}
if (request.Headers.Contains("X-Forwarded-Proto"))
{
visibleScheme = request.Headers.GetValues("X-Forwarded-Proto").First();
}
if (request.Headers.Contains("X-Forwarded-Port"))
{
try
{
visiblePort = int.Parse(request.Headers.GetValues("X-Forwarded-Port").First());
}
catch (Exception)
{ }
}
builder.Host = visibleHost;
builder.Scheme = visibleScheme;
builder.Port = visiblePort;
request.RequestUri = builder.Uri;
var response = await base.SendAsync(request, cancellationToken);
return response;
}
}
You wire the handler up in WebApiConfig.cs:
config.Routes.MapODataServiceRoute(
routeName: "odata",
routePrefix: "odata",
model: builder.GetEdmModel(),
pathHandler: new DefaultODataPathHandler(),
routingConventions: ODataRoutingConventions.CreateDefault()
);
config.MessageHandlers.Insert(0, new BehindProxyMessageHandler());
There is another solution, but it overrides url for the entire context.
What I'd like to suggest is:
Create owin middleware and override Host and Scheme properties inside
Register the middleware as the first one
Here is an example of middleware
public class RewriteUrlMiddleware : OwinMiddleware
{
public RewriteUrlMiddleware(OwinMiddleware next)
: base(next)
{
}
public override async Task Invoke(IOwinContext context)
{
context.Request.Host = new HostString(Settings.Default.ProxyHost);
context.Request.Scheme = Settings.Default.ProxyScheme;
await Next.Invoke(context);
}
}
ProxyHost is the host you want to have. Example: test.com
ProxyScheme is the scheme you want: Example: https
Example of middleware registration
public class Startup
{
public void Configuration(IAppBuilder app)
{
app.Use(typeof(RewriteUrlMiddleware));
var config = new HttpConfiguration();
WebApiConfig.Register(config);
app.UseWebApi(config);
}
}
A couple of years later, using ASP.NET Core, I figured that the easiest way to apply it in my service was to just create a filter that masquerades the host name. (AppConfig is a custom configuration class that contains the host name, among other things.)
public class MasqueradeHostFilterAttribute : ActionFilterAttribute
{
public override void OnActionExecuting(ActionExecutingContext context)
{
var appConfig = context.HttpContext.RequestServices.GetService<AppConfig>();
if (!string.IsNullOrEmpty(appConfig?.MasqueradeHost))
context.HttpContext.Request.Host = new HostString(appConfig.MasqueradeHost);
}
}
Apply the filter to the controller base class.
[MasqueradeHostFilter]
public class AppODataController : ODataController
{
}
The result is a nicely formatted output:
{ "#odata.context":"https://app.example.com/odata/$metadata" }
Just my two cents.
Using system.web.odata 6.0.0.0.
Setting the NextLink property too soon is problematic. Every reply will then have a nextLink in it. The last page should of course be free of such decorations.
http://docs.oasis-open.org/odata/odata-json-format/v4.0/os/odata-json-format-v4.0-os.html#_Toc372793048 says:
URLs present in a payload (whether request or response) MAY be
represented as relative URLs.
One way that I hope will work is to override EnableQueryAttribute:
public class myEnableQueryAttribute : EnableQueryAttribute
{
public override IQueryable ApplyQuery(IQueryable queryable, ODataQueryOptions queryOptions)
{
var result = base.ApplyQuery(queryable, queryOptions);
var nextlink = queryOptions.Request.ODataProperties().NextLink;
if (nextlink != null)
queryOptions.Request.ODataProperties().NextLink = queryOptions.Request.RequestUri.MakeRelativeUri(nextlink);
return result;
}
}
ApplyQuery() is where the "overflow" is detected. It basically asks for pagesize+1 rows and will set NextLink if the result set contains more than pagesize rows.
At this point it is relatively easy to rewrite NextLink to a relative URL.
The downside is that every odata method must now be adorned with the new myEnableQuery attribute:
[myEnableQuery]
public async Task<IHttpActionResult> Get(ODataQueryOptions<TElement> options)
{
...
}
and other URLs embedded elsewhere remains problematic. odata.context remains a problem. I want to avoid playing with the request URL, because I fail to see how that is maintainable over time.
Your question boils down to controlling the service root URI from within the service itself. My first thought was to look for a hook on the media type formatters used to serialize responses. ODataMediaTypeFormatter.MessageWriterSettings.PayloadBaseUri and ODataMediaTypeFormatter.MessageWriterSettings.ODataUri.ServiceRoot are both settable properties that suggest a solution. Unfortunately, ODataMediaTypeFormatter resets these properties on every call to WriteToStreamAsync.
The work-around is not obvious, but if you dig through the source code you'll eventually reach a call to IODataPathHandler.Link. A path handler is an OData extension point, so you can create a custom path handler that always returns an absolute URI which begins with the service root you desire.
public class CustomPathHandler : DefaultODataPathHandler
{
private const string ServiceRoot = "http://example.com/";
public override string Link(ODataPath path)
{
return ServiceRoot + base.Link(path);
}
}
And then register that path handler during service configuration.
// config is an instance of HttpConfiguration
config.MapODataServiceRoute(
routeName: "ODataRoute",
routePrefix: null,
model: builder.GetEdmModel(),
pathHandler: new CustomPathHandler(),
routingConventions: ODataRoutingConventions.CreateDefault()
);
I have an ASP.NET website project that until recent had all code in App_Code folder. It uses Entity Framework 4 as ORM. Application is divided into three "sections" (let's say one for each customer). Each section has it's own database (but same schema). This is due to performance reasons, databases are over 10GB each with millions of rows.
Each time a context object is created a Session variable which holds section ID is called and proprietary connection string is chosen for this context.
It looks like this (following are members of static Connection class):
public static MyEntities GetEntityContext()
{
if (HttpContext.Current.Session["section"] == null)
{
HttpContext.Current.Response.Redirect("~/Login.aspx");
}
var context = new MyEntities(GetEntityConnectionStringForSection((int)HttpContext.Current.Session["section"]);
return context;
}
private static string GetEntityConnectionStringForSection(int section)
{
switch (section)
{
case 1: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
case 2: return ConfigurationManager.ConnectionStrings["entity_2"].ConnectionString;
case 3: return ConfigurationManager.ConnectionStrings["entity_3"].ConnectionString;
default: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
}
}
It works very good and also handles situation when session timed out everytime any data access is performed.
Recently as I needed to share DB classes among two websites I moved all DB classes to separate class library and referenced System.Web library which I know is bad practice, but it's working.
Now the next step is to include unit and module tests which as I read is very difficult or impossible when using HttpContext in library, so I want to get rid of System.Web references. What is the best practice for this situation?
I think I can't just pass HttpContext to GetEntityContext() as it is also called from within my entity classes. Although this probably can be refactored. So maybe this is where I should go?
I also wondered if is it possible to somehow pass current section ID to this whole library? It cannot be just static property because as far as I understand it would be common for all users using the application. This should be user-specific.
Reassuming the objective is to make automated testing possible without loosing transparent Connection String choosing and session timeouts handling.
If I do something fundamentally wrong at this stage please also let me know. I can look again at this question tomorrow morning (8.00 am UTC) so please don't be discouraged by my silence till then.
EDIT:
Example of usage of Connection class in the library:
public partial class Store
{
public static List<Store> GetSpecialStores()
{
using (var context = Connection.GetEntityContext())
{
return context.Stores.Where(qq => qq.Type > 0).OrderBy(qq => qq.Code).ToList();
}
}
}
You can declare interface IContextProvider inside your library ans use it to retrieve context. Something like:
public interface IContextProvider
{
MyEntities GetEntityContext();
}
This will make your library testable. In your web project you can inject IContextProvider implementation into your library.
public class WebContextProvider : IContextProvider
{
public MyEntities GetEntityContext()
{
if (HttpContext.Current.Session["section"] == null)
HttpContext.Current.Response.Redirect("~/Login.aspx");
int sectionId = (int)HttpContext.Current.Session["section"];
string connectionString = GetEntityConnectionStringForSection(sectionId);
var context = new MyEntities(connectionString);
return context;
}
private static string GetEntityConnectionStringForSection(int section)
{
switch (section)
{
case 1: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
case 2: return ConfigurationManager.ConnectionStrings["entity_2"].ConnectionString;
case 3: return ConfigurationManager.ConnectionStrings["entity_3"].ConnectionString;
default: return ConfigurationManager.ConnectionStrings["entity_1"].ConnectionString;
}
}
}
Inject this interface to repositories or other data access classes.
public partial class Store
{
private IContextProvider contextProvider;
public Store(IContextProvider contextProvider)
{
this.contextProvider = contextProvider;
}
public List<Store> GetSpecialStores()
{
using (var context = contextProvider.GetEntityContext())
{
return context.Stores.Where(qq => qq.Type > 0).OrderBy(qq => qq.Code).ToList();
}
}
}
I searched a lot and still couldn't find a solid solution for this. Suppose you have methods in your application. This methods use "System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration" to access some setting in the web.config. If you try to test these methods, your tests will fail because your test project doesn't have web.config.
What is the best way to solve this problem. For projects with simple config file, I usually use a method like this as facade method.
public class Config
{
public static String getKeyValue(String keyName)
{
if (keyName == String.Empty) return String.Empty;
String result = "";
System.Configuration.Configuration rootWebConfig1 =
System.Web.Configuration.WebConfigurationManager.OpenWebConfiguration(null);
if (rootWebConfig1.AppSettings.Settings.Count > 0)
{
System.Configuration.KeyValueConfigurationElement reportEngineKey =
rootWebConfig1.AppSettings.Settings[keyName];
if (reportEngineKey != null)
{
result = reportEngineKey.Value;
}
}
return result;
}
}
Every time I tried to set the path for OpenWebConfiguration( ), I got the error "The relative virtual path is not allowed"
To make that scenario more testable, I usually take the approach of making a "settings manager" of my own, and giving it an interface. So for example:
public interface IConfig
{
string GetSettingValue(string settingName);
}
Then I can have my "real" implementation:
public sealed class Config : IConfig
{
public string GetSettingValue(string settingName)
{
// your code from your getKeyValue() method would go here
}
}
Then my code that uses it would take in an instance of this (this is an example of the Dependency Inversion Principal):
public void DoStuff(IConfig configuration)
{
string someSetting = configuration.GetSettingValue("ThatThingINeed");
// use setting...
}
So now for my production code, I can call DoStuff and pass in an instance of Config.
When I need to test, I can use a mocking tool (Moq, JustMock, RhinoMocks, etc) to create a fake IConfig that returns a known value without hitting the actual .config file, or you can do it without a mocking framework by making your own mocks (and store them in your test project).
public class ConfigMock : IConfig
{
private Dictionary<string, string> settings;
public void SetSettingValue(string settingName, string value)
{
settings[settingName] = value;
}
public string GetSettingValue(string settingName)
{
return settings[settingName];
}
}
and
[Test]
public void SomeExampleTest()
{
var config = new ConfigMock();
config.SetSettingValue("MySetting", "SomeValue");
var underTest = new MyClass();
underTest.DoStuff(config);
}
The easiest way to do this is to use a mocking library such as moq. It takes a bit of time to figure it out, but once you do you can abstract away most of your plumbing to return the values you need for repeatable, consistent testing.