I needed to tap into a list of activities in Orchard CMS; unpublished activity being one of the requirements. I have looked and found out that Orchard default Workflow activity list doesn't have a unpublished activity.
I have built a module that add my own custom Workflow Activities. I have had no problem creating activities and making them work but I have no idea how to bind one of these with an event. Even if I copy the publish activity that is found in the default activity folder of Workflow module, the copied activity doesn't get bind to any event.
How can I make it so that my activity class is called whenever someone unpublishes or drafts a post.
I have also created a thread here but so far no answers.
I couldn't find much help on Orchard CMS and ended up finding a solution myself. It took me a lot of time to get this done though.
First thing I found was that Orchard.Workflows.Activities has a file ContentActivity. In this file there are other classes that inherits the ContentActivity class ContentCreatedActivity, ContentUpdatedActivity and ContentPublishedActivity. All these classes are activities that subscribe to ContentActivity that is an event activity. They subscribe to the Create, Update and Publish events of the Orchard core.
If you look into Orchard.ContentManagement.Handlers.ContentHandler you'd see the list of default events provided by Orchard CMS core.
I was interested in the OnUnpublished event, so in my module I created a handler that would listen to that event.
using System.Collections.Generic;
using Orchard.ContentManagement;
using Orchard.ContentManagement.Handlers;
using Orchard.Workflows.Services;
namespace MyModule.Handlers {
public class WorkflowContentHandler : ContentHandler {
public WorkflowContentHandler(IWorkflowManager workflowManager) {
OnUnpublished<ContentPart>(
(context, part) =>
workflowManager.TriggerEvent("ContentUnpublished",
context.ContentItem,
() => new Dictionary<string, object> { {
"Content", context.ContentItem } }));
}
}
}
After which we create our custom workflow activity for Unpublished. This class inherits from ContentActivity like its siblings, so it can start workflow and would be an event.
using System;
using System.Collections.Generic;
using System.Linq;
using Orchard.Localization;
using Orchard.Workflows.Models;
using Orchard.Workflows.Services;
using Orchard.Workflows.Activities;
namespace MyModule.WorkFlow
{
public class ContentUnpublishedActivity : ContentActivity
{
public override string Name
{
get { return "ContentUnpublished"; }
}
public override LocalizedString Description
{
get { return T("Content is Unpublished."); }
}
}
}
And that's it. Once you've done this the new Content Unpublished activity would show up in the Workflow activity list. You can use it in conjunction to other Activities to execute your own workflow after any content has been unpublished.
I can't believe it was this easy. Took me 3 days to figure it out and I was pulling my hair that I don't have much of to start with.
The lack of support and resources for Orchard CMS really annoys me sometime. I hope this would help save some time for anyone who has run into similar problems.
Related
My goal
I want to create a new IdentityUser and show all the users already created through the same Blazor page. This page has:
a form through you will create an IdentityUser
a third-party's grid component (DevExpress Blazor DxDataGrid) that shows all users using UserManager.Users property. This component accepts an IQueryable as a data source.
Problem
When I create a new user through the form (1) I will get the following concurrency error:
InvalidOperationException: A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread-safe.
I think the problem is related to the fact that CreateAsync(IdentityUser user) and UserManager.Users are referring the same DbContext
The problem isn't related to the third-party's component because I reproduce the same problem replacing it with a simple list.
Step to reproduce the problem
create a new Blazor server-side project with authentication
change Index.razor with the following code:
#page "/"
<h1>Hello, world!</h1>
number of users: #Users.Count()
<button #onclick="#(async () => await Add())">click me</button>
<ul>
#foreach(var user in Users)
{
<li>#user.UserName</li>
}
</ul>
#code {
[Inject] UserManager<IdentityUser> UserManager { get; set; }
IQueryable<IdentityUser> Users;
protected override void OnInitialized()
{
Users = UserManager.Users;
}
public async Task Add()
{
await UserManager.CreateAsync(new IdentityUser { UserName = $"test_{Guid.NewGuid().ToString()}" });
}
}
What I noticed
If I change Entity Framework provider from SqlServer to Sqlite then the error will never show.
System info
ASP.NET Core 3.1.0 Blazor Server-side
Entity Framework Core 3.1.0 based on SqlServer provider
What I have already seen
Blazor A second operation started on this context before a previous operation completed: the solution proposed doesn't work for me because even if I change my DbContext scope from Scoped to Transient I still using the same instance of UserManager and its contains the same instance of DbContext
other guys on StackOverflow suggests creating a new instance of DbContext per request. I don't like this solution because it is against Dependency Injection principles. Anyway, I can't apply this solution because DbContext is wrapped inside UserManager
Create a generator of DbContext: this solution is pretty like the previous one.
Using Entity Framework Core with Blazor
Why I want to use IQueryable
I want to pass an IQueryable as a data source for my third-party's component because its can apply pagination and filtering directly to the Query. Furthermore IQueryable is sensitive to CUD
operations.
UPDATE (08/19/2020)
Here you can find the documentation about how to use Blazor and EFCore together
UPDATE (07/22/2020)
EFCore team introduces DbContextFactory inside Entity Framework Core .NET 5 Preview 7
[...] This decoupling is very useful for Blazor applications, where using IDbContextFactory is recommended, but may also be useful in other scenarios.
If you are interested you can read more at Announcing Entity Framework Core EF Core 5.0 Preview 7
UPDATE (07/06/2020)
Microsoft released a new interesting video about Blazor (both models) and Entity Framework Core. Please take a look at 19:20, they are talking about how to manage concurrency problem with EFCore
General solution
I asked Daniel Roth BlazorDeskShow - 2:24:20 about this problem and it seems to be a Blazor Server-Side problem by design.
DbContext default lifetime is set to Scoped. So if you have at least two components in the same page which are trying to execute an async query then we will encounter the exception:
InvalidOperationException: A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread-safe.
There are two workaround about this problem:
(A) set DbContext's lifetime to Transient
services.AddDbContext<ApplicationDbContext>(opt =>
opt.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")), ServiceLifetime.Transient);
(B) as Carl Franklin suggested (after my question): create a singleton service with a static method which returns a new instance of DbContext.
anyway, each solution works because they create a new instance of DbContext.
About my problem
My problem wasn't strictly related to DbContext but with UserManager<TUser> which has a Scoped lifetime. Set DbContext's lifetime to Transient didn't solve my problem because ASP.NET Core creates a new instance of UserManager<TUser> when I open the session for the first time and it lives until I don't close it. This UserManager<TUser> is inside two components on the same page. Then we have the same problem described before:
two components that own the same UserManager<TUser> instance which contains a transient DbContext.
Currently, I solved this problem with another workaround:
I don't use UserManager<TUser> directly instead, I create a new instance of it through IServiceProvider and then it works. I am still looking for a method to change the UserManager's lifetime instead of using IServiceProvider.
tips: pay attention to services' lifetime
This is what I learned. I don't know if it is all correct or not.
I downloaded your sample and was able to reproduce your problem. The problem is caused because Blazor will re-render the component as soon as you await in code called from EventCallback (i.e. your Add method).
public async Task Add()
{
await UserManager.CreateAsync(new IdentityUser { UserName = $"test_{Guid.NewGuid().ToString()}" });
}
If you add a System.Diagnostics.WriteLine to the start of Add and to the end of Add, and then also add one at the top of your Razor page and one at the bottom, you will see the following output when you click your button.
//First render
Start: BuildRenderTree
End: BuildRenderTree
//Button clicked
Start: Add
(This is where the `await` occurs`)
Start: BuildRenderTree
Exception thrown
You can prevent this mid-method rerender like so....
protected override bool ShouldRender() => MayRender;
public async Task Add()
{
MayRender = false;
try
{
await UserManager.CreateAsync(new IdentityUser { UserName = $"test_{Guid.NewGuid().ToString()}" });
}
finally
{
MayRender = true;
}
}
This will prevent re-rendering whilst your method is running. Note that if you define Users as IdentityUser[] Users you will not see this problem because the array is not set until after the await has completed and is not lazy evaluated, so you don't get this reentrancy problem.
I believe you want to use IQueryable<T> because you need to pass it to 3rd party components. The problem is, different components can be rendered on different threads, so if you pass IQueryable<T> to other components then
They might render on different threads and cause the same problem.
They most likely will have an await in the code that consumes the IQueryable<T> and you'll have the same problem again.
Ideally, what you need is for the 3rd party component to have an event that asks you for data, giving you some kind of query definition (page number etc). I know Telerik Grid does this, as do others.
That way you can do the following
Acquire a lock
Run the query with the filter applied
Release the lock
Pass the results to the component
You cannot use lock() in async code, so you'd need to use something like SpinLock to lock a resource.
private SpinLock Lock = new SpinLock();
private async Task<WhatTelerikNeeds> ReadData(SomeFilterFromTelerik filter)
{
bool gotLock = false;
while (!gotLock) Lock.Enter(ref gotLock);
try
{
IUserIdentity result = await ApplyFilter(MyDbContext.Users, filter).ToArrayAsync().ConfigureAwait(false);
return new WhatTelerikNeeds(result);
}
finally
{
Lock.Exit();
}
}
Perhaps not the best approach but rewriting async method as non-async fixes the problem:
public void Add()
{
Task.Run(async () =>
await UserManager.CreateAsync(new IdentityUser { UserName = $"test_{Guid.NewGuid().ToString()}" }))
.Wait();
}
It ensures that UI is updated only after the new user is created.
The whole code for Index.razor
#page "/"
#inherits OwningComponentBase<UserManager<IdentityUser>>
<h1>Hello, world!</h1>
number of users: #Users.Count()
<button #onclick="#Add">click me. I work if you use Sqlite</button>
<ul>
#foreach(var user in Users.ToList())
{
<li>#user.UserName</li>
}
</ul>
#code {
IQueryable<IdentityUser> Users;
protected override void OnInitialized()
{
Users = Service.Users;
}
public void Add()
{
Task.Run(async () => await Service.CreateAsync(new IdentityUser { UserName = $"test_{Guid.NewGuid().ToString()}" })).Wait();
}
}
I found your question looking for answers about the same error message you had.
My concurrency issue appears to have been due to a change that triggered a re-rendering of the visual tree to occur at the same time as (or due to the fact that) I was trying to call DbContext.SaveChangesAsync().
I solved this by overriding my component's ShouldRender() method like this:
protected override bool ShouldRender()
{
if (_updatingDb)
{
return false;
}
else
{
return base.ShouldRender();
}
}
I then wrapped my SaveChangesAsync() call in code that set a private bool field _updatingDb appropriately:
try
{
_updatingDb = true;
await DbContext.SaveChangesAsync();
}
finally
{
_updatingDb = false;
StateHasChanged();
}
The call to StateHasChanged() may or may not be necessary, but I've included it just in case.
This fixed my issue, which was related to selectively rendering a bound input tag or just text depending on if the data field was being edited. Other readers may find that their concurrency issue is also related to something triggering a re-render. If so, this technique may be helpful.
Well, I have a quite similar scenario with this, and I 'solve' mine is to move everything from OnInitializedAsync() to
protected override async Task OnAfterRenderAsync(bool firstRender)
{
if(firstRender)
{
//Your code in OnInitializedAsync()
StateHasChanged();
}
{
It seems solved, but I had no idea to find out the proves. I guess just skip from the initialization to let the component success build, then we can go further.
/******************************Update********************************/
I'm still facing the problem, seems I'm giving a wrong solution to go. When I checked with this Blazor A second operation started on this context before a previous operation completed I got my problem clear. Cause I'm actually dealing with a lot of components initialization with dbContext operations. According to #dani_herrera mention that if you have more than 1 component execute Init at a time, probably the problem appears.
As I took his advise to change my dbContext Service to Transient, and I get away from the problem.
#Leonardo Lurci Had covered conceptually. If you guys are not yet wanting to move to .NET 5.0 preview, i would recommend looking at Nuget package 'EFCore.DbContextFactory', documentation is pretty neat. Essential it emulates AddDbContextFactory. Ofcourse, it creates a context per component.
So far, this is working fine for me so far without any problems...
I ensure single-threaded access by only interacting with my DbContext via a new DbContext.InvokeAsync method, which uses a SemaphoreSlim to ensure only a single operation is performed at a time.
I chose SemaphoreSlim because you can await it.
Instead of this
return Db.Users.FirstOrDefaultAsync(x => x.EmailAddress == emailAddress);
do this
return Db.InvokeAsync(() => ...the query above...);
// Add the following methods to your DbContext
private SemaphoreSlim Semaphore { get; } = new SemaphoreSlim(1);
public TResult Invoke<TResult>(Func<TResult> action)
{
Semaphore.Wait();
try
{
return action();
}
finally
{
Semaphore.Release();
}
}
public async Task<TResult> InvokeAsync<TResult>(Func<Task<TResult>> action)
{
await Semaphore.WaitAsync();
try
{
return await action();
}
finally
{
Semaphore.Release();
}
}
public Task InvokeAsync(Func<Task> action) =>
InvokeAsync<object>(async () =>
{
await action();
return null;
});
public void InvokeAsync(Action action) =>
InvokeAsync(() =>
{
action();
return Task.CompletedTask;
});
#Leonardo Lurci has a great answer with multiple solutions to the problem. I will give my opinion about every solution and which I think it is the best one.
Making DBContext transient - it is a solution but it is not optimized for this cases..
Carl Franklin suggestion - the singleton service will not be able to control the lifetime of the context and will depend on the service requester to dispose the context after use.
Microsoft documentation they talk about injecting DBContext Factory into a component with the IDisposable interface to Dispose the context when the component is destroied. This is not a very good solution, because a lot of problems happen with it, like: performing a context operation and leaving the component before it finishes that operation, will dispose the context and throw exception..
Finally. The best solution so far is to inject the DBContext Factory in the component yes, but whenever you need it, you create a new instance with using statement like bellow:
public async Task GetSomething()
{
using var context = DBFactory.CreateDBContext();
return await context.Something.ToListAsync();
}
Since DbFactory is optimazed when creating new context instances, there is no significante overhead, making it a better choice and better performing than Transient context, it also disposes the context at the end of the method because of "using" statement.
Hope it was useful.
I am using MVCSitemapProvider by Maarten Balliauw with Ninject DI in MVC4. Being a large-scale web app, enumerating over the records to generate the sitemap xml accounts for 70% of the page load time. For that purpose, I went for using new sitemap files for each level-n dynamic node provider.
<mvcSiteMap xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://mvcsitemap.codeplex.com/schemas/MvcSiteMap-File-4.0" xsi:schemaLocation="http://mvcsitemap.codeplex.com/schemas/MvcSiteMap-File-4.0 MvcSiteMapSchema.xsd">
<mvcSiteMapNode title="$resources:SiteMapLocalizations,HomeTitle" description="$resources:SiteMapLocalizations,HomeDescription" controller="Controller1" action="Home" changeFrequency="Always" updatePriority="Normal" metaRobotsValues="index follow noodp noydir"><mvcSiteMapNode title="$resources:SiteMapLocalizations,AboutTitle" controller="ConsumerWeb" action="Aboutus"/>
<mvcSiteMapNode title="Sitemap" controller="Consumer1" action="SiteMap"/><mvcSiteMapNode title=" " action="Action3" controller="Consumer2" dynamicNodeProvider="Comp.Controller.Utility.NinjectModules.PeopleBySpecDynamicNodeProvider, Comp.Controller.Utility" />
<mvcSiteMapNode title="" siteMapFile="~/Mvc2.sitemap"/>
</mvcSiteMapNode>
</mvcSiteMap>
But, it doesn't seem to work. For localhost:XXXX/sitemap.xml, the child nodes from Mvc2.sitemap don't seem to load.
siteMapFile is not a valid XML attribute in MvcSiteMapProvider (although you could use it as a custom attribute), so I am not sure what guide you are following to do this. But, the bottom line is there is no feature that loads "child sitemap files", and even if there was, it wouldn't help with your issue because all of the nodes are loaded into memory at once. Realistically on an average server there is an upper limit of around 10,000 - 15,000 nodes.
The problem that you describe is a known issue. There are some tips available in issue #258 that may or may not help.
We are working a new XML sitemap implementation that will allow you to connect the XML sitemap directly to your data source, which can be used to circumvent this problem (at least as far as the XML sitemap is concerned). This implementation is stream-based and has paging that can be tied directly to the data source, and will seamlessly page over multiple tables, so it is very efficient. However, although there is a working prototype, it is still some time off from being made into a release.
If you need it sooner rather than later, you are welcome to grab the prototype from this branch.
You will need some code to wire it into your application (this is subject to change for the official release). I have created a demo project here.
Application_Start
var registrar = new MvcSiteMapProvider.Web.Routing.XmlSitemapFeedRouteRegistrar();
registrar.RegisterRoutes(RouteTable.Routes, "XmlSitemap2");
XmlSitemap2Controller
using MvcSiteMapProvider.IO;
using MvcSiteMapProvider.Web.Mvc;
using MvcSiteMapProvider.Xml.Sitemap.Configuration;
using System.Web.Mvc;
public class XmlSitemap2Controller : Controller
{
private readonly IXmlSitemapFeedResultFactory xmlSitemapFeedResultFactory;
public XmlSitemap2Controller()
{
var builder = new XmlSitemapFeedStrategyBuilder();
var xmlSitemapFeedStrategy = builder
.SetupXmlSitemapProviderScan(scan => scan.IncludeAssembly(this.GetType().Assembly))
.AddNamedFeed("default", feed => feed.WithMaximumPageSize(5000).WithContent(content => content.Image().Video()))
.Create();
var outputCompressor = new HttpResponseStreamCompressor();
this.xmlSitemapFeedResultFactory = new XmlSitemapFeedResultFactory(xmlSitemapFeedStrategy, outputCompressor);
}
public ActionResult Index(int page = 0, string feedName = "")
{
var name = string.IsNullOrEmpty(feedName) ? "default" : feedName;
return this.xmlSitemapFeedResultFactory.Create(page, name);
}
}
IXmlSiteMapProvider
And you will need 1 or more IXmlSitemapProvider implementations. For convenience, there is a base class XmlSiteMapProviderBase. These are similar to creating controllers in MVC.
using MvcSiteMapProvider.Xml.Sitemap;
using MvcSiteMapProvider.Xml.Sitemap.Specialized;
using System;
using System.Linq;
public class CategoriesXmlSitemapProvider : XmlSitemapProviderBase, IDisposable
{
private EntityFramework.MyEntityContext db = new EntityFramework.MyEntityContext();
// This is optional. Don't override it if you don't want to use last modified date.
public override DateTime GetLastModifiedDate(string feedName, int skip, int take)
{
// Get the latest date in the specified page
return db.Category.OrderBy(x => x.Id).Skip(skip).Take(take).Max(c => c.LastUpdated);
}
public override int GetTotalRecordCount(string feedName)
{
// Get the total record count for all pages
return db.Category.Count();
}
public override void GetUrlEntries(IUrlEntryHelper helper)
{
// Do not call ToList() on the query. The idea is that we want to force
// EntityFramework to use a DataReader rather than loading all of the data
// at once into RAM.
var categories = db.Category
.OrderBy(x => x.Id)
.Skip(helper.Skip)
.Take(helper.Take);
foreach (var category in categories)
{
var entry = helper.BuildUrlEntry(string.Format("~/Category/{0}", category.Id))
.WithLastModifiedDate(category.LastUpdated)
.WithChangeFrequency(MvcSiteMapProvider.ChangeFrequency.Daily)
.AddContent(content => content.Image(string.Format("~/images/category-image-{0}.jpg", category.Id)).WithCaption(category.Name));
helper.SendUrlEntry(entry);
}
}
public void Dispose()
{
db.Dispose();
}
}
Note that there is currently not an IXmlSiteMapProvider implementation that reads the nodes from the default (or any) SiteMap, but creating one is similar to what is shown above, except you would query the SiteMap for nodes instead of a database for records.
Alternatively, you could use a 3rd party XML sitemap generator. Although, nearly all of them are set up in a non-scalable way for large sites, and most leave it up to you to handle the paging. If they aren't streaming the nodes, it will not realistically scale to more than a few thousand URLs.
The other detail you might need to take care of is to use the forcing a match technique to reduce the total number of nodes in the SiteMap. If you are using the Menu and/or SiteMap HTML helpers, you will need to leave all of your high-level nodes alone. But any node that does not appear in either is a good candidate for this. Realistically, nearly any data-driven site can be reduced to a few dozen nodes using this technique, but keep in mind every node that is forced to match multiple routes in the SiteMap means that individual URL entries will need to be added in the XML sitemap.
I've written an Xtext-based plugin for some language. I'm now interested in creating a new independent view (as a separate plugin, though it requires my first plugin), which will interact with the currently-active DSL document - and specifically, interact with the model Xtext parsed (I think it's called the Ecore model?). How do I approach this?
I saw I can get an instance of XtextEditor if I do something like this when initializing my view:
getSite().getPage().addPartListener(new MyListener());
And then, in MyListener, override partActivated and partInputChanged to get an IWorkbenchPartReference, which is a reference to the XtextEditor. But what do I do from here? Is this even the right approach to this problem? Should I instead use some notification functionality from the Xtext side?
Found it out! First, you need an actual document:
IXtextDocument doc = editor.getDocument();
Then, if you want to access the model:
doc.modify(new IUnitOfWork.Void<XtextResource>() { // Can also use just IUnitOfWork
#Override public void process(XtextResource state) throws Exception {
...
}
});
And if you want to get live updates whenever it changes:
doc.addModelListener(new IXtextModelListener() {
#Override public void modelChanged(XtextResource resource) {
for (EObject model : resource.getContent()) {
...
}
}
});
I'm currently PoCing a solution for OData interaction from Java. We have an WCF odata repository available. I began preliminary coding using the restlet API because it has code generation available but since using it I've encountered the situation where a newly created object doesn't have it's ID set upon creation and the addEntity method in the generated service class doesn't appear to return the ID?
Which is a more comprehensive solution, that from Restlet or OData4j?
Thanks,
Mark.
you can manually return the id where you are implementing the producer register method
for example:
producer.register(yourModelClass.class, "yourModelClass", new Func1<Object,Iterable<yourModelClass>>() {
public Iterable<yourModelClass> apply(Object queryInfo) {
return null;
}
}
}, "yourID");
I have the following bootstrap
public class NancyBootStrapper: DefaultNancyBootstrapper
{
protected override void ConfigureRequestContainer(TinyIoC.TinyIoCContainer container, NancyContext context)
{
base.ConfigureRequestContainer(container, context);
var ravenSession = container.Resolve< IRavenSessionProvider >().GetSession();
container.Register( ravenSession );
}
}
When my Nancy app tries to instantiate BlogService using the following constructor
public BlogService(IDocumentSession documentSession)
{
this.documentSession = documentSession;
}
the application blows up stating that it can't resolve document session, I have also tried the following within my test method (removing the constructor injection).
public void BuildCategories()
{
var container = TinyIoCContainer.Current;
documentSession = container.Resolve< IDocumentSession >();
documentSession.Store(new Category{Title = "test"});
documentSession.Store(new Category{Title = ".net"});
documentSession.SaveChanges();
}
This also blows up, pointing out that it can't resolve documentSession.
Now this is the first time I have used either NancyFX or TinyIoC so I could be doing something fundamentally wrong though I should mention that the documentSession does resolve within a Nancy module..
Can any one offer a fix or some suggestions?
When is the BlogService supposed to be instantiated? -My guess would be once for the application, in which case I believe you are registering the session in the wrong bootstrapper method, and should do it in ConfigureApplicationContainer.
I've been playing & digging into both NancyFx and the TinyIoC code bases and have figured out how to fix this issue... I don't like the fix... but hay it works :)
Basically, I am creating a RavenDB document session in the bootstrapper method configureRequestContainer as it is best practice to use the request as your unit of work scope.
Unfortunately anything that is auto wired by tinyIoC within configureApplicationContainer does not have any constructor injection performed using the child container being used by the Nancy request (this includes those that are marked as MultiInstance or as PerRequestSingleton.
To get around this, you need to re-register any components that depend on your per request components within the same child container.
As I said, I don't like the fix, but it is ultimately a fix :)