RavenDB Ids and ASP.NET MVC3 Routes - asp.net-mvc

Just building a quick, simple site with MVC 3 RC2 and RavenDB to test some things out.
I've been able to make a bunch of projects, but I'm curious as to how Html.ActionLink() handles a raven DB ID.
My example: I have a Document called "reasons" (a reason for something, just text mostly), which has reason text and a list of links. I can add, remove, and do everything else fine via my repository.
Below is the part of my razor view that lists each reason in a bulleted list, with an Edit link as the first text:
#foreach(var Reason in ViewBag.ReasonsList)
{
<li>#Html.ActionLink("Edit", "Reasons", "Edit", new { id = Reason.Id }, null) #Reason.ReasonText</li>
<ul>
#foreach (var reasonlink in Reason.ReasonLinks)
{
<li>#reasonlink.URL</li>
}
</ul>
}
The Problem
This works fine, except for the edit link. While the values and code here appear to work directly (i.e the link is firing directly), RavenDB saves my document's ID as "reasons/1".
So, when the URL happens and it passes the ID, the resulting route is "http://localhost:4976/Reasons/Edit/reasons/2". So, the ID is appended correctly, but MVC is interpreting it as its own route.
Any suggestions on how I might be able to get around this? Do I need to create a special route to handle it or is there something else I can do?

I just downloaded the latest version of RavenDB and tried this out.
public class Entity {
public int Id { get;set; }
public string Text { get;set; }
}
When I saved it to RavenDB, the id in Raven was "entities/1", but the mapping in RavenDB client was able to successfully interpret the Id from what was in the database to the integer that I wanted.
var entity = session.Load<Entity>(1);
Assert.IsTrue(entity.Id == 1);
You do not need a extension method, and this way you would not need to alter any routes as mentioned above, because you will be dealing with good ol' integers. The string Ids were almost a deal breaker, but amazingly this works so RavenDB is back in the hunt.
Note: I figured this out from watching a Rob Ashton talk and realizing that all his document classes had integers as Ids.

I was having a similar issue and came up with my own solution before I found the link to Shiju Varghese blog post referenced by #jfar.
It might not be as clean and simple as the solutions provided in the blog post, but I do believe it can compete as a solution none the less. So here goes:
In a standard model class, when using RavenDB, we normally have an id property like so:
public string Id { get; set; }
What I did, was to add another id property like so:
public int? IdInt
{
get { return int.Parse(Id.Substring(Id.IndexOf("/") + 1)); }
}
This will give us the number part of the given RavenDB id.
I then had a class that looked something like this:
[Bind(Exclude = "IdInt")]
public class Item
{
public string Id { get; set; }
public int? IdInt
{
get { return int.Parse(Id.Substring(Id.IndexOf("/") + 1)); }
}
...
}
Note that I have excluded the IdInt property, as I don't want the model binder to handle it.
Furthermore, note, that the IdInt property is nullable. This is to avoid problems with the model binder later on, when we are creating new items and the Id property is null.
Then in the routes I declared a rule similar to this:
routes.MapRoute(
"WithParam", // Route name
"{controller}/{action}/{id}" // URL with parameters
);
Later on using an ActionLink or something similar we can do the following:
#Html.ActionLink("Details", "Details", new { id = item.IdInt })
And lastly when we press the rendered link, we are sent to the appropriate action which could look something like this:
public ActionResult Details(int id)
{
var item = _session.Load<Item>(id);
return View(item);
}
The reason why this will work is because of the Load method, which takes a ValueType as parameter and then automatically resolves the number to the correct RavenDB id.
What we have achieved with this approach is a url that looks something like this:
/items/details/1
As I said in the beginning, this solution is less elegant than the previous suggested solutions, however, this approach will give you a cleaner url as you can work with the id's as you normally would.

FYI, the link posted by #jfar was exactly the article. The following is the solution I used from the article:
Solution 2 - Modify ASP.NET MVC Route
Modify the ASP.NET MVC routes in the
Global.asax.cs file, as shown in the
following code:
routes.MapRoute(
"WithParam", // Route name
"{controller}/{action}/{*id}" // URL with parameters
);
We just put "*" in front of the id
variable that will be working with the
default Id separator of RavenDB

Related

Getting comment ID from URL

I'm writing a simple forum with ASP, using the MVC template with user login.
It's really new to me and kind of difficult to grasp. I managed to implement posting topics and comments, deleting them but the edit is giving me some major problem.
Here's my action:
public ActionResult EditReply()
{
int.TryParse((string)Url.RequestContext.RouteData.Values["id"], out int id);
Topic topic = db.Topics.Find(id);
int.TryParse((string)Url.RequestContext.RouteData.Values["id"], out int commentId);
Comment comment = topic.Comments.Find(x => x.Id == commentId);
return View(comment);
}
I get "object reference not set to an instance of an object". Debugging shows me that the comment variable is empty due to unsuccessful getting of the ID because it seems that the commentId variable's value is 0. It works for topicId but won't work for the commentId. However, the URL where I get the error shows http://localhost:49834/Home/EditReply?TopicId=16&CommentId=43
so the Id is there but I cannot extract it. I'm really new to ASP. Any sort of input will be greatly appreciated.
Thanks!
If you're using ASP.NET MVC then a simple update to your Action's signature will get the values you need.
public ActionResult EditReply(int TopicId, int CommentId)
{
Topic topic = db.Topics.Find(TopicId);
Comment comment = topic.Comments.Find(x => x.Id == CommentId);
return View(comment);
}
This will use the default model binding that is built in to MVC.
MVC will do the work for you. Define your action as
public ActionResult EditReplay(int topicId, int commentId) { …
And the model binding will use the query string or form values to populate parameters. With MVC you rarely, if ever, need to directly look at the request.
(If the parameters are optional, make the types nullable: int? commentId.)

Redirect with multiple parameters of the same name in ASP.NET MVC?

I am trying to implement POST-Redirect-GET in MVC using multiple named parameters.
I can do this with one parameter:
return RedirectToAction("MyGetView", new { bookId = id });
I could hardcode multiple parameters:
return RedirectToAction("MyGetView, new {bookId = id1, bookId=id2});
But how do I get from an IEnumerable< int> of Ids, which is of variable length, to a correct query string without constructing it by hand?
My current code looks like this:
var querystring= string.Join("", BookIds.Select(x => string.Format("bookId={0}&", x)));
querystring= querystring.Trim('&');
return Redirect("MyGetView?" + querystring);
It works fine, but it seems like there should be a better way.
(I want the parameters to be visible in the URL, so that users can bookmark the page. I believe this means I cannot use TempData.)
First, it's not wrong to use query parameters where the ASP.NET MVC Routes fail to work, and they do with arrays (basically). How is your "clean" URL route supposed to look like?
Example: /Books/View/6 (Works nice for one Book, 6 is the int ID)
But what do you want to have for multiple Books? /Books/View/6,5,134 maybe?
In this case you could just use your own convention of formatting the Url as a list of IDs.
Your redirect would look like: return RedirectToAction("View", "Book", new { Id = allIds.Join(",") });
And your View action can support this:
public ActionResult View(string id)
{
if (id == null)
throw new Exception... // Not expected
var ids = id.Split(new char[]{ ',' });
// Further processing...
}
If your're not satisfied with this approach (you might have issues when number of items is getting bigger) you can see what others tried, but it's basically what you already do, or I'm not sure if the other solutions are worth the effort.

Is there simple way to use bookmarks in controller action's generated urls?

Currently I am working with simple Forum module in ASP.NET MVC 3 which i will add later to my main application. The possibility to link to certain blocks like div used to present thread replies is very useful.
I figured out something which work and propably will be enough for my needs, I just wonder if there is something more elegant and simple aswell. I found a solution using ActionFilters, and since I'm quite begginner in MVC I would like to find some easier solution (if exists). Well i will propably learn ActionFilters soon aswell :)
So here is what I've done:
public ActionResult ShowThread(int id, int? postID)
{
var thread = db.ForumThreads.Find(id);
if (postID != null)
{
return Redirect(Url.Action("ShowThread",new {id=id})+"#post-"+postID.ToString());
}
return View(thread);
}
I know it is quite simple, but it is working. Also it doesn't check if the postID is valid yet, but it is not a part of question.
The solution is to use one of RedirectToAction overloads: http://msdn.microsoft.com/en-us/library/dd470154(v=vs.108).aspx.
Perhaps, in your case, the next one would do: http://msdn.microsoft.com/en-us/library/dd460291(v=vs.108).aspx
And the call would be:
return this.RedirectToAction("ShowThread", new { id = id, post = postID });
Another (simpler, but not safer!) solution is to format the URL you need to redirect to and to use the Redirect() method like this:
var redirectUrl = string.Format("/Home/ShowThread/{0}?post={1}", id, postID);
return this.Redirect(redirectUrl);
Pay attention to your URL mappings, though. The examples above assume the method
public ActionResult ShowThread(int id, int? post)
is in HomeController and the default route has not been changed. Otherwise you should
adjust the URL prepending the controller name (w/o Controller), or
change your default route to map to the controller's name.

Can you remove the HTML Field Prefix from strongly typed models in MVC 3?

I have a view model like this:
public class EditVM
{
public Media.Domain.Entities.Movie Movie { get; set; }
public IEnumerable<Genre> Genres { get; set; }
}
Movie is the real entity I wish to edit. Genres is simply present to populate a drop down. I would prefer that when I call:
#Html.TextBoxFor(m => m.Movie.Title)
inside my strongly typed view that the input control have a name = "Title" instead of "Movie.Title"
I do not wish to split my view into partial views or lose my strongly typed view by using ViewData or the like.
Is there a way to express to the View that I do not wish to have the Movie. prefix? I noticed that you can set:
ViewData.TemplateInfo.HtmlFieldPrefix = "x";
in the controller, but unfortunately it seems only to allow adding an additional prefix. Setting it to "" does nothing.
Is there any work around for this? Or am I stuck with the unfortunate prefix that isn't really necessary in this case if I wish to keep strongly typed views and lambdas?
Thanks for any help.
Update:
Here's the controller actions to maybe make things a bit clearer.
public ActionResult Edit(int? id)
{
var vm = new EditVM
{
Movie = id.HasValue ? _movieSvc.Find(id.Value) : new Movie(),
Genres = AppData.ListGenres()
};
return View(vm);
}
[HttpPost]
public void Edit([Bind(Prefix = "Movie")]Movie m)
{
_movieSvc.AddOrUpdateMovie(m); //Exceptions handled elsewhere
}
No, in order to do what you want you would have to rewrite the Html helpers, and then you would have to write your own model binder. Seems like a lot of work for minimal gain.
The only choice is a Partial view in which you pass the Movie object as the model. However, this would require you to write your own model binder to have it be recognized.
The reason you have to do m.Movie.Title is so that the ID has the correct name, so the model binder can recognize it as a member of your model.
Based on your update:
Your options are:
Use non-strongly typed helpers.
Use a partial view.
Rewrite the stronly typed helpers
Don't use the helpers at all, and write the values to the HTML
Personally, i'd just use 1 or 2, probably 2.
EDIT:
Based on your update above. Change your code to this (note, Genres does not get posted back to the server, so m.Genres will just be null on postback):
[HttpPost]
public void Edit(EditVM m)
{
_movieSvc.AddOrUpdateMovie(m.Movie); //Exceptions handled elsewhere
}
EDIT:
I did just think of an alternative to this. You could simply do this:
#{ var Movie = Model.Movie; }
#Html.TextBoxFor(m => Movie.Title)
However, if there was a validation error, you would have to recreate your EditVM.
I have a view model like this
I think that you might have some misunderstanding about what a view model is. A view model shouldn't contain any reference to your domain models which is what those Movie and Genre classes seem to be. I mean creating a new class that you suffix with VM and in which you stuff all your domain models as properties is not really a view model. A view model is a class that is specifically designed to meet the requirements of your view.
A much more correct view model would looks like this:
public class EditVM
{
public string MovieTitle { get; set; }
public IEnumerable<GenreViewModel> Genres { get; set; }
}
and in your view you would have:
#Html.EditorFor(x => x.MovieTitle)
#Html.EditorFor(x => x.Genres)
Another option is to either use the TextBox(string name, object value) overload instead of the TextBoxFor:
#Html.TextBox("Title", Model.Movie.Title)
You could also specify the input tag HTML instead of using a helper.
Another option is to take EditVM as your postback parameter. This is what I would do. My post action parameter is always the same type of the .cshtml model. Yes there will be properties like lists that are null, but you just ignore those. It also allows you to gracefully handle post errors as well because if there is an error you'll need to return an instance of that view model anyhow, and have the values they submitted included. I usually have private methods or DB layer that handles retrieving the various lists that go into the ViewModel, since those will be empty on postback and will need to be repopulated, while not touching the properties that were in the post.
With your post method as it is now, if you need to return the same view, you've gotta create a new EditVM and then copy any posted values into it, and still populate the lists. With my method, you eliminate one of those mapping steps. If you are posting more than one thing, are you going to have umpteen different parameters on your post action? Just let them all come naturally into a single parameter typed to the EditVM of the View. While maybe having those null properties in the VM during the postback feels icky, you get a nice predictable consistency between View and postback IMO. You don't have to spend alot of time thinking about what combination of parameters on your post method will get you all the pieces of data from the form.

A smart way to handle Return URLs in an MVC environment

A problem I come up against again and again is handling redirection to the previous page after a user runs some action such as clicking a 'Back To ...' link or saving the record they are editing.
Previously whenever I have needed to know what page to return to, I would provide a returnURL parameter to my current view.
http://blah.com/account/edit/1?returnURL="account/index"
This isn't a very clean way of handling this situation, as sometimes the return URL contains parameters such as search strings, etc, which have to be included in the URL.
http://blah.com/account/edit/1?returnURL="account/index?search="searchTerm""
Also, this creates an issue when a user can go another page forward before coming back to the page with the returnURL because you have to pass the returnURL through all visited pages.
Simply calling the browser's Back functionality isn't really sufficient either, because you might want the page to refresh, e.g. to show the edits you just saved in the previous page.
So my question is, has anyone found a smart way to handle this kind of situation, specifically in an MVC environment?
Note: I am using ASP .NET MVC so if possible I'd like answers to pertain to that, however any ideas are welcome.
What's wrong with setting a cookie, or using a session variable? The only reason you wouldn't is if you don't control the page that calls into you, in which case your only options are query strings, post values, or referrer.
I thought I might add my answer to the question to see if others think it's a good idea.
I'm simply passing it through to the controller using TempViewData:
#{
TempData["returnURL"] = Request.Url.AbsoluteUri;
}
and then accessing it in a similar way to this (in my real version I check that the key is in TempData and that the returnURL is a real URL):
return Redirect(TempData["returnURL"].ToString());
If it needs to continue on past the first page change (i.e. Search page -> Edit page -> Edit Section page) I'm adding it again
TempData["returnURL"] = TempData["returnURL"];
Check my blog post on it: Using cookies to control return page after login on asp.net mvc 3
Just like #Mystere Man mentioned, you can just use a cookie or session for it. I went for cookies back when I had a similar situation a while ago.
Try register a new route of which the url is /{controller}/{action}/{id}/returnurl/{*url} and then use a RedirectToAction in the action that accepts url as a parameter
Request.UrlReferrer.AbsoluteUri
though i'd still argue that you shouldn't be creating your own "back" button.
Use an interceptor or an aspect:
Intercept each request in some fashion (e.g., a #Before aspect) and save the requested URL to the session, overwriting it each time
In your view layer, access that Session object as needed, in your case for the back link.
This kind of design allows you to always have the most recent request available if you want to use it. Here's an example to write an aspect / interceptor in .NET. Additionaly, PostSharp is a .NET aspect project.
At present, a quick and dirty method has eluded me... so I'm using a practical method.
On a conceptual level, the 'back-ability' of a page should be determined by the page that you're currently on. The View can infer this (in most cases) if the parameters captured in the Controller are passed to it via the ViewModel.
Example:
Having visited Foo, I'm going to Bar to view some stuff, and the back button should return to Foo.
Controller
public ActionResult Foo(string fooId) // using a string for your Id, good idea; Encryption, even better.
{
FooModel model = new FooModel() { fooId = fooId }; // property is passed to the Model - important.
model.Fill();
return View("FooView", model);
}
public ActionResult Bar(string fooId, string barId)
{
BarModel model = new BarModel() { fooId = fooId; barId = barId };
model.Fill()
return View("BarView", model)
}
ViewModels
public class FooModel
{
public string fooId { get; set; }
public void Fill()
{
// Get info from Repository.
}
}
public class BarModel
{
public string fooId { get; set; }
public string barId { get; set; }
public void Fill()
{
// Get info from Repository.
}
}
View (Partial) // No pun intended... or maybe it was. :)
Your BarView can now interpret from its model where it needs to go back to (using fooId).
On your BarView (using MVC2 syntax):
Back
You can use Html.ActionLink as well.
Alternatively:
You can inherit your ViewModels from a BaseViewModel, which can have a protected property returnURL. Set this where necessary.
Example:
On your ViewModel:
public class BarModel : BaseViewModel
{
public string fooId { get; set; }
public string barId { get; set; }
public void Fill()
{
returnURL = string.Format("/Foo?fooId={0}", fooId)
// Get info from Repository.
}
}
On View:
Back
Would this be better handled by partial actions that display without leaving the page and using JQuery to make a dialog/wizard workflow?
Then you only need to react to the 'Finish' button on the dialog to refresh the original view.
For the part of your question regarding "saving the record they are editing" I would think the post-redirect-get (PGR) pattern would apply to you.
This might be a good place to read about it if you are not familiar with it.
http://en.wikipedia.org/wiki/Post/Redirect/Get
http://blog.andreloker.de/post/2008/06/Post-Redirect-Get.aspx
Encode the returnUrl using Url.Encode(returnUrl) for inclusion in the URL.
When ready to redirect, use Url.Decode(returnUrl) and use the value for the actual redirect.

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