I have some issue with validation of parameters passed to a controller method.
Following the suggestion from the tutorial, I am using the same controller method for "save" and "create new" of an entity. See example in
http://www.playframework.org/documentation/1.2.4/guide9
So, my controller method looks like:
public static void saveEntity(long l, Long itemId,
#Required(message="error.shouldspecifyname") String name,
#Required(message="error.shouldspecifycategory") String category)
If 'itemId' is not part of the data sent via an HTTP request - it is supposed to be set to 'null'.
Unfortunately, it seems like "Play" is automatically adding a validation error on the "missing" parameter.
When looking into the validation errors' list, every time 'itemId' is 'null' - I am getting an error Incorrect value for field itemId
Is it a documented behavior? Any way to override it, or "get rid" of the error.
I am handling the errors simply using redirection, like:
if(validation.hasErrors() )
{
validation.keep();
showSomePage();
}
So the errors are displayed "out of the context" they get generated. This is the reason the "automatic" error bothers me.
Thanks for any hint.
Most likely it fails to validate itemId because it's declared as Long, are you sure you have "Long" there ant not just "long"? We are using validation with controllers every where and it works with #Required and passed "null" to "Long" values.
Worst case you can remove error from validation object based on "itemId" key, also if you're using controller to save model object, you might want to use:
public static void saveEntity(#Required #Valid MyEntity entity) {
if(validation.hasErrors() ) {
validation.keep();
showSomePage();
}
entity.save();
}
It will automaticly hook your changes inside existing entity if you pass ID from page with:
<input type="hidden" name="myEntity.id" value="${myEntity.id}">
Related
I'm investigating Web Api in ASP.NET vNext using the daily builds. In a web api 2x project, I use HttpParameterBinding and ParameterBindingAttribute in some situations (see http://bit.ly/1sxAxdk); however, I can't seem to find either in vNext. Do/will these classes exist? If not, what are my alternatives?
Edit (1-22-15):
I want to be able to serialize a complex JS object to a JSON string, put the JSON string in a hidden form field (say name="data"), submit the form, and then bind my parameter to that JSON object on the server. This will never be done by a human, but rather by a machine. I also want this very same mechanism to work if the JSON is sent directly in the request body instead of form data. I also need this to work for several different types of objects.
I've been able to accomplish this scenario in Web Api 2.2 in a few different ways, including a custom ModelBinder; however, I remember reading an MSFT blog post that suggested to use a ModelBinder for query string binding, formatters for request body, and HttpParameterBinding for more general scenarios. Is it okay to read the request body in a ModelBinder ASP.NET 5, or is there a better mechanism for that? If so, then case closed and I will port my ModelBinder with a few minor changes.
I'm not sure that IInputFormatter will work for me in this case either.
Here are two rough approaches
Approach 1:
A quick and dirty approach would be to start with a Dto model
public class Dto
{
public Serializable Result { get; set; }
public Serializable FromForm
{
get { return Result; }
set { Result = value; }
}
[FromBody]
public Serializable FromBody
{
get { return Result; }
set { Result = value; }
}
}
public class Serializable
{
}
And an action method
public IActionResult DoSomething(Dto dto)
{
// Do something with Dto.Result
}
Then write a custom model binder for Serializable, that just works with Request.Form this way you never actually read the body yourself, and Form only reads it if it of type Form.
The down side of this is that ApiExplorer will not provide correct details (but I think since this is none-standard you are going to be in trouble here anyways).
Approach 2
You can alternatively just use the code from BodyModelBinder and create a custom binder for Serializable type above, that first tries to get it from the Form, and if it fails tries to get it from the Body. The Dto class in that case is not necessary.
Here is some pseudo code
if (inputType is yourtype)
{
if (request.Form["yourkey"] != null)
{
Use Json.Net to deserialize your object type
}
else
{
fall back to BodyModelBinder code
}
}
With this approach you can make it generic, and ApiExplorer will say the way to bind the type is unknown/custom (we haven't decided on the term yet :) )
Note:
Instead of registering the model binder you can use the [ModelBinder(typeof(customBinder))] attribute to apply it sparingly.
Here is a link to the BodyModelBinder code.
There is a new [FromHeader] attribute that allows you to bind directly to http header values if that is what you need.
https://github.com/aspnet/Mvc/issues/1671
https://github.com/aspnet/Mvc/search?utf8=%E2%9C%93&q=fromheader
Consider the following problem.
The user has chosen to create a document by clicking on the Create document and then he writes data into the document. The url for creating the document is /document/save.
For the subsequent write up, the existing document must be saved instead of creating a new one.
Here is my code for that.
#Controller
public MyController implements Controller, TemplateTypeAware
{
#RequestMapping("/document/save")
public String saveOrCreateDocument(#ModelAttribute DocumentWrapper wrapper, ModelAndView m)
{
if(m.getModel().get("document_id")==null)
{
Document doc=createDocument(wrapper);
m.addObject("document_id",doc.getId());
}
else
{
saveDocument(m.getModel().get("document_id"), wrapper);
}
return documentView;
}
}
Template:
<form>
<input type="hidden" name="document_id" th:value="*{document_id}"/>
<!-- other fields -->
</form>
The problem here is, I am getting document_id always null. Is there any work around for this problem?
Thanks in advance. Hope you will reply as soon as possible.
Form fields will be automatically bound to your DocumentWrapper fields if they have matching names, that means DocumentWrapper needs a field named document_id, otherwise the document_id request parameter won't be bound to your object.
Model attributes will be exposed to the view, at this point the model will be empty, you can add attributes in your handler method and they will become in your view, but request parameters won't be in the model. That explains why you always get null.
If you just need the document_id parameter, use #RequestParam:
#RequestMapping("/document/save")
public String saveOrCreateDocument(#RequestParam("document_id") Long documentId, Model m) {
...
}
Please refer to the binding section of Spring MVC: http://docs.spring.io/spring-framework/docs/current/spring-framework-reference/html/mvc.html#mvc-ann-requestparam
I'm really lost trying to create custom generic validation messages for my MVC3 application.
I read many tutorials and the biggest part of them suggest one of these options:
Create an App_GlobalResources folder and inside that put my custom resource, them I change global.asax, passing the string name of my resource to DefaultModelBinder.ResourceClassKey property. Change the resource's build action to "Embeded Resource".
Right click the project, then go properties, click "Resources" tab and create your custom resource. Set it's access modifier to "Public".
The first one didn't work to me, I have the following keys in my resource:
DefaultModelBinder_ValueRequired, InvalidPropertyValue, PropertyValueInvalid, PropertyValueRequired
and none of them was used when my I tried to submit and form with empty value in a required attribute of my model.
I've put this code at global.asax Application_Start method:
DefaultModelBinder.ResourceClassKey = "My_Resource_Name";
With the second method, I've created an resource with the same keys as the first one. None of them was used by default when a property is invalid or empty (I've changed the ResourceClassKey in global.asax too, but without success). But when I added some parameters to data annotation in my model:
[Required(ErrorMessageResourceType = typeof(MyResourceFile), ErrorMessageResourceName = "MyCustomKey")]
When the attribute of that data annotation is empty, my message defined with "MyCustomKey" is used!
But I really don't want to manually set this to all my attributes, I want to replace the default error messages like: "The {0} field is required."
That message is part of DataAnnotations. The default message is compiled into the DataAnnotations assembly in the resource file under System.ComponentModel.DataAnnotations.Resources.DataAnnotationsResources.resources and is RequiredAttribute_ValidationError=The {0} field is required. You can try to download the source, change that part and rebuild it.
There doesn't seem to be a simple global way of changing it. You could try this, otherwise it looks like you are stuck with adding your attribute to every field. Or use something like this:
public class SomeModel
{
[Required(ErrorMessage = "The article is required")]
public string Article { get; set; }
[StringLength(512, ErrorMessage = "Must be less than 512 characters.")]
public string URL { get; set; }
}
I am reading an enum value from the db then bind it to the model. When i post the form with ajax, somehow the enum is unbound or the model property in null or zero but it display properly on the view. I have posted code below. Im using entityframework and mvc3
//model code constructor
public CarModel(Car car)
{
State=(CarState)car.State;
//car.State comes in as an int
//etc setting other variables
}
//CarState property
public CarState {get;set;}
//model code
#Html.DisplayFor(m=>m.CarState)
//Controller code()
Save(CarModel car)
{
//I have code that saves the changes
}
The minute i get to "car", CarState has no value.
It's not quite clear how you are passing this value to the controller action. You have only shown some #Html.DisplayFor(m=>m.CarState) but obviously this only displays a label in the view. It doesn't send anything back to the server. If you want to send some value back you will have to use an input field inside the form.
For example:
#Html.EditorFor(m => m.CarState)
or use a HiddenFor field if you don't want the user to edit it.
In any case you need to send that value to the server if you expect the model binder to be able to retrieve it. The model binder is not a magician. He cannot invent values. He binds values to your model from the Request.
I was researching something and came across this blog post at buildstarted.com about model binders. It actually works pretty darn well for my purposes but I am not sure exactly whats going on behind the scenes. What I did was create a custom ModelBinder called USerModelBinder:
public class UserModelBinder : IModelBinder
{
public object BindModel(ControllerContext controllerContext, ModelBindingContext bindingContext)
{
ValueProviderResult value = bindingContext.ValueProvider.GetValue("id");
MyEntities db = new MyEntities();
User user = db.Users.SingleOrDefault(u => u.UserName == value.AttemptedValue);
return user;
}
}
Then in my Global.asax.cs I have:
ModelBinders.Binders.Add(typeof(User), new UserModelBinder());
My understanding is that using the model binder allows me to NOT have to use the following lines in every controller action that involves a "User". So instead of passing in an "id" to the action, the modelbinder intercepts the id, fetches the correct "item"(User in my case) and forwards it to the action for processing.
MyEntities db = new MyEntities();
User user = db.Users.SingleOrDefault(u => u.UserName == value.AttemptedValue);
I also tried using an annotation on my User class instead of using the line in Global.asax.cs:
[ModelBinder(typeof(UserModelBinder))]
public partial class User
{
}
I'm not looking for a 30 page white paper but I have no idea how the model binder does what it does. I just want to understand what happens from when a request is made to the time it is served. All this stuff "just working" is not acceptable to me, lol. Also, is there any difference between using the annotation versus adding it in Global.asax.cs? They seem to work the same in my testing but are there any gotchas?
Usually the Model Binder (in MVC) looks at you Action method and sees what it requires (as in, the objects types). It then tries to find the values from the HTTP Request (values in the HTTP Form, QueryString, Json and maybe other places such as cookies etc. using ValueProviders). It then creates a new object with the parameters that it retrieves.
IMO What you've done is not really "model binding". In the sense that you've just read the id and fetched the object from the DB.
example of usual model binding:
// class
public class SomeClass
{
public int PropA {get;set;}
public string PropB {get;set;}
}
// action
public ActionResult AddSomeClass(SomeClass classToBind)
{
// implementation
}
// pseudo html
<form action="">
<input name="PropA" type="text" />
<input name="PropB" type="text" />
</form>
if you post a form that contains the correct values (lets say you post a form with PropA and PropB ) the model binder can identify that you've sent those values in the form and build a SomeClass object.
If you really want to create a real working example you should use a strongly typed View and use HtmlHelper's EditorFor (or EditorForModel) to create all the correct names that MVC needs.
--
for reference MVC's default binder is the DefaultModelBinder, and some (there are more, you can look around in the System.Web.Mvc namespace) ValueProviders that it uses by default are the FormValueProvider and the QueryStringValueProvider
So, as I already said, how this basically works is that the default model binder reads the model that the action is recieving (say SomeClass in the example) reads what are the values that it can read (say PropA and PropB) and asks the ValueProviders for the correct values for the properties.
Also, if I recall correctly, you can also see the value providers in runtime using the ValueProviderFactories static class.
A ModelBinder looks at the arguments of the selected Controller action's method signature, then converts the values from the ValueProviders into those arguments.
This happens when the ControllerActionInvoker invokes the action associated with the ControllerContext, because the Controller's Execute() method told it to.
For more about the ASP.NET MVC execution process, see Understanding the MVC Application Execution Process