I have a scenario where I am using a registered helper ifeq conditional that is comparing the object being used within my each statement and a separate object that is public to the view file. i.e. blog_comment and user object.
However, I can't seem to figure out a way to access the user object for the fact that it doesn't have a relationship to the each statement of blog_comment. Is there a way to access non-related objects within a handlebars expression?
Two objects that are publicly accessible by the view:
blog_comments (Being looped through)
user (represents the information of the user currently logged in)
Here is my ifeq conditional:
hbs.registerHelper('ifeq', function(value1, value2, options){
return((value1 === value2) ? options.fn(this) : options.inverse(this));
});
Here is my view file: (comparing blog_comments.userId to user.userId)
{{#blog_comments}}
<i>{{createdAtDateSlug}}</i>
{{#ifeq userId user.userId}}Delete</p>
{{/ifeq}}
<p class="blog-comment">{{comment}}</p>
{{/blog_comments}}
I figured out the solution. Since I am trying to access a separate object, I need to get back to the root of the scope and then access the object and its property. i.e. #root.user.userId in {{ifeq userId #root.user.userId}}. This change resolved my issue
Related
If I pass an Object into the model and test it with the "?is_string" built-in, it will falsely return a true value.
Is it possible (without checking the class name) to have a proper type checks on Objects?
FreeMarker: 2.3.28
Code to reproduce:
public class Test {}
// In Test Controller
ModelAndView mv = new ModelAndView("test");
mv.addObject("test", new Test());
// In test.ftl
<#if test?is_string>
${test} - is a string!
</#if>
// Result
Test#455b31c - is a string
The problem is that that approach isn't really supported by FreeMarker. The Java objects are mapped to some template language values via Configuration.objectWrapper, and the template only sees the result of that mapping. Furthermore the template language has a different type system than Java, a simplistic one, without classes. (It was a design goal back then that the data-model is just some simple tree, and the templates will work no mater what objects are behind, as far as it still gives the same tree.) ?is_... doesn't check the Java type, but the type according the template language. As with the usual ObjectWrapper-s a "generic" object (means, nothing recognized like List, Map, Date, etc.) can be used as a strings whose value is whatever toString() returns, it's a string as far as the template language is concerned. It's kind of duck typed...
A workaround I can think of is that first check the value with ?is_hash, as that will catch the said generic objects (as they support ., they are hashes as well, not just strings). Or instead just check the property you expect to be present in a Test. Then on the "else" branch you can continue with ?is_string.
I'm having a problem on what is the best approach to design my service layer and use them in my controller. Here is my concern.
Currently I'm using this to delete categories
[HttpPost]
[ValidateAntiForgeryToken]
public IActionResult Delete(List<Guid> ids)
{
if(ids == null || ids.Count == 0)
return RedirectToAction("List");
_categoryService.DeleteCategories(_categoryService.GetCategoryByIds(ids));
_categoryService.SaveChanges();
return RedirectToAction("List");
}
my concern is should I just pass ids to DeleteCategories then call the GetCategoryByIds inside the DeleteCategories. And If I'm only going to delete 1 Category, is it better to add another method like DeleteCategory then in the controller check the length of the ids and if it is only 1, use DeleteCategory instead,
my concern is should I just pass ids to DeleteCategories then call the GetCategoryByIds inside the DeleteCategories.
Just pass the ID's to the DeleteCategories method. I wouldn't even bother calling GetCategoryByIds inside of it. There's no need to query the database for all the rest of the category information if you're just planning on deleting it.
And If I'm only going to delete 1 Category, is it better to add another method like DeleteCategory then in the controller check the length of the ids and if it is only 1, use DeleteCategory instead
I wouldn't bother with creating another method. You could just pass a list with one value in it. There's nothing a DeleteCategory method could do that you can't already do with DeleteCategories.
It all depends on your business logic
If the user has the option to select more than one category and delete them at once, then it makes sense to have the delete method accepts a list of ID and delete them all, if the user can delete only one category, then it should be DeleteById(int categoryId).
As for calling GetCategoryByIds, still depends on your logic, if you have some kind of authorization, then you must retrieve the category first, make sure the user has an access to delete the provided category and proceed if everything is fine.
A note about your code, your service should have the logic for data manipulation encapsulated inside, you should not expose the SaveChanges method and give the control to the controller to call it, or at least implement the Unit of Work pattern if you need to implement some kind of transaction.
I'm working in an ASP.NET (VB) Web Application with Windows/Active Directory Authentication
I am using a module so that I can call public subroutines and functions, and reference variables, without having to instantiate a new object to access them on each page.
Within that module, I have some Public variables that I am using in multiple pages throughout the web application. I've recently realized that the values for these public variables in the module get shared between all users.
THE GOAL:
I want the value for these global variables to be specific to a single user and not shared between all sessions, and I do not want to have to instantiate a new object/class on every page that uses the variable.
THE CATCH:
I don't want to store the value in a client-side variable such as a cookie or session. I want the value to be stored on the SERVER but specific to each client/user.
The only thing I can think to do is setup a global collection/dictionary and store the variables with the authenticated user names, but then I need to have specific functions to get and set the values. While this will work, it requires all the references to these variables on all pages in the application to be updated.
EXAMPLE OF THE PROBLEM:
The below code shows how I am creating the public variable within the module and how the value is being set from one page and used on another. I'd like to continue to use this variable in the same way and share it's value between pages, but the value of the variable needs to NOT be shared between users.
-- MODULE.VB --
Public Module MyMod
Public myVariable as String = ""
End Module
-- MAINPAGE.VB --
Partial Class _Default
Sub Page_Load() Handles MyBase.Load()
myVariable = "HELLO WORLD"
End Sub
End Class
-- NEXTPAGE.VB --
Partial Class _Default
Sub Page_Load() Handles MyBase.Load()
Response.Write(myVariable)
End Sub
End Class
There are a LOT of pages in this application that will need to be manually updated if I have to use my userID-indexed collection solution, so I'm hoping there is a way to simply scope these variables differently or a way to disable the sharing between sessions.
Thanks in advance!
You didn't indicate whether or not the variables need to be persisted across page round trips or whether they are just used within each page's lifecycle.
If they are not persisted across pages, then perhaps the easiest solution is to have all of your pages inherit from a based page class and then move the values from the module into the base page. This way you won't have to change any variable references, only page inheritance.
If you do want to persist the values, completing the above changes makes it much easier to implement. You can then turn the member variables on the base page into properties and embed your user specific caching and fetching in the getter and setter.
For example, instead of:
Public MyVariable As String = ""
You would have something like:
Public Property MyVariable As String
Get
Return GlobalMyVariableCache(UserNameKey)
End Get
Set (Value As String)
GlobalMyVariableCache(UserNameKey) = Value
End Set
End Property
The problem you are coming across is a very common one in web programming. A Module's members are static - meaning there is one instance of them across the entire AppDomain of your application. Every user that accesses these will get the same object - you have already learned this.
Your options are exactly what you described. You could possibly replace the public variable in your module with a property whose getter you write to access a user-specific field in a dictionary (please remember thread safety when writing this getter code).
The much easier solution would be to use the Session. Session values are stored server-side and are user specific. The only thing that get's sent client side is the session key, and if you are using .Net authentication, this is likely already getting sent.
Good luck,
I have 3 domains :
- EligibilityInclusion
- EligibilityExclusion
- EligibilitySummary
I build also eligibility.gsp (mix use of 3 templates : _inclusion, _exclusion, _summary ; and I'm also using JQueryUI tab to render each domain in one tab).
Everything fine for viewing, but now I would like to use only one controller to create, edit, list and show.
How can I handle 3 domains via only one controller?
(for example, I would like to use EligibilityController to handle my 3 domains)
What is the best usage:
- binding multiple objets?
- use command objects?
Unfortunately command objects don't help with the input model for a view, they are specifically designed to aide the output model for the binding and validation of request parameters. However you can roll your own View Model based on a command object if you are prepared to delve into some meta programming to to achieve the data binding for the creation of the view model.
Here's a basic approach. The following code constructs the Command Object which you can then pass as the model to the view in the controller:
class ItemCommand {
// attribute declarations ...
public void bindData(def domainInstance){
domainInstance.properties.keySet().each { prop ->
if(prop == "class"){
// not needed
} else if(prop == "metaClass") {
// not needed
} else if(this.properties.containsKey(prop)){
this."${prop}" = domainInstance."${prop}"
}
}
}
This will allow you to bind the data from different domain objects by calling bindData for each of the domain objects.
This is the essence of the solution I use. You will need to store the ids of the different domain objects (and the version attribute) as hidden fields if you intend to do updates to the domain objects.
You can't just submit multiple objects, if some of them have same field names, right?
I'd try to join the 3 objects into single Command with 3 fields, like: inclusionInstance1, inclusingInstance2, summaryInstance1, and name fields in gsp-s respectively, like name='command.inclusionInstance1.name'. Assigning command.properties = params should work when submitting the form.
Grails offers the ability to automatically create and bind domain objects to a hasMany List, as described in the grails user guide.
So, for example, if my domain object "Author" has a List of many "Book" objects, I could create and bind these using the following markup (from the user guide):
<g:textField name="books[0].title" value="the Stand" />
<g:textField name="books[1].title" value="the Shining" />
<g:textField name="books[2].title" value="Red Madder" />
In this case, if any of the books specified don't already exist, Grails will create them and set their titles appropriately. If there are already books in the specified indices, their titles will be updated and they will be saved. My question is: is there some easy way to tell Grails to remove one of those books from the 'books' association on data bind?
The most obvious way to do this would be to omit the form element that corresponds to the domain instance you want to delete; unfortunately, this does not work, as per the user guide:
Then Grails will automatically create
a new instance for you at the defined
position. If you "skipped" a few
elements in the middle ... Then Grails
will automatically create instances in
between.
I realize that a specific solution could be engineered as part of a command object, or as part of a particular controller- however, the need for this functionality appears repeatedly throughout my application, across multiple domain objects and for associations of many different types of objects. A general solution, therefore, would be ideal. Does anyone know if there is something like this included in Grails?
removeFrom*
Opposite of the addTo method in that it removes instances from an association.
Examples
def author = Author.findByName("Stephen King")
def book = author.books.find { it.title = 'The Stand' }
author.removeFromBooks(book)
Just ran into this issue myself. It's easy to solve. Grails uses java.util.Set to represent lists. You can just use the clear() method to wipe the data, and then add in the ones you want.
//clear all documents
bidRequest.documents.clear()
//add the selected ones back
params.documentId.each() {
def Document document = Document.get(it)
bidRequest.documents.add(document)
log.debug("in associateDocuments: added " + document)
};
//try to save the changes
if (!bidRequest.save(flush: true)) {
return error()
} else {
flash.message = "Successfully associated documents"
}
I bet you can do the same thing by using the "remove()" method in the case that you don't want to "clear()" all the data.
For a good explanation of deleting a collection of child objects with GORM have a look at the Deleting Children section of this blog post - GORM gotchas part 2
It's recommended reading, as are parts 1 and 3 of the series.
I am just starting to learn Grails myself and saw your question as an interesting research exercise for me. I do not think you can use the conventional data binding mechanism - as it fills in the blanks using some kind of Lazy map behind the scenes. So for you to achieve your goal your "save" method (or is it a function?) is unlikely to contain anything like:
def Book = new Book(params)
You need a mechanism to modify your controller's "save" method.
After some research, I understand you can modify your scaffolding template which is responsible for generating your controller code or runtime methods. You can get a copy of all the templates used by Grails by running "grails install-templates" and the template file you would need to modify is called "Controller.groovy".
So in theory, you could modify the "save" method for your whole application this way.
Great! You would think that all you need to do now is modify your save method in the template so that it iterates through the object entries (e.g. books) in the params map, saving and deleting as you go.
However, I think your required solution could still be quite problematic to achieve. My instinct tells me that there are many reasons why the mechanism you suggest is a bad idea.
For one reason, off the top of my head, imagine you had a paginated list of books. Could that mean your "save" could delete the entire database table except the currently visible page? Okay, let us say you manage to work out how many items are displayed on each page, what if the list was sorted so it was no longer in numerical order - what do you delete now?
Maybe multiple submit buttons in your form would be a better approach (e.g. save changes, add, delete). I have not tried this kind of thing in Grails but understand actionSubmit should help you achieve multiple submit buttons. I certainly used to do this kind of thing in Struts!
HTH
I'm just running into this same issue.
My application's domain is quite simple: it has Stub objects which have a hasMany relationship with Header objects. Since the Header objects have no life of their own, they're entirely managed by the Stub controller and views.
The domain class definitions:
class Stub {
List headers = new ArrayList();
static hasMany = [headers:Header]
static mapping = {headers lazy: false}
}
class Header {
String value
static belongsTo = Stub
}
I've tried the "clear and bind" method but the end result is that the "cleared" objects are left over in the database and grails will just create new instances for the ones that were not removed from the relationship. It does seem to work from an user's perspective, but it will leave lots of garbage objects in the database.
The code in the controller's update() method is:
stubInstance.headers.clear()
stubInstance.properties = params
An example: while editing the -many side of this relationship I have (for a given Stub with id=1):
<g:textField name="headers[0].value" value="zero" id=1 />
<g:textField name="headers[1].value" value="one" id=2 />
<g:textField name="headers[2].value" value="two" id=3 />
in the database there are 3 Header instances:
id=1;value="zero"
id=2;value="one"
id=3;value"two"
after removing header "one" and saving the Stub object the database will have headers:
id=1;value="zero"
id=2;value="one"
id=3;value"two"
id=4;value="zero"
id=5;value="two"
and the Stub object will now have an association with Headers with id=4 and id=5...
Furthermore, without the clearing of the list, if an index is not present in the submitted request.headers list, on data binding grails will keep the existing object at that location unchanged.
The solution that occurs to me is to bind the data, then check the Stub's headers for elements that are not present in the submitted list and remove them.
This looks like a pretty simple scenario, isn't there any built-in functionality to address it?
It's a bit overkill to have to write your own synchronization logic for maintaining relationships, especially when the quirks that make it non-trivial are caused by grails itself.
What about deletion, shouldn't the clear()'ed elements be gone from the database? Am I missing something in the relationship or domain object definitions?
class Stub {
List headers = new ArrayList();
static hasMany = [headers:Header]
static mapping = {
headers lazy: false
**headers cascade: "all-delete-orphan"**
}
}
class Header {
String value
static belongsTo = Stub
}
I have added the cascade property on the owning side of relationship and Now if you try to save the stub, it will take care of removing deleted items from the collection and delete them from the DataBase.