I have a parent model that has many child models, for example:
App.Blog = Ember.Object.extend({})
App.Comment = Ember.Object.extend({})
Then I have a view for the Blog:
window.App.BlogView = Ember.View.extend
templateName: 'app_templates_blog'
Now, when I initially retrieve a Blog via my REST API, it contains the first 10 Comments or so. Those are instantiated like this:
window.App.Blog.reopenClass
create: (obj) ->
Object.tap #_super(obj), (result) =>
if result.comments
result.comments = result.comments.map (p) => App.Comment.create(p)
I display by blog by calling BlogView.set('blog', blogInstance) and everything is displaying perfectly.
However!
I am implementing an infinite scroll, so when the end user gets to the bottom of the comments, I want to load more. I do this via REST, but I can't for the life of me get them to display by appending them.
This is what my morePosts() method looks like in BlogView:
moreComments: () ->
blog = #get('blog')
jQuery.getJSON "/blogs/#{blog.get('id')}/comments", (result) =>
comments = blog.get('comments')
result.each (c) => comments.push(App.Comment.create(c))
blog.set('comments', comments)
this.set('blog', blog)
However, this never seems to add the new comments. What am I doing wrong here?
To properly support Ember's bindings and observers, you need to use KVO aware getters and setters. Just as you use get and set for standard properties, you also have to use special methods for Arrays. In this case, you'd use pushObject. You can see a full list of the functions implemented here: https://github.com/emberjs/ember.js/blob/master/packages/ember-runtime/lib/mixins/mutable_array.js.
Related
Using the Play Framework (2.6) documentation; I am attempting to handle form submission. But I'm running into an issue in repopulating the form fields - which is what I want to do if it has errors (so users can edit their entry rather than having to re-enter).
newForm.bindFromRequest.fold(
errorForm => {
BadRequest(views.html.form(errorForm))
},
formData => {
val oWriteJso = Json.toJsObject(formData) match {
case x if(x.fields.nonEmpty) => getCreatedFieldValues(x)
case _ => None
}
val oRes = Redirect(routes.Application.index).flashing("success" -> "Entry saved!")
apiC.writeAndRedirect("c", collName, None, oWriteJso)(oRes)(request)
}
)
My issue is that the example in the documentation only shows how to pass errorForm directly to a form template (e.g. views.html.form) rather than being able to render the whole page again (i.e. using views.html.index or a Redirect) with the input form fields being populated from the previous request. I found this answer as the closest to this issue but it is a little old and I am using Scala so wasn't able to implement it. Just have no idea how anyone else is doing this or what the sensible, standard approach is. Thanks for any light on this_
If you use the Play helper functions for generating input tags in your view file. They should populate with your values from the last request.
For example you can create an HTML form in your view file using helper methods like this:
#helper.form(action = routes.Application.userPost()) {
#helper.inputText(userForm("name"))
#helper.inputText(userForm("age"))
}
You can take a look at Play documentation about helpers in view files at the following link:
https://www.playframework.com/documentation/2.7.x/ScalaForms#Showing-forms-in-a-view-template
I set the view.setModel(model), get the model for the view, and request for model.read("/entitySet('10000')").
The model is then filled up with /entitySet('10000')/properties.
But it is difficult to assign them to view fields, as now in the view, <Text text="{property}"> doesn't work. It has to be <Text text="{/entitySet('10000')/property}">.
On the other hand, if I set view's context binding to "/entitySet('10000')", then <Text text="{property}"> would start working.
Which one is the preferred method? When to use .read?
I almost never use .read if I want to use the results from an OData call directly in a binding context. The only time I use .read is if I want to manipulate the results before doing anything with them.
Look at this example from the sdk for instance: https://ui5.sap.com/#/entity/sap.ui.table.Table/sample/sap.ui.table.sample.OData
Syntax on this kind of binding is similar to read but with a few differences in events, and a few different types of methods depending on what you want to bind. Binding to a view for instance uses bindElement:
this.getView().bindElement("/entitySet('1000')");
After this, fields on that particular entity can be accessed as <Text text="{property}" />.
Here's an example from one of my current apps with events and some other call parameters:
this.getView().bindElement({
path: `/Orders('${currentOrderNumber}')`,
parameters: {
expand: 'Texts'
},
events: {
dataRequested: _ => this.getView().setBusy(true),
dataReceived: data => {
if (!this.getView().getBindingContext()) {
// navigate to `Not Found` view
}
},
change: _ => this.getView().setBusy(false)
}
});
For a table, it's slightly different, since it depends on the aggregation you wish to bind, such as
oTable.bindRows({
path: "properties"
});
Which is the same as:
<Table rows="{properties}" />
It's always important to be more expressive. Use the API that is specifically designed to do that one task.
Comparing the two variants:
myModel.read(sPath) with text="{/path/property}"
myControl.bindElement(sPath) with text="{property}"
I'd be perplexed about the 1st call whereas in the 2nd call, I'd know exactly what you want to achieve (You want to bind element. Alternatively, bindObject can be also used).
The same applies to the framework. Since you're telling exactly what you want to achieve, the framework can improve its behavior based on your intent. E.g.: in (route)PatternMatched handler when the user navigates to the same page, .bindElement with the same path won't trigger another request since the model already stored the entity from the previous call. It can show the result immediately.
With .read, however, the framework doesn't know what you want to achieve, so it sends the request right away regardless of the application state.
Additionally, the 1st variant is anything but future-proof. It relies on the cached results. It's almost a side-effect that it works at all. The problem is that there is no guarantee that this behavior will continue to work in later versions. Also there won't be read method in V4 ODataModel.
TL;DR
v2.ODataModel#read
Does not create context from the response. Repeating .read("<same path>") always sends a new request.
Less expressive. Encourages app developers to work with a client-side model (e.g. JSONModel).
Application loses context awareness, increasing TCO, less future-proof.
bindElement or bindObject
Creates context from the response and stores it internally so that the same request can return the data immediately.
Clearly expresses the intent; application as well as framework can work with the existing APIs.
More future-proof: v4.ODataModel does not support manual read. Imagine you've built your applications with the v2ODataModel.read-jsonModel.setData approach, and you need to migrate to v4. Have fun. :)
I honestly think that v2.ODataModel#read should have never become a public method. I wouldn't encourage anyone to use .read except of when reading the $count value manually.
If the entity values need to be formatted, there are formatters and binding types out of the box which are also easy to extend.
If the application needs to restructure the response body, usually it's a sign of a poor design of the data model or the service not conforming to the OData spec.
I almost agree with Jorg, but not entirely:
It really depends on what are you trying to achieve. If looking to display data from backend then the easiest way to go is with this.getView().bindElement()
but if you are in need to manipulate data before displaying (like formatting text, displaying images from base64 strings, etc) OR if you would like to create new entity using some of existing data, OR update the existing data - the this.getModel(sName).read() is the way to go - as you can set read entity with all its deep entities to JSONModel in successCallback and manipulate it from the localModel.
If using localModel the dataBinding is pretty much the same in the view - except you have to additionally give model name to take data from. So for example, if in successCallback of your Model.read() you set your data to Model named "localModel":
this.getModel().read(sObjectPath, {
urlParameters: {
$expand: ""
},
success: function (oData) {
// "localModel" is name you gave in onInit function to your new JSONMOdel, when setting it to View e.g. this.getView().setModel(oJSONMOdel, "localModel")
this.getModel("localModel").setData(oData);
}
})
then in XML view you would indicate that
<Text text="{localModel>/mainPropertyName}"/>
// for displaying deep entities as List items or in Table
<List items="{localModel>/deepEntityName}">
<StandardListItem title="{localModel>propertyNamefromDeepEntity}" />
</List>
From my experience working with more complex apps that Read-Only - I always use Model.read().
My question is this: How can you implement a default server-side "filter" for a navigation property?
In our application we seldom actually delete anything from the database. Instead, we implement "soft deletes" where each table has a Deleted bit column. If this column is true the record has been "deleted". If it is false, it has not.
This allows us to easily "undelete" records accidentally deleted by the client.
Our current ASP.NET Web API returns only "undeleted" records by default, unless a deleted argument is sent as true from the client. The idea is that the consumer of the service doesn't have to worry about specifying that they only want undeleted items.
Implementing this same functionality in Breeze is quite simple, at least for base entities. For example, here would be the implementation of the classic Todo's example, adding a "Deleted" bit field:
// Note: Will show only undeleted items by default unless you explicitly pass deleted = true.
[HttpGet]
public IQueryable<BreezeSampleTodoItem> Todos(bool deleted = false) {
return _contextProvider.Context.Todos.Where(td => td.Deleted == deleted);
}
On the client, all we need to do is...
var query = breeze.EntityQuery.from("Todos");
...to get all undeleted Todos, or...
var query = breeze.EntityQuery.from("Todos").withParameters({deleted: true})
...to get all deleted Todos.
But let's say that a BreezeSampleTodoItem has a child collection for the tools that are needed to complete that Todo. We'll call this "Tools". Tools also implements soft deletes. When we perform a query that uses expand to get a Todo with its Tools, it will return all Tools - "deleted" or not.
But how can I filter out these records by default when Todo.Tools is expanded?
It has occurred to me to have separate Web API methods for each item that may need expanded, for example:
[HttpGet]
public IQueryable<Todo> TodoAndTools(bool deletedTodos = false, bool deletedTools = false)
{
return // ...Code to get filtered Todos with filtered Tools
}
I found some example code of how to do this in another SO post, but it requires hand-coding each property of Todo. The code from the above-mentioned post also returns a List, not an IQueryable. Furthermore this requires methods to be added for every possible expansion which isn't cool.
Essentially what I'm looking for is some way to define a piece of code that gets called whenever Todos is queried, and another for whenever Tools is queried - preferably being able to pass an argument that defines if it should return Deleted items. This could be anywhere on the server-side stack - be it in the Web API method, itself, or maybe part of Entity Framework (note that filtering Include extensions is not supported in EF.)
Breeze cannot do exactly what you are asking for right now, although we have discussed the idea of allowing the filtering of "expands", but we really need more feedback as to whether the community would find this useful. Please add this to the breeze User Voice and vote for it. We take these suggestions very seriously.
Moreover, as you point out, EF does not support this.
But... what you can do is use a projection instead of an expand to do something very similar:
public IQueryable<Object> TodoAndTools(bool deleted = false
,bool deletedTools = false) {
var baseQuery = _contextProvider.Context.Todos.Where(td => td.Deleted == deleted);
return baseQuery.Select(t => new {
Todo: t,
Tools: t.Tools.Where( tool => tool.Deleted = deletedTools);
});
}
Several things to note here:
1) We are returning an IQueryable of Object instead of IQueryable of ToDo
2) Breeze will inspect the returned payload and automatically create breeze entities for any 'entityTypes' returned (even within a projection). So the result of this query will be an array of javascript objects each with two properties; 'ToDo' and 'Tools' where Tools is an array of 'Tool' entities. The nice thing is that both ToDo and Tool entities returned within the projection will be 'full' breeze entities.
3) You can still pass client side filters based on the projected property names. i.e.
var query = EntityQuery.from("TodoAndTools")
.where("Todo.Description", "startsWith", "A")
.using(em);
4) EF does support this.
I'm working on a sample app for Facebook, using Flash Builder and Flex.
Now, I've got everything up and running - but there's one problem, specifically with the work history part.
When I try to display the user's work history..here's the code for logging in:
protected function login():void
{
FacebookDesktop.login(loginHandler, ["user_birthday", "user_work_history"]);
}
Here, loginHandler's a callback function, that then goes ahead and displays data about the user:
protected function loginHandler(success:Object,fail:Object):void
{
if (success){
currentState = "LoggedIn";
fname.text = success.user.name;
userImg.source=FacebookDesktop.getImageUrl(success.uid,"small");
birthdayLbl.text=success.user.birthday;
workLbl.text=success.user.work;
}
}
Now, the problem occurs with success.user.work - it ends up printing the following:
[object,Object],[object,Object],[object,Object],[object,Object]
Obviously, I'm doing something wrong..but I can't figure out what exactly it is. Would be grateful for some pointers!
Thanks!
Rudi.
The object contained in success.user.work is most likely an array of objects, each item representing a work period, so you'll have to treat it as such. Either use a list and a custom renderer for each item, or create a string by iterating over the array, and appending the fields that you're interested in.
To see what the individual objects contain, either use a breakpoint during debug and inspect them, or check to see if they're documented in the facebook development documentation.
I have the following in a config.ini file: (Zend_Form_Element)
site_status.name = "site_status"
site_status.type = "select"
site_status.label = "Status"
site_status.options.multiOptions.active.key = "Active"
site_status.options.multiOptions.active.value = "Active"
site_status.options.multiOptions.active.key = "Inactive"
site_status.options.multiOptions.active.value = "Inactive"
As you can see this is supposed to be a dropdown (select) box, however it is being rendered as a standard text box. What am I doing wrong?
--> Edit
Rather than tying the elements to a form, I am trying to tie them to a database: In my code it would look something like this:
[{tablename}] // the table name would represent a section in the ini
{column}.name = "{column_name/form_field_id}";
{column}.type = "{form_element_type}"
{column}.label = "{form_element_label}"
...
From there I would pull in the database table(s) that the form would represent data for (one or more tables as necessary). As far as the reasoning for this approach is that (down the road), I want to define (either by ini or some other storage method), a configuration file that would be a list of fields/elements that belong to a specific form (that a non-programmer type could easily edit), that the 'generic' form class would read, pull in the element info, and create the form on the fly.
I do realize however this poses another problem which I haven't yet figured out, and that is how to use table lookups for select elements (without coding the database retrieval of the lookup into the form, so that a non-user could easily just define it without any programming, purely configuration, but that is a whole other topic not part of my question here. (and I think I have viable ideas/solutions to that part of the problem anyhow) -- extra config entries and a generic routine pretty much.
I hope that clarifies my thought process and reason why I am doing it the way I am in the example above.
I have not yet played with using a Zend_Config to construct an instance of Zend_Form.
But a look at the code suggests that Zend_Form::addElement() doesn't directly take a Zend_Config instance as a param. Rather, it looks like you need pass your Zend_Config instance to the form constructor. It also seems that the config format needs to be a little deeper in order to map config keys to setXXX() calls.
In path/to/config/myForm.ini:
[myForm]
myForm.elements.site_status.name = "site_status"
myForm.elements.site_status.type = "select"
myForm.elements.site_status.label = "Status"
myForm.elements.site_status.options.multiOptions.active.key = "Active"
myForm.elements.site_status.options.multiOptions.active.value = "Active"
myForm.elements.site_status.options.multiOptions.inactive.key = "Inactive"
myForm.elements.site_status.options.multiOptions.inactive.value = "Inactive"
Then instantiating:
$formConfig = new Zend_Config_Ini('path/to/config/myForm.ini', 'myForm');
$form = new Zend_Form($formConfig);
Not tested, but looking at this example:
Using Zend_Form with Zend_Config - Andrew Vayanis
it feels like it should go something like the above.
Update
In view of the comments/feedback from #Aaron, two more approaches.
We could extend Zend_Form, implementing a method called something like addElementByConfig in which we would pass the shallow Zend_Config instance that describes the element itself. In fact, we could even just override addElement(), taking a recursive approach: if the first param is an instance of Zend_Config, then call addElement() using the component data.
If the atomicity and re-usability are the primary benefits we seek in using Zend_Config to describe an element, then perhaps we just make a custom element extending Zend_Form_Element. Then we could use these elements in any forms we wish.