Assume i have a book entity with an isbn field.
When entered a isbn number, i want 2 fields to be updated: title and author.
My controller looks like this:
def ajaxGetBook = {
def book = Book.findByIsbn(params.isbn)
if(book==null) book = new Book()
render book as JSON
}
So my call works, and i get a full JSON Book.
Now i would like to update 2 texfields by the update attribute
<g:remoteField action="ajaxGetBook" update="title" name="isbn" value="${bookInstance?.book?.isbn}" paramName="isbn"/>
Now the title field gets updated with the full book object, so that doesn't work.
Is it possible to update field title with only the JSON book.title?
Is it possible to update more fields at once?
I could render book.title as JSON but that works for only one field.
Thank you
Well, the g:remoteField tag is explicitly for one field, so you can't use it to update more than one. So, you're left with 2 easy choices:
Use 2 g:remoteField calls... this isn't a bad option, as they would happen in near parallel, as they are Async calls.
Roll your own Ajax. use g:remoteFunction instead, and have the JS function that you place in the "success" attribute take your book, and update the appropriate HTML fields.
Related
I have a Django model, DocumentComments, with two datetime fields, created and updated. I am working on a search function that parses a search string and returns a Q expression to query the DocumentComments model based on the values in the search string.
I need to write something like Q(created.year=xxxx), where created.year is the year in the created datetime field. But "keywords can't be expressions" as Django has been telling me all morning.
I tried using a custom model manager and annotating the default queryset with a year field, but that did not work as I can't seem to access the created.year value in the get_queryset function.
class DocumentCommentManager(models.Manager):
def get_queryset(self):
c_year = self.created.year
u_year = self.updated.year
return super(DocumentCommentManager, self).get_queryset().annotate(created_year=c_year, updated_year=u_year)
What am I missing, or what is a better way to accomplish my goal?
Thanks!
Mark
I was able to solve my problem using Django's db function Extract (https://docs.djangoproject.com/en/3.1/ref/models/database-functions/#extract)
My DocumentCommentManager:
from django.db.models.functions import Extract
class DocumentCommentManager(models.Manager):
def get_queryset(self):
return super(DocumentCommentManager, self).get_queryset().annotate(created_year=Extract("created","year"))
This solves my original problem of adding a calculated datetime field to the model queries.
I still have not found a general way to add a calculated field to a model query using Q expressions. If you can share any examples, that would be great!
Say I have the following Model:
class Book(Model):
title = CharField(verbose_name="Book title")
and a ModelSerializer:
class BookSerializer(ModelSerializer):
class Meta:
model = Book
fields = "__all__"
I would like to have a function get_verbose_names which returns verbose names of the fields in the model. This is what I have so far:
def get_verbose_names(serializer):
return [field.label for field in serializer.get_fields().values()]
It seems to work fine but problems occur when I use this for the builtin User model. The only fields which work are ID, E-mail, Active, Superuser status and Staff status. The special thing about those fields is that their verbose name differs from their name. Django REST Framework is probably hiding a super-smart logic which checks this and refuses to set the field label to its verbose name in such cases.
Do Django REST Framework's fields have the verbose names hidden somewhere, or they don't copy them from the original Django model fields at all and I am screwed? Or will the trick be to override this logic? I tried and could not find it.
Django REST Framework really has the mentioned "super-smart logic". It is the function needs_label in utils.field_mapping:
def needs_label(model_field, field_name):
"""
Returns `True` if the label based on the model's verbose name
is not equal to the default label it would have based on it's field name.
"""
default_label = field_name.replace('_', ' ').capitalize()
return capfirst(model_field.verbose_name) != default_label
Probably the easiest way to bypass this annoying feature is to do this:
def get_verbose_names(serializer):
return [field.label or name.replace("_", " ").capitalize()
for name, field in serializer.get_fields().items()]
Explained in words, check the field label and if none was auto-generated for it, use the needs_label logic to determine it.
Is there a way of returning items from a database in django-nonrel, using 'order_by' on a foreignkey?
Full details are as follows:
#Models.py
class Post(models.Model):
article = models.TextField(help_text='Paste or type HTML in here')
pub_date = models.DateField()
....
class TagItems(models.Model):
title = models.CharField(max_length=200)
....
class TagRel(models.Model):
the_post = models.ForeignKey('Post')
the_tag = models.ForeignKey('Tag')
TagRel defines a ManytoMany relationship between Post and TagItems classes.
I am wanting to get a list of articles for each tag.
#Desire output
My tag
-my first post
-my second post
My second tag
- my other post
- another post
All is good so far, as I use the following to filter the data:
def tagged_posts():
tag_items = TagItems.objects.all()
li =[]
for item in tag_items:
tag_rel_item = TagRel.objects.filter(the_tag__pk = item.pk)
li.append(tag_rel_item)
return {'list_of_objects': li}
I am using db-indexer to define the filter part of the query in db-indexes.py. All this works fine but I want to order my posts by publication dates.
Django docs tell me to use:
TagRel.objects.filter(the_tag__pk = item.pk).order_by('the_tag__pub_date')
But the order_by('the_tag__pub_date') part does not appear to be supported by django-nonrel.
The following also works in normal Django:
TagRel.objects.filter(the_tag__pk = item.pk).order_by('the_post')
This works because the Posts are already sorted by date in the model.
But this also does not appear to work in django-nonrel.
So my question is how do I return my posts ordered by date (latest>oldest)?
Thanks in advance
I'm taking a guess at this - you're using a ManyToManyField. I believe that's implemented using a ListProperty on App Engine's datastore.
See the section in the datastore documentation labeled "Properties With Multiple Values Can Have Surprising Behaviors":
http://code.google.com/appengine/docs/python/datastore/queries.html
That's most likely why your results appear unsorted. ManyToMany relations aren't supported natively in GAE. You'd probably have to sort them yourself after you get the results back.
My main question here is dealing with the pramas map when having a one-to-many relationship managed within one dynamic form, as well as best practices for dealing with one-to-many when editing/updating a domain object through the dynamic form. The inputs for my questions are as follows.
I have managed to hack away a form that allows me to create the domain objects shown below in one Dynamic form, since there is no point in having a separate form for creating phone numbers and then assigning them to a contact, it makes sense to just create everything in one form in my application. I managed to implement something similar to what I have asked in my Previous Question (thanks for the people who helped out)
class Contact{
String firstName
String lastName
// ....
// some other properties
// ...
static hasMany = [phones:Phone]
static mapping = {
phones sort:"index", cascade: "all-delete-orphan"
}
}
class Phone{
int index
String number
String type
Contact contact
static belongsTo = [contact:Contact]
}
I basically managed to get the values from the 'params' map and parse them on my own and create the domain object and association manually. I.e. i did not use the same logic that is used in the default scaffolding, i.e.
Contact c = new Contact(params)
etc...., i just looped through all the params and hand crafted my domain objects and saved them and everything works out fine.
My controller has code blocks that look like this (this is stripped down, just to show a point)
//create the contact by handpicking params values
def cntct = new Contact()
cntct.firstName = params.firstName
cntct.lastName = params.lastName
//etc...
//get array of values for number,type
def numbers = params['phone.number']
def types = params['phone.type']
//loop through one of the arrays and create the phones
numbers.eachWithIndex(){ num, i ->
//create the phone domain object from
def phone = new Phone()
phone.number = num
phone.type = types[i]
phone.index = i
cntct.addToPhones(phone)
}
//save
My questions are as follows:
What is the best practice of handeling such a situation, would using Command objects work in this case, if yes where can i found more info about this, all the examples I have found during my search deal with one-to-one relationships, I couldn't find an example for one-to-many?
What is the best way to deal with the relatiohsips of the phones in this case, in terms of add/removing phones when editing the contact object. I mean the creation logic is simple since I have to always create new phones on save, but when dealing with updating a contact, the user might have removed a phone and/or editing an exiting one and/or added some new phones. Right now what I do is just delete all the phones a contact has and re-create them according to what was posted by the form, but I feel that's not the best way to do it, I also don't think looping over the existing ones and comparing with the posted values and doing a manual diff is the best way to do it either, is there a best practice on how to deal with this?
Thanks, hopefully the questions are clear.
[edit] Just for more information, phone information can be added and deleted dynamically using javascript (jquery) within the form [/edit]
disclaimer: i do not know if the following approach works when using grails. Let me know later.
See better way for dynamic forms. The author says:
To add LineItems I have some js that calculates the new index and adds that to the DOM. When deleting a LineItem i have to renumber all the indexes and it is what i would like to avoid
So what i do
I have a variable which stores the next index
var nextIndex = 0;
When the page is loaded, i perform a JavaScript function which calculates how many child The collection has and configure nextIndex variable. You can use JQuery or YUI, feel free.
Adding a child statically
I create a variable which store the template (Notice {index})
var child = "<div>"
+= "<div>"
+= "<label>Name</label>"
+= "<input type="text" name=\"childList[{index}].name\"/>"
+= "</div>"
+= "</div>"
When the user click on the Add child button, i replace {index} - by using regex - by the value stored in the nextIndex variable and increment by one. Then i add to the DOM
See also Add and Remove HTML elements dynamically with Javascript
Adding a child dinamically
Here you can see The Paolo Bergantino solution
By removing
But i think it is the issue grow up when deleting. No matter how many child you remove, does not touch on the nextIndex variable. See here
/**
* var nextIndex = 3;
*/
<input type="text" name="childList[0].name"/>
<input type="text" name="childList[1].name"/> // It will be removed
<input type="text" name="childList[2].name"/>
Suppose i remove childList1 What i do ??? Should i renumber all the indexes ???
On the server side i use AutoPopulatingList. Because childList1 has been removed, AutoPopulatingList handles it as null. So on the initialization i do
List<Child> childList = new AutoPopulatingList(new ElementFactory() {
public Object createElement(int index) throws ElementInstantiationException {
/**
* remove any null value added
*/
childList.removeAll(Collections.singletonList(null));
return new Child();
}
});
This way, my collection just contains two child (without any null value) and i do not need to renumber all the indexes on the client side
About adding/removing you can see this link where i show a scenario wich can gives you some insight.
See also Grails UI plugin
Thanks,
Your answer brought some insight for me to do a wider search and I actually found a great post that covers all the inputs in my question. This is just a reference for anyone reading this. I will write a blog entry on how I implemented my case soon, but this link should provide a good source of ino with a working exmaple.
http://www.2paths.com/2009/10/01/one-to-many-relationships-in-grails-forms/
Most of the time I use ajax to manage such problem.
So when the user clicks add new phone I get the template UI from the server for manageability purpose ( the UI just same GSP template that I use to edit, update the phone), so this way you are not mixing your UI with your js code, whenever you want to change the UI you have to deal only with our GSP code.
Then after getting the UI I add it to the page using jquery DOM manipulation. Then after filling the form when they hit add(save) the request is sent to the server via ajax and is persisted immediately.
When the user clicks edit phone the same UI template is loaded from the server filled with existing phone data, then clicking update will update the corresponding phone immediately via ajax, and same thing applies to delete operation.
But one day I got an additional scenario for the use case that says, "until I say save contact no phone shall be saved on the backend, also after adding phones to the contact on the ui if navigate away to another page and come back later to the contact page the phones I added before must be still there." ugh..
To do this I started using the Session, so the above operations I explained will act on the phone list object I stored on the session instead of the DB. This is simple perform all the operation on the phonesInSession but finally dont forget to do this(delete update):
phonesToBeDeleted = phonesInDB - phonesInSession
phonesToBeDeleted.each{
contact.removeFromPhones(it)
it.delete()
}
I know I dont have to put a lot of data in session but this is the only solution I got for my scenario.
If someone has got similar problem/solution please leave a comment.
First, in all your input fields names you add an #:
<input type="text" name="references[#].name"/>
Second, add call a function before submitting:
<g:form action="save" onsubmit="replaceAllWildCardsWithConsecutiveNumbers();">
Third, this is the code for the function that you call before submitting the form:
function replaceAllWildCardsWithConsecutiveNumbers(){
var inputs = $('form').find("[name*='#']");
var names = $.map(inputs, function(el) { return el.name });
var uniqueNames = unique(names);
for (index in uniqueNames) {
var uniqueName = uniqueNames[index];
replaceWildCardsWithConsecutiveNumbers("input", uniqueName);
replaceWildCardsWithConsecutiveNumbers("select", uniqueName);
}
}
function unique(array){
return array.filter(function(el, index, arr) {
return index === arr.indexOf(el);
});
}
function replaceWildCardsWithConsecutiveNumbers(inputName, name){
counter = 0;
$(inputName + "[name='" + name + "']").each(function (i, el) {
var curName = $(this).attr('name');
var newName = curName.replace("#", counter);
$(this).attr('name', newName);
counter += 1;
});
}
Basically, what the code for replaceAllWildCardsWithConsecutiveNumbers() does, is to create a list for all input (or select) elements whose name contains an #. Removes the duplicates. And then iterates over them replacing the # with a number.
This works great if you have a table and you are submitting the values to a command object's list when creating a domain class for the first time. If you are updating I guess you'll have to change the value of counter to something higher.
I hope this helps someone else since I was stuck on this issue for a while myself.
I would like to populate a Treeview.
Here is what I have in DB :
table : Box
BoxID
BoxName
table Book :
BookID
BookName
BoxID (fk Box.BoxID)
table Chapter:
ChapterID
ChapterName
BookID (fk Book.BookID)
As you may know a treeview is made up of treenode object.
A treenode object have a text property and a tag property.
The "text" property is the text that it's display on the screen for this node and the "tag" is an "hidden" value (usually uses to identify a node)
So in my case; the fields ending with ID will be used in the "tag" property and the fields ending with Name will be used in the "text" property
example :
so for a book; I will use the BookID field for the "tag" property and BookName field for the "text" property
note : I use a dbml so I have a Book object, Box object and Chapter object and I use linq to get them from the db.
So my question is; what is the best practice to build this tree?
I have a solution but it's really ugly because it looks like I'm duplicating the code.
The problem is that the values I need to extract for the text and tag properties are identified by differents fields name in the db
So for the book level, I need to get the BookID field to populate the tag property of my node; for the box level, I need to get the BoxID field to populate the tag property , ....
How can I make a kind of generic way to do it ?
I hope I made myself clear enough, don't hesitate to ask me questions :)
Thx in advance
Here is what I have for the moment
I get the list of box with a linq (dbml) request.
List<Box> MyListofBox = getMyListofBox();
Treenode tnBox = null;
Treenode tnBook =null;
foreach(Box b in MyListofBox )
{
tnBox = new TreeNode();
tnBox.tag = b.BoxID;
tnBox.text = b.BoxName;
List<Book> MyListofBook = getMyListofBookByBoxID(b.BoxID)
foreach(Book boo in MyListofBook )
{
tnBook = new TreeNode();
tnBook.tag = boo.BookID;
tnBook.text = boo.BookName;
tnBox.nodes.add(tnBook);
}
mytreeview.nodes.add(tnBox);
}
but of course I don't like this solution...
do you have a better way ?
I would extract the you need from the database in the form of a struct, possibly via the anonnoumous type that has been added to C# together with linq. Then I would populate insert this data into the place in the tree.
From what I get, you are trying to get each property separately, which will not work so well, because then you will have to make a call to the database for each separate property, which is very wasteful.
Addition based on what you have added
I do not believe the code can be more compact - the names you call are similar, but not the same and the way you do it was what I was trying to explain earlier.
You could
Define an key/value interface that both Box and Book implement
Define a delegate that returns a TreeNode and create delegate methods that accept Box and Book
However, I think the code is fine as written. Sometimes you just have to code it and there's little point in further abstracting or optimizing it.
The only issue I see in the code is that you're making a database call in a loop. Whether or not that's a problem depends on the application.