I'm trying to make a form where I'm storing values outside of the context. Storing is done and working well but now I would like the update method to fill the form on rendering process. So I'm overriding update method of the Form class that way:
def update(self):
super(ConfigurationForm,self).update()
form = self.request.form
if not form:
#We are on a rendering process
provider = self.getProvider()
settings = provider.get()
#TODO: update widget values !?
settings is a dict where keys are equals to Interface fields's names.
So I have tried many ways to update widgets values:
Using dataconverter (too much complex and don't know if this is the only way
Updating the self.request.form dict and call again the update method
playing with field objects
What is the good way to achieve this ? (supporting all kind of field ?)
Don't do ignoreContext. Override getContent() to return a dict instead. The dict will be used as a pseudo context.
Related
There is documentation on using Python dict with z3c.form (loading & storing form data).
However, the z3c.form datamanager used for dicts is not registered for other types or interfaces (see reference), whereas annotations typically use something like PersistentDict.
How can I use the DictionaryField datamanager in this scenario? Ie. so that in my form's getContent method I merely return the PersistentDictannotation.
Well, unfortunately there seems no simple solution for this requirement.
I once faced the same problem using the datagrid field in a z3c form.
The following instruction solves the problem for the datagrid field, which is a list (PersistentList of dicts (PersistentMappings).
I guess you may adapt this solution for your case.
First you need to add the following code to the getContent method:
from plone.directives import form
class MyForm(form.SchemaEditForm):
schema = IMyFormSchema
ignoreContext = False
def getContent(self):
annotations = IAnnotations(self.context)
if ANNOTATION_KEY not in annotations:
annotations[ANNOTATION_KEY] = PersistentMapping()
return YourStorageConfig(annotations[ANNOTATION_KEY])
Important note: I wrap the annotation storage to satisfy the get/set behavior of the z3c form. Check the following YourStorageConfig implementation and you will see why :-).
class YourStorageConfig(object):
implements(IMyFormSchema)
def __init__(self, storage):
self.storage = storage
def __getattr__(self, name):
if name == 'storage':
return object.__getattr__(self, name)
value = self.storage.get(name)
return value
def __setattr__(self, name, value):
if name == 'storage':
return object.__setattr__(self, name, value)
if name == 'yourfieldname':
self.storage[name] = PersistentList(map(PersistentMapping, value))
return
raise AttributeError(name)
yourfieldname should be the field name you are using in the form schema.
To implement the a datagrid field, there is some more work to do, but this may be enough for your case.
Please post comments, or tracebacks, so I can provide further help. I'll gonna add more details/explanation if necessary ;-)
It turns out the answer is as easy as the following ZCML adapter registration:
<adapter
for="persistent.dict.PersistentDict zope.schema.interfaces.IField"
provides="z3c.form.interfaces.IDataManager"
factory="z3c.form.datamanager.DictionaryField"
/>
With that, the following customization of a form is sufficient to use (PersistentDict) annotations for loading & storing form data:
def getContent(self):
"return the object the form will manipulate (load from & store to)"
annotations = IAnnotations(self.context)
return annotations[SOME_ANNOTATIONS_KEY_HERE]
This is assuming that a PersistentDict has been previously stored at annotations[SOME_ANNOTATIONS_KEY_HERE] - otherwise the above code will result in KeyError. It would probably be a good idea to change above getContent so that if the annotation does not yet exist, it is created and initialized with some default values.
Finally, note that for some reason, z3c.form warns against enabling DictionaryField for every mapping type, so it may be prudent to for example subclass PersistentDict for form storage, rather than use it directly. I submitted an issue to z3c.form asking for clarification of that warning.
I am trying to make a replacement VB6 class for the Scripting.Dictionary class from SCRRUN.DLL. Scripting.Dictionary has (among other things) a "Keys" method that returns an array of keys, and a read/write "Item" property that returns the item associated with a key. I am confused about this, because both of them seem to be defaults for the class. That is:
For Each X In MyDict
Is equivalent to:
For Each X In MyDict.Keys
Which to me implies that "Keys" is the default operation for the class, but:
MyDict("MyKey") = "MyValue"
MsgBox MyDict("MyKey")
Is equivalent to:
MyDict.Item("MyKey") = "MyValue"
MsgBox MyDict.Item("MyKey")
Which to me implies that "Item" is the default operation for the class.
I've never before created a VB6 class that had a default operation, so upon realizing this, I thought perhaps I could define multiple default operations as long as they all have different signatures, which they do: Keys is nullary, the Item getter takes a Variant, and the Item setter takes two Variants. But this doesn't seem to be allowed: When I use "Tools/Procedure Attributes" to set the Keys function to be the default, and then I use it to set the Item property to be the default, the IDE complains that a default has already been set.
So I think I'm misunderstanding something fundamental here. What is going on in the Scripting.Dictionary object that makes it able to act as if "Keys" is the default in some contexts, but as if "Item" is the default in others? And whatever it is, can I accomplish the same thing in VB6?
OK, answering my own question: I haven't tried this yet, but I gather that "Item" should be made the default, and that I should add an entirely new function called "NewEnum" that looks something like the following (slightly modified from an example in Francesco Balena's "Programming Microsoft Visual Basic 6.0" book):
Public Function NewEnum() As IUnknown
Set NewEnum = m_Keys.[_NewEnum]
End Function
(where "m_Keys" is a Collection containing the keys), and then use Tools/Procedure Attributes to hide NewEnum and to set its ProcID to -4.
What you are observing is the difference between the default member and a collection enumerator. A COM object (including VB6 classes) can have both.
You can identify the default property of a class by looking in the Object Browser for the tiny blue globe or the words "default member of" in the description (see Contents of the Object Browser). The Object Browser will not identify an enumerator method, but if you look at the class's interface definition using OLE View or TypeLib Browser (free but registration required) it's DispId will be 0xfffffffc or -4.
In your own class, you can mark the default property by setting the Procedure ID to "(default)" in the Procedure Attributes dialog (see Making a Property or Method the Default). You already listed the steps for setting up the collection enumerator in your own answer, but you can find this listed as well in the Programmer's Guide topic Creating Your Own Collection Class: The House of Bricks.
Scripting.Dictionary has a dirty secret:
It does not handle enumeration at all, it returns big ugly Variant arrays and your For Each loops iterate over those.
This is one of the reasons why a Dictionary can actually be far less efficient than a standard VB6 Collection.
I have a Dexterity content type based on plone.directives.form.Schema which has a number of form hints for assigning defaults:
#form.default_value(field=ITrial['start_on'])
def default_start_on(data):
return datetime.now()
Some of the defaults are more complex, passing back objects that are themselves instances of Dexterity types. These objects are essential for the main type's setup, which is triggered by various events.
I'm now in the process of testing. Ideally, I'd like to be able to use something like:
item = createContentInContainer(folder, 'ctcc.model.trial', 'item')
That is, I'd like the defaults to be picked up by the item without having to be manually passed into the constructor.
If I was using zope.schema I could use FieldProperty to set up proxies to the schema fields. Is there something equivalent for Dexterity, or perhaps a function for pushing an object through form creation?
Solution: I ended up going with David's option #1, intercepting ObjectCreatedEvent.
#grok.subscribe(ITrial, IObjectCreatedEvent)
def create_trial(trial, event):
if getattr(trial, 'start_on', None) is None:
trial.start_on = default_start_on(None)
It stills feels like I'm replicating part of form behaviour, but at least it's using the same functions that are providing the form defaults.
As you've discovered, the #form.default_value decorator is respected by z3c.form forms, but not when items are created in other ways. You have several options:
Write a handler for the ObjectCreatedEvent for your content type which sets up the necessary default values. This is the simplest approach to implement, but may not work if there are other handlers of this event that need the values in place.
Create your own subclass of Dexterity's generic Item class, and use it instead of Item as the basis for your content type. Then you can customize the __init__ method to set whatever you want. This would require migration of existing content items though, if you already have some.
This is a more complicated option. Replace the factory utility used to construct the content type. createContentInContainer ends up looking for an IFactory utility with a name equal to the factory attribute of the content type's FTI. The default implementation is in plone.dexterity.factory but you could replace it with a different one that does more.
Is it possible to create a new array in windows workflow? More specifically, in the designer.
I've created a variable of System.Int32[], but when I use it I get a NullReferenceException.
I've tried New Int32(5), and various permutations of Dim - nothing I have tried has worked.
I was able to create the array and pass it as an in/out parameter - this works, however the workflow will need to determine the actual size of the array.
To create and instantiate an array, you have to set a default value to your variable with New Int32(FOO SIZE){} or use an Assign activity to instantiate it with the correct size in runtime
You can also use List(Of T) or any other .NET collection structure to achieve dynamic size.
Note that the value must be the right part of a set expression. So, you can google how to do it in VB.NET and you will be fine.
I assume that if you are creating the array in the designer, as you stated, it is either a workflow variable or a workflow argument. The "WF" way to do this would be to use the "Default Value" column under the "Variables" and/or "Arguments" tab.
If it is an argument then the Default Value column only works if the Direction is "In". If your argument is a property, or an Out, or In/Out direction then you would have to use the method mentioned by Davi.
If you are creating it under the "Variables" tag then using the Default value column would be the more built-in approach. The syntax in the default column would be the same syntax mentioned by Davi: New Int32(FOO SIZE) {}
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.