I want to modify a property of a participant which is an array of relationships during a transaction.
Let's assume I have a user that holds an array of keys like so:
participant User identified by userId {
o String userId
--> Key[] keys
}
asset Key identified by keyId {
o String keyId
}
transaction modifyUserKeys {
--> User user
}
Then in the transaction processor function I modify the array (as in adding and removing elements in it) and update the participant:
function modifyUserKeys(tx) {
let user = tx.user;
// create a new key via factory
var newKey = ...
user.keys.push(newKey);
return getParticipantRegistry('com.sample.User')
.then(function (participantRegistry) {
return participantRegistry.update(user);
});
}
In the documentation I saw a method called addArrayValue() which adds an element to an array. Now I'm unsure whether I'm meant to use this over conventional array manipulation like in my example.
What purpose does this addArrayValue() method have and am I able to e.g. remove elements from keys via keys.pop() or is it restricted to just the addition of new elements like the documentation suggests?
you can use conventional (push/pop) if you like (and as you've done on the array), but newKey would need to use newRelationship()
a useful example similar to what you're trying to achieve is here -> https://github.com/hyperledger/composer-sample-networks/blob/master/packages/fund-clearing-network/lib/clearing.js#L151 in Composer sample networks - addArrayValue() is also validating that it does not violate the model
Related
I'm wondering what's the best practice to do two separate fetches to data that would belong to the same Model. One to get all Users data and a separate one that would request their Traits and add them to each User.
I think I could create a reference in User, to fill the data, but im not sure how to create the custom reference since it should be an array.
export const User = types
.model('User', {
id: types.identifierNumber,
...
traits: types.maybeNull(TraitsbyUserReference),
})
const TraitsbyUserReference = types.maybe(
types.reference(Trait, {
get(identifier: string, parent): {
return (parent as Instance<typeof TraitsStore>).getAllTraits()
},
set(value) {
return value; // this is what doesnt work out because i'm fetching a whole array
},
}),
)
Also, is this a good practice or are there other better ways of getting this result?
Thanks!
In terms of defining the model, you might try switching from maybeNull to an optional array with a default value in your model -
...
traits: types.optional(types.array(Trait), []),
...
As such, the model will always be instantiated with an empty traits collection.
In terms of the TraitsbyUserReference, I am not following what abstraction that you need with the dynamic store look-up. You could create an action (e.g. User.actions(self => ...)) to look-up the traits as a separate api -
getUserTraits(){
/* this will vary based on your implementation of TraitsStore and how it is injected */
const traits = self.TraitsStore.getAllTraits(self.id);
self.traits = traits;
}
Right now, if I add a field to a Parse object and then save it, the new column shows up in the Parse dashboard.
For example, after running:
let media = new Parse.Object("Media");
media.set("foo", "bar");
await media.save();
I will have a new column called foo.
Is it possible to prevent this from happening?
Yes. This can be done using class-level permissions, which allow you to prevent fields being added to classes.
Parse lets you specify what operations are allowed per class. This lets you restrict the ways in which clients can access or modify your classes.
...
Add fields: Parse classes have schemas that are inferred when objects are created. While you’re developing your app, this is great, because you can add a new field to your object without having to make any changes on the backend. But once you ship your app, it’s very rare to need to add new fields to your classes automatically. You should pretty much always turn off this permission for all of your classes when you submit your app to the public.
You would have to add a beforeSave trigger for every one of your classes, keep a schema of all your keys, iterate over the request.object's keys, and see if there are any that do not belong in your schema. You can then either un-set them and call response.success(), or you can call response.error() to block the save entirely, preferably with a message indicating the offending field(s).
const approvedFields = ["field1", "field2", "field3"];
Parse.Cloud.beforeSave("MyClass", function(request, response) {
let object = request.object;
for( var key in object.dirtyKeys() ) {
if( approviedFields.indexOf(key) == -1 ) return response.error(`Error: Attempt to save invalid field: ${key});
}
response.success();
});
Edit:
Since this got a little attention, I thought I'd add that you can get the current schema of your class. From the docs: https://docs.parseplatform.org/js/guide/#schema
// create an instance to manage your class
const mySchema = new Parse.Schema('MyClass');
// gets the current schema data
mySchema.get();
It's not clear if that's async or not (you'll have to test yourself, feel free to comment update the answer once you know!)
However, once you have the schema, it has a fields property, which is an object. Check the link for what those look like.
You could validate an object by iterating over it's keys, and seeing if the schema.fields has that property:
Parse.Cloud.beforeSave('MyClass', (request, response) => {
let object = request.object;
for( var key in object.dirtyKeys() ) {
if( !schema.fields.hasOwnProperty(key) ) < Unset or return error >
}
response.success();
}
And an obligatory note for anyone just starting with Parse-Server on the latest version ,the request scheme has changed to no longer use a response object. You just return the result. So, keep that in mind.
I've got a method in UserService:
#Cacheable(value="user", key="#p0")
public User find(String name) {
return userRepository.findOneByName(name);
}
And it caches. But then I try to get all keys from 'user' cache:
CacheManager cacheManager = CacheManager.getInstance();
cacheManager.getCache("user").getKeys().forEach(o -> log.debug(o.toString()));
Output:
com.cache.domain.User#1
Instead, for example, 'John Doe'.
See the Javadoc of getKeys
Returns a list of all elements in the cache, whether or not they are expired.
That's actually returning the elements, no the ids. You may want to change your code to cast o to Element and output getObjectKey() instead.
You don't need to specify the key attribute. Since what you want is to use the single argument of your method (name) the cache abstraction will use that by default.
I have a block of code that is not working as I thought it would.
I have set an Entity up as follows and have a previous guid.
parentEnt = new Entity("vehicle_ent");
parentEnt.id = guid;
Now when I do a check with a statement:
if (parentEnt.Contains("attribute_field")) {
parentEnt["attribute_field"] = "test";
}
The above will never be called because the if statement fails.
However, if I remove the if statement. I am able to actually assign and run the code:
parentEnt["attribute_field"] = "test";
Is there something I am missing with the Contains Method? I thought it was used to check if the Entity contains the attribute?
On the Entity class, you can always assign an attribute like the example you provided whether or not it exists. If it exists, it will overwrite it (which is what you discovered).
So
parentEnt["attribute_field"] = "test";
Will always work, whether or not the attribute already has a value assigned.
When you run the constructor for a CRM entity object, and assign it a guid
Like
Entity parentEnt = new Entity("vehicle_ent");
parentEnt.id = guid;
you are creating a new object of the entity type with the 'vehicle_ent' logical name and a id of 'guid' At this point all the attribute/properties that belong to an entity with that name, are not created along with the entity object, and you only have an Entity class object with a LogicalName and id set.
If you want to check if an entity record with that id contains a certain attribute, you need to fetch is from the database, using your the organization service, like
ColumnSet attributes = new ColumnSet(true);
parentEnt = _service.Retrieve("vehicle_ent", guid, attributes);
After the retrieve is called you can check if the entity record contains the attribute you need to check.
I just add a couple of things:
The syntax entity[attributename] and entity.Attributes[attributename] are equivalent, the reason can be found inside the Entity metadata:
public object this[string attributeName] { get; set; }
the method maps at entity level the Attributes property (the type of this property is AttributeCollection an inherit from DataCollection<string,object> and the base type is an IEnumerable<KeyValuePair<TKey, TValue>>)
DataCollection contains this method:
// Summary:
// Gets or sets the value associated with the specified key.
//
// Parameters:
// key:
// Type: TKey. The key of the value to get or set.
//
// Returns:
// Type: TValue The value associated with the specified key.
public virtual TValue this[TKey key] { get; set; }
this method adds the key (our attributename) inside the collection if the key is not present before. For this you can assign a value to an attribute without using the Contains method first. Of course when you read the value you need to check if the key is present, this is the purpose of the Contains method, but to read the values the GetAttributeValue can be used as well (but it's necessary to pay attention to the default values returned when the attribute is not inside the collection)
I have a domain model which has a Customer, which in turn has 1 Address (1:1) and 1 or more Phone numers (1:M).
Customer has user supplied PK (a string), while Address and Phone use identity column (server generated).
I am struggling in trying to understand how to manage Breeze entity creation for a "Add new Customer" screen.
The form on the screen allows user to enter Customer, Address, and Phone data.
I am using Durandal and Knockout so my "customeradd.js" viewmodel looks something like this:
// -- snip ---
var customer = ko.observable(),
hasChanges = ko.computed(function () {
return datacontext.hasChanges();
});
var vm = {
hasChanges: hasChanges,
customer: customer,
activate: activate
};
return vm;
function activate() {
customer(datacontext.createCustomer());
}
// -- snip ---
and my "/services/datacontext.js" :
// -- snip ---
breeze.NamingConvention.camelCase.setAsDefault();
var manager = new breeze.EntityManager(config.remoteServiceName);
var hasChanges = ko.observable(false);
manager.hasChangesChanged.subscribe(function (eventArgs) {
hasChanges(eventArgs.hasChanges);
});
function createVehicle() {
return manager.createEntity("Customer");
}
// -- snip ---
My questions are following:
Once I create a Customer, do I need to create Address and list of Phones and add them to Customer entity before making it a KO observable? Or is this done automatically by createEntity() method?
How do I create a Customer but without having to specify the Id? If I set the key to null or '', Breeze complains ("Error: Cannot attach an object to an EntityManager without first setting its key or setting its entityType 'AutoGeneratedKeyType' property to something other than 'None'"). However, if I generate the temp key (using either breeze.core.getUuid() or something else), then it shows up in my Id form field, and I really want the end user to specify it....Do I have to resort to extending the entity with extra field and then do the swapping and validation before saving (I don't like this idea at all)? Is there a better way?
In order to enable/disable buttons on my form I am tracking if there are changes in EntityManager. But every time entity is created, it is automatically in 'added' state so hasChanges is true. What I want is for changes to be picked up only if user edits the form (and therefore makes changes to underlaying entity). What is the best way to approach this?
BTW, I have seen this recommendation to register custom constructor for entity (I have already implemented it but I am still not clear how to let user supply their own id and to flag entity as modified only when user edits it...)
I realize this has been up for a while, but here are my thoughts (in case anyone comes looking).
If you use the entityManager to create your customerl and everything is specified correctly in the metadata, you can just create the customer and add phone numbers/addresses as needed. Breeze automatically makes an entity's properties observable (if specified correctly and if breeze knows that KO is being used)
If you can only do it the way that you say, then you are stuck. Ideally, you would have a user-entered ID which is NOT the key (though you could still force it to be unique) and a database-generated key, which Breeze will manage behind the scenes (assigning a negative key until it is saved to the data store, then updating the key and all related keys without any input from you).
if you use the 2nd approach for answer 2, then your buttons can easily be enabled and disabled using ko data-binding. When you create the entity, save its value to the viewmodel (custSource). Then you can add to the save button the data-bind="disable: custSource == Customer(), enable: custSource != Customer()". (You might need to play around with the syntax -- I haven't tested that part yet)
I don't think you need a custom constructor unless you are doing something different from what I understand.
PS. you should be aware that I believe Breeze wants Knockout defined as 'ko', while Durandal definitely expects it to be 'knockout', so you will probably need a 'map' property in your require.config
I think you could solve some of your problems by taking a slightly different approach to your entity creation. Here's your current approach:
Create a customer entity
User modifies that entity
Save the changes
Instead, try this:
User enters customer information
Create and save the customer entity
I realize that this doesn't really answer your questions, but I've found the second approach to be much easier to implement. Just have the user enter all the information you need to create a customer, and then supply those values to createEntity.
customeradd.js
// -- snip ---
var vm = {
customerId: ko.observable(),
address: ko.observable(""),
phoneNumbers: ko.observableArray([]),
submit: submit
};
return vm;
function submit() {
datacontext.createCustomer(
vm.customerId(),
vm.address(),
vm.phoneNumbers());
}
// -- snip ---
/services/datacontext.js
// -- snip ---
/**
* Creates a new customer.
* #param {int} id - The customer's id number.
* #param {string} address - The customer's address.
* #param {string[]} phoneNumbers - An array of the customer's phone numbers.
*/
function createCustomer(id, address, phoneNumbers) {
return manager.createEntity("Customer",
{
id: id,
address: address,
phoneNumber: phoneNumbers
});
}
// -- snip ---