I try to delete a record, a DELETE request is sent to the server but the request seems not correct:
What is done:
DELETE
/books
+ body json format
What I expect:
DELETE
/books/123
+ no body
What is really expected in ember-model ?
How can I achieve my expectation (DELETE books/123)
Looking at the source code, it seams clear how ember-model does the DELETE operation:
deleteRecord: function(record) {
var primaryKey = get(record.constructor, 'primaryKey'),
url = this.buildURL(record.constructor, get(record, primaryKey)),
self = this;
return this.ajax(url, record.toJSON(), "DELETE").then(function(data) {
self.didDeleteRecord(record, data);
});
}
basically the resulting format is: DELETE /books/123 + JSON body.
If your backend expects something else then the only way to change it would be to rewrite the deleteRecord for your custom needs. But IMO the simplest thing you could do is to just ignore the JSON body.
Hope it helps.
Related
I have a route that pulls data from a REST API. The first time a user enters, there won't be any data saved, so I need to create the record with some default values. I figure I need to do this here in the route so the user can see my default values (which in my actual app aren't just null), rather than creating during the save action.
If, however, there is data in the database, I need to return that record. Right now I'm stuck and must not be doing something right (probably has to do with promises, but I'm not sure).
The error I get is:
Error while processing route: project.dates Assertion Failed:
Expected an object as `data` in a call to `push` for star#model:project-date: ,
but was undefined
Here's my route code:
var project = this.modelFor('project');
var projectDates = this.store.find('project-date', project.id);
if (projectDates) {
return projectDates;
} else {
return this.store.createRecord('project-date', {
project: project.id,
start: null,
checkpointA: null,
finish: null
};
}
The puzzling thing is that if I just negate my if statement to get the other return value (like so: if (!projectDates)) then I still get the error above, but it also loads up the model! I have confirmed that the API (or my mock API) is returning data in the right format, as an object.
Okay, as I suspected, I could use promises stuff to solve this, just had to keep googling until I found something that jogged the right idea.
Here is how to set the model to the found record, or else create a new record:
model: function() {
var project = this.modelFor('project');
var projectDates = this.store.find('project-date', project.id).catch(function() {
return this.store.createRecord('project-date', {
project: project.id,
start: null,
checkpointA: null,
finish: null
};
});
return projectDates;
}
How do I increment a number in AWS Dynamodb?
The guide says when saving an item to simply resave it:
http://docs.aws.amazon.com/mobile/sdkforios/developerguide/dynamodb_om.html
However I am trying to use a counter where many users may be updating at the same time.
Other documentation has told me to use and UpdateItem operation but I cannot find a good example to do so.
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.Modifying.html
However, I cannot find a method to implement the expression. In the future I will be adding values to arrays and maps. Will this be the same? My code is in Obj C
Currently my code looks like:
AWSDynamoDBUpdateItemInput *updateItemInput = [AWSDynamoDBUpdateItemInput new];
updateItemInput.tableName = #"TableName";
updateItemInput.key = #{
UniqueItemKey:#"KeyValue"
};
updateItemInput.updateExpression = #"SET counter = counter + :val";
updateItemInput.expressionAttributeValues =#{
#":val":#1
};
It looks like you're missing the last bit of code that actually makes the update item request:
AWSDynamoDB *dynamoDB = [AWSDynamoDB defaultDynamoDB];
[[dynamoDB updateItem:updateItemInput]
continueWithBlock:^id(AWSTask *task) {
if (task.error) {
NSLog(#"The request failed. Error: [%#]", task.error);
}
if (task.exception) {
NSLog(#"The request failed. Exception: [%#]", task.exception);
}
if (task.result) {
//Do something with result.
}
return nil;
}];
In DynamoDB if you want to increment the value of the any propertie/field you can use the UpdateItemRequest with action option ADD. I used in android this method would update the existing value of the field. Let me share the code snippet. You can use any actions such like add,delete,put etc.
.....
AttributeValue viewcount = new AttributeValue().withS("100");
AttributeValueUpdate attributeValueUpdate = new AttributeValueUpdate().withAction(AttributeAction.ADD).withValue(viewcount);
updateItems.put(UploadVideoData.FIELD_VIEW_COUNT, attributeValueUpdate);
UpdateItemRequest updateItemRequest = new UpdateItemRequest().withTableName(UploadVideoData.TABLE_NAME)
.withKey(primaryKey).withAttributeUpdates(updateItems);
UpdateItemResult updateItemResult = amazonDynamoDBClient.updateItem(updateItemRequest);
....
You can see the above code will add 100 count into the existing value of that field.
This code is for android but the technique would remain the same.
Thank you.
I want to be able to retrieve a certain conversation when its id is entered in the URL. If the conversation does not exist, I want to display an alert message with a record not found.
here is my model hook :
model: function(params){
return this.store.filter('conversation', { status : params.status}, function(rec){
if(params.status == 'all'){
return ((rec.get('status') === 'opened' || rec.get('status') === 'closed'));
}
else{
return (rec.get('status') === params.status); <--- Problem is here
}
});
}
For example, if I want to access a certain conversation directly, I could do :
dev.rails.local:3000/conversations/email.l#email.com#/convid
The problem is when I enter a conversation id which doesn't exist (like asdfasdf), ember makes call to an inexisting backend route.
It makes a call to GET conversation/asdfasdf. I'm about sure that it is only due to the record not existing. I have nested resources in my router so I'm also about sure that it tries to retrieve the conversation with a non existing id.
Basically, I want to verify the existence of the conversation before returning something from my hook. Keep in mind that my model hook is pretty much set and won't change, except for adding a validation on the existence of the conversation with the id in the url. The reason behind this is that the project is almost complete and everything is based on this hook.
Here is my router (some people are going to tell me you can't use nested resources, but I'm doing it and it is gonna stay like that so I have to work with it because I'm working on a project and I have to integrate ember in this section only and I have to use this setup) :
App.Router.map(function(){
// Routing list to raw namespace path
this.resource('conversations', { path : '/' }, function() {
this.resource('conversation', { path : '/:conversation_id'});
});
});
This also happens when I dont specify any id and I use the hashtag in my url like this :
dev.rails.local:3000/conversations/email.l#email.com#/ would make a call to conversation/
I know it is because of my nested resource. How can I do it?
By passing a query to filter (your { status : params.status}) you are asking Ember Data to do a server query. Try removing it.
From the docs at http://emberjs.com/api/data/classes/DS.Store.html#method_filter:
Optionally you can pass a query, which is the equivalent of calling find with that same query, to fetch additional records from the server. The results returned by the server could then appear in the filter if they match the filter function.
So, remove the query:
model: function(params){
return this.store.filter('conversation', function(rec) {
if (params.status == 'all') {
return rec.get('status') === 'opened' || rec.get('status') === 'closed';
} else {
return rec.get('status') === params.status;
}
});
}
Ok so here is what I did. I removed my nested resource because I realised I wasn't using it for any good reason other than redirecting my url. I decided to manually redirect my url using javascript window.location.
This removed the unwanted call (which was caused by the nested resource).
Thanks to torazaburo, you opened my eyes on many things.
I am attempting to retrieve a single record - the "note" for a user.
This is in a Route:
this.store.find('note', {user_id: App.user.id}).then(function (note) {
window.console.log(note, arguments);
App.set('note', note.content[0]);
});
It works fine when a record exists already but I want to create a new record ready for saving later if the API doesn't return anything.
I have read this page in the guide but there's nothing about failure handling: http://emberjs.com/guides/models/finding-records/
What does the REST API need to return when it doesn't find a record?
How do I handle this result properly and specifically, so that when store.find doesn't return a model I can call store.createRecord?
Found an answer here in a question about promises.
store.find returns a promise so that's what I needed to search for rather than trying to search for how to handle find() failing.
The resultant code is as follows:
store.find('note', {user_id: App.user.id}).then(function (note) {
App.set('note', note.content[0]);
}, function () {
App.set('note', store.createRecord('note', {user_id: App.user.id, user: App.user}));
});
I have a DS.Store which uses the DS.RESTAdapter and a ChatMessage object defined as such:
App.ChatMessage = DS.Model.extend({
contents: DS.attr('string'),
roomId: DS.attr('string')
});
Note that a chat message exists in a room (not shown for simplicity), so in my chat messages controller (which extends Ember.ArrayController) I only want to load messages for the room the user is currently in:
loadMessages: function(){
var room_id = App.getPath("current_room.id");
this.set("content", App.store.find(App.ChatMessage, {room_id: room_id});
}
This sets the content to a DS.AdapterPopulatedModelArray and my view happily displays all the returned chat messages in an {{#each}} block.
Now it comes to adding a new message, I have the following in the same controller:
postMessage: function(contents) {
var room_id = App.getPath("current_room.id");
App.store.createRecord(App.ChatMessage, {
contents: contents,
room_id: room_id
});
App.store.commit();
}
This initiates an ajax request to save the message on the server, all good so far, but it doesn't update the view. This pretty much makes sense as it's a filtered result and if I remove the room_id filter on App.store.find then it updates as expected.
Trying this.pushObject(message) with the message record returned from App.store.createRecord raises an error.
How do I manually add the item to the results? There doesn't seem to be a way as far as I can tell as both DS.AdapterPopulatedModelArray and DS.FilteredModelArray are immutable.
so couple of thoughts:
(reference: https://github.com/emberjs/data/issues/190)
how to listen for new records in the datastore
a normal Model.find()/findQuery() will return you an AdapterPopulatedModelArray, but that array will stand on its own... it wont know that anything new has been loaded into the database
a Model.find() with no params (or store.findAll()) will return you ALL records a FilteredModelArray, and ember-data will "register" it into a list, and any new records loaded into the database will be added to this array.
calling Model.filter(func) will give you back a FilteredModelArray, which is also registered with the store... and any new records in the store will cause ember-data to "updateModelArrays", meaning it will call your filter function with the new record, and if you return true, then it will stick it into your existing array.
SO WHAT I ENDED UP DOING: was immediately after creating the store, I call store.findAll(), which gives me back an array of all models for a type... and I attach that to the store... then anywhere else in the code, I can addArrayObservers to those lists.. something like:
App.MyModel = DS.Model.extend()
App.store = DS.Store.create()
App.store.allMyModels = App.store.findAll(App.MyModel)
//some other place in the app... a list controller perhaps
App.store.allMyModels.addArrayObserver({
arrayWillChange: function(arr, start, removeCount, addCount) {}
arrayDidChange: function(arr, start, removeCount, addCount) {}
})
how to push a model into one of those "immutable" arrays:
First to note: all Ember-Data Model instances (records) have a clientId property... which is a unique integer that identifies the model in the datastore cache whether or not it has a real server-id yet (example: right after doing a Model.createRecord).
so the AdapterPopulatedModelArray itself has a "content" property... which is an array of these clientId's... and when you iterate over the AdapterPopulatedModelArray, the iterator loops over these clientId's and hands you back the full model instances (records) that map to each clientId.
SO WHAT I HAVE DONE
(this doesn't mean it's "right"!) is to watch those findAll arrays, and push new clientId's into the content property of the AdapterPopulatedModelArray... SOMETHING LIKE:
arrayDidChange:function(arr, start, removeCount, addCount){
if (addCount == 0) {return;} //only care about adds right now... not removes...
arr.slice(start, start+addCount).forEach(function(item) {
//push clientId of this item into AdapterPopulatedModelArray content list
self.getPath('list.content').pushObject(item.get('clientId'));
});
}
what I can say is: "its working for me" :) will it break on the next ember-data update? totally possible
For those still struggling with this, you can get yourself a dynamic DS.FilteredArray instead of a static DS.AdapterPopulatedRecordArray by using the store.filter method. It takes 3 parameters: type, query and finally a filter callback.
loadMessages: function() {
var self = this,
room_id = App.getPath('current_room.id');
this.store.filter(App.ChatMessage, {room_id: room_id}, function (msg) {
return msg.get('roomId') === room_id;
})
// set content only after promise has resolved
.then(function (messages) {
self.set('content', messages);
});
}
You could also do this in the model hook without the extra clutter, because the model hook will accept a promise directly:
model: function() {
var self = this,
room_id = App.getPath("current_room.id");
return this.store.filter(App.ChatMessage, {room_id: room_id}, function (msg) {
return msg.get('roomId') === room_id;
});
}
My reading of the source (DS.Store.find) shows that what you'd actually be receiving in this instance is an AdapterPopulatedModelArray. A FilteredModelArray would auto-update as you create records. There are passing tests for this behaviour.
As of ember.data 1.13 store.filter was marked for removal, see the following ember blog post.
The feature was made available as a mixin. The GitHub page contains the following note
We recommend that you refactor away from using this addon. Below is a short guide for the three filter use scenarios and how to best refactor each.
Why? Simply put, it's far more performant (and not a memory leak) for you to manage filtering yourself via a specialized computed property tailored specifically for your needs