situation: Lets's think about basic process of object creation on a client (with CRUD backend).
Let's imagine that we have two "Create" buttons on a page.
first case:
Clicking on the first button will cause to redirect to /create route, where our form located.
After we fill the form with data, we post it to a backend and it retrieves an id of a newly created object.
second case:
Clicking on the second button will cause to send creation request to the backend, then after we got a new object id, we will be redirected to /edit/:id, where our form located (same form).
After we fill the form with data, we send it to a backend and save already existed object (post by id).
question:
What's the pros and cons of those two cases, when to use each of them?
In the first case you can include the validation of the fields in the time of creation
and you only need to create an insert so one database call.
In the second case you are creating an empty entry that will appear in the grids of an application with no data.
Also if your database has required fields, you have to fill them with default data.
Validation will be more difficult since you need to allow empty ex Mobile in data entry
while phone might be required.
Another problem with this is that that you are basically doing two operations. One if for the Insert of the row and one is for the update of the row
However this methodology is easier to implement the live update of text when typing so any disconnects etc will not lose any data. This methodology is also good for collaboration between two clients using websockets ex inserting the row at the same time.
Related
I would like to create the following form:
Step 1: The user enters his contact details.
Step 2: A confirmation page, where the user has the possibility to confirm or edit his entered data again (back to step 1)
The contact details are stored in an entity domain object. The properties have annotations for validation.
My problem:
When I pass the contact object to the confirmation page, I get the message
Could not serialize Domain Object Vendor\Extension\Domain\Model\Object. It is neither an Entity with identity properties set, nor a Value Object.
I understand that I cannot pass a non-persistent domain object. A tip I found was to convert the object to an array and back again later. This works to display the input on the confirmation page. But if the user edits the data, I lose the validation functionality when converting to an array.
Another possibility would be to persist the object already after step 1 (temporarily?) . The problem here is that the data must not be displayed in the backend (they are not yet confirmed). In addition, unused data is created if the user cancels the process.
Is it possible to save objects temporarily?
What is the most elegant solution to this problem?
If you only wan't to create a form, why don't you use a form plugin like Ext:form or Ext:powermail? These have a summary page by default. And you have the possibility to write the entered data into you're database.
I have started designing addToCart method as HTTP POST in my RESTful API. This looks good when the client adds to cart a product first time (POST create a new entry on server). But, the same HTTP rule breaks when the client browses through the site and adds the same item again; where we should not create a new entry but only update the quantity of existing item.
Isn't using POST to update resource wrong? What is the way to implement this? or how to interpret this situation.
Note: Client/UI front which uses my api would not remember if its already there on server. Please consider any ecommerce application's addtocart as example.
I think the difficulties here are already present in how you add the original item to the cart.
When you add an item to cart, are you creating a new object (the item)? Or are you modifying an existing item (the cart)? To me it makes more sense to say the latter. POSTing an item seems like it should be reserved for a different situation, when you add a new item to your store.
Conceptually, the cart is then like a vector of all the items in your store, associated with a number (0 for almost all of them). Adding something to the cart means incrementing this number for one of the items, regardless of whether it is already more than 0.
You can use PATCH to send a part object / update to an existing object.
It's based on your model. IMHO a POST is also fine if you are modelling a new intent or cart-operation with it, which can be basically anything.
I'm pretty new to web programming. The whole project links two shops together.
One of our customer's who owns the first shob has provided some sort of an Event API which sends a request to one of our simple html/js files when an event occurs (different ones are specified - e.g. a new customer was created which needs to be synchronised between the shop databases). Included in his GET request is an URL as parameter.
We have to parse this given URL, sending a request to this URL and "reading" what the actual content of the event is (name of the new customer etc.), writing it into our database and giving a reponse to the initial request from the other shop (sucess or failure).
How can I do this in a simple way in an html/js file without setting up web services etc.? Don't bother about the database actions, its taken care of .. its about the automatic redirecting ..
Many Thx ..
J
I rewrote the title and content 3 times before posting it, I don't find the right way to ask this :P
I have a page that manage a list of notes, I have a CRUD on that page but the items are created and saved in javascript (using knockoutjs).
I create a new note, I add it to the model in javascript and it show up in the page.
The way Im saving the notes to the database is when I add it to the model, I send it via Ajax (async) to the server. So I have my note on screen and in the database really fast.
I send a note without Id to the server and EF will take care of the Id.
So far so good.
Imagine that I add a note but I dont refresh the webpage, so the note is in the database, is in the javascript model too but in the model it doesn't have the id yet.
I make some changes to the note and yeah, I want to update the note in the database... but... how?
I send my note to the server with the changes, but remember, the item still have no Id so I can't say:
Hey EF, give me the note with the ID == xx and we are going to update that note.
The others properties can be changed on the webpage so I have nothing that identifies the note apart from the Id, who doesn't work here.
I tried this:
Send the new note to the server, insert it on the database, retrieve it again (to pick the Id), send it back to javascript and update the object with the Id. So when I edit, I have the Id. Yeah, but the "save" call need to be sync and that destroy the experience.
Any ideas?
EDIT: The sync options is not that slow at the end but there have to be a async way and meh, the thing of "Insert on database", "Retrieve the last item I inserted" and "return back to the client" is a little hackish.
You could return the id of the new record in your asynch call. If you are using jQuery you can subscribe to the "success" callback and as long as your controller returns a JSON with the id of the new record you could update your model on the client side.
Even with this approach, you will need to have a way to identify the item updated on the client side (which is really the root of your question.) For that you can probably generate a random GUID on the client side, send it to the server when saving, and return it to jQuery when returning the ID so that you can identify the correct element to update on the page.
Im pretty new to ASP.NET MVC, trying to figure out my way around.
Currently i return a ViewModel which has a IEnumeable Events as its only property. This ViewModel is StronglyTyped to a UserControl which dislays the IEnumable Events in tabular form.
One of the properties of the Event Model is an XElement, which contains some XML loaded from the DB.
Now i've added a link to the end of the tablular data to be able to view the XML in a separate page. How do i pass this data to another page for viewing?
I would post a request back to the server with some sort of Id for the Event-object and have the receiving end send back the XML related to that Id.
if you're looping through the Event objects in your IEnumerable, you can do something like:
<%= Html.ActionLink("GetXml", "Events", new { id = currentEvent.Id }) %>;
Now create an Action on your EventsController (given that you have one) like so:
public ActionResult GetXml(int id)
and retrieve the XML to pass back to the View
There are basically two ways of bringing data from one page to another using ASP.NET MVC (or any other language/framework which follows the HTTP protocol):
Sessions: Use a session to store the data you need, and load it back up at the next page.
Post the needed data back to the server. This way, the server can hold it and display it on the next page. Posted data usually comes from input or textarea elements. If you use input type="hidden" you can give it a value which represents your data. This way, you can post it back and forth till you arrive where you want.
Besides what Arve is advising, you could also consider TempData.
If you use the Get-Post-Redirect/Forward concept for you app, you could do something like:
GET - Initial Request comes in, Server responds with View and model data. User selects an item which leads to ...
POST - User selects one of the items from #1, triggering a post. That particular item can be fetched from repository, placed in TempData and then...
REDIRECT/FORWARD - The redirect collects the information out of TenpData and uses it as the model for the new View.
here is an example http://www.eworldui.net/blog/post/2008/05/08/ASPNET-MVC-Using-Post2c-Redirect2c-Get-Pattern.aspx