I am new to JSP/Servlets/MVC and am writing a JSP page (using Servlets and MVC pattern) that displays information about recipies, and want the ability for users to "comment" on it too.
So for the Servlet, on doGet(), it grabs all the required info into a Model POJO and forwards the request on to a JSP View for rendering. That is working just fine.
I'd like the "comment" part to be a separate JSP, so on the RecipeView.jsp I can use to separate these views out. So I've made that, but am now a little stuck. The form in the CommentOnRecipe.jsp posts to a CommentAction servlet that handles the recording of the comment just fine. So when I reload the Recipe page, I can see the comment I just made.
I'd like to:
Reload the page automatically after commenting (no AJAX for now)
Block the user from making more than one comment on each Recipe over a 1 day timeframe (via a Cookie). So I store a cookie indicating the product ID whenever the user makes a comment, so we can check this later? How would it work in a MVC context?
Show a message to the user that they have already commented on the Recipe when they visit one
which they have commented on
I'm confused about using beans/including JSPs etc on how to achieve this.
I know in ASP.NET land, it would be a UseControl that I would place on a page, or in ASP.NET MVC, it would be a PartialView of some sort. I'm just confused with the way this works in a JSP/Servlets/MVC context.
you can use response.sendRedirect() or forward APIs in javax.servlet to redirect to a new page or refresh the same page (redirect to the same page/path so that the beans/data gets refreshed)
about restricting to one comment per day - yes you can use cookie but the problem is that user might use another browser type (chrome, FF, Safari) and will be able to make multiple comments.
Ideally you should store the lastCommentTime in the model/persistent store and tie it to the user information - this way your model object can expose an API that checks the last comment time and returns true/false depending on whether user can comment or not.
You can use this API in your servlet/JSP to show/hide the comment button, for example and also show a message
Related
Recently I have started to deal with dynamic content in my RazorPages web application. I found out about AJAX and have started to incorporate it into my application since it helps me display information to the user. For example, when a user presses a button, some information is taken from an input field and sent to the server, as usual. I use the server response (OnGet or OnPost return value) to display information to the user without them reloading the page.
However, I cannot figure out how to incorporate model binding into this. When I use AJAX I can build the message myself but the model binder of RazorPages was made to this automatically - which is great and I use it a lot, but how can I access the return value of my OnGet or OnPost when I created a form and used tag helpers to allow model binding? I know that I can return Content(string) in these methods but that will show an empty page with the string I return, of course.
My question is: How can I access such a string to display it to the user? Am I even on the right track here or is there maybe a better way to solve this kind of issue?
I would recommend checking out some of the Razor Pages tutorials as they cover the basics of posting form data using Razor pages:
https://www.learnrazorpages.com/razor-pages/forms
Best of luck on your programming journey.
I am looking for the best way to handle a session-persistant search form in a "shopping cart" like web application using the Spring MVC Framework.
I want to be able to navigate back to this search page, with last filters already set, from any other page in the application. This is not a master detail search results page, only a form with filters on a table of elements displayed underneath.
I can store my search filters in the user session, but what about multi-tabs navigation and browser back button handling ?
I also considered using Spring WebFlow to adress this.
Any suggestions ?
That sounds like a good job for the conversation scope of Spring WebFlow. Objects which are stored in this scope are saved until the current flow is terminated (or by timeout). The usual way to use it in your case would be to create a new flow/conversation when the user starts browsing the webpage and saves the search parameters in the conversation scope. When going back to the search page later, the parameters are retrieved from this scope (if there are available).
The conversation scope solves the multi-tabs problem and avoid to have to send back to the server every time the data (as you would have to do if you only use the request scope).
I have an app with 3 sections:
Main menu;
Context Menu - Related to selected item in main menu;
and Page body - Related to selected item in context menu;
"Main menu" and "Context menu" are based on membership. I don't want to load them everytime my page loads, because that would consume resources database. So, I'm using ajax to load main menu only one time, and when an item is selected, I load the context menu for that item.
My problem is: Every form's post will erase my menu.
Question: Will I have to build my entire application using ajax? I don't wanna do that, because it is too much simpler do a post in the form then send all data to controller with ajax.
Until now, I have 2 options:
Load my menus with ajax and the page body with IFRAME, so the post's will not render again my menus.
Do everything using ajax;
Is there any alternative to load my menus with ajax and be able to use form's post?
Sorry if I wasn't clear enough.
The sentence that gave me a pause is this "I don't want to load them everytime my page loads, because that would consume resources database."
You see, I've build quite a lot of apps, that display menus and sub-menus based on user roles (what you called membership). This has never been an issue from the resources or database perspective.
You can access all the membership information that you need once, when your used is being logged in. In the simplest case user's identity will be stored in the context along with the roles they have (HttpContext.User), so you do not to need a database lookup at all to get this information on every request. Note that with this scenario no ajax is required either.
If for whatever reason you can't store your membership information in the context like this, you still can store in in session (if in-memory) or in encrypted Cookies.
Now, I understand, that I don't all the details of your scenario, and that may be in your scenario what you are trying to do is warranted, however I suggest you think it through again, as under normal circumstances what you indicate is a problem (database resource) should not be a problem at all.
The bottom line is: if you alter your application that it stores the membership information when user logs on you won't have your problem to start with.
You don’t have to build all of your application using Ajax. But in this scenario Ajax may be the best way forward.
Following is my suggestion
Create your data entry for inside a dev
Have each input controller marked with a class (say ‘dataEntry’)
Create a javascript function to iterate the dev and build a list of all elements that has class dataEntry
Build a json object using the list. Use the name of each element as property name and value as the property value
Use jquery ajax to post this to the controller action
[optional] you can use .done and .fail methods to take action on success or failures of the call
I know this may look intimidating, but if you have many data entry forms, you can re-use this code.
I started integrating SecureSocial in my play/scala app, but I don't really like all the redirects it does between it's different views.
example - try to login from it's default login page and if you put in a wrong pass you will be redirected to a different page (url) but with the same login form. the only thing that is different is that there is an error message...
I want a simple login form (user/password provider) at the corner of my main page that submits it's data using ajax, this data is validated on the server and a response is made to either display error message/s or change the window.location.
Next to this form I will put a link to go to a more advanced login page that adds the option to use other providers like fb/twitter etc..
But from that page I also want to use ajax to submit the details and get the response.
I tried to browse into the SecureSocial source but got a little lost in there.
Can any one give me an idea how to use SecureSocial's but without using any of it's views?
NOTE: I'm not interested in customizing their views, It's not just a CSS/design issue, I want to handle the login details Ajaxly and not with normal form submission followed by redirects...
After some more rummaging around in SecureSocial code I got a better understanding of how it operates.
You can use any of the providers you listed in the play.plugins file seperatly to authenthicate the user's info from your own login/auth code. just make sure you send the right parameters that the provider needs.
I liked the way SecureSocial's ProviderController class dynamically decided what provider to use, based on a parameter. But I didn't like the responses it made - redirect.. I wanted to respond to an ajax request with some data and let the client side js handle it.
This is my solution:
pretty much copy all of ProviderController code to my own Auth.scala file (a Controller).
Changed the redirects related to "case ex, case _", kept the redirect on successful auth as it adds the SecureSocial session key related to the user.
Removed all the SecureSocial related routes from my routes file.
Put an additional hidden field with the logintype (userpass/google/fb/etc...) and configured my login ajax post to sent this along with the post to my Auth controller.
If you need more info comment here and I'll edit the answer.
I am aiming to create a payment module. Its users shall be redirected away from the site's URL in order for the transaction to be processed by a third party at a different URL. I would then like customers to be redirected back to a generic 'success' page that notifies them the order was a success. I have tried redirecting to the default success page (checkout.thankyou.php), but I get lots of errors; all the constants etc. that the application requires have obviously been lost during the redirect.
I would like to be able to retrieve the theme currently enabled in the configuration and use it to insert some basic HTML into the view. I would also like to access the database to perform some queries.
Can anybody advise? I am very stuck, and cannot find anything useful in the documentation! Thank you.
Can you be more specific about what type of information you want in your success page? If you just want basic HTML, then there's no reason you can't just write a basic Joomla article and redirect to that instead of trying to redirect to a VM partial. Again, if it's just basic HTML (no data from the transaction), then you can simply use a code inspector (like FireFox Inspect Element) to track down the CSS classes you like from the template and simply use them in your Joomla article to make it look like the VM template. You can find most of them in components/com_virtuemart/themes/default/themes.css.
If you need to display actual transaction data in your Thank You message, be prepared for a bit more work. You're probably going to have to write a cookie containing the record data BEFORE it gets sent offsite, and then read the cookie just prior to rendering the Thank You page.