Im making a quiz in MVC. After all the questions have been answered, the results is written to the database when the quiz is completed. So far so good.
There are both multichoice and singlechoice questions.
The answers and questions are taken from a database, and are going to change over time.
During the quiz i keep track of the replies from the user, by using a few sessions.
I have a int (index) to keep track of which question is the current, the prev. and the next.
I have a List<-int-> with QuestionID's.
I have a List<-List<-int->-> with answers-ids so i can see what answers fit what question.
Everything is going very smooth as long as the user use my "previous question" and "next question" buttons, but if the user uses the "back" and "forward" buttons it ruins my index.
So my question is how do i prevent this from happening?
Can i force the user back to "home", clear the sessions and start again, if he presses the back-button?
Let me know if you need more information...
In webforms I would add the "current index" to the ViewState and reset my Session index to that value, if present.
MVC doesn't have ViewState, so maybe you can use a <input type=hidden> for a similar effect.
Related
Let's say I have a language that models a part of stackoverflow. Users are held in one resource, questions in another.
Users:
user fred : fred#foobar.com
user notfred : notfred#foobar.com
Questions:
question 123 by fred message "smart question"
question 124 by notfred message "not so smart question"
Now, the user "fred" wants to remove his account, but this wouldn't work because after loading both resources into my ResourceSet I would have a non-empty Resource#getErrors().
I can work around this by filtering XtextLinkingDiagnostic from the errors, but still other users reading the "smart question" cannot tell anymore that it was asked by someone called "fred". The info is still there, I can access it for example when I set a LinkingDiagnosticMessageProvider with LazyLinkingResource#setDiagnosticMessageProvider(...); however, the best thing I can now do is, show other users validation errors that "fred" was deleted, but they wouldn't know "fred" wrote the message they are just reading. Knowing this would help them a lot because everybody knows that "fred" writes great questions, right?
Long story short, I have an application into which users can load a declaration and a definition file. In very few cases something goes wrong and both files don't match perfectly, which means the definition has entries that are not declared in the declaration. However, I know that ~95% of the entries will still match!
Users cannot fix this quickly, but it is likely that they are happy just editing the 95% definitions, but they still need to be able to read the names of the 5% declarations without editing them!
I am not currently using any UI-parts of Xtext to edit the definitions, but rather a custom UI in form of a table. The current state with the missing declarations is that everything except a value column will be empty. The reference ID would be in another column, and knowing this ID would help the user a lot! Is there a clean way to achieve this?
Have a look at the 'Node Model' e.g. org.eclipse.xtext.nodemodel.util.NodeModelUtils.findNodesForFeature(EObject, EStructuralFeature) allows you to access the text that is written in the file
This is my most confused aspect that I continually have to ask people about. They have given me answers like 'if it works with data it goes in the model'... but to me that is pretty much ALL of it.
Does anyone have a better way to explain this?
Perfect example from my current code:
I have a listing of posts that can be favorited or not favorited. On the front end, i differentiate the different ones by dynamically adding class="favorite" to the HTML depending on if its a favorite or not.
So basically ... <li class="item<%= is_favorite?(current_user.id) %>">
Part of me thinks this should go in the model because its going to be running a statement to find a record that matches :resource_id and :user_id...
but another part of me thinks its going to be in the controller because its directly outputting the word " favorite" which is used in html
My second mini question is, is it the-rails-way to put methods that the controller uses in the same controller? as long as they remain un-routed, etc. Or is that not the right spot?
You're thinking properly.
The right answer is that you should use presenters or decorators.
See this railscast for inspiration.
I have a search page which finds candidates.
From this page you can click view to find more information about the candidate.
When on the candidate view you can click edit or do a number of other actions which would return you too the candidates view.
My problem is from the candidates view I need to add a button to go back to the search results.
I originally thought of using a JS button with history -1 but because the user can do other action from inside the view this won't work.
I am still quite new to rails so not sure of my options... I am thinking some sort of caching of the results and then maybe a hidden field to keep track of the location of the cache(don't think this is the best solution as keeping track of the hidden value could get abit messy!)
Thanks, Alex
I would probably use a session variable to store this information.
First, make sure your form that posts to the search page is a GET operation, this way the search details are in your query string. Then in your search action, you can grab the request URL and store it in the session:
session[:search_results] = request.url
Now in your view for the results, you can do your "Back to search results" like this:
link_to "Back to search results", session[:search_results]
You have a couple of options:
Cache the results, as you've suggested. The potential downsides to this are that it takes memory, and if new valid records get added, you won't see them. You could store the cache in Session, or in the database (though in the latter case, you don't gain much).
I'd suggest just remembering the last search term, either in session or using hidden fields. You end up re-running the query when you go to the search results page, but in a properly indexed DB, that shouldn't be a big deal.
Good luck!
You can include the parameters for the query on the subpage. Eg.: /foo/search?q=stuff displays search result. Each result then has a link like /foo/:id?q=stuff. And on the subpage, you will have the parameter available to link back to the main page.
This solution doesn't use any server side state, which is generally accepted as the better way to build web applications. Not only does it mean that you browser will behave as expected, with respect to bookmarks, multiple tabs etc., but it also ensures that proper caching can be employed. Further, it lowers the complexity of your application, making it easier to debug and extend.
You could put the search results in a "search_results" table keyed by the user id. Then when the user hits the page, always load from a query on that table.
If anybody does come across this page and you need a button that goes back to the previous page and still display those search results (just like the google chrome button), just use :back.....
<%= link_to(image_tag("back.svg"), :back, :class => 'back_btn') %>
Let's say I have a table called positions (as in job positions). On the position show page I display all the detail about the job - awesome. At the bottom I need the prospective applicant to input their professional license # before continuing onto the next page which is the actual applicant creation form. I also need to take that license # and have it populate that field on the applicant form (again on the proceeding page).
I realize there are a couple ways to do this. Possibly the more popular option would be to store that value in the session. I am curious how to do this in the simplest manner?
My idea:
Create a table specifically for license #'s.
Add a small form on the position show page to create license # (with validation)
Store newly created license in session - not sure what to put in which controller?
On applicant creation form populate from session the license #.
This would assume applicants only have one license.
Thoughts?
Appreciate the help!
Don't store this in the session! Pass that as an hidden field.
Let's say the user starts the form, then open the form again in a new window or something... then the session variable would be shared between the two forms. Other problems would occur if the cookie gets removed (session expire, user clear cache...)
This is not good. The best way is using a POST variable. GET works as well but messes up the URL
Seems like a good idea. As for #3, for whatever controller is called in the transition from 2 -> 4, that would be the controller where you store the session, as such:
session[:license_number] = your_license_number_information
From there, it can be called the same way (session[:license_number]) to get it.
The hidden field is safer for data persistence. However is not not then coded in the HTML output? That can be a great data security issue.
This is a trade-off to be considered.
On Stack Overflow, the profile page lists a "last seen" property. This doesn't seem to be updated on every page view (for performance reasons, obviously). How would you implement it in a heavy-traffic web app? Would you update it only on certain pages? Or cache the last time you logged the user's last visit and wait a specific amount of time before updating the database? Or something completely different?
On a heavy-traffic site like Stack Overflow, I would only update the "last seen" variable when a user actually does something. Lurking around and reading questions and answers shouldn't count as a user being "seen" by the system. Asking and answering questions, or voting on them should be actions that update when a user is last seen.
I won't talk about the implementation details because that's already covered by other answers (and I would probably get it wrong).
You'll probably find "What strategy would you use for tracking user recent activity?" to be helpful. The issues are similar.
I would use a SESSION. And only set it the first visit of the session. Also resetting it every hour or so for if people leave the browser open. In php something like this:
if(!isset(!_SESSION['lastSeen'])){
$_SESSION['lastSeen'] = time();
updateLastSeenInDatabaseOrSomething();
}
else{
if($_SESSION['lastSeen'] < time() + 2 * 60 * 60){ //2 hours
$_SESSION['lastSeen'] = time();
updateLastSeenInDatabaseOrSomething();
}
}
Something like that but then with OO and not doing the same thing twice.
Consider using the "Command" design pattern for this. It will help you two ways - answer the question at hand and also implement an "undo/redo" feature. You should maintain a list of command objects designed per that pattern.