So, I thought that I could add a new element to the user Session to add some functionality.
I honestly thought I could do this:
SomeFunction(param1, NEWparam)
{
Session("MyNewParam") = NEWparam;
//So this would create a new session element called 'MyNewParam', right..?
...
}
That gets called when the user presses a button and then another webpage loads up.
The result, with this new line of code: The next web page doesn't load. Nothing happens.
Any and all comments are welcomed.
Solutions or helpful comments would be great.
Your syntax is right. However, I've run into an issue before where Classic ASP didn't want to take a session variable if it wasn't explicitly typed though. I'm not sure why this is, but it's worked for me in the past.
Session("MyNewParam") = parseInt(NEWparam);
Obviously, you could use String(), parseFloat()... or whatever. As I said, the syntax is right otherwise, so if the code isn't working you may want to start looking at other parts of the function that might be causing the problem.
Related
saw this example
var sess;
app.get('/',function(req,res){
sess=req.session;
//Session set when user Request our app via URL
if(sess.email)
{
/*
* This line check Session existence.
* If it existed will do some action.
*/
res.redirect('/admin');
}
else{
res.render('index.html');
}
});
app.post('/login',function(req,res){
sess=req.session;
//In this we are assigning email to sess.email variable.
//email comes from HTML page.
sess.email=req.body.email;
res.end('done');
});
my tiny understanding is: when user login， server generates session id to him/her, assuming this is the login for the 1st time.
But in the above login code,
1. sess = req.session，sounds like client creates a session object at first ?
or client is creating a session storage space ?
2. who sets session.id or sessionID ?
3. any better example ?
The original sample is here
https://codeforgeek.com/2014/09/manage-session-using-node-js-express-4/
I am also learning node just like you. If you continue your journey, you will encounter so many similar curiousness because way node works behind the modules.
I also had so many question marks but I couldn't afford to search for right answer everytime. what I suggest is get node-inspector, a node debugger tool, and actually follow through.
That way you will actually understand what each module is doing.
instruction: https://www.youtube.com/watch?v=03qGA-GJXjI
Big tip that this instruction doesnt tell is fact that node breakpoint is bit weird.
I would definitely use "debugger;" code which puts breakpoint, rather than breakpointer that provided by tool.
At http://localhost:3000/books, I have an index page where I have a list of books.
When you click on one of the links, the action to which it is bound, book, gets fired:
However, when you click on one of the links from one of the book pages, the book action doesn't get fired:
Note that the URL does change when the links are clicked, from both the index page and the book pages, but the problem that I'm having is that book doesn't get activated when you click on a link to a book page from another book page. How can I fix a situation like this?
FYI, here is a repo where this problem can be reproduced.
The method book doesn't get called twice because your view is already setup. The change in the url only triggers an reactive update in your view.
What is it that you are trying to achieve?
As it turns out, Volt computations are a way to solve this problem. By using the params collection, you can attach computations to changes in the URL. I solved this issue and got book to run on changes in the URL like so: https://github.com/ylluminarious/volt_action_problems/commit/5fcefc16d7b14a980f68ce572a80f25540d21636.
Sorry for the late reply. This is a known issue thats on my to fix list. As GDP2 mentioned, you can use .watch! to handle it, or the probably better way to do it is to write your controllers in a more functional way so that the data being pulled from params is used in methods instead of setting instance variables.
So for example, if your using the params in a query, instead of doing something like:
attr_reader :query
def index
#item = store.items.where(name: params._name).first
end
You could do something like:
def query
store.items.where(name: params._name).first
end
This might seem less efficient, but there's a lot of caching and this is pretty much just as efficient.
Once I get time though, I'll make it retrigger the action method when accessed data changes. (Sorry, just haven't gotten to it.)
I'm using Magento's built in Googleanalytics module which is working fine for page views, but not for conversions. The account is set up fine on Google, but it's not adding the addTrans part in the checkout/onepage/success page.
I've done a lot of digging this morning, and found that the observer does observe the "checkout_onepage_controller_success_action" correctly, and does indeed run. It does the following:
$block = Mage::app()->getFrontController()->getAction()->getLayout()->getBlock('google_analytics');
if ($block) {
$block->setOrderIds($orderIds);
}
I've done some echoing, and it does retrieve the block, and it also sets the order ids correctly. However, in the block itself, if I echo out $this->getOrderIds(); its empty.
My next thought was that perhaps it could be using two GA blocks on the page, and maybe its passing the data to the first one but echoing the HTML of the 2nd one, but I've no clue how to start checking that! The Googleanalytics.xml file only has one block it in, and I don't use that block name anywhere else!
Anyone experienced similar? Or have any idea where I can go from here?
EDIT:
The Ga.php block includes the transaction code if $this->getOrderIds() returns an array, which it is not doing. However, the observer is doing $block->setOrderIds($order_ids); which is passing through an array containing an order id. So the observer is passing the ids to the block, and the block is receiving them (setting up a method of setBlockIds and echoing out the argument, does show the array), but when the block tries to access its own data, it's suddenly not there ($block->getData() returns an array of properties but there is no order_ids property).
I also figured maybe it could be that its echoing the blocks HTML before setting the order id, so I added some variables in to check that and it's not that - its definitely setting the order_ids before trying to get them again, but its still not working!
I'm completely stumped! My only idea now is to modify the Ga.php block to use Magento's registry instead of it's own _data property, which is really not a nice way of doing it!
I think i've been an utter tool. Magento wasn't tracking conversions on the live site because I hadn't put the account code in the configuration part, but I had on my test site.
I had previously put my own analytics code in the template, so I had tracked page views.
When I saw no conversions (despite putting the account code in my test site), I started making orders on the test site and then viewing the source of the order success page. Firefox loads its source as a new request...which automatically goes to the empty basket page. So obviously, it wasn't showing the addTrans or anything, because it had already done that.
A quick check in firebug revealled it was working as it should.
So in the end, after a day of searching, I had to change "No" to "Yes" in the admin, and type in the account code. Great.
In the last three days I've struggled trying to find a way to accomplish what I though was supposed to be a simple thing. Doing this on my own or searching for a solution in the web, didn't help. Maybe because I'm not even sure what to look for, when I do my researches.
I'll try to explain as much as I can here: maybe someone will be able to help me.
I won't say how I'm doing it, because I've tried to do it in many ways and none of them worked for different reasons: I prefer to see a fresh advice from you.
In most of the pages of web application, I have two links (but they could be more) like that:
Option A
Option B
This is partial view, retured by a controller action.
User can select or both (all) values, but they can't never select none of them: meaning that at least one must be always selected.
These links must che accessible in almost all pages and they are not supposed to redirect to a different page, but only to store this information somewhere, to be reused when action needs to filter returned contents: a place always accessible, regarding the current controller, action or user (including non authenticated users) (session? cookie?).
This information is used to filter displayed contents in the whole web application.
So, the problem is not how to create the business logi of that, but how (and where) to store this information:
without messing with the querystring (means: keeps the querystring as empty/clean as possible)
without redirecting to other pages (user must get the current page, just with different contents)
allow this information to persists between all views, until user click again to change the option(s)
My aim is to have this information stored in a model that will contains all options and their selection status (on/off), so the appropriates PartialView will know how to display them.
Also, I could send this model to the "thing" that will handle option changes.
Thanks.
UPDATE
Following Paul's advice, I've took the Session way:
private List<OptionSelectionModel> _userOptionPreferences;
protected List<OptionSelectionModel> UserOptionPreferences
{
get
{
if (Session["UserOptionPreferences"] == null)
{
_userOptionPreferences= Lib.Options.GetOptionSelectionModelList();
}
else
{
_userOptionPreferences= Session["UserOptionPreferences"].ToString().Deserialize<List<OptionSelectionModel>>();
}
if (_userOptionPreferences.Where(g => g.Selected).Count() == 0)
{
foreach (var userOptionPreferencesin _userOptionPreferences)
{
userOptionPreferences.Selected = true;
}
}
UserOptionPreferences= _userOptionPreferences;
return _userOptionPreferences;
}
private set
{
_userOptionPreferences= value;
Session["UserOptionPreferences"] = _userOptionPreferences.SerializeObject();
}
}
Following this, I've overridden (not sure is the right conjugation of "to override" :) OnActionExecuting():
protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
GetOptionSelections();
base.OnActionExecuting(filterContext);
}
GetOptionSelections()...
private void GetOptionSelections()
{
if (String.IsNullOrEmpty(Request["optionCode"])) return;
var newOptionCode = Request["optionCode "];
foreach (var userOptionPreferencesin UserOptionPreferences)
{
if (userOptionPreferences.OptionCode == newOptionCode )
userOptionPreferences.Selected = !userOptionPreferences.Selected;
}
}
This code I think can be better, but right now I just want to make it work and it doesn't.
Maybe there are also other issues there (quite sure, actually), but I believe the main issue is that OnActionExecuting is called by each action in a controller that inherit from BaseController, therefore it keeps toggling userOptionPreferences.Selected on/off, but I don't know how to make GetOptionSelections() being called only once in each View: something like the old Page_Load, but for MVC.
Last update AKA solution
Ok, using the session way, I've managed to store this information.
The other issue wasn't really on topic with this question and I've managed to solve it creating a new action that take cares of handling the option's change, then redirects to the caller URL (using the usual returnUrl parameter, but as action parameter).
This way, the option change is done only once per call.
The only thing I don't really like is that I can't simply work with the UserOptionPreferences property, as it doesn't change the session value, but only the value in memory, so I have to set the property with the new object's status each time: not a big deal, but not nice either.
This is a place to use session.
The session will keep your setting between requests while keeping it out of the url querystring. It seems that you have probably tried this already, but try it again and if you have problems ask again. I think it will be the best way for you to solve this problem.
I recently had a problem with multiple form posting in an ASP.NET MVC application. The situation was basically, if someone intentionally hammered the submit button, they could force data to be posted multiple times despite validation logic (both server and client side) that was intended to prohibit this. This occurred because their posts would go through before the Transaction.Commit() method could run on the initial request (this is all done in nHibernate)
The MVC ActionMethod looked kind of like this..
public ActionResult Create(ViewModelObject model)
{
if(ModelState.IsValid)
{
// ...
var member = membershipRepository.GetMember(User.Identity.Name);
// do stuff with member
// update member
}
}
There were a lot of solutions proposed, but I found the C# lock statement, and gave it a try, so I altered my code to look like this...
public ActionResult Create(ViewModelObject model)
{
if(ModelState.IsValid)
{
// ...
var member = membershipRepository.GetMember(User.Identity.Name);
lock(member) {
// do stuff with member
// update member
}
}
}
It worked! None of my testers can reproduce the bug, anymore! We've been hammering away at it for over a day and no one can find any flaw. But I'm not all that experienced with this keyword. I looked it up again to get clarification...
The lock keyword marks a statement block as a critical section by obtaining the mutual-exclusion lock for a given object, executing a statement, and then releasing the lock
Okay, that makes sense. Here is my question.
This was too easy
This solution seemed simple, straightforward, clear, efficient, and clean. It was way too simple. I know better than to think something that complicated has that simple a solution. So I wanted to ask more experienced programmers ...
Is there something bad going on I should be aware of?
No it's not that easy. Locking only works if the same instance is used.
This will not work:
public IActionResult Submit(MyModel model)
{
lock (model)
{
//will not block since each post generates it's own instance
}
}
Your example could work. It all depends on if second-level caching is enabled in nhibernate (and thus returning the same user instance). Note that it will not prevent anything from being posted to the database, just that each post will be saved in sequence.
Update
Another solution would be to add return false; to the submit button when it's being pressed. it will prevent the button from submitting the form multiple times.
Here is a jquery script that will fix the problem for you (it will go through all submit buttons and make sure that they will only submit once)
$(document).ready(function(){
$(':submit').click(function() {
var $this = $(this);
if ($this.hasClass('clicked')) {
alert('You have already clicked on submit, please be patient..');
return false;
}
$this.addClass('clicked');
});
});
Add it do you layout or to a javascript file.
Update2
Note that the jquery code works in most cases, but remember that any user with a little bit of programming knowledge can use for instance HttpWebRequest to spam POSTs to your web server. It's not likely, but it could happen. The point I'm making is that you should not rely on client side code to handle problems since they can be circumvented.
Yeah, it's that easy, but - there may be a performance hit. Remember that a Monitor lock restricts that code to be run by only one thread at a time. There is a new thread for each HTTP Request, so that means only one of those requests at any given time can access that code. If it's a long running procedure, or a lot of people are trying to access that part of the site at the same time - you might start to sluggish responses.
It's that easy, but be careful what object you lock on. It should be the same one for all the threads - for example, it could be a static object.
lock is syntactic sugar for a Monitor, so there is quite a bit going on under the cover.
Also, you should keep an eye out for deadlocks - they can happen when you lock on two or more objects.