I'm working with Java and JSP. I have to create something like a promotion which has start date and end date. Within the start date and end date, it will show a form that is corresponding to the promotion; otherwise, it will be just show a normal page. I have done the validation based on the time they open the page. I can manipulate the time in Unit Testing by making the current time to any time I want.
However, the problem is when I want to pass this to client to test. They want to see how it's like on the promotion day? Does the promotion really show on a particular time? Does it really close afterwards? One possible way is to secretly pass current date as HTTP param when trying to access the page. Doing so, client can check how the system behaves on a particular day but it's very dangerous indeed. Anyone who knows this will be able to access the promotion anytime they want. I don't know what the best way to handle this.
What's your suggestion?
It sounds like a bad idea basing ANY of your JSP (server-side) code on time being sent from a client. It would be much better to handle this entirely server side and have some way of configuring the time via which you and your client can do testing.
1) if the client is really concerned (or your application is complex) - it may be that the ONLY way to do such a test reasonably is to change the server time as suggested by Nathan Hoad's comment. Every other test comes with confidence since it relies on something other than the time ticking over and "triggering" the promotion to start or end. Also keep in mind the activities that occur during the promotion - do they use the system time to make decisions or store the date/time in a database etc?
2) if #1 isn't a real issue I would have your code that checks the time (for the trigger of the promotion) to call a custom function in your code (eg. getCustomTime()). That method will by default return the system time, but also checks to see if an offset has been configured and use that to offset the actual time. The offset can be dynamically configured.
Good luck.
Firstly, you shouldn't be putting this functionality onto a live production server, so the "very dangerous" exposure shouldn't happen.
I'd try a "belt and braces" approach:
Set up a demo server that only has read-only access so can't do any damage
Tell the client the secret parameter to use
Have the "client promotion demo" feature switchable on/off from an admin console
(If you're really nervous) limit access to only the client's IP
The client can access the demo box and check everything works perfectly. When they are happy, you deploy to production, but with the "demo mode" disabled, so only the "time-sensitive" way of accessing the promotion will work.
You don't have to tweak the time on your server to demo this to the client. Just have a promotion that is expired in the system, one that is currently active and another that is in the future on three different items, and show the customer the effects.
Either that, or create a promotion during your presentation that takes effect one minute in the future, lasts for 2-3 minutes and then expires, then talk through it and click around and show them the effects.
Related
I am using S3 Lifecycle Rule to move objects to Glacier. Since objects will be moved to glacier storage I need to make sure my application RDS is also
updated with similar details.
As per my discussion over this thread AWS Lambda for objects moved to glacier, there is no way currently to generate SQS notification to get notified about object being moved to glacier.
Also, as per my understanding currently Lifecycle rule will be evaluated once in a day, but there is not specific time when this will happen in a day. If there was i was planning to have a scheduler which will run after that and update status of archived objects in RDS.
Is there a way that you can suggest which will be close enough to sync this status changes between AWS & RDS?
Let me know your feedback or if you need more information on this to understand use case.
=== My Current approach is as per below.
Below is exact flow that I have implemented, please review and let me know if there is anything that could have been done in better way.
When object is uploaded to system I am marking it with status Tagged and also capturing creation date. My Lifecycle rule is configured with 30 days from creation. So, I have a scheduler which calculates difference between today's date and object creation date for all objects with status Tagged, and check if diff is greater than equal to 30. If so, it updates status to Archived.
If user performs any operation on object with status Archived, we explicitly check in s3 whether object is actually moved to glacier or not. If not we perform operation requested. If moved to glacier we initiate restore process and wait for restore to finish to initiate operation requred.
I appreciate your thoughts and would like to hear your inputs on above approach that i have taken.
Regards.
If I wanted to implement this, I would set the storage class of the object inside my database as "Glacier/Archived" at the beginning of the day it is supposed to transition.
You already know your lifecycle policies, and, as part of object metadata, you also know the creation time of each object. Then it becomes a simple query, which can be scheduled to run every night at 12:00 AM.
You could further enhance your application by defining an algorithm that checks if an object has transitioned to Glacier today, at the moment when object access is requested, it would go and explicitly check if it is actually transitioned or not. If it is marked as Glacier/Archive for more than a day, then checking is no longer required.
Of course, if for any reason, the above solution doesn't work for you, it is possible to write a scanner application to continuously check the status of those objects that are supposed to transition at "DateTime.Today" and are not marked as Glacier/Archive yet.
I'm using Java EE (JDBC, MVC, DAO) and MySql.
I'm making my own project, so all architecture's design - my responsibility.
I have a system "Facultative", where i have entity Facultative, that store information about course, lecturer and start and duration.
Now, it is also storing a field "Status": Wait (not started), Started and Ended.
And this is a place, i have problem: how should information be updated?
Of course, it is possible, to give this function to the admin, but it seems to easy and not efficient.
I have idea - not store field "status" at DB, but to check what status in Model Entity (by checking start date/duration).
I'm using MVC Pattern and not sure if it is correct to add such method to Class.
Thank you in advance.
This is really an issue of the "world" you are modeling. Ask yourself this:
Do courses ever fail to start at the scheduled time?
Do you want to explicitly model that?
If the answer to both of those questions is "yes", then you can't treat the status field as derived from (just) the start and end dates (and the current date). And similarly, automatically setting a (non-derived) status field based on the dates is dubious.
On the other hand ... setting the status administratively would be a bad idea too, since it needs to be done at a particular time; i.e. when the lecture actually starts.
But then ... actually modeling this accurately needs to acknowledge that there is a "gap" between the information in your database, and what is actually happening in the real world. It is (probably) impractical to ensure that the database is 100% accurate. So the pragmatic solution is to accept that: make it a "feature" of the system.
If you take the pragmatic view, then making status derived should be good enough. (Change its name to notional_status or something, and change the start and end fields to scheduled_start and scheduled_end or something.)
Storing the start date and end date (or duration) and deriving the status makes the most sense to me.
The main advantage is the data wont need to be updated as the Status transitions from Wait to Started and Started to Ended and just take care of itself as time passes naturally.
I have a list of users across various companies who are using one of the functionality that our website provides. Whenever they contact our business group , we need to send a url via email to the requestor in order for them to upload some data. All these external users do not have any dedicated account. However we do not want a static link to be provided to them as this can be accessed by anyone over the internet. We want dynamic links to be generated. Is this something that is usually done? Is there an industry accepted way of doing this? Should we ensure that the dynamic link expires after a certain amount of time - if so , are there any design options?
Thanks a lot!
Usually, parameters to urls and not the actual urls are what's dynamic. Basically you generate params that are stored somewhere, typically on the database, and send email with the url and the parameter(s). This url is valid for only a limited period of time and possibly only for one request.
Answers to questions:
yes, this is something that is quite commonly used in, for example, unsubscribing from a mailing list or validating an account with a working email address
I'm not aware of any single way that is "industry accepted", there are many ways of doing it, but the idea is not that complex - you just need to decide on a suitable token format
normally you should ensure that the link expires after a certain amount of time. Depending on the use case that can be some days, a week or something else. In practice, you'd remove or disable the generated parameters in your database. However, if this data is something that might be needed for extended periods of time, you might want to think up a functionality so that it can be retrieved later on.
You may have a static URL taking a token as parameter. Eg. http://www.mycompany.com/exchange/<UUID> or http://www.mycompany.com/exchange?token=<UUID>.
The UUID could have a validity in a time range or be limited to a single use (one access or one upload).
Other variant is to use exists cookies on that site in web browser (of course, if they are).
But there are some drawbacks in this solution:
User can open link in different machine, different browser. User can clean all cookies or they can expire after it was visited your site last time when user try to go on granted URL. In these cases user won't access your page.
I'm making a server with Java that will provide chat services for flash clients. The server will store data about each user on a .txt file somewhere on the server. For example when a user logs in, information about this user is requested to the DatabaseManger class. It will then search through the database and return the information. The point is that when allot of people log in a short amount of time the server is doing allot of checks again and again.
The idea that I want to implement is that a connection class does something like this:
String userData = DatabaseManager.getUserData(this.username);
The DatabaseManager then doesn't search immediately, it stores this request in an array of requests, then in a fixed interval it goes through the database 1 time and returns data to the clients that requested this. This way when 15 people log in in a second it wont go through all the information 15 times. How to implement this?
You use a real DBMS like everyone else on the planet. I'm eager to hear a reason why someone wouldn't choose a DB for this application. I can't think of anything that would prevent it. Back in the day, RDBMS were ungainly, expensive, complicated beasts. Today, they're as readily available as tabloids at the checkout counter.
There are few excuses to not to a DB nowadays, and arguably there are more excuses to use the DB than the file system for most any application.
As above I'd recommend using an existing database solution like HSQLDB, you'd be far better off in the long run doing things this way rather than hacking your own solution together.
If you really want to do this anyway, have a look at the ScheduledExecutorService. You can then fire off a request to the executor service with a delay, and in that delay listen for more data and add it to the query.
I currently have an Android application that displays a schedule for a ferry boat. The application can display the full schedule (just a giant list), but the selling point in the application is it will display when the next two ferries are departing and how long from the current time that departure is.
I am relatively new to Java and currently use large Switch() statements in my code. Basically it gets the current phone time and compares it to all of the times in the schedule at which point it displays the next two departure times and then calculates the difference between current time and the departure times.
I am sure that a switch statement is not the best idea for speed purposes as well as code changing purposes. For example if one time changes its a bunch of lines of code to go in and fix for that one time change. Also if the entire schedule changes everyone has to update their app for the time change to take effect. My ideal situation would be to store a file somewhere on my webserver that could be downloaded and inserted into a hashmap (I think is the correct term) that would load the new schedule if there was a time change.
Not sure how confusing this is, but it would be greatly appreciated if someone could explain how I might use a hashmap or something else you might recommend to get this task accomplished. Currently the variables are the two ferry terminals as well as the day of the week since the schedule changes per day (monday, tues-friday, saturday, sunday).
Below is a screenshot of the application so you can understand it if my post wasn't clear. Thank you in advance.
Screenshot:
Store the schedule objects in a sorted array. You can then binary search the array for the first value greater than the current time. You'll probably use some parent array consisting of the location and applicable day of the week.
You can easily write that kind of data structure to a file that is read & parsed by the application for updates instead of being compiled into the code.
Details of this? First, understand resources in Android. If no updated schedule exists, fall back to the default resource.
Second, use an HTTP head request to check if a newer file exists. If it does, parse, download & save state. Saving Android Activity state using Save Instance State.
Finally, XML is handy for data distribution, even if it's not fast. Everybody understands it and it's easy to update or hand off.
<ferry location=0 time=2045>
<day>1</day>
<day>2</day>
<day>3</day>
<day>4</day>
<day>5</day>
</ferry>
<ferry location=0 time=0800>
<day>6</day>
</ferry>
You will need something like a database to hold the schedule data. That will help you to seperate code from data. I'm not familiar with Android but i think there is a interface to sqlite database on the device.
Further, as this is an application on a small device you may connect to the schedule database on a server thru the internet connection. That way you have to maintain schedule data only in one place (on the server) and clients will use always up to date data.