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  • Synthetic database records

    - by michipili
    Assume we are getting some statistics from a customer which we analyse and we send our comments to the customer. Now, the customer tells us that the statistic they computed between January and March are based on a wrong methodology and sends us corrected series. We want perform analysis with the wrong and with the correct set of data, which are huge and only differ from January to March. Therefore, we need something like synthetic database records implementing the following logic: synthetic[1] = wrong_data synthetic[2] = correct_data between Januar and March, wrong_data otherwise With this, we can easily perform our analyses on synthetic records. Should such synthetic records be implemented in the application logic or on the side of the database? What are common pitfalls of such an implementation?

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  • How to name multi-setter?

    - by IAdapter
    I'm struggling with how to name this method, I don't like the "set" prefix, because I feel it should be reserved for normal "dumb" setters and some tools might not like it (i did not check it in checkstyle, pmd, etc., but I got a feeling they won't like it.) for example (in java, but I feel its language agnostic) public void setField1Field2(String field1, String field2) { this.field1 = field1; this.field2 = field2; } The only purpose of this method is ONLY to set, this method is needed and cannot be joined with any other (because of framework used).

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  • Should i continue my self-taught coding practice or learn how to do coding professionally?

    - by G1i1ch
    Lately I've been getting professional work, hanging out with other programmers, and making friends in the industry. The only thing is I'm 100% self-taught. It's caused my style to extremely deviate from the style of those that are properly trained. It's the techniques and organization of my code that's different. It's a mixture of several things I do. I tend to blend several programming paradigms together. Like Functional and OO. I lean to the Functional side more than OO, but I see the use of OO when something would make more sense as an abstract entity. Like a game object. Next I also go the simple route when doing something. When in contrast, it seems like sometimes the code I see from professional programmers is complicated for the sake of it! I use lots of closures. And lastly, I'm not the best commenter. I find it easier just to read through my code than reading the comment. And most cases I just end up reading the code even if there are comments. Plus I've been told that, because of how simply I write my code, it's very easy to read it. I hear professionally trained programmers go on and on about things like unit tests. Something I've never used before so I haven't even the faintest idea of what they are or how they work. Lots and lots of underscores "_", which aren't really my taste. Most of the techniques I use are straight from me, or a few books I've read. Don't know anything about MVC, I've heard a lot about it though with things like backbone.js. I think it's a way to organize an application. It just confuses me though because by now I've made my own organizational structures. It's a bit of a pain. I can't use template applications at all when learning something new like with Ubuntu's Quickly. I have trouble understanding code that I can tell is from someone trained. Complete OO programming really leaves a bad taste in my mouth, yet that seems to be what EVERYONE else is strictly using. It's left me not that confident in the look of my code, or wondering whether I'll cause sparks when joining a company or maybe contributing to open source projects. In fact I'm rather scared of the fact that people will eventually be checking out my code. Is this just something normal any programmer goes through or should I really look to change up my techniques?

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  • Is there any CSS selector to reach an element outside of the current container?

    - by acidrums4
    (And excuse me for my bad english, for starters...) Sorry if this is a noob question, but I really don't know if the following is possible. I'm doing a html5 portfolio. I'm following a tuto from codrops to visually filter works with only css3 (http://tympanus.net/codrops/2012/01/09/filter-functionality-with-css3/). There, user can select which category want to see with some <input type="radio">'s. But those selectors are under the same container (a <section>) and give visibility for the elements via CSS using a general sibling combinator (~). So in that example, the CSS code goes like this: .ff-container input.ff-selector-type-all:checked ~ label.ff-label-type-all, .ff-container input.ff-selector-type-1:checked ~ label.ff-label-type-1, .ff-container input.ff-selector-type-2:checked ~ label.ff-label-type-2, .ff-container input.ff-selector-type-3:checked ~ label.ff-label-type-3{ background: linear-gradient(top, #646d93 0%,#7c87ad 100%); color: #424d71; text-shadow: 0px 1px 1px rgba(255,255,255,0.3); box-shadow: 0px 0px 0px 1px #40496e, 0 1px 2px rgba(0,0,0,0.1) inset; } The thing is I want to put those <input type="radio">'s on the <head> section of my portfolio, but obviously the ~ selector won't work there. So my question is that is there any selector, hack or something that can do that? Something like .ff-container input.ff-selector-type-all:checked $ header > label.ff-label-type-all { awesomeness:100%; } I really don't want to use Javascript/Jquery for that... Thank you so much in advance!

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  • How important is index size when searching?

    - by Michael K
    My company has recently began using Apache Solr to search its data. As we learn how to use it we have gone down the path of indexing multiple fields to get the results we need. Most of these are either N-Grammed or Edge-N-Grammed. Gramming by nature takes up a lot of space, which takes more time to search. Space is cheap, but time is less so. Index time is not too important, since a delta-import (only get the changes since last index) is extremely quick and you only pay a penalty on the first import. What we've not been able to determine is what effect the index size has on query times. Obviously a larger index takes longer to search, but the time added by n-gramming a field is difficult to predict. How do you determine whether a field is worth gramming? Can you predict how much longer a query will take when you gram a field?

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  • Is there an industry standard for systems registered user permissions in terms of database model?

    - by EASI
    I developed many applications with registered user access for my enterprise clients. In many years I have changed my way of doing it, specially because I used many programming languages and database types along time. Some of them not very simple as view, create and/or edit permissions for each module in the application, or light as access or can't access certain module. But now that I am developing a very extensive application with many modules and many kinds of users to access them, I was wondering if there is an standard model for doing it, because I already see that's the simple or the light way won't be enough.

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  • Storing revisions of a document

    - by dev.e.loper
    This is a follow up question to my original question. I'm thinking of going with generating diffs and storing those diffs in the database 'History' table. I'm using diff-match-patch library to generate what is called a 'patch'. On every save, I compare previous and new version and generate this patch. The patch could be used to generate a document at specific point in time. My dilemma is how to store this data. Should I: a Insert a new database record for every patch? b. Store these patches in javascript array and store that array in history table. So there is only one db History record for document with an array of all the patches. Concerns with: a. Too many db records generated. Will be slow and CPU intensive to query. b. Only one record. If record is somehow corrupted/deleted. Entire revision history is gone. I'm looking for suggestions, concerns with either approach.

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  • Footer not showing in website depending on which item is loaded [on hold]

    - by samyb8
    I designed a website which is having an issue, but I checked the html tagging very well and cannot fix it. If you go to this item: http://www.tahara.es/store/headbands/11/Ivory-Turquoise-headband You will see the FOOTER display normally. However if you go to this other item: http://www.tahara.es/store/headscarves/15/Grey-and-ivory-with-stoned-flower-Headscarf The footer does not show. Any clue of what I am missing or adding? The footer DIV is like this: <div id="footer">

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  • How can I get non-programmer colleagues on board with bespoke software rather than Dynamics CRM + Sharepoint?

    - by Bendos
    I am working with a company which designs and builds one-off machines. They have been 'dabbling' with hosted Dynamics CRM and Sharepoint (on different servers!) in an attempt to centralise their data and help colleagues collaborate more effectively across projects. They haven't used either system to their potential. Now we are looking at the engineering department who already use a form of version control software for the various CAD files (Autodesk Vault) however it is becoming increasingly necessary to implement more of a generic file version control system as they use many more files than can be managed in Vault (sometimes just photos or scans of paper documents), hence why they were looking at using Sharepoint. However... as the 'programmer' of the bunch, I can see several scenarios which don't seem to fit well with the Dynamics + Sharepoint approach; simple reports based on cross-table queries, exporting certain metrics as a spreadsheet, defining project hierarchies and many-many relationships, and as such I have been pushing for an in-house developed 'ECM' / 'ERP' software package (perhaps in .NET or php). Some colleagues seem to attach a greater value to the MS software (perhaps becuase it has a logo!) but don't see that it's just a framework, not a solution. Can anyone provide a good example of when custom software would actually be better than using Dynamics + Sharepoint and how do I relate that to non-technical staff?

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  • Can observer pattern be represented by cars and traffic lights?

    - by eeerahul
    I wanted to verify with all of you, if I have a correct Observer Pattern analogy. The scenario is as follows: Consider, at a junction, there is a traffic signal, having red, yellow and green lights respectively. There are vehicles facing the traffic signal post. When it shows red, the vehicles stop, when it shows green, the vehicles move on. In case, it is yellow, the driver must decide whether to go or to stop, depending on whether he/she has crossed the stop line or not. At the same time, there are vehicles that do not care about the signal. They would do as they like. The similarities are that, the Traffic Signal happens to be the subject, notifying its states by glowing the appropriate lights. Those looking at it and following the signal are the ones subscribed to it, and behave according to the state of the subject. Those who do not care about it, are sort-of un-subscribed from the traffic signal. Please tell me, if you think this is a correct analogy or not?

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  • MVVM application architecture, where to put dependency injection configuration class, BusinessLayer and Common interfaces?

    - by gt.guybrush
    Planning my architecture for an MVVM application I come to this: MyApp.UI View MyApp.BusinessLayer ViewModel MyApp.DataAccessLayer RepositoryImplEF MyApp.DomainLayer DomainObject RepositoryInterface MyApp.Common Logging Security Utility (contains some reflection method used by many levels) CustomException MyApp.UnitTest I was inspired by Domain-driven-desing, test-driven-development and onion architecture but not sure to have done all well. I am not sure of a couple of things: where to put dependency injection configuration class? In the common project? where to put BusinessLayer interfaces? in Domain layer? where to put Common interfaces? in Domain layer? But Common in referenced from domain (for some reflection utilities and for DI if the response to 1. is yes) and circular reference isn't good

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  • Alternatives to sql like databases

    - by user613326
    Well i was wondering these days computers usually have 2GB or 4GB memory I like to use some secure client server model, and well an sql database is likely candidate. On the other hand i only have about 8000 records, who will not frequently be read or written in total they would consume less then 16 Megabyte. And it made me wonder what would be good secure options in a windows environment to store the data work with it multi-client single server model, without using SQL or mysql Would for well such a small amount of data maybe other ideas better ? Because i like to keep maintenance as simple as possible (no administrators would need to know sql maintenance, as they dont know databases in my target environment) Maybe storing in xml files or.. something else. Just wonder how others would go if ease of administration is the main goal. Oh and it should be secure to, the client server data must be a bit secure (maybe NTLM files shares https or...etc)

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  • Maya and Game Engines (i.e. Environment Testing)

    - by DiscreteGenius
    What does it mean if I'm designing an environment and I want to test it in the game engine, to see what its like to "run" [or fly] around my environment? I heard an instructor say that exact thing in a Maya training video and I'd like to know more about "How Game Engines and Maya are related to each other." He stated this would be done to see how things look in "size" (e.g. I assume he meant: 'How big is the cathedral, bridge, wall, building, etc.'). I've tried to research such information but it's too complicated, and detailed. I just want a simplistic response to my query. Thanks to everyone willing to help and not criticize my question.

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  • Too complex/too many objects?

    - by Mike Fairhurst
    I know that this will be a difficult question to answer without context, but hopefully there are at least some good guidelines to share on this. The questions are at the bottom if you want to skip the details. Most are about OOP in general. Begin context. I am a jr dev on a PHP application, and in general the devs I work with consider themselves to use many more OO concepts than most PHP devs. Still, in my research on clean code I have read about so many ways of using OO features to make code flexible, powerful, expressive, testable, etc. that is just plain not in use here. The current strongly OO API that I've proposed is being called too complex, even though it is trivial to implement. The problem I'm solving is that our permission checks are done via a message object (my API, they wanted to use arrays of constants) and the message object does not hold the validation object accountable for checking all provided data. Metaphorically, if your perm containing 'allowable' and 'rare but disallowed' is sent into a validator, the validator may not know to look for 'rare but disallowed', but approve 'allowable', which will actually approve the whole perm check. We have like 11 validators, too many to easily track at such minute detail. So I proposed an AtomicPermission class. To fix the previous example, the perm would instead contain two atomic permissions, one wrapping 'allowable' and the other wrapping 'rare but disallowed'. Where previously the validator would say 'the check is OK because it contains allowable,' now it would instead say '"allowable" is ok', at which point the check ends...and the check fails, because 'rare but disallowed' was not specifically okay-ed. The implementation is just 4 trivial objects, and rewriting a 10 line function into a 15 line function. abstract class PermissionAtom { public function allow(); // maybe deny() as well public function wasAllowed(); } class PermissionField extends PermissionAtom { public function getName(); public function getValue(); } class PermissionIdentifier extends PermissionAtom { public function getIdentifier(); } class PermissionAction extends PermissionAtom { public function getType(); } They say that this is 'not going to get us anything important' and it is 'too complex' and 'will be difficult for new developers to pick up.' I respectfully disagree, and there I end my context to begin the broader questions. So the question is about my OOP, are there any guidelines I should know: is this too complicated/too much OOP? Not that I expect to get more than 'it depends, I'd have to see if...' when is OO abstraction too much? when is OO abstraction too little? how can I determine when I am overthinking a problem vs fixing one? how can I determine when I am adding bad code to a bad project? how can I pitch these APIs? I feel the other devs would just rather say 'its too complicated' than ask 'can you explain it?' whenever I suggest a new class.

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  • Many ui panels needs interaction with same object

    - by user877329
    I am developing a tool for simulating systems like the Gray-Scott model (That is systems where spatial distribution depends on time). The actual model is loaded from a DLL or shared object and the simulation is performed by a Simulation object. There are at least two situations when the simulation needs to be destroyed: The user loads a new model The user changes the size of the domain To make sure nothing goes wrong, the current Model, Simulation, and rendering Thread are all managed by an ApplicationState object. But the two cases above are initiated from two different UI objects. Is it then ok to distribute a reference to the ApplicationState object to all panels that need to access at least one method on the ApplicationState object? Another solution would be to use aggregation so that the panel from which the user chooses model knows the simulation parameter panel. Also, the ApplicationState class seems somewhat clumsy, so I would like to have something else

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  • Law of Demeter in MVC regarding Controller-View communication

    - by Antonio MG
    The scenario: Having a Controller that controls a view composed of complex subviews. Each one of those subviews is a separated class in a separate file. For example, one of those subviews is called ButtonsView, and has a bunch of buttons. The Controller has to access those buttons. Would accessing those buttons like this: controllerMainView.buttonsView.firstButton.state(); be a violation of the LOD? On one hand, it could be yes because the controller is accessing the inner hierarchy of the view. On the other, a Controller should be aware of what happens inside the view and how is composed. Any thoughts?

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  • Storing images in file system and returning URLs or virtually resizing and returning byte arrays?

    - by ismaelf
    I need to create a REST web service to manage user submitted images and displaying them all in a website. There are multiple websites that are going to use this service to manage and display images. The requirements are to have 5 pre-defined image sizes available. The 2 options I see are the following: The web service will create the 5 images, store them in the file system and and store the URL's in the database when the user submits the image. When the image is requested, the web service will return an array of URLs. I see this option to be a little hard on the hard drive. The estimates are 10,000 users per site, and lets say, 100 sites. The heavy processing will be done when the user submits the image and each image is going to be pulled from the File System. The web service will store just the image that the user submits in the file system and it's URL in the database. When the user request images, the web service will get the info from the DB, load the image on memory, create its 5 instances and return an object with 5 image arrays (I will probably cache the arrays). This option is harder on the processor and memory. The heavy processing will be done when the images get requested. A plus I see for option 2 is that it will give me the option to rewrite the URL of the image and make them site dependent (prettier) than having a image repository for all websites. But this is not a big deal. What do you think of these options? Do you have any other suggestions?

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  • What are the best practices to use NHiberante sessions in asp.net (mvc/web api) ?

    - by mrt181
    I have the following setup in my project: public class WebApiApplication : System.Web.HttpApplication { public static ISessionFactory SessionFactory { get; private set; } public WebApiApplication() { this.BeginRequest += delegate { var session = SessionFactory.OpenSession(); CurrentSessionContext.Bind(session); }; this.EndRequest += delegate { var session = SessionFactory.GetCurrentSession(); if (session == null) { return; } session = CurrentSessionContext.Unbind(SessionFactory); session.Dispose(); }; } protected void Application_Start() { AreaRegistration.RegisterAllAreas(); FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); RouteConfig.RegisterRoutes(RouteTable.Routes); BundleConfig.RegisterBundles(BundleTable.Bundles); var assembly = Assembly.GetCallingAssembly(); SessionFactory = new NHibernateHelper(assembly, Server.MapPath("/")).SessionFactory; } } public class PositionsController : ApiController { private readonly ISession session; public PositionsController() { this.session = WebApiApplication.SessionFactory.GetCurrentSession(); } public IEnumerable<Position> Get() { var result = this.session.Query<Position>().Cacheable().ToList(); if (!result.Any()) { throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.NotFound)); } return result; } public HttpResponseMessage Post(PositionDataTransfer dto) { //TODO: Map dto to model IEnumerable<Position> positions = null; using (var transaction = this.session.BeginTransaction()) { this.session.SaveOrUpdate(positions); try { transaction.Commit(); } catch (StaleObjectStateException) { if (transaction != null && transaction.IsActive) { transaction.Rollback(); } } } var response = this.Request.CreateResponse(HttpStatusCode.Created, dto); response.Headers.Location = new Uri(this.Request.RequestUri.AbsoluteUri + "/" + dto.Name); return response; } public void Put(int id, string value) { //TODO: Implement PUT throw new NotImplementedException(); } public void Delete(int id) { //TODO: Implement DELETE throw new NotImplementedException(); } } I am not sure if this is the recommended way to insert the session into the controller. I was thinking about using DI but i am not sure how to inject the session that is opened and binded in the BeginRequest delegate into the Controllers constructor to get this public PositionsController(ISession session) { this.session = session; } Question: What is the recommended way to use NHiberante sessions in asp.net mvc/web api ?

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  • How can I designed multi-threaded application for larger user base

    - by rokonoid
    Here's my scenario, I need to develop a scalable application. My user base may be over 100K, every user has 10 or more small tasks. Tasks check every minute with a third party application through web services, retrieving data which is written in the database, then the data is forwarded to it's original destination. So here's the processing of a small task: while(true){ Boolean isNewInformationAvailable = checkWhetherInformationIsAvailableOrNot(); If(isNewInformationAvailable ==true){ fetchTheData(); writeToDatabase(); findTheDestination(); deliverTheData(); isAvailable =false; } } Here is the question: as the application is large, how should I approach designing this. I'm going to use Java to write it. Should I use concurrency, and how would you manage the concurrency?

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  • What is a normalized Vector?

    - by draiden
    Can someone explain the following code? I need to learn what each part means so I can turn it into enemy movement in a space shoot-em-up Vec2d playerPos; Vec2d direction; // always normalized float velocity; I get the above is naming two 2d Vector objects, and creating a variable called velocity. I'm not sure what the normalized comment is about, though. update() { direction = normalize(playerPos - enemyPos); playerPos = playerPos + direction * velocity; }

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  • Implementing Command Pattern in Web Application

    - by KingOfHypocrites
    I'm looking to implement the command pattern in a web application (asp.net c#)... Since the commands come in text format from the client, what is the best way to translate the string to a command object? Should I use reflection? Currently I just assume the command that comes in matches the file name of a user control. This is a bit of a hack. Rather than have a select case statement that says if string = "Dashboard" then call Dashboard.Execute(), is there a pattern for working with commands that originate as strings?

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  • I know of three ways in which SRP helps reduce coupling. Are there even more? [closed]

    - by user1483278
    I'd like to figure all the possible ways SRP helps us reduce coupling. Thus far I can think of three: 1) If class A has more than one responsibility, these responsibilities become coupled and as such changes to one of these responsibilities may require changes to other of A's responsibilities. 2) Related functionality usually needs to be changed for the same reason and by grouping it togerther in a single class, the changes can be made in as few places as possible ( at best changes only need be made to the class which groups together these functionalities) 3) Assuming class A performs two tasks ( thus may change for two reasons ), then number of classes utilising A will be greater than if A performed just a single task ( reason being that some classes will need A to perform first task, other will need A for second task, and still others will utilise it for both tasks ).This also means that when A breaks, the number of classes ( utilising A ) being impaired will be greater than if A performed just a single task. Can SRP also help reduce coupling in any other way, not described above? Thank you

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  • What kind of graphics would you like better? [ pictures ] [closed]

    - by Roger Travis
    I am looking forward to make an android game, something angrybirds style. I've already made my own engine and now have to decide what kind of graphics should I make. It could be either realistic, like that or a doodle-style like this Right now the first one looks more appealing to me... on the other hand, doodle-graphics are very easy to draw and their transparency doesn't seem to slow down the engine much. What do you think?

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  • Designing a user-defined list to be stored in a relational database - Should I include user index?

    - by Zaemz
    By index, I mean, as the user creates the list, each item receives an integer index for its place in that particular list. Since there will be a table of ListItems, I'd prefer to avoid using the name "Index" for the field. Then I was thinking - should I even include the list index in the database? I figured I would because the list would be created in the same fashion every time, then. Or I could order the list for the user based on its actual primary key, since the list items are created in succession anyway... What should I do?

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  • Integrating with a payment provider; Proper and robust OOP approach

    - by ExternalUse
    History We are currently using a so called redirect model for our online payments (where you send the payer to a payment gateway, where he inputs his payment details - the gateway will then return him to a success/failure callback page). That's easy and straight-forward, but unfortunately quite inconvenient and at times confusing for our customers (leaving the site, changing their credit card details with an additional login on another site etc). Intention & Problem description We are now intending to switch to an integrated approach using an exchange of XML requests and responses. My problem is on how to cater with all (or rather most) of the things that may happen during processing - bearing in mind that normally simplicity is robust whereas complexity is fragile. Examples User abort: The user inputs Credit Card details and hits submit. An XML message to the provider's gateway is sent and waiting for response. The user hits "stop" in his browser or closes the window. ignore_user_abort() in PHP may be an option - but is that reliable? might it be better to redirect the user to a "please wait"-page, that in turn opens an AJAX or other request to the actual processor that does not rely on the connection? Database goes away sounds over-complicated, but with e.g. a webserver in the States and a DB in the UK, it has happened and will happen again: User clicks together his order, payment request has been sent to the provider but the response cannot be stored in the database. What approach could I use, using PHP to sort of start an SQL like "Transaction" that only at the very end gets committed or rolled back, depending on the individual steps? Should then neither commit or roll back have happened, I could sort of "lock" the user to prevent him from paying again or to improperly account for payments - but how? And what else do I need to consider technically? None of the integration examples of e.g. Worldpay, Realex or SagePay offer any insight, and neither Google or my search terms were good enough to find somebody else's thoughts on this. Thank you very much for any insight on how you would approach this!

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