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Questions tagged [validation]

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Rails validation: Which method is preferred

In Ruby on Rails there are two ways to validate, for instance, the presence of input fields. Say I want to make sure the user has filled out my fields called value and name. I could put in my model ...
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  • 121
2 votes
0 answers
389 views

What's the best pattern to validate a conditional entity? [duplicate]

I'm developing an ASP.NET MVC 5 website and I have a view with a grid. In this grid I have a column which represents an URL property. This url is a link to download some files, but this url should be ...
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  • 153
2 votes
4 answers
143 views

If I have a method that needs verification in order to proceed, do I call it inside the method or before? [duplicate]

This has been bothering me. This is more of a pragmatic problem than technical. Imagine I have a SaveOrderChanges method which, as its name implies, will save the order changes when the user submits ...
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  • 275
1 vote
1 answer
595 views

File validation rules

I have an application that can accept CSV files to run some operations. The files look like: CREATE USER:username,last_name,first_name,age user1,Smith,John,23 user2,Poppins,Mary,257 There are a ...
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  • 1,177
2 votes
2 answers
999 views

When writing a library or an API, when should and when shouldn't I validate or automatically correct errors in data provided by another developer?

I have a fairly good understanding of when data validation should and shouldn't exist when it comes when writing an application that is only dealt with by an end-user, and all the different tiers of ...
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4 votes
3 answers
156 views

How do I model this relationship so that it is valid by construction?

Imagine a device class that represents a physical real world mobile device, with fields like Enabled, Platform, Model IMEI, etc. Then, an operation class, which is something that needs to be done to a ...
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  • 267
30 votes
7 answers
7k views

Should I validate a method call's return value even if I know that the method can't return bad input?

I'm wondering if I should defend against a method call's return value by validating that they meet my expectations even if I know that the method I'm calling will meet such expectations. GIVEN User ...
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  • 1,277
1 vote
2 answers
3k views

Pattern for validating rules having different signatures

I have a class in charge of responding to an input event and maybe triggering another event. To decide, it has several rules to check. I'm trying to get away from a class looking like this: public ...
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  • 135
2 votes
1 answer
405 views

Use of validators for simple validations

I've been working in Liferay code, and I've come across this construct a few times: List<?> list; ... if (Validator.isNotNull(list)) { //do stuff }} The source code for Validator.java ...
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  • 643
1 vote
1 answer
1k views

Always set form input max length?

Background I'm looking to put together a single page web application with many form inputs. I've run into issues with other web pages where there is an ugly SQL error sent to the user if the ...
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  • 113
8 votes
2 answers
2k views

What is best practice to handle whitespaces when letting the user edit the configuration, the name=value pairs?

For instance, you let the user define the notorious path variable. How do you interpret apppath = C:\Program Files\App? This looks like a programming language adopted practice to ignore the white ...
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  • 1
1 vote
0 answers
226 views

How to consume inconsistent REST API with Mongo DB backend?

We are using a third party REST API and we are building one of the pages on our ASP.NET site around the data it delivers. We get results in JSON, and interact with it mostly using .NET MongoDB Driver. ...
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  • 181
2 votes
3 answers
502 views

Coerce bad input or always crash early

The general consensus seems to favor the Crash Early approach, the most reputable source being the acclaimed Pragmatic Programmer book. And while I understand and agree with the advice in many ...
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2 votes
2 answers
4k views

Why all consider UAT a validation activity? It contradicts the original idea

Virtually any book dealing with software testing mentions that user acceptance testing (UAT) is an ultimate validation activity, often quoting Boehms informal definition: "Validation: Are building the ...
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6 votes
6 answers
4k views

Domain Model, validation, and pushing errors to the model

Looking into DDD and something I noticed is that business logic should be in the model, otherwise you just have property bags. That said how do you handle pieces of validation that require a trip to ...
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  • 161
7 votes
8 answers
891 views

Do objects with validation logic in their domain really represent their real world counterparts?

I asked a question about whether validation behavior should be treated the same as other types of behavior in regard to the concept of OOP being "data + behavior". I got some good answers back that ...
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  • 459
6 votes
3 answers
5k views

OOP: Behavior + Data, but what about 'validation' behaviors?

EDIT: Thanks for all the great answers! In reading these responses I realized that I'm approaching this from the wrong angle so I wrote a new question here. I had this discussion with my superior ...
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  • 459
4 votes
1 answer
367 views

Difference between patterns: Specification, Guarding, Conditions, Monads, Validation,

I'm currently trying to get my head around a few patterns (especially the ones mentioned in the title above) that are made to address different problems and are being used in different parts of the ...
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  • 151
1 vote
1 answer
796 views

Is there a set of standards for data validation rules? [closed]

I'm trying to develop a generic data validation engine for web forms. Basically, the idea is to write a library that loads a JSON "validation schema", and then generates the appropriate server-side ...
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  • 329
3 votes
2 answers
254 views

Should I throw guard exceptions that will be thrown by internal methods anyway? [duplicate]

I have some fairly simple code (C#): /// <summary> /// Truncates a string to a maximum length. /// </summary> /// <param name="value"> The string to truncate. &...
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  • 1,194
1 vote
2 answers
1k views

Where should the "not empty field" validation code be written on a 3-layer application?

When working with the 3-layer model, where should the validation code be placed? for: not empty fields, unchecked options, null values, wrong-written dates, etc. To keep total isolation between a ...
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  • 113
1 vote
2 answers
426 views

Writing a simple code validator

I know that programming languages can be defined in EBNF which can be converted into regular expressions. Right now I am working on a very simple BASIC interpreter for a project. The code has to be ...
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  • 133
5 votes
2 answers
1k views

Where to put format validation in a CQRS “stylish” domain model?

It feels right to put format validation inside the domain objects (VOs or entities) because it is the natural place for high cohesion and the domain knows best what every domain description/attribute/...
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  • 153
2 votes
3 answers
352 views

Property value validations on POCO entities

Sorry in advance if this question is so trivial. The situation There is a Customer entity whose ID is limited to two letters (A to Z) in the database. Also, a user can enter the ID value from a ...
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1 vote
1 answer
2k views

Presenter accessing the value in text box using sender object

I have following method in my presenters which validates the user inputs on the UI. Basically to capture the value of the text property of the text box, it uses sender object which was passed in by ...
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  • 315
3 votes
4 answers
140 views

Can I save & store a user's submission in a way that proves that the data has not been altered, and that the timestamp is accurate?

There are many situations where the validity of the timestamp attached to a certain post (submission of information) might be invaluable for the post owner's legal usage. I'm not looking for a service ...
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19 votes
4 answers
7k views

Managing client-side and server-side validations in one place

I'm 100% on board with the case that one should definitely use both client-side and server-side data validations. However, in the frameworks and environments I've worked in, the approaches I've seen ...
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  • 2,331
2 votes
2 answers
792 views

Allowing enum to express a valid combination of values

Suppose in a manufacturing environment, there are certain stock materials available for use in a product. For example, there are only a few different sizes of copper tube, each having a specific ...
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  • 167
3 votes
2 answers
391 views

Is input validation necessary?

This is a very naive question about input validation in general. I'm a MATLAB user (1.5 years old) and I learned about input validation techniques such as "parse" and "validatestring". In fact, ...
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0 votes
1 answer
289 views

DataSet Validation vs. ASP.NET MVC Validation

I have a general question on where to put validation. I have an asp.net mvc that gets/sets data from/to a DataSet. Currently, the fields in the form are validated by the form itself (e.g. for ...
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  • 103
5 votes
4 answers
13k views

Best way of validating Class properties

Background: I have a CSV file, which I need to ready and validate each element in each row and create a collection of a class, having valid data. i.e CSV File looks like: EmpID,FirstName,...
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0 votes
1 answer
97 views

How to prevent re-checking already-checked data?

I have a class with a validId($id) method that is called by the constructor and by public function load($id). The method queries the database to see if the id exists and returns true/false. The ...
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1 vote
3 answers
3k views

How can I write complex validation and business logic that can be reused in both direct data model changes and pending dialog changes?

I was hoping for some advice: I need to design a software solution for a medium-sized java / Swing application. The application will have about 200 use cases requiring complex data validation and ...
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2 votes
3 answers
287 views

Can Setter Validation affect performance?

In a scenario where you use an ORM to map your entities to the DB and you have setter validations (nullable, date lower than today validation, etc), every time the ORM gets a result, it will pass into ...
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  • 167
5 votes
2 answers
3k views

Validation and data persistence in a domain model

My (first and current) workplace (a .NET shop) suffers from an over-abundance of anemic domain models, to the extent that I don't really know how validation and data persistence should be handled in a ...
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  • 828
11 votes
2 answers
4k views

Where to validate domain model rules that depend on database content?

I'm working on a system that allows Administrators to define Forms that contain Fields. The defined Forms are then used to enter data to the system. Sometimes the Forms are filled by a human via a GUI,...
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0 votes
4 answers
308 views

Should user input of a contact form be validated?

On software company websites I visit the first time, I often open the "Contact us" page and try to submit the contact form with all fields empty. I am just curios if they validate the user input. If ...
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  • 796
11 votes
1 answer
5k views

Duck typing, data validation and assertive programming in Python

About duck typing: Duck typing is aided by habitually not testing for the type of arguments in method and function bodies, relying on documentation, clear code and testing to ensure correct use. ...
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  • 362
10 votes
6 answers
4k views

If the model is validating the data, shouldn't it throw exceptions on bad input?

Reading this SO question it seems that throwing exceptions for validating user input is frowned upon. But who should validate this data? In my applications, all validations are done in the business ...
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12 votes
5 answers
995 views

Strengthening code with possibly useless exception handling

Is it a good practice to implement useless exception handling, just in case another part of the code is not coded correctly? Basic example A simple one, so I don't loose everybody :). Let's say I'm ...
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  • 453
4 votes
8 answers
3k views

Best Practice for Argument Checking

Say I have a web service with a method MyWebServiceMethod(string passedValue). The web service calls a method MyServiceMethod(string passedValue) where the value from the web service is passed along. ...
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4 votes
3 answers
399 views

Complex Mutual Exclusion Validation Logic

I need to validate some form inputs in complex way. E.g. <select id="options" multiple="multiple"> <option>A</option> <option>B</option> <option>C</option&...
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4 votes
3 answers
549 views

Approach to use for user email address change in application?

As the title says, if the user wants change their email address in the application, in terms of programming, what approach (process) to use? Where do you store the new email address until the user ...
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  • 149
4 votes
7 answers
6k views

Why validate XML?

I am looking for an explanation on just why XML needs to be validated. I have been testing DTD's and Schema's for the past month and recently tried to find out why I am doing this. I know it makes the ...
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1 vote
3 answers
1k views

Form validation and file structure

I have a form (lets say a registration form) and onsubmit, it calls a function to validate as follows: $.ajax({ url : "/ajax/validate.php", type : "POST", data : $(".form")....
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  • 139
4 votes
2 answers
4k views

What is the best practice for method parameter validation in a library? [closed]

I develop a game library in javascript, containing many classes. I hesitate on the behavior that I should follow concerning method parameter validation: Should I check the validity of parameters ...
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  • 159
4 votes
2 answers
1k views

Design strategies for storing and validating serial numbers

We are writing software to track Foo Widgets. Each Foo Widget has a serial number. The serial number is an 32-character alphanumeric string. The string is separated into five sets. Each set is ...
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2 votes
2 answers
426 views

How do you track third party services SSL certificates?

Recently Windows Azure Storage SSL certificate unexpectedly expired and since a lot of dependent services defaulted to "refuse to connect to a site with expired SSL certificate" that became a serious ...
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  • 4,309
20 votes
6 answers
12k views

Validation of the input parameter in caller: code duplication?

Where is the best place to validate input parameters of function: in caller or in function itself? As I would like to improve my coding style, I try to find the best practices or some rules for this ...
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  • 345
1 vote
1 answer
494 views

What is a practical level of abstraction in a web application? [closed]

(Originally asked on StackOverflow - https://stackoverflow.com/questions/14896121/what-is-a-practical-level-of-abstraction-in-a-web-application) I still consider myself a newcomer to OO programming, ...
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