Kimserey's blog

How does NgModule work in Angular The first time I saw the NgModule decorator and its arguments I was completely lost. I couldn’t understand what was the meaning of imports, declarations, exports, providers or bootstrap and I had a hard time finding clear explanations. So today I will go through each attributes and provide an explanation together with an example to understand what is the role of each NgModule argument. 1. How does a NgModule declaration look like? 2. Imports 3. Exports 4. Declarations 5. Providers The full source code is available on my GitHub https://github.com/Kimserey/ng-samples . 1. How does a NgModule declaration look like? Angular utilises the typescript decorators to define NgModule . It accepts imports , declarations , exports and providers . A typical declaration would look like that: import { CommonModule } from '@angular/common'; import { NgModule } from '@angular/core'; import { SquareComponent } from './square.component'...

Saving data with Entity Framework Core with SQLite Entity Framework is a framework abstracting away all the complexity of dealing with storage. This abstraction is also known as ORM ~ object-relational mapping. There is a number of provider which are implementation of the storage like SQL server or MySql or also SQLite, the one we will be seeing in this post. SQLite is a embedded database. The whole database is contained within a single .db file which makes it highly portable, so portable that it is the default database installed in mobile OS like iOS and Android . It is extremely easy to use and to maintain. It also offer a powerful implementation of SQL . Today we will see how we can make use of Entity Framework with SQLite provider in a ASP.NET Core application. 1. Install EF and create a new DbContext 2. Create migrations 3. Use in ASP NET Core 1. Install EF and create a new DbContext Start by installing the packages: Install-Package Microsoft.EntityFrameworkCore.SQL...

Razor syntax and helpers Razor is a HTML templating engine which allows us to construct HTML pages from a combination of data and HTML markup. The power of Razor resides in its typesafety and support for well known operators, conditional if else and iterators for while foreach . It allows us to directly use our C# models in the templates and call functions accessible by the view. Together with intellisense, it is quick way to build UI. Today we will explore some of the features from Razor: 1. Syntax 2. Layout and partial views 3. View components 4. Tag helpers 1. Syntax Razor expressions can written in two ways, implicit or explicit notation. For implicit notation, we start with @ and then we directly have access to values either from the view itself or some we created in the view or static functions. @{ var a = 10; } <label>@a</label> One useful property of the view is the Model . It gives access to the model linked to the page. By going @Model.XXX ...

Attribute route in ASP NET Core Attribute route in ASP NET Core is an easy way to define URL routes for Web API projects. There can be instance where it gets confusing because of all the options provided. Today we will see the meaning of the different options and how they affect the constructed route. This post will be composed by 3 parts: 1. Route attribute 2. Route values and token replacement 3. "/" or "" 1. Route attribute There are two ways to define routing, convention and attribute. When both are set, attribute route takes priority over convention route. In this post we will only discuss attribute route. Attribute route is specified using the [Route(...)] attribute. The route attribute can be set on controllers and actions. Setting the attribute on a controller will prefix all action route by the controller route. So for example specifying the following: Route("values") public class ValuesController: Controler { Route("list") ...

Opinions and decisions, how to be a successful team mate I have been working for more than 8 years in the software industry and have dealt with loads of developers from junior to senior.There are multiple points which can make a successful team mate. One of them is knowing when to express opinions and when to take decisions . One thing I have learnt is that decisions, forcefully agreed on, will most likely not be respected by the team. I also learnt that decisions come from opinions and the way we express opinions will dictate the level of respect team mates attributes to you and the level of trust they place in you. Just like in sport, respect and trust are the most important values to have. Today I would like to explore the different scenarios where we, as developer, should express our opinions and also when should we, as developer, take decisions. 1. Opinions Those are rules that I have followed and which have lend me into building lasting relationships with team mates. There a...

Filters in ASP NET Core - what are they and how to use them ASP NET Core comes with a concept of filters. Filters intercept the stages of the MVC pipeline and allows us to run code before/after their executions. They are meant to be used for cross-cutting concerns; logics which is required accross the whole application, generally not business oriented. One example is authorization where in a Web API, we would use to prevent unauthorized request to execute the code in our controllers. In order to do that we would have a filter at the entrance of the pipeline. In fact, ASP NET Core has predefine stages, the diagram can be found on the documentation https://docs.microsoft.com/en-us/aspnet/core/mvc/controllers/filters . Another example of a cross-cutting concern would be for logging and timing functions. While the concept of filters is easy to understand, the way to implement those aren’t always straight forward, especially when the filter instantiation itself requires simple objects. In ...

Different types of authorization in ASP.NET Core Last week I touched on how we could authenticate users using Resource Owner Password flow with identity server. Authentication is the act of taking the information provided and verifying the “identity” of the user, ensuring that Alice (our beloved example user) is who she “claims” to be. In the program itself, we take her credentials and verify it and create an identity stating that the user is Alice and has claims A, B and C. Authentication is the first part of the access security, the second part is the authorization. The difference being that for authorization, we know who the user is, what we are verifying is if Alice is allowed to perform what she is trying to perform. The easiest example is the difference between user access and admin access commonly seen in software where users are authenticated but aren’t authorized to perform all the actions available in the system. ASP.NET Core comes with a set of useful tools to perform a...