How to add\pre-fill https://www. to input fields with type URL?

This is quick post for something I had to implement today. It's related to input fields with type="url".

What did I do?

Opened Visual Studio Code on the Views folder of a large ASP.NET MVC project and then searched for asp-for=(.*)URL using Regular Expression. That linked me to all the places (Razor .cshtml views) which had a @model (Model\ViewModel) class which happens to have an URL property.

Some of those Model\ViewModel properties didn't have the [Url] data annotation. I proceeded to add it to properties where it was missing. This data annotation is responsible for correctly generating the <input type="url" ... > on the HTML when using Razor's html helpers like this for example:

<input asp-for="Organization.URL" class="form-control">
It'll generate this HTML code:

<input class="form-control"
data-val-url="The URL field is not a valid fully-qualified http, https, or ftp URL."
With that in place I crafted some jQuery\JavaScript code that does the magic:

* For all inputs with type URL and which are empty,
* we add https://www. when the input has focus.
function addHttpsWwwToInputTypeUrl() {
$("input[type='url'][value='']").focus(function () {
The code is self-explanatory. It selects all inputs with type="url" and which are empty. Once the input gets focus, https://www. is added automatically to the input's value. The user now only has to complete the URL address. No more typing https://www. everytime.

The only thing necessary now is to call this JavaScript function in a central place so that it can be applied everywhere in your project.

That's it... a simple but nice user experience to have in your app. Hope it helps.

Creating a ReactJS To Do application with user Authentication\Authorization [ Introduction ] - part 1

This is going to be a series of posts in which I'll show how I managed to get a simple yet functional ReactJS application working. I plan to write 1 blog post per major component detailing how it works and integrates into the app.

This was my start with ReactJS and I worked in this application for almost 1 month as seen by the git commits here. I went from 0% ReactJS knowledge to to some % knowledge of how things work in this UI\presentation framework.


The motivation to learn it is that it's mainstream nowadays. ReactJS is also used to develop mobile apps... besides that, for a job application test I had to develop a To Do application with a set of requirements.


Programming assignment for web development candidates

You can choose any programming language and web development framework, database, and web server you like. The web application you need to build is a basic todo list application with the following requirements:

- Users can view their todo list;
- Users can add, remove, modify and delete todo entries;
- Each todo entry includes a single line of text, due date and priority;
- Users can assign priorities and due dates to the entries;
- Users can sort todo lists using due date and priority;
- Users can mark an entry as completed;
- You don't need to spend time on UI/UX design, if you do, it will be a bonus;
- Provide a RESTful API which will allow a third-party application to trigger actions on your app (same actions available in the app);
- Provide authentication and authorization service for both the app and the API;
- As complementary item to the last requirement, you should be able to create users in the system via an interface, eg a signup/register screen.

Web Tech Stack

I took the challenge! Developed a SPA - Single Page Application using ReactJS. Why not!? I also used Visual Studio Code as the IDE in tandem with the web tech stack in which I'm experienced with: C#, ASP.NET Core Web API, SQL Server, etc.

The App

The following is the app's homepage:

Figure 1 - App home page

The left side menu when clicked gives access to the Todos form and grid.

Figure 2 - Left side menu

The right side menu allows the user to login\logout and check their profile.

Figure 3 - Right side menu

In order to be able to access the Todos form\grid the user must be authenticated.

Figure 4 - Todo form + grid


Everything was developed in Mac OS and as such the database that stores todo data is an SQL Server container image running in Docker.

Figure 5 - SQL Server database image running in Docker


The Web API was implemented using an ASP.NET Core Web API project. There's also a Swagger protected help page configured.

Figure 6 - Web API Swagger help page

Source code structure

The following screenshots show how the code is structured:

Figure 7 - App structure in Visual Studio Code Explorer window

- src folder holds all the source code files for the ReactJs app.

- TodoApi holds the source code files for an ASP.NET Web API project.

The ReactJS project skeleton was created\bootstrapped with Create React App as described in the README file.

Expanding the src folder we have this:

Figure 8 - ReactJS SPA app source code files

Expanding the TodoApi folder we have this:

Figure 9 - Todo ASP.NET Web API source code files

App dependencies

The ReactJS app uses the following dependencies as listed in package.json:

"dependencies": {
"@auth0/auth0-spa-js": "^1.6.3",
"@date-io/date-fns": "^1.3.13",
"@material-ui/core": "^4.9.1",
"@material-ui/icons": "^4.9.1",
"@material-ui/pickers": "^3.2.10",
"@testing-library/jest-dom": "^5.1.1",
"@testing-library/react": "^9.4.0",
"@testing-library/user-event": "^8.1.0",
"axios": "^0.19.2",
"date-fns": "^2.9.0",
"formik": "^2.1.4",
"moment": "^2.24.0",
"react": "^16.12.0",
"react-dom": "^16.12.0",
"react-router-dom": "^5.1.2",
"react-scripts": "^3.3.1",
"react-toastify": "^5.5.0",
"yup": "^0.28.1"

Git history

The git history is a nice way to remember what I did along the way:

Git History on master by all authors

Adding Auth0 placeholders...
340657a (HEAD -> master, origin/master) by Leniel Macaferi , Sat May 02 2020 (54 minutes ago)
1 file changed, 2 insertions(+), 2 deletions(-)

Small fixes...
5b98458 by Leniel Macaferi , Fri Feb 21 2020 (2 months ago)
2 files changed, 3 insertions(+), 3 deletions(-)

- Added Roles claim... it's retrieved from Auth0 access_token; - Improved footer; - Added missing toastify messages; - Improved Profile.
2cd5cd3 by Leniel Macaferi , Tue Feb 11 2020 (3 months ago)
5 files changed, 84 insertions(+), 19 deletions(-)

- Added Bearer token support to Swagger so that it's now possible to authorize with a token prior to testing the Web API endpoints; - In TodoItemsController the current user is now extracted while getting Todos so that the user can only retrieve their todos; - Added User property to TodoItem model; - Externalized getUser from Auth0 so that it can be called from stateful ReactJS components like Todo.js; - Made use of getUser() on Todo component; - Beautified Profile component.
b704348 by Leniel Macaferi , Mon Feb 10 2020 (3 months ago)
8 files changed, 122 insertions(+), 19 deletions(-)

- Added scopes and protected Get Todos Web API call with read:todos scope. - Added Profile component
13a8675 by Leniel Macaferi , Sun Feb 09 2020 (3 months ago)
13 files changed, 173 insertions(+), 62 deletions(-)

- Made Get Todos protected by using [Authorize] attribute; - Added JwtBearer support to the ASP.NET Core Web API; - Moved BrowserRouter to index.js so that the works as expected. More info here: - Externalized getTokenSilently in Auth.js to be able to pass it to axios request interceptor.
ab74c14 by Leniel Macaferi , Sat Feb 08 2020 (3 months ago)
12 files changed, 182 insertions(+), 51 deletions(-)

Added Auth0 to be able to authenticate and authorize users.
7ab2538 by Leniel Macaferi , Fri Feb 07 2020 (3 months ago)
9 files changed, 892 insertions(+), 170 deletions(-)

- Added search todo functionality; - Improved the todos table by adding Table pagination actions and made the header sticky; - Improved todo form by disabling the save button when there are errors or when the form is not dirty yet, that is, the user has not changed anything yet; - Added global error message with the help of toastify;
2d59cf4 by Leniel Macaferi , Thu Feb 06 2020 (3 months ago)
5 files changed, 190 insertions(+), 44 deletions(-)

- Commented out InMemoryDatabase in the Web API project and started using a full featured SQL Server database with UseSqlServer. Accomplished that on Mac OS side using Docker and a Developer version of SQL Server 2017; More info here: - Added Swagger to the Web API project; - Changed Web API default port from 7777 to 8888; - Improved global Progress bar. Set its position to absolute so that it won't push content down when it is displayed; - Moved todo related components to their own folder.
581da74 by Leniel Macaferi , Wed Feb 05 2020 (3 months ago)
16 files changed, 72 insertions(+), 29 deletions(-)

- Added cancel button to todo form. This is useful when the user is editing a todo and wants to cancel the action; - Implemented an improved version of todo form using the HOC [Higher Order Component] withFormik; this allowed passing a parent component [Todo] function down to the child component EnhancedTodoForm which is hooked to the the TodoForm component; Amazing stuff! :-) - route icons are now dynamically retrieved; - Added react-toastify libray to be able to show customized messages to user.
469e858 by Leniel Macaferi , Tue Feb 04 2020 (3 months ago)
12 files changed, 328 insertions(+), 100 deletions(-)

- Added request and response interceptors to axios: ... this will allow a hooking place to display toasts (messages) to the user. This is one of the next thing to be added; - Added a menu tp AppBar using a Drawer component"; - Started using react-router:; - routes are exported from routes.js; - Added About and Home pages.
7412ec3 by Leniel Macaferi , Mon Feb 03 2020 (3 months ago)
17 files changed, 3682 insertions(+), 3186 deletions(-)

- Got editTodo working; - Improved themes; - Removed unused npm packages.
4afd71e by Leniel Macaferi , Sat Feb 01 2020 (3 months ago)
8 files changed, 158 insertions(+), 866 deletions(-)

- Delete todo(s) done; - WIP Edit todo; - Added axiosInterceptor which handles  the animation when any Web API is called. It shows a Material-UI ; - Externalized custom styles in themes.js; - Many improvements in Todos table.
9d3e032 by Leniel Macaferi , Fri Jan 31 2020 (3 months ago)
13 files changed, 236 insertions(+), 139 deletions(-)

Handling setSelected after deletion happens...
9be189f by Leniel Macaferi , Thu Jan 30 2020 (3 months ago)
1 file changed, 8 insertions(+), 3 deletions(-)

Added delete todo functionality with a gotcha:
5ad3cbd by Leniel Macaferi , Thu Jan 30 2020 (3 months ago)
7 files changed, 77 insertions(+), 52 deletions(-)

Added material UI Table component to be able to better visualize and operate on Todos.
febb4b3 by Leniel Macaferi , Thu Jan 30 2020 (3 months ago)
3 files changed, 371 insertions(+), 17 deletions(-)

- Created a global theme with createMuiTheme; - Improved AppBar - Got addTodo POST call to Web API working and TodoList updating as expected.
6f8a5fb by Leniel Macaferi , Thu Jan 30 2020 (3 months ago)
8 files changed, 700 insertions(+), 174 deletions(-)

Styled App structure and TodoForm with Material UI components.
38f169d by Leniel Macaferi , Wed Jan 29 2020 (3 months ago)
8 files changed, 357 insertions(+), 196 deletions(-)

Got Formik form fields working with material-ui
b309899 by Leniel Macaferi , Wed Jan 29 2020 (3 months ago)
10 files changed, 1027 insertions(+), 246 deletions(-)

- Added formik, yup and react-formik-ui. - Created a Todo form with formik.
bd8b355 by Leniel Macaferi , Mon Jan 27 2020 (3 months ago)
7 files changed, 771 insertions(+), 60 deletions(-)

Started integrating UI with Web API...
614c68e by Leniel Macaferi , Sun Jan 26 2020 (3 months ago)
9 files changed, 243 insertions(+), 83 deletions(-)

- Added ASP.NET Core 3.1 Todo Web API
06ce6d3 by Leniel Macaferi , Sun Jan 26 2020 (3 months ago)
15 files changed, 409 insertions(+), 4 deletions(-)

- Added handleChange event handler to todo-item component; - Handled todo complete state with setState; - Added Bootstrap:
c15ff51 by Leniel Macaferi , Sat Jan 25 2020 (3 months ago)
8 files changed, 147 insertions(+), 38 deletions(-)

Converted some functional components to ES6 classes.
64dad12 by Leniel Macaferi , Sat Jan 25 2020 (3 months ago)
3 files changed, 53 insertions(+), 30 deletions(-)

- Got todo items displayed from a todo list JSON file. - Used to create a React TodoItem component dynamically avoiding code repetition.
84cf3fc by Leniel Macaferi , Sat Jan 25 2020 (3 months ago)
5 files changed, 94 insertions(+), 25 deletions(-)

Created basic components and applied some styles including dynamic styling with JavaScript.
90ac727 by Leniel Macaferi , Sat Jan 25 2020 (3 months ago)
6 files changed, 128 insertions(+), 18 deletions(-)

Added .eslintrc.json and modified app name.
f1953ac by Leniel Macaferi , Fri Jan 24 2020 (3 months ago)
4 files changed, 14480 insertions(+), 1 deletion(-)

Initial commit from Create React App
04291f4 by Leniel Macaferi , Fri Jan 24 2020 (3 months ago)
18 files changed, 9789 insertions(+)

Source code

GitHub repository:

Figure 10 - GitHub repo with % of source code by type


So stay tuned because in the next part I'll start covering the components in a top down approach, that is, we'll start looking at the index.js file where everything gets hooked up.

Adding title attribute to Social Identity Providers [IDPs] buttons when using Azure AD B2C custom policies

This is a simple post that shows how you can achieve exactly what the blog title says...

You'll need only some jQuery code once you enable JavaScript for the custom policy.

By default the social login buttons are shown only with text. They don't have title attributes that are used as tooltips by default when hovering the button during 2 seconds or so.

Let's say that for the social IDPs buttons we want to show only the button logo instead of the button text to make the screen overall look & feel cleaner. However it'd be nice to show a title\tooltip to inform the user what IDP that button refers to in case they don't get it by only seeing the logo.

To accomplish that follow these 2 straightforward steps:

1 - Enable JavaScript execution inside UserJourneyBehaviors in your Azure B2C custom sign in\sing up policy .xml file:


2 - Add this code in the corresponding policy signin.html page:


    // Adding title to each Social button...
    $(".accountButton").each(function (index)
      var title = $(this).text();

      $(this).prop('title', title);


Once loading the B2C login page you should see something as this when you hover your cursor over any social IDP button:

Enabling and using JavaScript allows us to extend functionality in many places.

Automate moving measures between Power BI files .pbix, renaming and finding and replacing strings in DAX formula\expression

Yesterday I had to accomplish a task that got me thinking: this is going to take a hell of a lot of time to finish.

The user story is this: I have a Power BI .pbix file that is used somewhat as a staging\debugging file to try and test measures. Once the job is done I usually move things over to the final\main Power BI file which will be handed in to the client. Note that this final Power BI file already has report pages implemented. That's way I try things in a different file since the work can be done in a cleaner\faster model.
The problem this time was that I had to create\move lots of measures and so I'd have to do this measure by measure from the debugging file to the main file. It would take me about 1 hour to finish. Unfortunately Power BI has no built in copy\paste of measures between files as of today in its version 2.72.5556.801 64-bit (August 2019). At least we can copy and paste the visuals from one file to the other.

OK. Problem defined. Let's Google for a solution. The solution found was this awesome post titled Bulk measure handling (copy between reports/format changes). In this post the guy mentions the tool Tabular Editor. Well that was what I was looking for, really.

Just downloaded it directly from its GitHub repo here.

Followed the steps on that post and voilá: I could get more than 30 measures copied from one .pbix file to another. Great! This took me about 10 minutes to get done. 1\6 of the time previously estimated for that cumbersome\manual work. Check the following printscreen:

1st printscreen - measures moved from one Power BI file (on the left) to the other Power BI file (on the right)

2nd printscreen - batch renaming selected formulas in blue
There was another task that needed to be accomplished and it was a little bit different: needed to duplicate those copied measures. Tabular Editor makes it easy too. Just select all of them, right click and pick Duplicate # measures. Boom! You have all measures duplicated as seen in the printscreen on the right. Note that it adds a "copy" word to the measure name. So once the measures are duplicated we need to rename them and that's easy too. Select all duplicated measures, right click and pick Batch rename.

Just replaced the uppercase U in each formula name to a uppercase C as seen in the second printscreen above. Repeated the process and replaced " copy" with a blank string. That's it. Measures duplicated and renamed accordingly. Nonetheless there's still a missing step before theses measures are ready to go: change a table column name in the DAX formula\expression in each of these measures that got duplicated and renamed. How to get this done using Tabular Editor? Well, reading through its docs we can find this Advanced Scripting section. If you look at the first printscreen above you'll note that I wrote some C# code there that does exactly what is needed. See the code below:

Selected.Measures.ForEach(m => {
    var e = m.Expression;
        e = e.Replace("[Unit]", "[Company]");
        // For debugging purposes
m.Expression = e;     

What this piece of code is doing is that for each of the selected measures in blue on the left (see printscreens above), the measure DAX formula\expression is stored in a variable called e. I then check if this formula contains the word [Unit] that is the table column name that needs to be replaced. If the expression\formula contains this word it gets replaced with the word [Company] that refers to the other column name that is to be used in these duplicated formulas. After that the modified DAX formula is assigned back to the measure.

When finished with Tabular Editor, click Save. Return to Power BI and hit the Refresh button to reload the model.

This post is just a sample that showcases the power of Tabular Editor. You can manage and play with measures in any way imaginable.

I hope it helps someone that wants to accomplish trivial things in a more actionable way instead of having to copy\paste, rename and replace manually because that sucks.

Note: when trying to save back the modifications done in Tabular Editor an error was being displayed. Something along this line:

Failed to save modifications to the server. Error returned: 'Unexpected column name: Received column 'ObjectID.Expression' in rowset 'ObjectTranslations'. Expected column 'ObjectID.Set'.'.

I did the following to get rid of the nasty error message: opened Tabular Editor File menu and selected Preferences... checked "Allow unsupported Power BI features (experimental)". When we do this a new Translations folder appear in the Model tree. I just deleted the en-US that was under this folder (see printscreen below). Then tried saving again and it worked.

3rd printscreen - enabling Allow unsupported Power BI features (experimental) in Tabular Editor

Using IOptions from .NET Core in .NET Framework 4.5.1+ - Ninject dependency injection version

This post is based on this awesome article I found @ Medium:

Configuration Management in Legacy .NET Applications (.NET Framework 4.5.1+)

I wanted to use the cool IOptions interface to grab some configs from appsettings.json. The sad thing is that it's intended to be used with .NET Core but the article mentioned above tells us that we can circumvent that with some extension code.

I won't be able to use it anymore because I just found out that I can't in the current project setup I'm working on.

As I had already converted the AutoFac code to Ninject, I'm just sharing it here in case it's useful...

You'll need to test it.

Note: make sure you have installed the following NuGet packages:

- Microsoft.Extensions.Configuration
- Microsoft.Extensions.Options
- Microsoft.Extensions.Options.ConfigurationExtensions

Using Power BI parameter to specify Excel workbook path in Power Query

This is a quick post to share something that I did just now and that worked. I tried to search for some sample but couldn't find. Maybe my search query was not that right...

Let's say you use an Excel workbook as your data source in Power BI. Than you collaborate with a team and as we know, not everyone has the same folder structure setup. This can cause a problem when trying to Refresh data in Power BI. How can we "overcome" this in a simple way?

Just create a Power BI parameter and pass it to the Power Query responsible for opening the Excel workbook.

In the following printscreen you see that I created a parameter called Excel workbook path. I set this path to where the workbook is located in my machine.

Then we can use this parameter in Power Query like this:

= Excel.Workbook(File.Contents(#"Excel workbook path"&"Contingency Drawdown.xlsx"), null, true)

I was having some difficulty trying to make the string concatenation work, that is, joining the parameter with the workbook name. Tried some variants and got it working with the string concatenation token &.

As you see the workbook name doesn't change (it's hardcoded) however the path is customizable by the parameter "Excel workbook path".

We just need to change this parameter value to point to our folder structure and we're done. Now we can make use of this parameter to open all Excel sheets (tables in Power BI) in a single shot.

Hope it helps.


Power BI Introduction: Working with Parameters in Power BI Desktop —Part 4

Impersonation in Windows Service with ASP.NET Core

In a project one of the requirements was to be able to impersonate the current logged on Windows user.

The ASP.NET Core 2.1 project was hosted in a Windows Service. More info about this here:
Host ASP.NET Core in a Windows Service

The problem was that when doing WindowsIdentity.GetCurrent().Name; what was being returned was the account name used as Log On as for the service. That makes sense since it is that account that is executing the service.

This particular project needed to get the current logged on Windows user and check their permissions system wide, that is, check which claims the current user making use of the service has. Claims are the key component by which the outcome of all Web-based authentication and authorization requests are determined. More info on that here: The Role of Claims.

This way we can assure a user belongs to a specific User Group, the user has read permission on some folder, etc.

After trying some options, nothing worked. Then I decided to search for “Windows Authentication in ASP.NET Core” using Google and it lead me to this page: Configure Windows Authentication in ASP.NET Core.
Since we’re not hosting the app in IIS, that was a no go. However there’s another option below that page and it’s called HTTP.sys. HTTP.sys server supports self-hosted scenarios on Windows and that was the way to go.

First thing we need to do is make use of it when creating the WebHost object:

public static IWebHostBuilder CreateWebHostBuilder(string[] args,
    IConfigurationRoot config) =>
               // Using HTTP.sys for Windows Authentication support
               .UseHttpSys(options =>
                   options.Authentication.Schemes =
                   AuthenticationSchemes.NTLM | AuthenticationSchemes.Negotiate;
                   options.Authentication.AllowAnonymous = false;

Then in Startup.cs inside the method ConfigureServices we do:

// This method gets called by the runtime.
// Use this method to add services to the container.
public void ConfigureServices(IServiceCollection services)
    services.AddLogging(builder =>
        builder.AddFilter("Microsoft", LogLevel.Warning)
               .AddFilter("System", LogLevel.Warning)
    // HTTP.sys server
    // HttpSysDefaults requires the following import:
    // using Microsoft.AspNetCore.Server.HttpSys;

That's it.

Now to impersonate the user we do the following:

public async Task<IActionResult> MethodWithImpersonatedWindowsUser(
[FromQueryAttribute] string filePath)
    // The user used as Log On as for the Windows Service
    var serviceUser = WindowsIdentity.GetCurrent().Name;
    // The user to be impersonated
    var userToImpersonate = (WindowsIdentity)HttpContext.User.Identity;
    // Impersonating the current Windows user [HttpContext.User.Identity]...
    var result = await WindowsIdentity.RunImpersonated(
                                     userToImpersonate.AccessToken, async () =>
        // This time WindowsIdentity.GetCurrent() will retrieve the impersonated
        // user with its claims...
        var impersonatedUser = WindowsIdentity.GetCurrent().Name;
        // Your business logic code here...
    return result;

I saw lots of people asking the same question I made prior to knowing how to handle this requirement: why are we seeing the service user returned instead of the current logged on user when doing WindowsIdentity.GetCurrent()? The answers were to the point: in Windows you can have many user sessions (Remote Desktop, etc) where all are logged on at the same time making use of the Windows Service. So, how to get the current logged on user while still making use of the service? That must come from the HttpContext, that is, from the request arriving from the browser. WindowsIdentity.RunImpersonated makes it all possible. It runs the specified lambda action as the impersonated Windows identity.