Table of Content

• Introduction
• Required Tools Needed
• Setting Up
  • Cloudinary Account
  • Visual Studio
  • Auth0 Account
• Coding Proper
• Test One
• Adding Cloudinary Credentials to the Project
• Test Two
• Test Three
• Test Four
• Cloudinary Check
• Adding Auth0 to the Project
• Test Five
• The End

We are going to build an image or photo gallery using Cloudinary Api as the remote image server, Auth0 for authentication with C# Asp.Net Core as the backend technology. This project is aimed at providing a working tool for human right activist by automating image upload process as they embark on their work in difficult and hazard situations. The users of this tutorial must have some proficiency in C# technology.

Required Tools We Need

1. Sign up with Cloudinary
2. Get Visual Studio 2019
3. Sign up with Auth0
4. Note pad
5. Sql server

Setting Up
Cloudinary Account

The first thing to do is to sign up on Cloudinary here https://cloudinary.com/documentation/cloudinary_get_started so that we can get access to the required Api for image upload.
Upon successful sign up, the following are automatically generated for you:
Cloud name:
API Key:
API Secret:
API Environment variable:

So click on the account settings section to see what your Api key, Cloud name and Api secret are. Copy out this values and keep it in your notepad.
Since we intend to use Cloudinary within a DotNet application, we will rely heavily on this Cloudinary documentation for DotNet https://cloudinary.com/documentation/dotnet_integration.
At this moment, this would be all for Cloudinary. Next we set up our coding environment.

Setting Up
Visual Studio
The IDE for this project is visual studio 2019, so open your browser and go to https://visualstudio.microsoft.com/downloads/ click on Visual studio 2019 and download the community version.
Installation and set up procedure for the visual studio 2019 can be found here https://www.tektutorialshub.com/visual-studio/how-to-download-and-install-visual-studio-2019/
Launch the newly installed app and select create a project and select Asp.Net Core Web Application Net 5 as the version. Lets call the name of this project ImageGallery.

Fig 1.0
Run the project to ensure everything is fine.

Fig 1.1
You should see a web browser fired up automatically similar to this shown below:

Fig 1.2
Go to the Url section of this page above and now copy the text written there. This should be similar to this https://localhost:44375/ . This value will be our call back Url which will be used much later in the project. For now just save it inside your notepad:
Setting Up
Auth0 Account

If you don’t already have an account with Auth0, the first thing you have to do us is to sign up for free by using this link https://auth0.com/ click the sign up button to sign up and follow the prompts.
Choose a Region where you want the app to be hosted then click the Create account button.
Next click on the link written “Create Application” it is similar to the figure below.

Fig 1.3
The Auth0 service will ask that you supply the following values such as :

• Name: This is asking you to fill in the name of your DotNet application
• Application Type: Select the type of application you want to build
• What Technology are using to build your project :Select Asp.Net Core v3

A client Id number will be automatically generated for you, copy this and paste it inside the notepad.

Fig 1.4

Next you have to make Auth0 to be aware of your Asp.Net app, by clicking the Settings button in the figure above.

Fig 1.5

Copy and paste the following parameters Name, Domain, Client Id, Client secret which were automatically generated for you into the notepad document above.
Scroll down to the Application Url section of the settings, copy the call back Url from the notepad and paste this into the “Allowed Call Back Url” box and then attach /callback at the end of the text.
Next we also copy and past the call back Url into the “Allowed Logout Url”

Fig 1.6
Let’s quickly have a snap shot of what we have in our notepad file

Fig 2.0

Coding Proper
We will return now to the visual studio and start proper coding for the project.
Right click on the solution file and click add new project. This will take you to the same screen where we selected the type of Asp.Net core template that we chose initially.
Go to the search box and type class library and select Class Library (.Net Core), name this SimpleImageGallery.Data
We need one more class library so repeat the process a second time but this time around, we will call the name of this class library SimpleImageGallery.Services.

Fig 2.1
We will refer to SimpleImageGallery.Data as the Data layer. This layer will handle all data access issues such as entity model classes, database class , Migration files etc.
We will refer to SimpleImageGallery.Services as the Service layer.

Project Referencing

Now we need to make the three separate projects above communicate with each other.
Starting from the ImageGallery project, click on dependencies, add SimpleImageGallery.Data and SimpleImageGallery.Services respectively as dependencies.
Now move to the SimpleImageGallery.Services project add SimpleImageGallery.Data as a dependencies.
Now right click the data layer and add a folder, name this folder Models, add a class, to the Models folder name this class GalleryImage.cs
Entity Models

We add another entity class Image tag

Right click on the web ImageGallery project and select ManageNugget package.
add Microsoft.EntityFrameworkCore.Design as dependency.

Database Context
Next we need to add the Database context class lets call this class SimpleImageGalleryDbContext.
The SimpleImageGalleryDbContext will represent our data access class i.e. the class via which we can talk to the database.
Add the following nuggets packages as dependencies.

Fig 2.2
We will add three different packages below to the data access layer one after following the process above.

1. MicrosoftEntityFrameworkCore (5.0.10)
2. MicrosoftEntityFrameworkCore.SqlServer (5.01.0)
3. MicrosoftEntityFrameworkCore.Tools (5.01.0)

Add DbSet properties to the SimpleImageGalleryDbContext and initialize it with the code as written below.
See the snippet below:

Fig 2.3
We need to add connection strings to the appsettings.json file
Just before the "AllowedHosts": "*" add the your connection strings.

Now we have to register the Sql server in the StartUp class.

Now we are all set to run our migration
Select Package manager console and type the command below Add-Migration firstMigration press the enter key.

Fig 2.5
Next enter this second command Update-Database at the PM> prompt and press enter.
Open your Sql server to confirm that your new database has been created there.

Fig 2.6
Now lets go over to the Web app project (ImageGallery) open it and add a class to the models folder there. Lets call this class UploadImageModel

Next we will add another class to the models folder and name it GalleryDetailModel. The GalleryDetailModel will have five properties as shown below.

Interface Declarations
Right click on the Data layer project and click add a class name it IImageService.
Copy the following codes into this interface class

Head over to the Service layer, add a new class which will implement the IImageService.
Create a constructor of the ImageService class and then inject an instance of the SimpleImageGalleryDbConetx class.

Fig 3.0
Copy the codes below as shown below

The GetWithTag is similar to the GetById method except that it returns the images alongside the tag description of each images.

Views
Return to the web project , right click on the Views folder and add another folder name it Gallery.
Add a file to the folder call name it Index.cshtml

Fig 3.1

Delete all the text in fig 3.1 replace with the codes below.

Also, right click on the Views folder and add another folder name it Image then add a new view file call it UploadImage.cshtml

Fig 3.2

The code above basically helps to create a form with a minimalist styling for presenting an image on the browser.
Controller
Add a new controller to the controller’s folder name it GalleryController. Inject the Image service as a constructor injection into this controller

Fig 3.3
Next we write the Http action method and name it Index

CSS Styling
Open the wwwroot folder in the web project, click the CSS folder and double click on the site.css file to open it.
This file already contains the basic CSS styling that is used to render the default Asp.Net core Mvc page when the project is run, we will only modify this file to accommodates the changes that we want to see whenever the Upload.cshtml file is rendered on the browser.
Add this code below to the site.css file

Add Upload Button
Next we need to add an upload button to the navigation bar so that we can begin to upload images to the database
To do this, open the _Layout.cshtml file located in the Shared folder. When this file is opened, it already contains some default codes used for rendering the layout.

Fig 3.4
Identify the portion of the _Layout.cshtml that has the code similar to the one below then delete

Lastly, before we test our application, go to the Startup class and lets modify the Mvc route.

Fig 3.5
Locate the app.UseEndPoints method and it should look like what is above.

Register Interface Service
Now we need to register the IImage interface class in the StartUp class by adding the snippet below.

Test One
Run the app, you should see a web browser similar to this below

Fig 3.6
If you have a similar web browser as shown above then you should congratulate yourself, else, try to go over the steps above a second time so as to trace where you missed out.
Now you can see the Upload button has been successfully added but when the Upload button is clicked, we get a 404 page not found error, so lets fix this.

Image Upload Service
To be able to use the Cloudinary service in our project, we need to have an interface that will hold the implementation of how we want this Cloudinary Api to function within our application. So return back to the Web project, right click to add a folder name it Infrastructures.
Add an interface class to the Infrastructures name it ICloudinaryImageUpload.cs. Inside this interface class add the code snippet below.

Task UploadPicture(UploadImageModel model);

Add another class to the Infrastructures folder name it CloudinaryImageUpload.cs. This class has to implement the ICloudinaryImageUpload interface

Fig 4.0
Adding Cloudinary Credentials to the Project
Now we need to add the Cloudinary Api credentials that we got upon sign up into our project. We can hide this in the appsettings.json file. Now open the appsettings.json file and add the following code snippets as a json object.

Fig 4.1
Go to the CloudinaryImageUpload class and add the Cloudinary credentials to this class as a private properties

Fig 4.2
Next we initialize all the private properties of the Cloudinary Api credentials as shown below.

Now lets write the logic that will expose our application to the remote Cloudinary service

We will write a small private function to handle passing in tags when uploading images for us and then call it in the method above see code snippet below

Fig 4.3
Inside this controller class, we need two methods, the first will handle a Get Http action while the second will handle the POST Http action respectively.

Test Two
Run the application and click on the Upload button, you should see this exception shown in fig 4.4 below.

See the figure below

Fig 4.4

What the exception is saying is that we need to register the ICloudinaryImageUpload in the configure method of the StartUp class.
Now go to the configure method of the StartUp class and register the above Interface as a Scooped service using the codes snippet below:
services.AddScoped();

Your code should look like the image below

Fig 4.5
Test Three
Now we are ready to test our application again to see how we are doing.
Run the application and then click the Upload button.

Fig 4.6
Fill in the boxes, choose any image from your local machine and then click submit.

Fig 5.0

Test Four
For test four, we simply want to confirm that our uploaded images are stored up in the Cloudinary server and also on our local database.

Local DataBase Check
So lets check the database first,
Launch your Sql database, navigate to your database and open the GalleryImages table to check

Fig 5.1

Just pay attention to the Url of the last two images, we can see the Url path to the images we uploaded to the Cloudinary server sitting right there on our local database. You can copy this Url and past it into your browser to see the exact image.

Cloudinary Check
Next login into your Cloudinary account on the browser, click the Media Library button and you should see the uploaded image here.

Fig 5.2

Fig 5.3

At this point we are 85% done with our project.
Now we need to configure authentication.
Adding Auth0 to the Project

We will use the Auth0 authentication Api, which we have already signed up for at the beginning of this tutorial or you click here
The first thing we have to do is to add the Auth0 credentials i.e. Domain, ClientId, ClientSecret to the appsettings.json file
See the figure below

Fig 5.4

The next thing we will do is to go to the Web project and add the necessary nugget packages we need in other to be able to use theAuth0 authentication Api.
Go to the manage Nugget manager window and type this
Microsoft.Asp.NetCore.Authentication.OpenIdConnect, then install it.
Then we will follow the Auth0 DotNet documentation
here

Fig 5.5

Click here to learn more

Test Five

Launch the application again and click on Login button.
It should take you to the Auth0 login page see below.

Fig 5.6
Provide your username and password that you had used to sign up on Auth0 then click on Continue.

At this point we are sure that our application is working well.
But at the moment when a user clicks on the Upload button , the user is able to upload images immediately without login in into our application. This is not supposed to be so. The ideal situation is such that a user must login first before he or she could be allowed to upload an image.

To fix this, we return back to the ImageController and then add the Authorize attribute on the Upload action method see Fig 6.0 below.

Fig 6.0
Test the application again by clicking on the Upload button and then the application should immediately direct you to the Auth0 login page as above.

This is the end of this tutorial.

Please drop me comments, questions, let me know about what you are building with what you have learnt.
The entire code can be found here
Thank you for your time.
Content created for the Hackmamba Jamstack Content Hackathon using Auth0 and Cloudinary