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frontend

Frontend

This is the frontend, which consumes the exposed Trubudget API.

Peer dependencies

This project is based on the create-react-app starter kit provided by the Facebook Incubator. The main part of the project configuration is encapsulated into the create-react-app and not accessible. If you need to access project configuration you can eject the project, which will then move the configuration into the project. More information here: https://github.com/facebookincubator/create-react-app

Production vs. Development Mode

It is common for Modern Single Page Application to run in in different modes. This also apply to the TruBudget frontend. We decide between:

  • Development Mode: Is started with node and offers JIT, Hot Reloading and Debug Logging. The node process spawns an own webserver, performance is degraded but developer experience is best
  • Production Mode: Application is pre-build and transpiled to an ES5 Version of Javascript (compatible with a variety of browser), no log output, optimized file-sized. The production mode outputs static files which need to be hosted on a separate webserver (in our case NGINX). Performance is best, developer experience (due to compiling and deployment to separate server) lowest.

Using the frontend in Development Mode

When actively developing the frontend, it makes sense to do so in the Development mode. Developing the frontend brings two challenges:

  • Quickly add or adapt functionality in the frontend
  • Interact with the frontend to test the changes (and therefore attach it to an API)

Install & Run the Frontend

Running the frontend on your machine is pretty easy. Please ensure you have an up to date version of node (>= 8.9.0).

If you have yarn installed:

yarn install
yarn start

or, if you have npm installed:

npm install
npm start

After some compilation it will open the browser and load the frontend. But the first thing you will realize, the frontend won't allow you to do much. You need a "backend" (therefore an API + BC) to make the frontend work.

Proxy the API calls of the Frontend

The frontend needs to talk to the API, but since the Frontend is hosted in its own and separate NodeJS environment, accessing the API will result in a CORS error. To make development easier, the node environment is able to proxy API requests (more here).

Therefore adapt the route to your api in the package.json file.

  "proxy": "http://localhost:33331"

Using the frontend in Production Mode

Modern Single Page Applications need to be transpiled to be compatible to older browser versions. On top of that, the Application is minimized, uglified and bundled into a single file for maximum performance. You can create a production build by:

yarn build

or, if you have npm installed:

npm run build

This will create a production build of the application which will be located in the build/ folder. The content of the folder needs to be simply put on a webserver. If you are interested on how your application performs in production mode, you can simply use the Dockerfile.

docker build -t trubudget-frontend .
docker run -p 80:80 -it trubudget-frontend

This will build the application and run it in an NGINX webserver which is accessible under http://localhost/ Similar to the development mode we need to proxy the API calls.

Reverse proxying API in NGINX

In production we use NGINX to act as reverse-proxy. That means, the browser will request http://localhost/ for static resources (like the html, js, images) which will be served by NGINX. On top of that, the Application will try to connect to the API through http://localhost/api which obviously cant be served through NGINX (in fact the API might run somewhere).

The solution is to proxy the calls to the designated API's (e.g. API or Test-API). This can be done by configuring the nginx.conf file.

If you take a look at the NGINX config nginx.conf you will see that the proxy is not configured. Thats because we run a script to configure the API locations dynamically when the Dockerfile is running (see configureServer.sh).

The Proxy Paths are defined through 2 environment variables of the container:

  • API_HOST (default: localhost)
  • API_PORT (default: 8080)

That means, running the following docker commands

docker build -t trubudget-frontend .
docker run \
  -p 80:80 \
  -e API_HOST=127.0.0.1 \
  -e API_PORT=8080 \
  -it trubudget-frontend

will result in the following nginx.conf file.

location ^~ /api/ {
  proxy_pass http://api:8080/;
}

Here you can see how NGINX is reverse-proxing the requests to the API endpoints to the respective APIs. If you run the API's under a separate hostname you have to adapt this file.

Architecture

public Folder

The public folder contains all static assets. During development mode (when started with npm start) the content is accessible under http://adress/.

src Folder

All Javascript code which needs to be transpiled must be in this folder. During build it will be transpiled and bundled and included into the index HTML file

Inside the src folder the Javascript files are separated into a pages directory and plain javascript files (e.g. api.js). The pages directory contains all code which is specific to certain pages on the frontend (e.g. Notification Page). The plain javascript files are covering logic which is needed across several pages (e.g. API, Stores).

State management

Redux is the state management library of choice. In general the complete state of the application is running through the Flux-like flow of Redux.

Redux Components

The main store and root reducer is defined in src/store.js and src/reducers. When adding new pages, and in therefore new reducers, you need to add them to the root reducer.

In general the essential building blocks of redux (e.g. actions, reducers) are inside the page specific folders (e.g. src/pages/Navigation/actions.js). To use redux together with React wie use

Code styling

Indenting and formatting rules are described in the .editorconfig which can be found inside the root folder. Make sure using an editor which can read EditorConfigs (e.g. Atom, Visual Studio Code).

Linting is done through ESLint but the configuration is abstracted away through the create-react-app interface.

User Management

The initial users are bootstraped via API when the applications are started and if you want to add additional users the frontend provides an admin dashboard. The admin dashboard is reachable via Login Page or directly on the /admin endpoint. Use the admin credentials to login onto the dashboard. If BC_ADDRESS_VERIFICATION is disabled each frontend with the corresponding blockchain node is able to add users and roles, otherwise if BC_ADDRESS_VERIFICATION is enabled only blockchain nodes with admin rights are allowed to add users and roles.

Email notifications

To enable/disable email notifications for blockchain simply set the REACT_APP_EMAIL_SERVICE_ENABLED to "true" or unset it. When enabled the frontend requesting a email-notifications readiness call when entering the login screen. If the email notification service is ready the email section in the user profile is activated and visible so the user can create/edit the email-address where he/she wants to get notifications to. More details about the email notification service can be found in the email notification documentation

Environment Variables

See Environment Variables