# CARTA Frontend
The CARTA frontend is used in conjunction with the [CARTA backend](https://github.com/CARTAvis/carta-backend), and for general use a pre-built production frontend is usually installed alongside the backend automatically. However, a user may wish to install the frontend component separately in order to test beta versions, for example, or to develop it.

## Pre-built production packages
The simplest way to install the frontend component is to use the pre-built production packages from NPM (for any OS with Node.js installed), our PPA (Debian packages for Ubuntu), or our RPM repository (for RHEL based systems).

### NPM

Pre-built production frontends can be obtained from the [npmjs.com carta-frontend repository](https://www.npmjs.com/package/carta-frontend?activeTab=explore).

If you have Node.js and `npm` already installed on your system, you can install a production frontend using the following command:

```
npm i carta-frontend
```
The files will be installed to your `node-modules` directory. For a system-wide 'global' installation (using the `-g` flag) this is located at `/usr/lib/node_modules`, whereas for a local user installation, it is located at `$PWD/node_modules`.

You can install specific frontend versions by appending `@` plus the version number. For example,
```
npm i carta-frontend@4.1.0
npm i carta-frontend@5.0.0-beta.1c
```
The available versions are listed in the [npmjs.com carta-frontend versions tab](https://www.npmjs.com/package/carta-frontend?activeTab=versions).

Alternatively, the pre-built production frontend can be downloaded directly without npm. For example,
```
wget https://registry.npmjs.org/carta-frontend/-/carta-frontend-5.0.0.tgz
```
The standalone `tgz` archive file extracts as `package/build` in your current directory.

You can start the CARTA backend with a non-default frontend by specifying its location with the `--frontend_folder` flag. For example,
```
./carta-backend --frontend_folder $HOME/package/build
```

### PPA

A Personal Package Archive (PPA) is a third-party package repository for Ubuntu. We supply pre-built production frontends at the [CARTAvis-team PPA on the Ubuntu Lauchpad](https://launchpad.net/~cartavis-team/+archive/ubuntu/carta).

To install the latest release version:
```
sudo add-apt-repository ppa:cartavis-team/carta
sudo apt-get update
sudo apt-get install carta-frontend
```

The Ubuntu package install location for the frontend is `/usr/share/carta/frontend/`.

The PPA also provides a `carta` metapackage which automatically installs the CARTA frontend and backend packages. In addition to the latest release versions, beta versions are provided in a parallel set of packages.


### RPM

RPMs are for users of Red Hat Enterprise Linux (RHEL) and other Red Hat-based Linux distributions, e.g. CentOS. 
To install the latest release version, add the appropriate repository file depending on whether you are using RHEL8 (**el8**) or RHEL9 (**el9**):

```
sudo curl https://packages.cartavis.org/cartavis-el8.repo --output /etc/yum.repos.d/cartavis.repo
```
or
```
sudo curl https://packages.cartavis.org/cartavis-el9.repo --output /etc/yum.repos.d/cartavis.repo
```
Then the frontend component can be installed using `dnf` or `yum`:
```
sudo dnf install carta-frontend
```
The RPM package install location for the frontend is `/usr/share/carta/frontend/`.

The RPM repo also provides a `carta` metapackage which automatically installs the CARTA frontend and backend packages. In addition to the latest release versions, beta versions are provided in a parallel set of packages.


## Development

If you wish to modify or develop the CARTA frontend, you may build a production or non-production frontend from source. Here are the instructions to do so:

### Prerequisites

The build process relies heavily on `npm` and `nodejs`, so make sure they are installed and accessible.

We recommend using [Docker](https://www.docker.com) or [Singularity](https://apptainer.org/docs/) to perform WebAssembly compilation. If neither is available, the Emscripten compiler (`emcc` version 4.0.3 recommended) needs to be available in the build environment. Installation instructions are available on the [Emscripten homepage](https://emscripten.org/docs/getting_started/downloads.html).

### Build process (using Docker/Singularity)
Initialise submodules and install package dependencies:
```
git submodule update --init --recursive
npm install
```
WebAssembly libraries can be built with `npm run build-libs-docker` or `npm run build-libs-singularity`.
Additional build steps (building WebAssembly wrappers, protocol buffer modules and compiling the Typescript code) are performed by `npm run build-docker` or `npm run build-singularity`. This produces a production build in the `build` folder.

To run a development build server, simply run `npm run start`. 

### Build process (without Docker/Singularity)
If your build environment does not have access to Docker or Singularity, WebAssembly compilation must be performed in an environment with access to the Emscripten compiler. 

Initialise submodules and install package dependencies:
```
git submodule update --init --recursive
npm install
```

WebAssembly libraries can be built with `npm run build-libs`.
Additional build steps (building WebAssembly wrappers, protocol buffer modules and compiling the Typescript code) are performed by `npm run build`. This produces a production build in the `build` folder.

To run a development build server, simply run `npm run start`.

## Developer documentation

Automatically generated documentation can be found at [cartavis.org/carta-frontend](https://cartavis.org/carta-frontend/).

[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.3377984.svg)](https://doi.org/10.5281/zenodo.3377984)
