# Bower Repositories

The Bower format is not compatible with H2 or PostgreSQL databases.

[Bower](http://bower.io/) is a package manager for front-end web development. JavaScript developers using Bower gain convenient access to a large amount of packages from the remote Bower registry. This reduces the complexity of their development efforts and improves the resulting applications.

Earlier versions of Nexus Repository supported the Bower registry format for hosted and proxy repositories. This allows the repository manager to take advantage of the packages in the official Bower registry and other public registries without incurring repeated downloads of packages.

The official Bower registry is available for searches at [http://bower.io/search](http://bower.io/search) and for package retrieval via the URL `https://registry.bower.io`.

You can publish your packages to a private Bower registry as a hosted repository on the repository manager and then expose the remote and private repositories to Bower as a repository group, which is a repository that merges and exposes the contents of multiple repositories in one convenient URL. This allows you to reduce time and bandwidth usage for accessing Bower packages a registry as well as share your packages within your organization in a hosted repository.

## Proxying Bower Repositories

You can set up a Bower proxy repository to access a remote repository location, for example, the official Bower registry at `https://registry.bower.io` which is configured as the default on Bower.

To proxy a Bower registry, you simply create a new _bower (proxy)_ as documented in [Repository Management](https://help.sonatype.com/en/repository-management.html "Repository Management") in detail.

Minimal configuration steps are:

- Define _Name_
- Define URL for _Remote storage_ e.g. `https://registry.bower.io`
- Select a _Blob store_ for _Storage_

The Bower-specific configuration section includes the setting to enable the rewrite of package URLs. This causes Bower to retrieve components and their dependencies through the repository manager even if original metadata has hard-coded URLs to remote repositories. This setting Force Bower to retrieve packages via the proxy repository is enabled by default.

If deactivated, no rewrite of the URL occurs. As a result, the original component URL is exposed. Turning off rewrite capabilities proxies the information directly from the remote registry without redirecting to the repository manager to retrieve components.

## Hosting Bower Repositories

Creating a Bower-hosted repository allows you to register packages in the repository manager. The hosted repository acts as an authoritative location for these components. This effectively creates an asset that becomes a pointer to an external URL (such as a Git repository).

To add a hosted Bower repository, create a new repository with the recipe _bower (hosted)_ as documented in [Repository Management](https://help.sonatype.com/en/repository-management.html "Repository Management").

Minimal configuration steps are:

- Define _Name_ e.g. `bower-internal`
- Select _Blob store_ for _Storage_

## Bower Repository Groups

A repository group is the recommended way to expose all your Bower repositories from the repository manager to your users, with minimal additional client-side configuration. A repository group allows you to expose the aggregated content of multiple proxy and hosted repositories as well as other repository groups with one URL in tool configuration. Do this by creating a new repository with the _bower (group)_ recipe as documented in [Repository Management](https://help.sonatype.com/en/repository-management.html "Repository Management").

Minimal configuration steps are:

- Define _Name_ e.g. `bower-all`
- Select _Blob store_ for _Storage_
- Add Bower repositories to the _Members_ list in the desired order

## Installing Bower

Bower is typically installed with npm. Since the repository manager supports NPM repositories for proxying, we recommend configuring the relevant NPM repositories and npm as documented in [npm Registry](https://help.sonatype.com/en/npm-registry.html "npm Registry") prior to installing Bower. Once this is completed you can install Bower with the usual command.

```
npm install -g bower
```

Bower version 1.5 or higher is required and can be verified with

```
$ bower -v
1.7.7
```

In addition, Bower requires a custom URL resolver to allow integration with Nexus Repository. The resolver is an API introduced in Bower version 1.5. Bower fetches component and version information through the repository manager, then automatically searches and saves the component in the repository. You can install the resolver with:

```
npm install -g bower-nexus3-resolver
```

Alternatively you can install the resolver on a per-project basis instead by adding it as a dependency in your `package.json`:

```
"devDependencies" : {
   "bower-nexus3-resolver" : "*"
}
```

## Configuring Bower Package Download

Once you have set up your repositories for Bower packages, and installed Bower and the custom resolver, you can create a `.bowerrc` JSON file to access registry URLs. The `registry` value is configured to access the Bower repository group that exposes the proxy and hosted repositories together. The `resolvers` configuration is necessary so that Bower uses the required custom resolver.

**Global `.bowerrc` file in your home directory for package download via the group bower-all**

```
{
  "registry" : {
    "search" : [ "http://localhost:8081/repository/bower-all" ]
   },
 "resolvers" : [ "bower-nexus3-resolver" ]
}
```

The `.bowerrc` file can be located in various locations. For global configuration for a specific developer working on multiple projects, the user's home directory is a suitable location. If multiple files exist, they are merged. Details can be found [in Bower configuration documentation](https://bower.io/docs/config/).

With this configuration in place, any further Bower command invocations trigger package downloads via the repository manager.

Running an `install` command logs the download via the repository manager:

```
$ bower install jquery
bower jquery#*
  not-cached nexus+http://localhost:8081/repository/bower-all/jquery#*
bower jquery#*
  resolve nexus+http://localhost:8081/repository/bower-all/jquery#*
bower jquery#*
  resolved nexus+http://localhost:8081/repository/bower-all/jquery#2.2.0
bower jquery#^2.2.0  install jquery#2.2.0

jquery#2.2.0 bower_components/jquery
```

If anonymous access to the repository manager is disabled, you have to specify the credentials for the accessing the repository manager as part of the URL like `http://username:password@host:port/repository/bower-all` and add a `nexus` section to your `.bowerrc` file.

```
{
  "nexus" : {
    "username" : "myusername",
    "password" : "mypassword"
  }
}
```

Downloaded packages are cached, do not have to be retrieved from the remote repositories again and can be inspected in the user interface.

## Browsing Bower Repositories and Searching Packages

You can browse Bower repositories in the user interface inspecting the components and assets and their details, as described in [Searching for Components](https://help.sonatype.com/en/searching-for-components.html "Searching for Components").

Searching for Bower packages can be performed in the user interface, too. It finds all packages that are currently stored in the repository manager, either because they have been pushed to a hosted repository or they have been proxied from an upstream repository and cached in the repository manager.

## Registering Bower Packages

If you are authoring your own packages and want to distribute them to other users in your organization, you have to register them to a hosted repository on the repository manager. This establishes a metadata file in the repository that links to the source code repository. Typically this is a git repository. The consumers can then download it via the repository group as documented in [Configuring Bower Package Download](https://help.sonatype.com/en/bower-repositories.html#configuring-bower-package-download "Configuring Bower Package Download").

You can specify the URL for the target hosted repository in the `register` value in your `.bowerrc` file. If you are registering all packages you create in the same hosted repository you can configure in the your global configuration file e.g. located in your users home directory:

```
{
    "registry" : {
        "search" : [\
            "http://localhost:8081/repository/bower-all"\\
        ],
        "register" : "http://localhost:8081/repository/bower-internal"
   },
   "resolvers" : [ "bower-nexus3-resolver" ]
}
```

Alternatively, if you desire to use a per-project `.bowerrc` file that you potentially version in your source code management system with the rest of the package code, you can use a simplified file:

```
"registry": {
   "register": "http://localhost:8081/repository/bower-internal"
   }
```

Authentication is managed in the same manner as for proxying with anonymous access disabled as documented in [Configuring Bower Package Download](https://help.sonatype.com/en/bower-repositories.html#configuring-bower-package-download "Configuring Bower Package Download"), e.g. `"register": "http://admin:admin123@localhost:8081/repository/bower-hosted"`. With this configuration, you can run a command such as:

```
bower register example-package git://gitserver/project.git
```

All semantic version tags on the git repository are now exposed as versions for this package and consumers can install the package via the repository group like any other package.

```
bower install example-package
```