Skeleton for Google Chrome extensions

• includes awesome messaging module
• grunt-based build system
• node.js modules
• unit-tests in mocha
• CircleCI friendly

Installation:

git clone [email protected]:salsita/chrome-extension-skeleton.git

# in case you don't have Grunt yet:
sudo npm install -g grunt-cli

Build instructions:

cd chrome-extension-skeleton
npm install
grunt

Directory structure:

/build             # this is where your extension (.crx) will end up,
                   # along with unpacked directories of production and
                   # develop build (for debugging)

/code
    /css           # CSS files
    /html          # HTML files
    /images        # image resources

    /js            # entry-points for browserify, requiring node.js `modules`

        /libs      # 3rd party run-time libraries, excluded from JS-linting
        /modules   # node.js modules (and corresponding mocha
                   #   unit tests spec files)

    manifest.json  # skeleton manifest file, `name`, `description`
                   #   and `version` fields copied from `package.json`

Gruntfile.js       # grunt tasks (see below)
circle.yml         # integration with CircleCI
crxmake.sh         # official build script for packing Chromium extensions
mykey.pem          # certificate file, YOU NEED TO GENERATE THIS FILE, see below
lint-options.json  # options for JS-linting
package.json       # project description file (name, version, dependencies, ...)

Grunt tasks:

• clean: clean build directory
• test: JS-lint and mocha test, single run
• test-cont: continuos test loop
• default: clean, test, build step (copy all necessary files to build directory, browserify JS sources, prepare production version (using uglify), pack the crx (using official shell script), and copy the resulting crx to CircleCI artifacts directory (only when on CircleCI))

After you clone:

1. In package.json, rename the project, description, version, add dependencies and any other fields necessary.

2. Generate your .pem key and store it in the root as mykey.pem file. On unix / mac, the command to generate the file is openssl genrsa 2048 | openssl pkcs8 -topk8 -nocrypt > mykey.pem. Note: the generated file is in .gitignore file, it won't be (and should NOT be) commited to the repository unless you know what you are doing.

3. Add content (HTML, CSS, images, JS modules), update code/manifest.json, leave only JS entry-points you use (remove the ones you don't need).

4. When developing, write unit-tests, use test-cont Grunt task to check that your JS code passes linting tests and unit-tests.

5. When ready to try out the extension in the browser, use default Grunt task to build it. In build directory you'll find develop version of the extension in unpacked-dev subdirectory (with source maps), and production (uglified) version in unpacked-prod directory. The .crx packed version is created from unpacked-prod sources.

6. When done developing, publish the extension and enjoy it (profit!).

Use any 3rd party libraries you need (both for run-time and for development / testing), place them either to code/js/libs, in case the library is not an npm module, or use regular npm node.js modules (that will be installed into node_modules directory). These libraries will be encapsulated in the resulting code and will NOT conflict even with libraries on pages where you inject the resulting JS scripts to (for content scripts).

For more information, please check also README.md files in subdirectories.

Under the hood:

If you want to understand better the structure of the code and how it really works, please check the following sources:

• introductory blog post,
• blog post on messaging system,
• or this overall prezi.

Legacy version

Before this version of the skeleton, we used RequireJS modules, jasmine-based unit tests and older chrome.extension.{onMessage|sendMessage} API for message exchange between background and content scripts. This version is still available in legacy branch here.