protected function parseComposerContent($resource)
    {
        $composer = (array) JsonFile::parseJson($this->getContents($resource));
        if (empty($composer['content']) || 'base64' !== $composer['encoding'] || !($composer = base64_decode($composer['content'], true))) {
            throw new \RuntimeException('Could not retrieve '.$this->repoConfig['filename'].' from '.$resource);
        }

        return $composer;
    }