assertNull(pluginHelper.getArtifact(null, "1.0.0"));
        assertNull(pluginHelper.getArtifact("test", null));
        assertNull(pluginHelper.getArtifact("", "1.0.0"));
        assertNull(pluginHelper.getArtifact("test", ""));
    }

    public void test_isExcludedName_crawler() {
        assertTrue(pluginHelper.isExcludedName(ArtifactType.CRAWLER, "fess-crawler"));

    // POST /api/admin/plugin
    @Execute
    public JsonResponse<ApiResult> post$index(final InstallBody body) {
        validateApi(body, messages -> {});
        final Artifact artifact = ComponentUtil.getPluginHelper().getArtifact(body.name, body.version);
        if (artifact == null) {
            return asJson(
                    new ApiResult.ApiErrorResponse().message("invalid name or version").status(ApiResult.Status.BAD_REQUEST).result());

        return item;
    }

    private Artifact getArtifactFromInstallForm(final InstallForm form) {
        final String[] values = form.id.split(":");
        return ComponentUtil.getPluginHelper().getArtifact(values[0], values[1]);
    }

    /**
     * Installs the specified artifact in a background thread.
     * Also removes any previously installed versions of the same plugin.
     *

     *
     * @param name the name of the artifact
     * @param version the version of the artifact
     * @return the artifact if found, null otherwise
     */
    public Artifact getArtifact(final String name, final String version) {
        if (StringUtil.isBlank(name) || StringUtil.isBlank(version)) {
            return null;
        }