Haketilo

 * IMPORT is_privileged_url

 * IMPORT query_best

 * IMPORT gen_nonce

 * IMPORT inject_csp_headers

 * IMPORT apply_stream_filter

 * IMPORT is_chrome

let storage;

function on_headers_received(details)

{

    const url = details.url;

    if (is_privileged_url(details.url))

	return;

    const [pattern, settings] = query_best(storage, details.url);

    const allow = !!(settings && settings.allow);

    const nonce = gen_nonce();

    const policy = {allow, url, nonce};

    let headers = details.responseHeaders;

    let skip = false;

    for (const header of headers) {

	if ((header.name.toLowerCase().trim() === "content-disposition" &&

	     /^\s*attachment\s*(;.*)$/i.test(header.value)))

	    skip = true;

    }

    headers = inject_csp_headers(details, headers, policy);

    skip = skip || (details.statusCode >= 300 && details.statusCode < 400);

    if (!skip) {

	/* Check for API availability. */

	if (browser.webRequest.filterResponseData)

	    headers = apply_stream_filter(details, headers, policy);

    }

    return {responseHeaders: headers};

}

async function start_webRequest_operations()

{

    storage = await get_storage();

    const extra_opts = ["blocking", "responseHeaders"];

    if (is_chrome)

	extra_opts.push("extraHeaders");

    browser.webRequest.onHeadersReceived.addListener(

	on_headers_received,

	{urls: ["<all_urls>"], types: ["main_frame", "sub_frame"]},

	extra_opts

    );

}

start_webRequest_operations();