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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
/**
* This modules focuses on redirecting requests to a particular local file.
*/
const lazy = {};
ChromeUtils.defineESModuleGetters(lazy, {
});
XPCOMUtils.defineLazyServiceGetter(
lazy,
"mimeService",
"@mozilla.org/mime;1",
"nsIMIMEService"
);
function readFile(file) {
const fstream = Cc["@mozilla.org/network/file-input-stream;1"].createInstance(
Ci.nsIFileInputStream
);
fstream.init(file, -1, 0, 0);
const data = NetUtil.readInputStreamToString(fstream, fstream.available());
fstream.close();
return data;
}
/**
* Given an in-flight channel, we will force to replace the content of this request
* with the content of a local file.
*
* @param {nsIHttpChannel} channel
* The request to replace content for.
* @param {String} path
* The absolute path to the local file to read content from.
*/
function overrideChannelWithFilePath(channel, path) {
// For JS it isn't important, but for HTML we ought to set the right content type on the data URI.
let mimeType = "";
try {
// getTypeFromURI will throw if there is no extension at the end of the URI
mimeType = lazy.mimeService.getTypeFromURI(channel.URI);
} catch (e) {}
// Redirect to a data: URI as we can't redirect to file:// URI
// without many security issues. We are leveraging the `allowInsecureRedirectToDataURI`
// attribute used by WebExtension.
const file = lazy.FileUtils.File(path);
const data = readFile(file);
const redirectURI = Services.io.newURI(
`data:${mimeType};base64,${btoa(data)}`
);
channel.redirectTo(redirectURI);
// Prevents having CORS exception and various issues because of redirecting to data: URI.
channel.loadInfo.allowInsecureRedirectToDataURI = true;
}
export const NetworkOverride = {
overrideChannelWithFilePath,
};