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Revision 13a707c6

Added by koszko over 1 year ago

serialize and deserialize entire Response object when relaying fetch() calls to other contexts using sendMessage

View differences:

background/CORS_bypass_server.js
2 2 
 * This file is part of Haketilo.
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 *
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 * Function: Allow other parts of the extension to bypass CORS by routing their
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 *           request through this background script using one-off messages.
5 
 *           requests through this background script using one-off messages.
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 *
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 * Copyright (C) 2022 Wojtek Kosior <koszko@koszko.org>
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 *
......
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 */
44 44 

  		




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#FROM common/browser.js IMPORT browser


  		




  
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#FROM common/misc.js    IMPORT uint8_to_hex, error_data_jsonifiable


  		




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async function get_prop(object, prop, result_object, call_prop=false) {


  		




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    try {


  		




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	result_object[prop] = call_prop ? (await object[prop]()) : object[prop];


  		




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    } catch(e) {


  		




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	result_object[`error_${prop}`] = "" + e;


  		




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    }


  		




  
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/*


  		




  
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 * In this file we implement a fetch()-from-background-script service. Code in


  		




  
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 * other parts of the extension shall call sendMessage() with arguments to


  		




  
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 * fetch() and code here will call fetch() with those arguments and send back


  		




  
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 * the response.


  		




  
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 *


  		




  
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 * We have to convert the Response from fetch() into a JSON-ifiable value and


  		




  
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 * then convert it back (using Response() constructor) due (among others) the


  		




  
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 * limitations of Chromium's messaging API:


  		




  
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 * https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Chrome_incompatibilities#data_cloning_algorithm


  		




  
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 *


  		




  
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 * We also catch possible errors from fetch() (e.g. in case of an invalid URL)


  		




  
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 * and send their data in JSON-ifiable form so that the error object can be


  		




  
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 * later re-created.


  		




  
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 */


  		




  
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/* Make it possible to serialize Response object. */


  		




  
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async function response_data_jsonifiable(response) {


  		




  
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    return {


  		




  
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	status:     response.status,


  		




  
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	statusText: response.statusText,


  		




  
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	headers:    [...response.headers.entries()],


  		




  
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	body:       uint8_to_hex(new Uint8Array(await response.arrayBuffer()))


  		




  
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    };


  		




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}


  		




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async function perform_download(fetch_data, respond_cb) {


  		




  
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async function perform_download(fetch_data) {


  		




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    try {


  		




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	const response = await fetch(fetch_data.url);


  		




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	const result = {};


  		




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	for (const prop of (fetch_data.to_get || []))


  		




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	    get_prop(response, prop, result);


  		




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	const to_call = (fetch_data.to_call || []);


  		




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	const promises = [];


  		




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	for (let i = 0; i < to_call.length; i++) {


  		




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	    const response_to_use = i === to_call.length - 1 ?


  		




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		response : response.clone();


  		




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	    promises.push(get_prop(response_to_use, to_call[i], result, true));


  		




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	}


  		




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	await Promise.all(promises);


  		




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	return result;


  		




  
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	const response = await fetch(fetch_data.url, fetch_data.init);


  		




  
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	return response_data_jsonifiable(response);


  		




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    } catch(e) {


  		




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	return {error: "" + e};


  		




  
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	return {error: error_data_jsonifiable(e)};


  		




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    }


  		




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}


  		




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