commit 4fb5ca496d2fb6b3f96114be3a85c9fcde7f0d3d Author: David Fifield <david@bamsoftware.com> Date: Sat Mar 30 02:08:33 2019 -0600 Refactoring, use a Request object. --- webextension/browser/background.js | 84 +++++++++++++++++++------------------- 1 file changed, 41 insertions(+), 43 deletions(-) diff --git a/webextension/browser/background.js b/webextension/browser/background.js index 0b896e9..b8c5197 100644 --- a/webextension/browser/background.js +++ b/webextension/browser/background.js @@ -124,42 +124,38 @@ function Mutex() { const headersMutex = new Mutex(); const proxyMutex = new Mutex(); -async function roundtrip(request) { - // Process the incoming request spec and convert it into parameters to the - // fetch API. Also enforce some restrictions on what kinds of requests we - // are willing to make. - // https://developer.mozilla.org/en-US/docs/Web/API/WindowOrWorkerGlobalScope/f... - let url; - let init = {}; +async function roundtrip(params) { + // Process the incoming request parameters and convert them into a Request. + // https://developer.mozilla.org/en-US/docs/Web/API/Request/Request#Parameters + let input = params.url; + let init = { + method: params.method, + body: params.body != null ? base64_decode(params.body) : undefined, + // headers will get further treatment below in headersFn. + headers: params.header != null ? params.header : {}, + // Do not read nor write from the browser's HTTP cache. + cache: "no-store", + // Don't send cookies. + credentials: "omit", + // Don't follow redirects (we'll get resp.status:0 if there is one). + redirect: "manual", + }; - if (request.url == null) { + // Also enforce restrictions on what kinds of requests we are willing to + // make. + if (input == null) { throw new Error("request spec failed validation: missing \"url\""); } - if (!(request.url.startsWith("http://") || request.url.startsWith("https://"))) { + if (!(input.startsWith("http://") || input.startsWith("https://"))) { throw new Error("request spec failed validation: only http and https URLs are allowed"); } - url = request.url; - - if (request.method !== "POST") { + if (init.method !== "POST") { throw new Error("request spec failed validation: only POST is allowed"); } - init.method = request.method; - - // Don't set init.headers; that is handled in the onBeforeSendHeaders listener. - - if (request.body != null && request.body !== "") { - init.body = base64_decode(request.body); - } - - // Do not read nor write from the browser's HTTP cache. - init.cache = "no-store"; - // Don't send cookies. - init.credentials = "omit"; - // Don't follow redirects (we'll get resp.status:0 if there is one). - init.redirect = "manual"; + let request = new Request(input, init); // We need to use a webRequest.onBeforeSendHeaders listener to override - // certain header fields, including Host (passing them to fetch in + // certain header fields, including Host (creating a Request with them in // init.headers does not work). But onBeforeSendHeaders is a global setting // (applies to all requests) and we need to be able to set different headers // per request. We make it so that any onBeforeSendHeaders listener is only @@ -177,21 +173,21 @@ async function roundtrip(request) { } headersCalled = true; - // Convert request.header from object to array form. - // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/w... - let headers = Object.entries(request.header != null ? request.header : {}) - .map(x => ({name: x[0], value: x[1]})); - // Remove all browser headers that conflict with requested headers. - let overrides = {}; - for (let name of Object.keys(headers)) { - overrides[name.toLowerCase()] = true; + let removals = new Map(); + for (let name of Object.keys(init.headers)) { + removals.set(name.toLowerCase()); } // Also remove some unnecessary or potentially tracking-enabling headers. for (let name of ["Accept", "Accept-Language", "Cookie", "Origin", "User-Agent"]) { - overrides[name.toLowerCase()] = true; + removals.set(name.toLowerCase()); + } + let requestHeaders = details.requestHeaders.filter(header => !removals.has(header.name.toLowerCase())); + // Append the requested headers in array form. + // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/w... + for (let [name, value] of Object.entries(init.headers)) { + requestHeaders.push({name, value}); } - let browserHeaders = details.requestHeaders.filter(x => !(x.name.toLowerCase() in overrides)); - return {requestHeaders: browserHeaders.concat(headers)}; + return {requestHeaders}; } catch (error) { // In case of any error in the code above, play it safe and cancel // the request. @@ -228,14 +224,14 @@ async function roundtrip(request) { } try { - // Set our listener that overrides the headers for this request. + // Set a listener that overrides the headers for this request. // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/w... browser.webRequest.onBeforeSendHeaders.addListener( headersFn, {urls: ["http://*/*", "https://*/*"]}, ["blocking", "requestHeaders"] ); - // Set our listener that overrides the proxy for this request. + // Set a listener that overrides the proxy for this request. // https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/p... browser.proxy.onRequest.addListener( proxyFn, @@ -243,9 +239,11 @@ async function roundtrip(request) { ); // Now actually do the request and build a response object. - let resp = await fetch(url, init); - let body = await resp.arrayBuffer(); - return {status: resp.status, body: base64_encode(body)}; + let response = await fetch(request); + return { + status: response.status, + body: base64_encode(await response.arrayBuffer()), + }; } finally { // With certain errors (e.g. an invalid URL), our onBeforeSendHeaders // and onRequest listeners may never get called, and therefore never