feat: net.fetch() supports custom protocols (#36606)

docs/api/net.md

@@ -101,6 +101,10 @@ Limitations:
 * The `.type` and `.url` values of the returned `Response` object are
   incorrect.
 
+Requests made with `net.fetch` can be made to [custom protocols](protocol.md)
+as well as `file:`, and will trigger [webRequest](web-request.md) handlers if
+present.
+
 ### `net.isOnline()`
 
 Returns `boolean` - Whether there is currently internet connection.

docs/api/session.md

@@ -768,6 +768,10 @@ Limitations:
 * The `.type` and `.url` values of the returned `Response` object are
   incorrect.
 
+Requests made with `ses.fetch` can be made to [custom protocols](protocol.md)
+as well as `file:`, and will trigger [webRequest](web-request.md) handlers if
+present.
+
 #### `ses.disableNetworkEmulation()`
 
 Disables any network emulation already active for the `session`. Resets to

lib/browser/api/net-client-request.ts

@@ -10,7 +10,7 @@ const {
 } = process._linkedBinding('electron_browser_net');
 const { Session } = process._linkedBinding('electron_browser_session');
 
-const kSupportedProtocols = new Set(['http:', 'https:']);
+const kHttpProtocols = new Set(['http:', 'https:']);
 
 // set of headers that Node.js discards duplicates for
 // see https://nodejs.org/api/http.html#http_message_headers
@@ -195,7 +195,20 @@ class ChunkedBodyStream extends Writable {
 
 type RedirectPolicy = 'manual' | 'follow' | 'error';
 
-function parseOptions (optionsIn: ClientRequestConstructorOptions | string): NodeJS.CreateURLLoaderOptions & { redirectPolicy: RedirectPolicy, headers: Record<string, { name: string, value: string | string[] }> } {
+const kAllowNonHttpProtocols = Symbol('kAllowNonHttpProtocols');
+export function allowAnyProtocol (opts: ClientRequestConstructorOptions): ClientRequestConstructorOptions {
+  return {
+    ...opts,
+    [kAllowNonHttpProtocols]: true
+  } as any;
+}
+
+type ExtraURLLoaderOptions = {
+   redirectPolicy: RedirectPolicy;
+   headers: Record<string, { name: string, value: string | string[] }>;
+   allowNonHttpProtocols: boolean;
+}
+function parseOptions (optionsIn: ClientRequestConstructorOptions | string): NodeJS.CreateURLLoaderOptions & ExtraURLLoaderOptions {
   const options: any = typeof optionsIn === 'string' ? url.parse(optionsIn) : { ...optionsIn };
 
   let urlStr: string = options.url;
@@ -203,9 +216,6 @@ function parseOptions (optionsIn: ClientRequestConstructorOptions | string): Nod
   if (!urlStr) {
     const urlObj: url.UrlObject = {};
     const protocol = options.protocol || 'http:';
-    if (!kSupportedProtocols.has(protocol)) {
-      throw new Error('Protocol "' + protocol + '" not supported');
-    }
     urlObj.protocol = protocol;
 
     if (options.host) {
@@ -247,7 +257,7 @@ function parseOptions (optionsIn: ClientRequestConstructorOptions | string): Nod
     throw new TypeError('headers must be an object');
   }
 
-  const urlLoaderOptions: NodeJS.CreateURLLoaderOptions & { redirectPolicy: RedirectPolicy, headers: Record<string, { name: string, value: string | string[] }> } = {
+  const urlLoaderOptions: NodeJS.CreateURLLoaderOptions & { redirectPolicy: RedirectPolicy, headers: Record<string, { name: string, value: string | string[] }>, allowNonHttpProtocols: boolean } = {
     method: (options.method || 'GET').toUpperCase(),
     url: urlStr,
     redirectPolicy,
@@ -257,7 +267,8 @@ function parseOptions (optionsIn: ClientRequestConstructorOptions | string): Nod
     credentials: options.credentials,
     origin: options.origin,
     referrerPolicy: options.referrerPolicy,
-    cache: options.cache
+    cache: options.cache,
+    allowNonHttpProtocols: Object.prototype.hasOwnProperty.call(options, kAllowNonHttpProtocols)
   };
   const headers: Record<string, string | string[]> = options.headers || {};
   for (const [name, value] of Object.entries(headers)) {
@@ -308,6 +319,10 @@ export class ClientRequest extends Writable implements Electron.ClientRequest {
     }
 
     const { redirectPolicy, ...urlLoaderOptions } = parseOptions(options);
+    const urlObj = new URL(urlLoaderOptions.url);
+    if (!urlLoaderOptions.allowNonHttpProtocols && !kHttpProtocols.has(urlObj.protocol)) {
+      throw new Error('ClientRequest only supports http: and https: protocols');
+    }
     if (urlLoaderOptions.credentials === 'same-origin' && !urlLoaderOptions.origin) { throw new Error('credentials: same-origin requires origin to be set'); }
     this._urlLoaderOptions = urlLoaderOptions;
     this._redirectPolicy = redirectPolicy;

lib/browser/api/net-fetch.ts

@@ -1,5 +1,6 @@
 import { net, IncomingMessage, Session as SessionT } from 'electron/main';
 import { Readable, Writable, isReadable } from 'stream';
+import { allowAnyProtocol } from '@electron/internal/browser/api/net-client-request';
 
 function createDeferredPromise<T, E extends Error = Error> (): { promise: Promise<T>; resolve: (x: T) => void; reject: (e: E) => void; } {
   let res: (x: T) => void;
@@ -72,7 +73,7 @@ export function fetchWithSession (input: RequestInfo, init: RequestInit | undefi
   // We can't set credentials to same-origin unless there's an origin set.
   const credentials = req.credentials === 'same-origin' && !origin ? 'include' : req.credentials;
 
-  const r = net.request({
+  const r = net.request(allowAnyProtocol({
     session,
     method: req.method,
     url: req.url,
@@ -81,7 +82,7 @@ export function fetchWithSession (input: RequestInfo, init: RequestInit | undefi
     cache: req.cache,
     referrerPolicy: req.referrerPolicy,
     redirect: req.redirect
-  });
+  }));
 
   // cors is the default mode, but we can't set mode=cors without an origin.
   if (req.mode && (req.mode !== 'cors' || origin)) {

shell/browser/api/electron_api_url_loader.cc

@@ -18,14 +18,19 @@
 #include "mojo/public/cpp/system/data_pipe_producer.h"
 #include "net/base/load_flags.h"
 #include "net/http/http_util.h"
+#include "net/url_request/redirect_util.h"
 #include "services/network/public/cpp/resource_request.h"
 #include "services/network/public/cpp/simple_url_loader.h"
+#include "services/network/public/cpp/url_util.h"
+#include "services/network/public/cpp/wrapper_shared_url_loader_factory.h"
 #include "services/network/public/mojom/chunked_data_pipe_getter.mojom.h"
 #include "services/network/public/mojom/http_raw_headers.mojom.h"
 #include "services/network/public/mojom/url_loader_factory.mojom.h"
 #include "shell/browser/api/electron_api_session.h"
 #include "shell/browser/electron_browser_context.h"
 #include "shell/browser/javascript_environment.h"
+#include "shell/browser/net/asar/asar_url_loader_factory.h"
+#include "shell/browser/protocol_registry.h"
 #include "shell/common/gin_converters/callback_converter.h"
 #include "shell/common/gin_converters/gurl_converter.h"
 #include "shell/common/gin_converters/net_converter.h"
@@ -336,34 +341,49 @@ gin::WrapperInfo SimpleURLLoaderWrapper::kWrapperInfo = {
     gin::kEmbedderNativeGin};
 
 SimpleURLLoaderWrapper::SimpleURLLoaderWrapper(
+    ElectronBrowserContext* browser_context,
     std::unique_ptr<network::ResourceRequest> request,
-    network::mojom::URLLoaderFactory* url_loader_factory,
-    int options) {
-  if (!request->trusted_params)
-    request->trusted_params = network::ResourceRequest::TrustedParams();
+    int options)
+    : browser_context_(browser_context),
+      request_options_(options),
+      request_(std::move(request)) {
+  if (!request_->trusted_params)
+    request_->trusted_params = network::ResourceRequest::TrustedParams();
   mojo::PendingRemote<network::mojom::URLLoaderNetworkServiceObserver>
       url_loader_network_observer_remote;
   url_loader_network_observer_receivers_.Add(
       this,
       url_loader_network_observer_remote.InitWithNewPipeAndPassReceiver());
-  request->trusted_params->url_loader_network_observer =
+  request_->trusted_params->url_loader_network_observer =
       std::move(url_loader_network_observer_remote);
   // Chromium filters headers using browser rules, while for net module we have
   // every header passed. The following setting will allow us to capture the
   // raw headers in the URLLoader.
-  request->trusted_params->report_raw_headers = true;
-  // SimpleURLLoader wants to control the request body itself. We have other
-  // ideas.
-  auto request_body = std::move(request->request_body);
-  auto* request_ref = request.get();
+  request_->trusted_params->report_raw_headers = true;
+  Start();
+}
+
+void SimpleURLLoaderWrapper::Start() {
+  // Make a copy of the request; we'll need to re-send it if we get redirected.
+  auto request = std::make_unique<network::ResourceRequest>();
+  *request = *request_;
+
+  // SimpleURLLoader has no way to set a data pipe as the request body, which
+  // we need to do for streaming upload, so instead we "cheat" and pretend to
+  // SimpleURLLoader like there is no request_body when we construct it. Later,
+  // we will sneakily put the request_body back while it isn't looking.
+  scoped_refptr<network::ResourceRequestBody> request_body =
+      std::move(request->request_body);
+
+  network::ResourceRequest* request_ref = request.get();
   loader_ =
       network::SimpleURLLoader::Create(std::move(request), kTrafficAnnotation);
-  if (request_body) {
+
+  if (request_body)
     request_ref->request_body = std::move(request_body);
-  }
 
   loader_->SetAllowHttpErrorResults(true);
-  loader_->SetURLLoaderFactoryOptions(options);
+  loader_->SetURLLoaderFactoryOptions(request_options_);
   loader_->SetOnResponseStartedCallback(base::BindOnce(
       &SimpleURLLoaderWrapper::OnResponseStarted, base::Unretained(this)));
   loader_->SetOnRedirectCallback(base::BindRepeating(
@@ -373,7 +393,8 @@ SimpleURLLoaderWrapper::SimpleURLLoaderWrapper(
   loader_->SetOnDownloadProgressCallback(base::BindRepeating(
       &SimpleURLLoaderWrapper::OnDownloadProgress, base::Unretained(this)));
 
-  loader_->DownloadAsStream(url_loader_factory, this);
+  url_loader_factory_ = GetURLLoaderFactoryForURL(request_ref->url);
+  loader_->DownloadAsStream(url_loader_factory_.get(), this);
 }
 
 void SimpleURLLoaderWrapper::Pin() {
@@ -458,6 +479,42 @@ void SimpleURLLoaderWrapper::Cancel() {
   // This ensures that no further callbacks will be called, so there's no need
   // for additional guards.
 }
+scoped_refptr<network::SharedURLLoaderFactory>
+SimpleURLLoaderWrapper::GetURLLoaderFactoryForURL(const GURL& url) {
+  scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory;
+  auto* protocol_registry =
+      ProtocolRegistry::FromBrowserContext(browser_context_);
+  // Explicitly handle intercepted protocols here, even though
+  // ProxyingURLLoaderFactory would handle them later on, so that we can
+  // correctly intercept file:// scheme URLs.
+  if (protocol_registry->IsProtocolIntercepted(url.scheme())) {
+    auto& protocol_handler =
+        protocol_registry->intercept_handlers().at(url.scheme());
+    mojo::PendingRemote<network::mojom::URLLoaderFactory> pending_remote =
+        ElectronURLLoaderFactory::Create(protocol_handler.first,
+                                         protocol_handler.second);
+    url_loader_factory = network::SharedURLLoaderFactory::Create(
+        std::make_unique<network::WrapperPendingSharedURLLoaderFactory>(
+            std::move(pending_remote)));
+  } else if (protocol_registry->IsProtocolRegistered(url.scheme())) {
+    auto& protocol_handler = protocol_registry->handlers().at(url.scheme());
+    mojo::PendingRemote<network::mojom::URLLoaderFactory> pending_remote =
+        ElectronURLLoaderFactory::Create(protocol_handler.first,
+                                         protocol_handler.second);
+    url_loader_factory = network::SharedURLLoaderFactory::Create(
+        std::make_unique<network::WrapperPendingSharedURLLoaderFactory>(
+            std::move(pending_remote)));
+  } else if (url.SchemeIsFile()) {
+    mojo::PendingRemote<network::mojom::URLLoaderFactory> pending_remote =
+        AsarURLLoaderFactory::Create();
+    url_loader_factory = network::SharedURLLoaderFactory::Create(
+        std::make_unique<network::WrapperPendingSharedURLLoaderFactory>(
+            std::move(pending_remote)));
+  } else {
+    url_loader_factory = browser_context_->GetURLLoaderFactory();
+  }
+  return url_loader_factory;
+}
 
 // static
 gin::Handle<SimpleURLLoaderWrapper> SimpleURLLoaderWrapper::Create(
@@ -634,12 +691,9 @@ gin::Handle<SimpleURLLoaderWrapper> SimpleURLLoaderWrapper::Create(
       session = Session::FromPartition(args->isolate(), "");
   }
 
-  auto url_loader_factory = session->browser_context()->GetURLLoaderFactory();
-
   auto ret = gin::CreateHandle(
-      args->isolate(),
-      new SimpleURLLoaderWrapper(std::move(request), url_loader_factory.get(),
-                                 options));
+      args->isolate(), new SimpleURLLoaderWrapper(session->browser_context(),
+                                                  std::move(request), options));
   ret->Pin();
   if (!chunk_pipe_getter.IsEmpty()) {
     ret->PinBodyGetter(chunk_pipe_getter);
@@ -691,6 +745,45 @@ void SimpleURLLoaderWrapper::OnRedirect(
     const network::mojom::URLResponseHead& response_head,
     std::vector<std::string>* removed_headers) {
   Emit("redirect", redirect_info, response_head.headers.get());
+
+  if (!loader_)
+    // The redirect was aborted by JS.
+    return;
+
+  // Optimization: if both the old and new URLs are handled by the network
+  // service, just FollowRedirect.
+  if (network::IsURLHandledByNetworkService(redirect_info.new_url) &&
+      network::IsURLHandledByNetworkService(request_->url))
+    return;
+
+  // Otherwise, restart the request (potentially picking a new
+  // URLLoaderFactory). See
+  // https://source.chromium.org/chromium/chromium/src/+/main:content/browser/loader/navigation_url_loader_impl.cc;l=534-550;drc=fbaec92ad5982f83aa4544d5c88d66d08034a9f4
+
+  bool should_clear_upload = false;
+  net::RedirectUtil::UpdateHttpRequest(
+      request_->url, request_->method, redirect_info, *removed_headers,
+      /* modified_headers = */ absl::nullopt, &request_->headers,
+      &should_clear_upload);
+  if (should_clear_upload) {
+    // The request body is no longer applicable.
+    request_->request_body.reset();
+  }
+
+  request_->url = redirect_info.new_url;
+  request_->method = redirect_info.new_method;
+  request_->site_for_cookies = redirect_info.new_site_for_cookies;
+
+  // See if navigation network isolation key needs to be updated.
+  request_->trusted_params->isolation_info =
+      request_->trusted_params->isolation_info.CreateForRedirect(
+          url::Origin::Create(request_->url));
+
+  request_->referrer = GURL(redirect_info.new_referrer);
+  request_->referrer_policy = redirect_info.new_referrer_policy;
+  request_->navigation_redirect_chain.push_back(redirect_info.new_url);
+
+  Start();
 }
 
 void SimpleURLLoaderWrapper::OnUploadProgress(uint64_t position,

shell/browser/api/electron_api_url_loader.h

@@ -31,8 +31,13 @@ class Handle;
 namespace network {
 class SimpleURLLoader;
 struct ResourceRequest;
+class SharedURLLoaderFactory;
 }  // namespace network
 
+namespace electron {
+class ElectronBrowserContext;
+}
+
 namespace electron::api {
 
 /** Wraps a SimpleURLLoader to make it usable from JavaScript */
@@ -54,8 +59,8 @@ class SimpleURLLoaderWrapper
   const char* GetTypeName() override;
 
  private:
-  SimpleURLLoaderWrapper(std::unique_ptr<network::ResourceRequest> request,
-                         network::mojom::URLLoaderFactory* url_loader_factory,
+  SimpleURLLoaderWrapper(ElectronBrowserContext* browser_context,
+                         std::unique_ptr<network::ResourceRequest> request,
                          int options);
 
   // SimpleURLLoaderStreamConsumer:
@@ -99,6 +104,9 @@ class SimpleURLLoaderWrapper
       mojo::PendingReceiver<network::mojom::URLLoaderNetworkServiceObserver>
           observer) override;
 
+  scoped_refptr<network::SharedURLLoaderFactory> GetURLLoaderFactoryForURL(
+      const GURL& url);
+
   // SimpleURLLoader callbacks
   void OnResponseStarted(const GURL& final_url,
                          const network::mojom::URLResponseHead& response_head);
@@ -112,6 +120,10 @@ class SimpleURLLoaderWrapper
   void Pin();
   void PinBodyGetter(v8::Local<v8::Value>);
 
+  ElectronBrowserContext* browser_context_;
+  int request_options_;
+  std::unique_ptr<network::ResourceRequest> request_;
+  scoped_refptr<network::SharedURLLoaderFactory> url_loader_factory_;
   std::unique_ptr<network::SimpleURLLoader> loader_;
   v8::Global<v8::Value> pinned_wrapper_;
   v8::Global<v8::Value> pinned_chunk_pipe_getter_;

spec/api-net-spec.ts

@@ -1,8 +1,9 @@
 import { expect } from 'chai';
 import * as dns from 'dns';
-import { net, session, ClientRequest, BrowserWindow, ClientRequestConstructorOptions } from 'electron/main';
+import { net, session, ClientRequest, BrowserWindow, ClientRequestConstructorOptions, protocol } from 'electron/main';
 import * as http from 'http';
 import * as url from 'url';
+import * as path from 'path';
 import { Socket } from 'net';
 import { defer, listen } from './lib/spec-helpers';
 import { once } from 'events';
@@ -163,9 +164,9 @@ describe('net module', () => {
 
     it('should post the correct data in a POST request', async () => {
       const bodyData = 'Hello World!';
+      let postedBodyData: string = '';
       const serverUrl = await respondOnce.toSingleURL(async (request, response) => {
-        const postedBodyData = await collectStreamBody(request);
-        expect(postedBodyData).to.equal(bodyData);
+        postedBodyData = await collectStreamBody(request);
         response.end();
       });
       const urlRequest = net.request({
@@ -175,16 +176,72 @@ describe('net module', () => {
       urlRequest.write(bodyData);
       const response = await getResponse(urlRequest);
       expect(response.statusCode).to.equal(200);
+      expect(postedBodyData).to.equal(bodyData);
+    });
+
+    it('a 307 redirected POST request preserves the body', async () => {
+      const bodyData = 'Hello World!';
+      let postedBodyData: string = '';
+      let methodAfterRedirect: string | undefined;
+      const serverUrl = await respondNTimes.toRoutes({
+        '/redirect': (req, res) => {
+          res.statusCode = 307;
+          res.setHeader('location', serverUrl);
+          return res.end();
+        },
+        '/': async (req, res) => {
+          methodAfterRedirect = req.method;
+          postedBodyData = await collectStreamBody(req);
+          res.end();
+        }
+      }, 2);
+      const urlRequest = net.request({
+        method: 'POST',
+        url: serverUrl + '/redirect'
+      });
+      urlRequest.write(bodyData);
+      const response = await getResponse(urlRequest);
+      expect(response.statusCode).to.equal(200);
+      await collectStreamBody(response);
+      expect(methodAfterRedirect).to.equal('POST');
+      expect(postedBodyData).to.equal(bodyData);
+    });
+
+    it('a 302 redirected POST request DOES NOT preserve the body', async () => {
+      const bodyData = 'Hello World!';
+      let postedBodyData: string = '';
+      let methodAfterRedirect: string | undefined;
+      const serverUrl = await respondNTimes.toRoutes({
+        '/redirect': (req, res) => {
+          res.statusCode = 302;
+          res.setHeader('location', serverUrl);
+          return res.end();
+        },
+        '/': async (req, res) => {
+          methodAfterRedirect = req.method;
+          postedBodyData = await collectStreamBody(req);
+          res.end();
+        }
+      }, 2);
+      const urlRequest = net.request({
+        method: 'POST',
+        url: serverUrl + '/redirect'
+      });
+      urlRequest.write(bodyData);
+      const response = await getResponse(urlRequest);
+      expect(response.statusCode).to.equal(200);
+      await collectStreamBody(response);
+      expect(methodAfterRedirect).to.equal('GET');
+      expect(postedBodyData).to.equal('');
     });
 
     it('should support chunked encoding', async () => {
+      let receivedRequest: http.IncomingMessage = null as any;
       const serverUrl = await respondOnce.toSingleURL((request, response) => {
         response.statusCode = 200;
         response.statusMessage = 'OK';
         response.chunkedEncoding = true;
-        expect(request.method).to.equal('POST');
-        expect(request.headers['transfer-encoding']).to.equal('chunked');
-        expect(request.headers['content-length']).to.equal(undefined);
+        receivedRequest = request;
         request.on('data', (chunk: Buffer) => {
           response.write(chunk);
         });
@@ -210,6 +267,9 @@ describe('net module', () => {
       }
 
       const response = await getResponse(urlRequest);
+      expect(receivedRequest.method).to.equal('POST');
+      expect(receivedRequest.headers['transfer-encoding']).to.equal('chunked');
+      expect(receivedRequest.headers['content-length']).to.equal(undefined);
       expect(response.statusCode).to.equal(200);
       const received = await collectStreamBodyBuffer(response);
       expect(sent.equals(received)).to.be.true();
@@ -1446,6 +1506,9 @@ describe('net module', () => {
       urlRequest.end();
       urlRequest.on('redirect', () => { urlRequest.abort(); });
       urlRequest.on('error', () => {});
+      urlRequest.on('response', () => {
+        expect.fail('Unexpected response');
+      });
       await once(urlRequest, 'abort');
     });
 
@@ -2078,6 +2141,20 @@ describe('net module', () => {
     });
   });
 
+  describe('non-http schemes', () => {
+    it('should be rejected by net.request', async () => {
+      expect(() => {
+        net.request('file://bar');
+      }).to.throw('ClientRequest only supports http: and https: protocols');
+    });
+
+    it('should be rejected by net.request when passed in url:', async () => {
+      expect(() => {
+        net.request({ url: 'file://bar' });
+      }).to.throw('ClientRequest only supports http: and https: protocols');
+    });
+  });
+
   describe('net.fetch', () => {
     // NB. there exist much more comprehensive tests for fetch() in the form of
     // the WPT: https://github.com/web-platform-tests/wpt/tree/master/fetch
@@ -2167,5 +2244,83 @@ describe('net module', () => {
         await expect(r.text()).to.be.rejectedWith(/ERR_INCOMPLETE_CHUNKED_ENCODING/);
       });
     });
+
+    it('can request file:// URLs', async () => {
+      const resp = await net.fetch(url.pathToFileURL(path.join(__dirname, 'fixtures', 'hello.txt')).toString());
+      expect(resp.ok).to.be.true();
+      // trimRight instead of asserting the whole string to avoid line ending shenanigans on WOA
+      expect((await resp.text()).trimRight()).to.equal('hello world');
+    });
+
+    it('can make requests to custom protocols', async () => {
+      protocol.registerStringProtocol('electron-test', (req, cb) => { cb('hello ' + req.url); });
+      defer(() => {
+        protocol.unregisterProtocol('electron-test');
+      });
+      const body = await net.fetch('electron-test://foo').then(r => r.text());
+      expect(body).to.equal('hello electron-test://foo');
+    });
+
+    it('runs through intercept handlers', async () => {
+      protocol.interceptStringProtocol('http', (req, cb) => { cb('hello ' + req.url); });
+      defer(() => {
+        protocol.uninterceptProtocol('http');
+      });
+      const body = await net.fetch('http://foo').then(r => r.text());
+      expect(body).to.equal('hello http://foo/');
+    });
+
+    it('file: runs through intercept handlers', async () => {
+      protocol.interceptStringProtocol('file', (req, cb) => { cb('hello ' + req.url); });
+      defer(() => {
+        protocol.uninterceptProtocol('file');
+      });
+      const body = await net.fetch('file://foo').then(r => r.text());
+      expect(body).to.equal('hello file://foo/');
+    });
+
+    it('can be redirected', async () => {
+      protocol.interceptStringProtocol('file', (req, cb) => { cb({ statusCode: 302, headers: { location: 'electron-test://bar' } }); });
+      defer(() => {
+        protocol.uninterceptProtocol('file');
+      });
+      protocol.registerStringProtocol('electron-test', (req, cb) => { cb('hello ' + req.url); });
+      defer(() => {
+        protocol.unregisterProtocol('electron-test');
+      });
+      const body = await net.fetch('file://foo').then(r => r.text());
+      expect(body).to.equal('hello electron-test://bar');
+    });
+
+    it('should not follow redirect when redirect: error', async () => {
+      protocol.registerStringProtocol('electron-test', (req, cb) => {
+        if (/redirect/.test(req.url)) return cb({ statusCode: 302, headers: { location: 'electron-test://bar' } });
+        cb('hello ' + req.url);
+      });
+      defer(() => {
+        protocol.unregisterProtocol('electron-test');
+      });
+      await expect(net.fetch('electron-test://redirect', { redirect: 'error' })).to.eventually.be.rejectedWith('Attempted to redirect, but redirect policy was \'error\'');
+    });
+
+    it('a 307 redirected POST request preserves the body', async () => {
+      const bodyData = 'Hello World!';
+      let postedBodyData: any;
+      protocol.registerStringProtocol('electron-test', async (req, cb) => {
+        if (/redirect/.test(req.url)) return cb({ statusCode: 307, headers: { location: 'electron-test://bar' } });
+        postedBodyData = req.uploadData![0].bytes.toString();
+        cb('hello ' + req.url);
+      });
+      defer(() => {
+        protocol.unregisterProtocol('electron-test');
+      });
+      const response = await net.fetch('electron-test://redirect', {
+        method: 'POST',
+        body: bodyData
+      });
+      expect(response.status).to.equal(200);
+      await response.text();
+      expect(postedBodyData).to.equal(bodyData);
+    });
   });
 });

spec/fixtures/hello.txt

@@ -0,0 +1 @@
+hello world