feat: add no_proxy env variable (#361)

* feat: add support for no_proxy environment variable

Co-authored-by: bcoe <bencoe@google.com>
Co-authored-by: Justin Beckwith <justin.beckwith@gmail.com>

src/gaxios.ts

@@ -42,8 +42,6 @@ function hasFetch() {
 
 let HttpsProxyAgent: any;
 
-// Figure out if we should be using a proxy. Only if it's required, load
-// the https-proxy-agent module as it adds startup cost.
 function loadProxy() {
   const proxy =
     process.env.HTTPS_PROXY ||
@@ -57,6 +55,35 @@ function loadProxy() {
 }
 loadProxy();
 
+function skipProxy(url: string) {
+  const noProxyEnv = process.env.NO_PROXY ?? process.env.no_proxy;
+  if (!noProxyEnv) {
+    return false;
+  }
+  const noProxyUrls = noProxyEnv.split(',');
+  const parsedURL = new URL(url);
+  return !!noProxyUrls.find(url => {
+    if (url.startsWith('*.') || url.startsWith('.')) {
+      url = url.replace('*', '');
+      return parsedURL.hostname.endsWith(url);
+    } else {
+      return url === parsedURL.origin || url === parsedURL.hostname;
+    }
+  });
+}
+
+// Figure out if we should be using a proxy. Only if it's required, load
+// the https-proxy-agent module as it adds startup cost.
+function getProxy(url: string) {
+  // If there is a match between the no_proxy env variables and the url, then do not proxy
+  if (skipProxy(url)) {
+    return undefined;
+    // If there is not a match between the no_proxy env variables and the url, check to see if there should be a proxy
+  } else {
+    return loadProxy();
+  }
+}
+
 export class Gaxios {
   private agentCache = new Map<
     string,
@@ -220,7 +247,7 @@ export class Gaxios {
     }
     opts.method = opts.method || 'GET';
 
-    const proxy = loadProxy();
+    const proxy = getProxy(opts.url);
     if (proxy) {
       if (this.agentCache.has(proxy)) {
         opts.agent = this.agentCache.get(proxy);

test/test.getch.ts

@@ -250,14 +250,115 @@ describe('🥁 configuration options', () => {
     assert.deepStrictEqual(res.data, {});
   });
 
-  it('should use an https proxy if asked nicely', async () => {
-    sandbox.stub(process, 'env').value({https_proxy: 'https://fake.proxy'});
-    const body = {hello: '🌎'};
-    const scope = nock(url).get('/').reply(200, body);
-    const res = await request({url});
-    scope.done();
-    assert.deepStrictEqual(res.data, body);
-    assert.ok(res.config.agent instanceof HttpsProxyAgent);
+  describe('proxying', () => {
+    it('should use an https proxy if asked nicely', async () => {
+      const url = 'https://fake.proxy';
+      sandbox.stub(process, 'env').value({https_proxy: 'https://fake.proxy'});
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.ok(res.config.agent instanceof HttpsProxyAgent);
+    });
+
+    it('should not proxy when url matches no_proxy', async () => {
+      const url = 'https://example.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: 'https://example.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.strictEqual(res.config.agent, undefined);
+    });
+
+    it('should proxy if url does not match no_proxy env variable', async () => {
+      const url = 'https://example2.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: 'https://example.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.ok(res.config.agent instanceof HttpsProxyAgent);
+    });
+
+    it('should not proxy if no_proxy env var matches the origin or hostname of the URL', async () => {
+      const url = 'https://example2.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: 'example2.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.strictEqual(res.config.agent, undefined);
+    });
+
+    it('should not proxy if no_proxy env variable has asterisk, and URL partially matches', async () => {
+      const url = 'https://domain.example.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: '*.example.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.strictEqual(res.config.agent, undefined);
+    });
+
+    it('should proxy if no_proxy env variable has asterisk, but URL is not matching', async () => {
+      const url = 'https://domain.example2.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: '*.example.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.ok(res.config.agent instanceof HttpsProxyAgent);
+    });
+
+    it('should not proxy if no_proxy env variable starts with a dot, and URL partially matches', async () => {
+      const url = 'https://domain.example.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: '.example.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.strictEqual(res.config.agent, undefined);
+    });
+
+    it('should allow comma-separated lists for no_proxy env variables', async () => {
+      const url = 'https://api.google.com';
+      sandbox.stub(process, 'env').value({
+        https_proxy: 'https://fake.proxy',
+        no_proxy: 'example.com,*.google.com,hello.com',
+      });
+      const body = {hello: '🌎'};
+      const scope = nock(url).get('/').reply(200, body);
+      const res = await request({url});
+      scope.done();
+      assert.deepStrictEqual(res.data, body);
+      assert.strictEqual(res.config.agent, undefined);
+    });
   });
 
   it('should load the proxy from the cache', async () => {
@@ -267,7 +368,7 @@ describe('🥁 configuration options', () => {
     const res1 = await request({url});
     const agent = res1.config.agent;
     const res2 = await request({url});
-    assert.strictEqual(agent, res2.config.agent);
+    assert.deepStrictEqual(agent, res2.config.agent);
     scope.done();
   });