feat: add support for no_proxy environment variable

Refs #69

src/gaxios.ts

@@ -44,7 +44,11 @@ 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() {
+function loadProxy(url: string) {
+  const noProxy = process.env.no_proxy ?? process.env.NO_PROXY;
+  if (noProxy && url === noProxy) {
+    return;
+  }
   const proxy =
     process.env.HTTPS_PROXY ||
     process.env.https_proxy ||
@@ -55,7 +59,6 @@ function loadProxy() {
   }
   return proxy;
 }
-loadProxy();
 
 export class Gaxios {
   private agentCache = new Map<
@@ -219,7 +222,7 @@ export class Gaxios {
     }
     opts.method = opts.method || 'GET';
 
-    const proxy = loadProxy();
+    const proxy = loadProxy(opts.url);
     if (proxy) {
       if (this.agentCache.has(proxy)) {
         opts.agent = this.agentCache.get(proxy);

test/test.getch.ts

@@ -259,6 +259,36 @@ describe('🥁 configuration options', () => {
     assert.ok(res.config.agent instanceof HttpsProxyAgent);
   });
 
+  describe('no_proxy', () => {
+    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 still proxy if url does not match no_proxy', 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 load the proxy from the cache', async () => {
     sandbox.stub(process, 'env').value({HTTPS_PROXY: 'https://fake.proxy'});
     const body = {hello: '🌎'};