Adding support for beforeRedirect config option (#3852)

* Adding support for beforeRedirect config option

* Adding tests for beforeRedirect

* Update README.md

Co-authored-by: Prabodh Meshram <prabodh.meshram7@gmail.com>

* fix types

Co-authored-by: Prabodh Meshram <prabodh.meshram7@gmail.com>
Co-authored-by: Jay <jasonsaayman@gmail.com>

README.md

@@ -414,7 +414,18 @@ These are the available config options for making requests. Only the `url` is re
 
   // `maxRedirects` defines the maximum number of redirects to follow in node.js.
   // If set to 0, no redirects will be followed.
-  maxRedirects: 5, // default
+  maxRedirects: 21, // default
+
+  // `beforeRedirect` defines a function that will be called before redirect.
+  // Use this to adjust the request options upon redirecting,
+  // to inspect the latest response headers,
+  // or to cancel the request by throwing an error
+  // If maxRedirects is set to 0, `beforeRedirect` is not used.
+  beforeRedirect: (options, { headers }) => {
+    if (options.hostname === "example.com") {
+      options.auth = "user:password";
+    }
+  };
 
   // `socketPath` defines a UNIX Socket to be used in node.js.
   // e.g. '/var/run/docker.sock' to send requests to the docker daemon.

index.d.ts

@@ -1,5 +1,4 @@
 // TypeScript Version: 3.0
-
 export type AxiosRequestHeaders = Record<string, string | number | boolean>;
 
 export type AxiosResponseHeaders = Record<string, string> & {
@@ -98,6 +97,7 @@ export interface AxiosRequestConfig<D = any> {
   validateStatus?: ((status: number) => boolean) | null;
   maxBodyLength?: number;
   maxRedirects?: number;
+  beforeRedirect?: (options: Record<string, any>, responseDetails: {headers: Record<string, string>}) => void;
   socketPath?: string | null;
   httpAgent?: any;
   httpsAgent?: any;

lib/adapters/http.js

@@ -227,6 +227,9 @@ module.exports = function httpAdapter(config) {
       if (config.maxRedirects) {
         options.maxRedirects = config.maxRedirects;
       }
+      if (config.beforeRedirect) {
+        options.beforeRedirect = config.beforeRedirect;
+      }
       transport = isHttpsProxy ? httpsFollow : httpFollow;
     }
 
@@ -326,7 +329,7 @@ module.exports = function httpAdapter(config) {
 
     // Handle errors
     req.on('error', function handleRequestError(err) {
-      if (req.aborted && err.code !== 'ERR_FR_TOO_MANY_REDIRECTS') return;
+      if (req.aborted && err.code !== 'ERR_FR_TOO_MANY_REDIRECTS') reject(err);
       reject(enhanceError(err, config, null, req));
     });
 

lib/core/mergeConfig.js

@@ -80,6 +80,7 @@ module.exports = function mergeConfig(config1, config2) {
     'decompress': defaultToConfig2,
     'maxContentLength': defaultToConfig2,
     'maxBodyLength': defaultToConfig2,
+    'beforeRedirect': defaultToConfig2,
     'transport': defaultToConfig2,
     'httpAgent': defaultToConfig2,
     'httpsAgent': defaultToConfig2,

test/unit/adapters/http.js

@@ -241,6 +241,26 @@ describe('supports http with nodejs', function () {
     });
   });
 
+  it('should support beforeRedirect', function (done) {
+    server = http.createServer(function (req, res) {
+      res.setHeader('Location', '/foo');
+      res.statusCode = 302;
+      res.end();
+    }).listen(4444, function () {
+      axios.get('http://localhost:4444/', {
+        maxRedirects: 3,
+        beforeRedirect: function (options) {
+          if (options.path === '/foo') {
+            throw new Error('path not allowed');
+          }
+        }
+      }).catch(function (error) {
+        assert.equal(error.toJSON().message, 'path not allowed')
+        done();
+      });
+    });
+  });
+
   it('should preserve the HTTP verb on redirect', function (done) {
     server = http.createServer(function (req, res) {
       if (req.method.toLowerCase() !== "head") {