Updating docs and adding more tests.

Author: Sean Willis

README.md

@@ -342,6 +342,18 @@ proxyServer.listen(8015);
        "*": ""
      }
      ```
+*  **cookiePathRewrite**: rewrites path of `set-cookie` headers. Possible values:
+   * `false` (default): disable cookie rewriting
+   * String: new path, for example `cookiePathRewrite: "/newPath/"`. To remove the path, use `cookiePathRewrite: ""`. To set path to root use `cookiePathRewrite: "/"`.
+   * Object: mapping of paths to new paths, use `"*"` to match all paths.  
+     For example keep one path unchanged, rewrite one path and remove other paths:
+     ```
+     cookiePathRewrite: {
+       "/unchanged.path/": "/unchanged.path/",
+       "/old.path/": "/new.path/",
+       "*": ""
+     }
+     ```
 *  **headers**: object with extra headers to be added to target requests.
 *  **proxyTimeout**: timeout (in millis) when proxy receives no response from target
 

test/lib-http-proxy-passes-web-outgoing-test.js

@@ -289,7 +289,18 @@ describe('lib/http-proxy/passes/web-outgoing.js', function () {
       expect(this.res.headers['set-cookie']).to.have.length(2);
     });
 
-    it('does not rewrite domain', function() {
+    it('rewrites path', function() {
+      var options = {
+        cookiePathRewrite: '/dummyPath'
+      };
+
+      httpProxy.writeHeaders({}, this.res, this.proxyRes, options);
+
+      expect(this.res.headers['set-cookie'])
+        .to.contain('hello; domain=my.domain; path=/dummyPath');
+    });
+
+    it('does not rewrite path', function() {
       var options = {};
 
       httpProxy.writeHeaders({}, this.res, this.proxyRes, options);
@@ -298,15 +309,24 @@ describe('lib/http-proxy/passes/web-outgoing.js', function () {
         .to.contain('hello; domain=my.domain; path=/');
     });
 
-    it('rewrites path', function() {
+    it('removes path', function() {
       var options = {
-        cookiePathRewrite: '/dummyPath'
+        cookiePathRewrite: ''
       };
 
       httpProxy.writeHeaders({}, this.res, this.proxyRes, options);
 
       expect(this.res.headers['set-cookie'])
-        .to.contain('hello; domain=my.domain; path=/dummyPath');
+        .to.contain('hello; domain=my.domain');
+    });
+
+    it('does not rewrite domain', function() {
+      var options = {};
+
+      httpProxy.writeHeaders({}, this.res, this.proxyRes, options);
+
+      expect(this.res.headers['set-cookie'])
+        .to.contain('hello; domain=my.domain; path=/');
     });
 
     it('rewrites domain', function() {