breaking: remove redirect(back) for v3

Author: jonathanong

__tests__/response/redirect.test.js

@@ -45,34 +45,6 @@ describe('ctx.redirect(url)', () => {
       })
   })
 
-  describe('with "back"', () => {
-    it('should redirect to Referrer', () => {
-      const ctx = context()
-      ctx.req.headers.referrer = '/login'
-      ctx.redirect('back')
-      assert.strictEqual(ctx.response.header.location, '/login')
-    })
-
-    it('should redirect to Referer', () => {
-      const ctx = context()
-      ctx.req.headers.referer = '/login'
-      ctx.redirect('back')
-      assert.strictEqual(ctx.response.header.location, '/login')
-    })
-
-    it('should default to alt', () => {
-      const ctx = context()
-      ctx.redirect('back', '/index.html')
-      assert.strictEqual(ctx.response.header.location, '/index.html')
-    })
-
-    it('should default redirect to /', () => {
-      const ctx = context()
-      ctx.redirect('back')
-      assert.strictEqual(ctx.response.header.location, '/')
-    })
-  })
-
   describe('when html is accepted', () => {
     it('should respond with html', () => {
       const ctx = context()

docs/api/response.md

@@ -287,17 +287,11 @@ app.use(async (ctx, next) => {
 });
 ```
 
-### response.redirect(url, [alt])
+### response.redirect(url)
 
   Perform a [302] redirect to `url`.
 
-  The string "back" is special-cased
-  to provide Referrer support, when Referrer
-  is not present `alt` or "/" is used.
-
 ```js
-ctx.redirect('back');
-ctx.redirect('back', '/index.html');
 ctx.redirect('/login');
 ctx.redirect('http://google.com');
 ```
@@ -311,6 +305,11 @@ ctx.redirect('/cart');
 ctx.body = 'Redirecting to shopping cart';
 ```
 
+### response.back(url)
+
+  Similar to `.redirect(url)`, but first checks the `referer` header to redirect.
+  This is new in v3 as `.redirect(url, alt)` removes the special case `url = 'back'` option.
+
 ### response.attachment([filename], [options])
 
   Set `Content-Disposition` to "attachment" to signal the client

lib/response.js

@@ -273,29 +273,16 @@ module.exports = {
   /**
    * Perform a 302 redirect to `url`.
    *
-   * The string "back" is special-cased
-   * to provide Referrer support, when Referrer
-   * is not present `alt` or "/" is used.
-   *
    * Examples:
    *
-   *    this.redirect('back');
-   *    this.redirect('back', '/index.html');
    *    this.redirect('/login');
    *    this.redirect('http://google.com');
    *
    * @param {String} url
-   * @param {String} [alt]
    * @api public
    */
 
-  redirect (url, alt) {
-    // location
-    if (url === 'back') {
-      deprecate('Special-cased string "back" through redirect will be removed in v3, ' +
-        'consider migrating usage to ctx.back() instead.')
-      url = this.ctx.get('Referrer') || alt || '/'
-    }
+  redirect (url) {
     if (/^https?:\/\//i.test(url)) {
       // formatting url again avoid security escapes
       url = new URL(url).toString()