fix: handle upper case protocol like HTTP or HTTPS (#1805)

Co-authored-by: fengmk2 <suqian.yf@antgroup.com>

__tests__/response/redirect.js

@@ -20,6 +20,13 @@ describe('ctx.redirect(url)', () => {
     assert.strictEqual(ctx.status, 302)
   })
 
+  it('should formatting url before redirect', () => {
+    const ctx = context()
+    ctx.redirect('HTTP://google.com\\@apple.com')
+    assert.strictEqual(ctx.response.header.location, 'http://google.com/@apple.com')
+    assert.strictEqual(ctx.status, 302)
+  })
+
   it('should auto fix not encode url', done => {
     const app = new Koa()
 

lib/response.js

@@ -266,7 +266,7 @@ module.exports = {
   redirect (url, alt) {
     // location
     if (url === 'back') url = this.ctx.get('Referrer') || alt || '/'
-    if (url.startsWith('https://') || url.startsWith('http://')) {
+    if (/^https?:\/\//i.test(url)) {
       // formatting url again avoid security escapes
       url = new URL(url).toString()
     }