Lazily initialize `request.accept` and delegate `context.accept` (#1209)

lib/application.js

@@ -15,7 +15,6 @@ const context = require('./context');
 const request = require('./request');
 const statuses = require('statuses');
 const Cookies = require('cookies');
-const accepts = require('accepts');
 const Emitter = require('events');
 const util = require('util');
 const Stream = require('stream');
@@ -175,7 +174,6 @@ module.exports = class Application extends Emitter {
       secure: request.secure
     });
     request.ip = request.ips[0] || req.socket.remoteAddress || '';
-    context.accept = request.accept = accepts(req);
     context.state = {};
     return context;
   }

lib/context.js

@@ -204,6 +204,7 @@ delegate(proto, 'request')
   .access('query')
   .access('path')
   .access('url')
+  .access('accept')
   .getter('origin')
   .getter('href')
   .getter('subdomains')

lib/request.js

@@ -7,6 +7,7 @@
 
 const URL = require('url').URL;
 const net = require('net');
+const accepts = require('accepts');
 const contentType = require('content-type');
 const stringify = require('url').format;
 const parse = require('parseurl');
@@ -463,6 +464,27 @@ module.exports = {
       .slice(offset);
   },
 
+  /**
+   * Get accept object.
+   * Lazily memoized.
+   *
+   * @return {Object}
+   * @api private
+   */
+  get accept() {
+    return this._accept || (this._accept = accepts(this.req));
+  },
+
+  /**
+   * Set accept object.
+   *
+   * @param {Object}
+   * @api private
+   */
+  set accept(obj) {
+    return this._accept = obj;
+  },
+
   /**
    * Check if the given `type(s)` is acceptable, returning
    * the best match when true, otherwise `false`, in which

test/request/accept.js

@@ -0,0 +1,27 @@
+
+'use strict';
+
+const Accept = require('accepts');
+const assert = require('assert');
+const context = require('../helpers/context');
+
+describe('ctx.accept', () => {
+  it('should return an Accept instance', () => {
+    const ctx = context();
+    ctx.req.headers.accept = 'application/*;q=0.2, image/jpeg;q=0.8, text/html, text/plain';
+    assert(ctx.accept instanceof Accept);
+  });
+});
+
+describe('ctx.accept=', () => {
+  it('should replace the accept object', () => {
+    const ctx = context();
+    ctx.req.headers.accept = 'text/plain';
+    assert.deepEqual(ctx.accepts(), ['text/plain']);
+
+    const request = context.request();
+    request.req.headers.accept = 'application/*;q=0.2, image/jpeg;q=0.8, text/html, text/plain';
+    ctx.accept = Accept(request.req);
+    assert.deepEqual(ctx.accepts(), ['text/html', 'text/plain', 'image/jpeg', 'application/*']);
+  });
+});