91 lines
3.2 KiB
Markdown
91 lines
3.2 KiB
Markdown
---
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id: 589fc832f9fc0f352b528e78
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title: 用户公告
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challengeType: 2
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forumTopicId: 301546
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dashedName: announce-new-users
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---
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# --description--
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许多聊天室都有这个功能:所有已连接到服务器的在线用户都会看到有人加入或退出的提醒。 我们已经写好了处理连接和断开事件的代码,只要对这个方法稍作修改就可以实现这个功能。 在事件中,我们需要发送这三条信息:连接或断开的用户名、当前用户数量、事件类型(即需要知道用户究竟是连接还是断开)。
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请将事件名称更改为 `'user'`,其中应包含如下字段:'name'、'currentUsers'、'connected'(布尔值,连接上即为 `true`,断开则是 `false`)。 请务必更改两个 user count 事件,设置 disconnect 事件向 connected 字段发送 `false` ,而不是像 connect 事件一样发送 `true`。
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```js
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io.emit('user', {
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name: socket.request.user.name,
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currentUsers,
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connected: true
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});
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```
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现在客户端已具备足够的信息,来显示当前用户数,并在用户连接或断开连接时通知! 接下来我们需要在客户端监听 `'user'` 事件,然后用 jQuery 把 `#num-users` 节点的文本内容更新为 `'{NUMBER} users online'`。 同时,我们需要为无序列表添加一个 id 为 `messages` 且带有 `'{NAME} has {joined/left} the chat.'` 文本的 `<li>`。
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实现如下:
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```js
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socket.on('user', data => {
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$('#num-users').text(data.currentUsers + ' users online');
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let message =
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data.name +
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(data.connected ? ' has joined the chat.' : ' has left the chat.');
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$('#messages').append($('<li>').html('<b>' + message + '</b>'));
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});
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```
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完成上述要求后,你可以在下方提交你的页面链接。 如果你遇到了问题,可以参考 [这里](https://gist.github.com/camperbot/bf95a0f74b756cf0771cd62c087b8286) 的答案。
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# --hints--
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事件 `'user'` 应该包含,name、 currentUsers 和 connected。
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/_api/server.js').then(
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(data) => {
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assert.match(
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data,
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/io.emit.*('|")user\1.*name.*currentUsers.*connected/gis,
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'You should have an event emitted named user sending name, currentUsers, and connected'
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);
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},
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(xhr) => {
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throw new Error(xhr.statusText);
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}
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);
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```
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客户端应处理和显示 `'user'` 中的新数据。
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```js
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(getUserInput) =>
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$.get(getUserInput('url') + '/public/client.js').then(
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(data) => {
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assert.match(
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data,
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/socket.on.*('|")user\1[^]*num-users/gi,
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'You should change the text of "#num-users" within on your client within the "user" event listener to show the current users connected'
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);
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assert.match(
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data,
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/socket.on.*('|")user\1[^]*messages.*li/gi,
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'You should append a list item to "#messages" on your client within the "user" event listener to announce a user came or went'
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);
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},
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(xhr) => {
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throw new Error(xhr.statusText);
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}
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);
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```
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# --solutions--
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```js
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/**
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Backend challenges don't need solutions,
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because they would need to be tested against a full working project.
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Please check our contributing guidelines to learn more.
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*/
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```
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