Oxford Navigate Updated [2021]

The series is a six-level general English course (A1–C1) designed specifically for adult learners. It is built on academic research into how adults learn, focusing on a "bottom-up" approach to listening and reading to improve real-world comprehension. Core Components

The updated Oxford Navigate system offers numerous benefits to users, including: oxford navigate updated

Gamified activities that sync directly with the teacher’s gradebook. The series is a six-level general English course

Cheating prevention has been a headache for digital assessment. The previous Navigate used fixed question banks, allowing students to share answers. The update solves this with . oxford navigate updated

Oxford Navigate Updated [2021]

服务器负载测试工具(st-load)：

1. 模拟huge并发：2G内存就可以开300k连接。基于states-threads的协程。

2. 支持HLS解析和测试，下载ts片后等待一个切片长度，模拟客户端。支持HLS点播和直播。

3. 支持HTTP负载测试，所有并发重复下载一个http文件。可将80Gbps带宽测试的72Gbps。

4. 支持RTMP流测试，一个进程支持5k并发。使用nginx-rtmp的协议直接将chunk流解析为messgae。

state-threads用来模拟超级并发，并简化异步socket的逻辑为同步socket，http-parser解析http协议部分。

这两个库设计都很巧妙，所以我开了一个项目：https://github.com/winlinvip/st-load

state-threads之前就有写过文章说明，那时候主要是支持高并发的rtmp服务器，也是并发和异步变为同步的协程很方便。

http-parser用yum就可以search到，它其实设计得也相当巧妙，相当于只是解析buffer的http内容，并不负责网络部分。libcurl/poco等都带了网络处理，所以不合适。

举例说明，http_parser_parse_url这个函数，解析url，设计得非常有意思，不是返回字符串，而是返回位置索引，譬如主机头在什么位置长度多长等等。

[root@localhost ~]# yum install git unzip patch gcc gcc-c++ make
[root@localhost ~]# git clone https://github.com/winlinvip/st-load.git

[root@localhost st-load]# ./configure
[root@localhost st-load]# make

[root@localhost st-load]# ls objs/
http-parser-2.1 src st_hls_load st_rtmp_load st_rtmp_publish
Makefile st-1.9 st_http_load st_rtmp_load_fast
[root@localhost st-load]#
模拟RTMP用户
./st_rtmp_load -c 1 -r rtmp://127.0.0.1:1935/live/livestream
模拟HLS直播用户
./st_hls_load -c 1 -r http://127.0.0.1:3080/hls/hls.m3u8
模拟HSL点播用户
./st_hls_load -c 10000 -o -r http://127.0.0.1:3080/hls/hls.m3u8
模拟RTMP推流用户
./st_rtmp_publish -i doc/source.200kbps.768×320.flv -c 1 -r rtmp://127.0.0.1:1935/live/livestream
模拟RTMP多路推流用户
./st_rtmp_publish -i doc/source.200kbps.768×320.flv -c 1000 -r rtmp://127.0.0.1:1935/live/livestream_{i}

支持RTMP流播放测试，一个进程支持5k并发
支持RTMP流推流测试，一个进程支持500个并发。

The updated Oxford Navigate system offers numerous benefits to users, including:

Gamified activities that sync directly with the teacher’s gradebook.

Cheating prevention has been a headache for digital assessment. The previous Navigate used fixed question banks, allowing students to share answers. The update solves this with .

Oxford Navigate Updated [2021]

第一种方案：ffmpeg+nginx

新的ffmpeg已经支持HLS。（本人也参与了代码供献，给自己做个广告:)）

点播：

生成hls分片:

ffmpeg -i <媒体文件> -c:v libx264 -c:a -f hls /usr/local/nginx/html/test.m3u8

直播：

ffmpeg -i udp://@:1234 -c:v libx264 -c:a -f hls /usr/local/nginx/html/test.m3u8

建立web服务器：

默认配置就可以。

server {

listen 80;

server_name localhost;

#charset koi8-r;

#access_log logs/host.access.log main;

location / {

root html;

index index.html index.htm;

}

启动nginx。

客户端访问：http://IP/test.m3u8

在windows上可以用vlc播放。

第二个文案，用nginx-rtmp-module

rtmp {

server {

listen 1935;

chunk_size 4000;

#HLS

# For HLS to work please create a directory in tmpfs (/tmp/app here)

# for the fragments. The directory contents is served via HTTP (see

# http{} section in config)

# Incoming stream must be in H264/AAC. For iPhones use baseline H264

# profile (see ffmpeg example).

# This example creates RTMP stream from movie ready for HLS:

# ffmpeg -loglevel verbose -re -i movie.avi –vcodec libx264

# -vprofile baseline -acodec libmp3lame -ar 44100 -ac 1

# -f flv rtmp://localhost:1935/hls/movie

# If you need to transcode live stream use ‘exec’ feature.

application hls {

live on;

hls on;

hls_path /tmp/app;

hls_fragment 5s;

}

http {

server {

listen 80;

location /hls {

# Serve HLS fragments

types {

application/vnd.apple.mpegurl m3u8;

video/mp2t ts;

}

alias /tmp/app;

expires -1;

}

Oxford Navigate Updated [2021]

相对于 Apache，Nginx 占用的系统资源更少，更适合 VPS 使用。恶意盗链的 User Agent 无处不在，博客更换到 WordPress 没几天，就被 SPAM（垃圾留言）盯上，又被暴力破解后台用户名密码。以前介绍过 Apache 使用 .htaccess 屏蔽恶意 User Agent，今天来介绍 Nginx 屏蔽恶意 User Agent请求的方法。

先上规则&注释

#禁用未初始化变量警告
uninitialized_variable_warn off;
#匹配各种 bad user agent，返回403错误
if ($http_user_agent ~* "embeddedwb|NSPlayer|WMFSDK|qunarbot|mj12bot|ahrefsbot|Windows 98|MSIE 6.0; Windows 2000|EasouSpider|Sogou web spider") {
return 403;
}
#匹配POST方法，给变量iftemp赋值
if ($request_method ~* "POST") {set $iftemp X;}
#匹配 bad user agent，给变量iftemp赋值;这几个UA主要是发垃圾留言的
if ($http_user_agent ~* "MSIE 6.*NET|MSIE 7.*NET|MSIE 6.*SV1|MSIE 6.0; Windows NT 5.0") {
set $iftemp "${iftemp}Y";
}
#如果变量iftemp符合上面两个条件，返回403错误
if ($iftemp = XY) {return 403;}

禁用未初始化变量警告，不然会不停写入警告到错误日志error.log，如下

2014/09/11 09:21:11 [warn] 18649#0: *132 using uninitialized “iftemp” variable, client: 220.181.51.209, server: www.wilf.cn, request: “GET /wp-content/themes/dazzling/inc/fonts/glyphicons-halflings-regular.woff HTTP/1.0”, host: “www.wilf.cn”, referrer: “http://www.wilf.cn/”

2014/09/11 09:21:11 [warn] 18649#0: *92 using uninitialized “iftemp” variable, client: 66.249.79.55, server: www.wilf.cn, request: “GET /page/14?mod=pad&act=view&id=741 HTTP/1.1”, host: “www.wilf.cn”

Nginx 规则不支持2个以上的条件判断，绕个路，通过给变量两次赋值来完成2个条件判断。

Nginx 规则也是使用正则表达式匹配字符串，分析日志，根据需要自己定制。

检验成果的时候到了

183.60.214.51 — [10/Sep/2014:22:16:18 +0800] — Bytes: 13507 — GET /?mod=pad&act=view&id=460 HTTP/1.1 — 403 — – — Mozilla/5.0 (compatible; EasouSpider; +http://www.easou.com/search/spider.html) — – — –

220.181.125.169 — [11/Sep/2014:09:38:15 +0800] — Bytes: 169 — GET /page/51?mod=wap&act=AddCom&inpId=860 HTTP/1.1 — 403 — – — Sogou web spider/4.0(+http://www.sogou.com/docs/help/webmasters.htm#07) — – — –

EasouSpider 和 Sogou web spider，再也不见。

http://www.wilf.cn/post/block-bad-user-agent-on-nginx-sever.html