Curl追踪请求延时问题

背景原因：测试环境发现一个连接内网访问和外网访问延迟差别很大，内网访问很快。外网访问很慢。于是我们用curl来诊断问题所在的区域！

命令如下:

curl -o /dev/null -s -w %{time_namelookup}---%{time_connect}---%{time_starttransfer}---%{time_total}---%{speed_download}"\n" www.36nu.com

返回结果：

0.014---0.015---0.018---0.019---1516256.00

-o：把curl 返回的html、js 写到垃圾回收站[ /dev/null]

-s：去掉所有状态

-w：按照后面的格式写出rt

time_namelookup：DNS 解析域名www.36nu.com的时间

time_commect：client和server端建立TCP 连接的时间

time_starttransfer：从client发出请求；到web的server 响应第一个字节的时间

time_total：client发出请求；到web的server发送会所有的相应数据的时间

speed_download：下周速度 单位 byte/s

上面这条命令及返回结果可以这么理解：

0.014: DNS 服务器解析www.36nu.com 的时间单位是s

0.015: client发出请求，到c/s 建立TCP 的时间；里面包括DNS解析的时间

0.018: client发出请求；到s响应发出第一个字节开始的时间；包括前面的2个时间

0.019: client发出请求；到s把响应的数据全部发送给client；并关闭connect的时间

1516256.00 ：下载数据的速度

建立TCP连接到server返回client第一个字节的时间：0.018s – 0.015s = 0.003s

server把响应数据发送给client的时间：0.019s – 0.018 = 0.01s

#================================curl 其他参数详解============================

curl的部分时间等变量注释：

url_effective The URL that was fetched last. This is most meaningful if you've told curl to follow location: headers.

filename_effective The ultimate filename that curl writes out to. This is only meaningful if curl is told to write to a file with the --remote-name or --output option. It's most useful in combination with the --remote-header-name option. (Added in 7.25.1)

http_code http状态码，如200成功,301转向,404未找到,500服务器错误等。(The numerical response code that was found in the last retrieved HTTP(S) or FTP(s) transfer. In 7.18.2 the alias response_code was added to show the same info.)

http_connect The numerical code that was found in the last response (from a proxy) to a curl CONNECT request. (Added in 7.12.4)

time_total 总时间，按秒计。精确到小数点后三位。 （The total time, in seconds, that the full operation lasted. The time will be displayed with millisecond resolution.）

time_namelookup DNS解析时间,从请求开始到DNS解析完毕所用时间。(The time, in seconds, it took from the start until the name resolving was completed.)

time_connect 连接时间,从开始到建立TCP连接完成所用时间,包括前边DNS解析时间，如果需要单纯的得到连接时间，用这个time_connect时间减去前边time_namelookup时间。以下同理，不再赘述。(The time, in seconds, it took from the start until the TCP connect to the remote host (or proxy) was completed.)

time_appconnect 连接建立完成时间，如SSL/SSH等建立连接或者完成三次握手时间。(The time, in seconds, it took from the start until the SSL/SSH/etc connect/handshake to the remote host was completed. (Added in 7.19.0))

time_pretransfer 从开始到准备传输的时间。(The time, in seconds, it took from the start until the file transfer was just about to begin. This includes all pre-transfer commands and negotiations that are specific to the particular protocol(s) involved.)

time_redirect 重定向时间，包括到最后一次传输前的几次重定向的DNS解析，连接，预传输，传输时间。(The time, in seconds, it took for all redirection steps include name lookup, connect, pretransfer and transfer before the final transaction was started. time_redirect shows the complete execution time for multiple redirections. (Added in 7.12.3))

time_starttransfer 开始传输时间。在client发出请求之后，Web 服务器返回数据的第一个字节所用的时间(The time, in seconds, it took from the start until the first byte was just about to be transferred. This includes time_pretransfer and also the time the server needed to calculate the result.)

size_download 下载大小。(The total amount of bytes that were downloaded.)

size_upload 上传大小。(The total amount of bytes that were uploaded.)

size_header  下载的header的大小(The total amount of bytes of the downloaded headers.)

size_request 请求的大小。(The total amount of bytes that were sent in the HTTP request.)

speed_download 下载速度，单位-字节每秒。(The average download speed that curl measured for the complete download. Bytes per second.)

speed_upload 上传速度,单位-字节每秒。(The average upload speed that curl measured for the complete upload. Bytes per second.)

content_type 就是content-Type，不用多说了，这是一个访问我博客首页返回的结果示例(text/html; charset=UTF-8)；(The Content-Type of the requested document, if there was any.)

num_connects Number of new connects made in the recent transfer. (Added in 7.12.3)

num_redirects Number of redirects that were followed in the request. (Added in 7.12.3)

redirect_url When a HTTP request was made without -L to follow redirects, this variable will show the actual URL a redirect would take you to. (Added in 7.18.2)

ftp_entry_path The initial path libcurl ended up in when logging on to the remote FTP server. (Added in 7.15.4)

ssl_verify_result ssl认证结果，返回0表示认证成功。( The result of the SSL peer certificate verification that was requested. 0 means the verification was successful. (Added in 7.19.0))

1. #curl -o /dev/null -s -w %{http_code}:%{http_connect}:%{content_type}:%{time_namelookup}:%{time_redirect}:%{time_pretransfer}:%{time_connect}:%{time_starttransfer}:%{time_total}:%{speed_download} www.baidu.com

输出变量需要按照%{variable_name}的格式，如果需要输出%，double一下即可，即%%，同时，\n是换行，\r是回车，\t是TAB。

-w 指定格式化文件

-o 请求重定向到,不带此参数则控制台输出返回结果

-s 静默，不显示进度

1. #vim  curl-time.txt
2. \n
3. http: %{http_code}\n
4. dns: %{time_namelookup}s\n
5. redirect: %{time_redirect}s\n
6. time_connect: %{time_connect}s\n
7. time_appconnect: %{time_appconnect}s\n
8. time_pretransfer: %{time_pretransfer}s\n
9. time_starttransfer: %{time_starttransfer}s\n
10. size_download: %{size_download}bytes\n
11. speed_download: %{speed_download}B/s\n
12. ----------\n
13. time_total: %{time_total}s\n
14. \n

1. #curl -w "@curl_time.txt"  -s  -H "Content-Type: application/json" --insecure --header 'Host: passport.500.com' --data '{"platform":"android","userimei":"F5D815EA2BD8DBARD","app_channel":"10000","mbimei":"9DB358AF","version":"3.1.4","username":"hqzx","userpass":"976af4"}' --compressed https://119.147.113.177/user/login

1）以json格式数据

2）以&连接参数数据

1. #curl -d "data=7778a8143f111272&score=19&app_key=8d49f16fe034b98b&_test_user=test01" "http://127.0.0.1"

3) 附带文本数据，比如通过"浏览"选择本地的card.txt并上传发送post请求，

其中-F 为带文件的形式发送post请求，   blob为文本框中的name元素对应的属性值。<type="text" name="blob">

1. #curl  -F "blob=@card.txt;type=text/plain"  "http://172.16.102.208:8089/wiapi/score?leaderboard_id=7778a8143f111272&score=40&app_key=8d49f16fe034b98b&_test_user=test01"

安卓手机可以通过安装终端模拟器，然后在模拟器按以上方法使用curl调试定位app在移动数据网络环境下哪个环节出现慢的问题。