标签 curl 下的文章

1、curl -w参数

curl -h |grep "write-out"

-w, --write-out <format> Use output FORMAT after completion

2、显示所有时间示例

curl -o /dev/null -s -w "time_namelookup:%{time_namelookup}\ntime_connect: %{time_connect}\ntime_starttransfer: %{time_starttransfer}\ntime_total: %{time_total}\n"  "https://const.net.cn/"

输出:

time_namelookup:0.058759
time_connect: 0.069912
time_starttransfer: 0.147355
time_total: 0.167685

3、参数说明

time_namelookup: DNS 服务器域名解析的时间(以上时间单位都是s)
time_connect: client 发出请求,到 c/s 建立TCP 的时间;里面包括 DNS 解析的时间
time_starttransfer: client 发出请求;到 server 响应发出第一个字节开始的时间;包括前面的2个时间
time_total: 从请求发起到链接关闭的总耗时

4、官方英文说明

time_appconnect: 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_connect: The time, in seconds, it took from the start until the TCP connect to the remote host (or proxy) was completed.
time_namelookup: The time, in seconds, it took from the start until the name resolving was completed.
time_pretransfer: 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: The time, in seconds, it took for all redirection steps including 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: 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.
time_total: The total time, in seconds, that the full operation lasted.

5、格式可以使用字符串,格式化文件以及标准输入

The format can be specified as a literal "string", or you can have curl read the format from a file with "@filename" and to tell curl to read the format from stdin you write "@-".

6、使用格式文件示例

cat curl-format.txt

   time_namelookup:%{time_namelookup}\n
      time_connect:%{time_connect}\n
   time_appconnect:%{time_appconnect}\n
     time_redirect:%{time_redirect}\n    
  time_pretransfer:%{time_pretransfer}\n  
time_starttransfer:%{time_starttransfer}\n
------------------------------\n
        time_total:  %{time_total}\n

使用示例:

curl -o /dev/null -s -w "@curl-format.txt"  "https://const.net.cn/"

输出结果:

   time_namelookup:0.165160
      time_connect:0.240436
   time_appconnect:0.326137
     time_redirect:0.000000
  time_pretransfer:0.326211
time_starttransfer:0.412927
------------------------------
        time_total:  0.486244

1、查看curl与时间相关的选项

curl -h |grep time

有用的输出

--connect-timeout <seconds> Maximum time allowed for connection
--expect100-timeout <seconds> How long to wait for 100-continue
--keepalive-time <seconds> Interval time for keepalive probes
-m, --max-time <seconds> Maximum time allowed for the transfer
-y, --speed-time <seconds> Trigger 'speed-limit' abort after this time

2、控制连接超时--connect-timeout 5

curl -v --connect-timeout 1 https://const.net.cn

当出现连接超时时,会提示如下信息

curl: (28) Connection timed out after 1001 milliseconds

3、总超时时间--max-time
 我们希望curl程序在运行一段时间后,不管有没有执行完成都能正常退出。就用这个max-time

curl -v -m 60 https://const.net.cn

4、--speed-time 的用法
speed-time是用来根据速率来控制连接是否断开的。
用法:

curl -o const.log "https://const.net.cn" --speed-time 5 --speed-limit 1

是说将url内容保存到const.log中, 如果传输速度小于1字节/秒的状态持续5秒,该连接就会断开,并退出程序。