Jon’s recent Find the Time to First Byte Using Curl post reminded me about the additional timing details that cURL can provide.
cURL supports formatted output for the details of the request ( see the cURL manpage for details, under “-w, –write-out <format>” ). For our purposes we’ll focus just on the timing details that are provided.
Step one: create a new file, curl.txt, and paste in:
time_namelookup: %{time_namelookup}n time_connect: %{time_connect}n time_appconnect: %{time_appconnect}n time_pretransfer: %{time_pretransfer}n time_redirect: %{time_redirect}n time_starttransfer: %{time_starttransfer}n ----------n time_total: %{time_total}n content_type: %{content_type}n filename_effective: %{filename_effective}n http_code: %{http_code}n ftp_entry_path: %{ftp_entry_path}n http_connect: %{http_connect}n local_ip: %{local_ip}n local_port: %{local_port}n num_connects: %{num_connects}n num_redirects: %{num_redirects}n redirect_url: %{redirect_url}n remote_ip: %{remote_ip}n remote_port: %{remote_port}n size_download: %{size_download}n size_header: %{size_header}n size_request: %{size_request}n size_upload: %{size_upload}n speed_download: %{speed_download}n speed_upload: %{speed_upload}n ssl_verify_result: %{ssl_verify_result}n url_effective: %{url_effective}n
Step two, make a request:
curl -w "@curl.txt" -o /dev/null -s http://www.aikaiyuan.com/
What this does:
-w "@curl-format.txt"
tells cURL to use our format file-o /dev/null
redirects the output of the request to /dev/null-s
tells cURL not to show a progress meterhttp://wordpress.com/
is the URL we are requesting
And here is what you get back:
time_namelookup: 0.007 time_connect: 0.053 time_appconnect: 0.000 time_pretransfer: 0.053 time_redirect: 0.000 time_starttransfer: 0.630 ---------- time_total: 1.227 content_type: text/html; charset=UTF-8 curl: unknown --write-out variable: 'filename_effective' filename_effective: http_code: 200 ftp_entry_path: http_connect: 000 curl: unknown --write-out variable: 'local_ip' local_ip: curl: unknown --write-out variable: 'local_port' local_port: num_connects: 1 num_redirects: 0 redirect_url: curl: unknown --write-out variable: 'remote_ip' remote_ip: curl: unknown --write-out variable: 'remote_port' remote_port: size_download: 206721 size_header: 361 size_request: 170 size_upload: 0 speed_download: 168497.000 speed_upload: 0.000 ssl_verify_result: 0 url_effective: http://www.aikaiyuan.com/
Jon was looking specifically at time to first byte, which is the time_starttransfer line. The other timing details include DNS lookup, TCP connect, pre-transfer negotiations, redirects (in this case there were none), and of course the total time.
The format file for this output provides a reasonable level of flexibility, for instance you could make it CSV formatted for easy parsing. You might want to do that if you were running this as a cron job to track timing details of a specific URL.
For details on the other information that cURL can provide using -w
check out the cURL manpage.
转载请注明:爱开源 » Timing Details With cURL