如何让Curl为每个SSE事件打印日期时间戳？

我执行以下curl命令请求SSE流：

curl --request POST --url http://some-example.com/stream   --header 'Content-Type: application/json'   --data '{
"text": "hello"
}'

Shell输出的每个SSE事件仅包含数据内容：

data:{"id":"chatcmpl-75BRIh9KeZv274g1AtHNq5d5POzEJ","object":"chat.completion.chunk","created":1681469968,"model":"gpt-3.5-turbo-0301","choices":[{"delta":{"role":"assistant"},"index":0,"finish_reason":null}]}

data:{"id":"chatcmpl-75BRIh9KeZv274g1AtHNq5d5POzEJ","object":"chat.completion.chunk","created":1681469968,"model":"gpt-3.5-turbo-0301","choices":[{"delta":{"content":"hello"},"index":0,"finish_reason":null}]}

data:{"id":"chatcmpl-75BRIh9KeZv274g1AtHNq5d5POzEJ","object":"chat.completion.chunk","created":1681469968,"model":"gpt-3.5-turbo-0301","choices":[{"delta":{"content":"."},"index":0,"finish_reason":null}]}

我希望每个SSE事件前都打印对应的日期时间，例如：

2023-04-14 08:13:12.418 data:{"id":"chatcmpl-75BRIh9KeZv274g1AtHNq5d5POzEJ","object":"chat.completion.chunk","created":1681469968,"model":"gpt-3.5-turbo-0301","choices":[{"delta":{"role":"assistant"},"index":0,"finish_reason":null}]}

2023-04-14 08:13:12.528 data:{"id":"chatcmpl-75BRIh9KeZv274g1AtHNq5d5POzEJ","object":"chat.completion.chunk","created":1681469968,"model":"gpt-3.5-turbo-0301","choices":[{"delta":{"content":"hello"},"index":0,"finish_reason":null}]}

2023-04-14 08:13:12.568 data:{"id":"chatcmpl-75BRIh9KeZv274g1AtHNq5d5POzEJ","object":"chat.completion.chunk","created":1681469968,"model":"gpt-3.5-turbo-0301","choices":[{"delta":{"content":"."},"index":0,"finish_reason":null}]}

试过用-v --trace-time参数，但没效果，请问怎么实现这个需求？

解决方法 #

可以通过管道结合文本处理工具，给curl输出的每一行（每个SSE事件）添加时间戳，以下是两种可行方案：

方案1：使用awk #

将curl的输出传给awk，由awk在每行前拼接带毫秒的时间戳：

curl --request POST --url http://some-example.com/stream --header 'Content-Type: application/json' --data '{"text": "hello"}' | awk '{ print strftime("%Y-%m-%d %H:%M:%S.%3N"), $0 }'

• 注：部分系统默认的awk（比如macOS的awk）不支持%3N毫秒格式，可通过brew install gawk安装GNU awk替代。

方案2：使用perl #

perl的时间处理兼容性更强，适合多系统环境：
如果只需要秒级精度：

curl --request POST --url http://some-example.com/stream --header 'Content-Type: application/json' --data '{"text": "hello"}' | perl -ne 'use Time::HiRes qw(time); printf "%s %s", scalar localtime(time), $_'

需要毫秒级精度时：

curl --request POST --url http://some-example.com/stream --header 'Content-Type: application/json' --data '{"text": "hello"}' | perl -ne 'use Time::HiRes qw(gettimeofday); my ($sec, $usec) = gettimeofday(); my $msec = int($usec/1000); printf "%s.%03d %s", scalar localtime($sec), $msec, $_'

关于-v --trace-time无效的原因 #

--trace-time仅会给curl的调试日志（如请求头、响应头、连接信息等）添加时间戳，不会处理响应体中的SSE事件内容，因此对输出的data:行不起作用。

内容的提问来源于stack exchange，提问作者djy