调用ngx.say后无法再次调用设置状态码

wyj1017146866 · 2018-10-28T04:17:01+00:00

Hi folks, I gave a talk on using systemtap and ylang to dynamic trace unmodified and unplugged openresty/luajit/nginx/cpython/perl/postgresql/etc on Nginx C...

调用ngx.say后无法再次调用设置状态码

wyj1017146866

location = /test {

ngx.say("test...")

ngx.exit(500)

}

报错为：

attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/2.0", host: "localhost"

attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/1.1", host: "localhost"

根据报错来说，这是因为ngx.say提前将响应送出导致的。而且在（HTTP/1.1的）响应头中的确能看到TE: chunked

那么这个行为是by design的吗？有没有什么办法能改变这个行为呢？

hlee

这个是因为ngx.say相当于发送了消息包出去，而发送消息包的话必然要先发送消息头，而此时response code并没有被设置，于是默认为200，如果要返回500，在say之前调用一次ngx.status = 500即可

On Sat, Oct 27, 2018 at 2:17 PM Yj W <wyj101...@gmail.com> wrote:

location = /test {
ngx.say("test...")
ngx.exit(500)
}

报错为：
attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/2.0", host: "localhost"
attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/1.1", host: "localhost"

根据报错来说，这是因为ngx.say提前将响应送出导致的。而且在（HTTP/1.1的）响应头中的确能看到TE: chunked

那么这个行为是by design的吗？有没有什么办法能改变这个行为呢？

--

smallfish.xy

参考官方例子 https://github.com/openresty/lua-nginx-module#ngxexit

On Sun, Oct 28, 2018 at 2:19 PM House Lee <h...@vendasta.com> wrote:

这个是因为ngx.say相当于发送了消息包出去，而发送消息包的话必然要先发送消息头，而此时response code并没有被设置，于是默认为200，如果要返回500，在say之前调用一次ngx.status = 500即可

On Sat, Oct 27, 2018 at 2:17 PM Yj W <wyj101...@gmail.com> wrote:
location = /test {
ngx.say("test...")
ngx.exit(500)
}

报错为：
attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/2.0", host: "localhost"
attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/1.1", host: "localhost"

根据报错来说，这是因为ngx.say提前将响应送出导致的。而且在（HTTP/1.1的）响应头中的确能看到TE: chunked

那么这个行为是by design的吗？有没有什么办法能改变这个行为呢？

--

--

wyj1017146866

谢谢。我之后去查了文档发现这确实是by design的行为。

我现在是这样做

local responseText = ""
...
responseText = responseText .. "......"
...
ngx.status = 500
...
ngx.print(responseText)
return ngx.exit(ngx.status)

在 2018年10月28日星期日 UTC-4上午2:19:18，House Lee写道：

这个是因为ngx.say相当于发送了消息包出去，而发送消息包的话必然要先发送消息头，而此时response code并没有被设置，于是默认为200，如果要返回500，在say之前调用一次ngx.status = 500即可

On Sat, Oct 27, 2018 at 2:17 PM Yj W <wyj101...@gmail.com> wrote:
location = /test {
ngx.say("test...")
ngx.exit(500)
}

报错为：
attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/2.0", host: "localhost"
attempt to set status 500 via ngx.exit after sending out the response status 200, client: ::1, server: localhost, request: "GET /test HTTP/1.1", host: "localhost"

根据报错来说，这是因为ngx.say提前将响应送出导致的。而且在（HTTP/1.1的）响应头中的确能看到TE: chunked

那么这个行为是by design的吗？有没有什么办法能改变这个行为呢？

--