processing a request without body

[Maxim Dounin]

Hello!

On Sat, Jan 13, 2024 at 03:11:11PM +0800, Muhammad Nuzaihan wrote:

> Hi Maxim,
> 
> I did enable debug logs before i posted the question.
> 
> With json payload, my code is executed right after doing malloc and
> "http request body content length filter".
> 
> Without a json payload, it doesn't execute my request
> validation.That's why i thought it might be due to content length is
> 0.
> 
> Here is the debug log when i curl with an empty payload:
> 
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 rewrite phase: 0
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 test location: "/"
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 test location: "proxy/health"
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 test location: "proxy/unhealthy"
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 test location:
> "proxy/profile/alice/comment"
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 using configuration
> "/proxy/profile/alice/comment"
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http cl:0 max:1048576
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 rewrite phase: 2
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 post rewrite phase: 3
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 generic phase: 4
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http request body content
> length filter
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http read client request body

Clearly request body reading is called here, at the preaccess 
phase.  This implies that your code is called - nginx itself won't 
try to read the request body that early.  Everything else is up to 
your code.

> 2024/01/13 15:01:19 [debug] 2452969#0: *11 recv: eof:0, avail:0
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http client request body recv -2
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http client request body rest 1
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 event timer add: 3: 60000:183385517

Note that request body reading code blocks waiting for more data.

> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http finalize request: -4,
> "/proxy/profile/alice/comment?" a:1, c:2
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 http request count:2 blk:0
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 access phase: 7
> 2024/01/13 15:01:19 [debug] 2452969#0: *11 access phase: 8

Note that phase handling continues here: it shouldn't, since 
request body reading is in progress. 

This suggested that your code fails to stop phase handling after 
calling ngx_http_read_client_request_body(): note you should 
return NGX_DONE to stop processing unless there is an immediate 
error.

[...]

-- 
Maxim Dounin
http://mdounin.ru/