[squid-users] TCP_MISS only

[Alex Rousskov]

On 9/26/22 15:27, Andy Armstrong wrote:

> My aim – is that for any HTTP response from 192.168.0.2:3001 is
> cached and served from the cache.

> 1664219486.83610098 10.1.1.70 TCP_MISS/201 492 POST 
> http://192.168.0.2:3001/InternalCommunicationServices/message/email - 
> HIER_DIRECT/192.168.0.2 application/json

Squid does not cache responses with HTTP status code 201 (Created). Per 
HTTP protocol, such responses are not cachable "by default" and Squid is 
not smart enough to check whether a particular 201 response has headers 
that would allow Squid to overwrite that default. The specific response 
in question probably does not have those headers, but I am mentioning 
them here for completeness sake.

Furthermore, a "Created" response to a POST request probably does not 
contain anything you would want to cache -- things will probably break 
if that "create something" POST request is satisfied from the cache the 
next time around. You may need to study the HTTP server in question and 
adjust your goals from "cache any 192.168.0.2:3001 response" to 
something more nuanced, based on what that server does.


HTH,

Alex.




> My config is as follows:
> 
> http_port 3128
> 
> acl localnet src 10.0.0.0/8     # RFC1918 possible internal network
> 
> acl localnet src 172.16.0.0/12  # RFC1918 possible internal network
> 
> acl localnet src 192.168.0.0/16 # RFC1918 possible internal network
> 
> acl localnet src fc00::/7       # RFC 4193 local private network range
> 
> acl localnet src fe80::/10      # RFC 4291 link-local (directly plugged) 
> machines
> 
> acl SSL_ports port 443
> 
> acl Safe_ports port 80          # http
> 
> acl Safe_ports port 21          # ftp
> 
> acl Safe_ports port 443         # https
> 
> acl Safe_ports port 70          # gopher
> 
> acl Safe_ports port 210         # wais
> 
> acl Safe_ports port 280         # http-mgmt
> 
> acl Safe_ports port 488         # gss-http
> 
> acl Safe_ports port 591         # filemaker
> 
> acl Safe_ports port 777         # multiling http
> 
> acl Safe_ports port 1025-65535  # unregistered ports
> 
> acl CONNECT method CONNECT
> 
> http_access deny !Safe_ports
> 
> http_access deny CONNECT !SSL_ports
> 
> http_access allow localhost manager
> 
> http_access deny manager
> 
> http_access allow localnet
> 
> http_access allow localhost
> 
> http_access deny all
> 
> coredump_dir /squid/var/cache/squid
> 
> cache_dir ufs /var/spool/squid 1024 16 256
> 
> refresh_pattern -i http:\/\/192.168.0.2:3001\/.* 10080 100% 43200  
> override-lastmod
> 
> refresh_pattern ^ftp:                      1440      20%        10080
> 
> refresh_pattern ^gopher:             1440      0%          1440
> 
> refresh_pattern -i (/cgi-bin/|\?) 0             0%          0
> 
> refresh_pattern .                              0              20%        
> 4320
> 
> The problem I am finding is that each time my client makes a call via 
> the proxy, I see this in the logs:
> 
> 1664219486.83610098 10.1.1.70 TCP_MISS/201 492 POST 
> http://192.168.0.2:3001/InternalCommunicationServices/message/email - 
> HIER_DIRECT/192.168.0.2 application/json
> 
> I see the ‘TCP_MISS’,  the client receives the response from the remote 
> server, but on subsequent calls, it continues to trigger TCP_MISS and I 
> never manage to cache the response.
> 
> Please help me understand what I am missing from the configuration for 
> my intended use case.
> 
> Kind regards,
> 
> Andy Armstrong
> 
> 安迪阿姆斯特朗
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