为什么 Apache mod_rewrite 删除了 uri 部分？

Question

I'm trying to configure Apache as an encryption proxy https://chat.example.com for our websoket server http://localhost:8000 (on the same OS). I enabled mod_proxy, mod_proxy_http, mod_proxy_wstunnel, mod_rewrite and mod_ssl according to the official docs. Then I made a regular https GET request to the https://chat.example.com/connection/info?t=123144343 , but Apache rewrote it to http://localhost:8000/?t=123144343 instead of http://localhost:8000/connection/info?t=123144343 . Why?

<VirtualHost *:443>

    ServerAdmin admin@example.com
    ServerName chat.example.com

    RewriteEngine On

    RewriteCond %{HTTP:Upgrade} =websocket [NC]
    RewriteRule ^(.*)$ ws://localhost:8000/ [P,L]
    RewriteCond %{HTTP:Upgrade} !=websocket [NC]
    RewriteRule ^(.*)$ http://localhost:8000/ [P,L]

    ProxyRequests Off
    ProxyPreserveHost On

    SSLEngine on
    SSLProtocol +TLSv1 +TLSv1.1 +TLSv1.2 +TLSv1.3
    SSLCertificateFile /etc/ssl/certs/example.com.crt
    SSLCertificateKeyFile /etc/ssl/private/example.com.key
    SSLCertificateChainFile /etc/ssl/certs/example.com-chain.crt

    LogLevel rewrite:trace7
    ErrorLog /var/log/example.com/chat_error.log
    CustomLog /var/log/example.com/chat_access.log io

</VirtualHost>

[Wed Dec 25 18:57:16.057448 2019] [rewrite:trace2] [pid 9604:tid 140105269184256] mod_rewrite.c(483): init rewrite engine with requested uri /connection/info, referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057523 2019] [rewrite:trace3] [pid 9604:tid 140105269184256] mod_rewrite.c(483): applying pattern '^(.*)$' to uri '/connection/info', referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057566 2019] [rewrite:trace4] [pid 9604:tid 140105269184256] mod_rewrite.c(483): RewriteCond: input='' pattern='=websocket' [NC] => not-matched, referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057600 2019] [rewrite:trace3] [pid 9604:tid 140105269184256] mod_rewrite.c(483): applying pattern '^(.*)$' to uri '/connection/info', referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057637 2019] [rewrite:trace4] [pid 9604:tid 140105269184256] mod_rewrite.c(483): RewriteCond: input='' pattern='!=websocket' [NC] => matched, referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057670 2019] [rewrite:trace2] [pid 9604:tid 140105269184256] mod_rewrite.c(483): rewrite '/connection/info' -> 'http://localhost:8000/', referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057702 2019] [rewrite:trace2] [pid 9604:tid 140105269184256] mod_rewrite.c(483): forcing proxy-throughput with http://localhost:8000/, referer: https://example.com/personal/chats
[Wed Dec 25 18:57:16.057735 2019] [rewrite:trace1] [pid 9604:tid 140105269184256] mod_rewrite.c(483): go-ahead with proxy request proxy:http://localhost:8000/ [OK], referer: https://example.com/personal/chats

Answer 1

RewriteCond %{HTTP:Upgrade} =websocket [NC] RewriteRule ^(.*)$ ws://localhost:8000/ [P,L] RewriteCond %{HTTP:Upgrade} !=websocket [NC] RewriteRule ^(.*)$ http://localhost:8000/ [P,L]

You are capturing the URL-path with the RewriteRule pattern , ie. (.*) . However, you are not making use of this captured URL-path in the substitution and simply rewriting to the document root: http://localhost:8000/ . The query string is copied through to the substitution implicitly.

You need to include the captured URL-path in the substitution using the $1 backreference. For example:

RewriteCond %{HTTP:Upgrade} =websocket [NC]
RewriteRule ^(.*)$ ws://localhost:8000$1 [P,L]
RewriteCond %{HTTP:Upgrade} !=websocket [NC]
RewriteRule ^(.*)$ http://localhost:8000$1 [P,L]

Note that in a virtualhost context, the URL-path matched by the RewriteRule pattern is root-relative and includes the slash prefix, so the slash should not be included in the susbtitution (unless omitted from the captured pattern).

If this fails to work, then try using the REQUEST_URI server variable instead:

RewriteCond %{HTTP:Upgrade} =websocket [NC]
RewriteRule ^ ws://localhost:8000%{REQUEST_URI} [P,L]
RewriteCond %{HTTP:Upgrade} !=websocket [NC]
RewriteRule ^ http://localhost:8000%{REQUEST_URI} [P,L]

EDIT: Although, rather confusingly, I see from the question history (as I was surprised I didn't see this initially) that the code block in your original question already included the $1 backreference and it was only removed after your recent edit ?! (Although, with how it was implemented, it would have resulted in a double slash at the start of the URl-path.)