LocationMatch not matching like Location (Apache 2.4) - apache

Question

I'm trying to understand what is going on with LocationMatch. Right now I have a Location similar to the following,
<Location "/context">
RequestHeader set X-Forwarded-Proto https
RequestHeader set X-Forwarded-Port 443
ProxyPreserveHost On
ProxyPass http://example.com/context retry=0 connectiontimeout=300 timeout=300
ProxyPassReverse http://example.com/context
</Location>
Next I change only Location to LocationMatch, as below, and that works fine.
<LocationMatch "/context">
RequestHeader set X-Forwarded-Proto https
RequestHeader set X-Forwarded-Port 443
ProxyPreserveHost On
ProxyPass http://example.com/context retry=0 connectiontimeout=300 timeout=300
ProxyPassReverse http://example.com/context
</LocationMatch>
But as soon as I introduce a regular expression this no longer matches correctly. For example, I want to match paths starting with /context,
<LocationMatch "^/context">
RequestHeader set X-Forwarded-Proto https
RequestHeader set X-Forwarded-Port 443
ProxyPreserveHost On
ProxyPass http://example.com/context retry=0 connectiontimeout=300 timeout=300
ProxyPassReverse http://example.com/context
</LocationMatch>
I've been through the documentation multiple times and can't seem to figure out why this regex doesn't match. I've also seen SOQs like Apache LocationMatch matching urls starting with... but this regex doesn't work. I have a single VirtualHost on a vanilla Ubuntu apache2 install with this single LocationMatch. The entire conf file looks like this,
ProxyRequests off
PassEnv HTTPD_SERVER_NAME HTTPD_SERVER_ADMIN SSL_CERTIFICATE_FILE SSL_CERTIFICATE_KEY_FILE
<VirtualHost *:443>
SSLEngine on
SSLCertificateFile ${SSL_CERTIFICATE_FILE}
SSLCertificateKeyFile ${SSL_CERTIFICATE_KEY_FILE}
Protocols h2 http/1.1
ServerName ${HTTPD_SERVER_NAME}
ServerAdmin ${HTTPD_SERVER_ADMIN}
DocumentRoot /var/www/html
ErrorLog ${APACHE_LOG_DIR}/error.log
CustomLog ${APACHE_LOG_DIR}/access.log combined
SSLCipherSuite EECDH+AESGCM:EDH+AESGCM
# Requires Apache 2.4.36 & OpenSSL 1.1.1
SSLProtocol -all +TLSv1.3 +TLSv1.2
SSLOpenSSLConfCmd Curves X25519:secp521r1:secp384r1:prime256v1
# Older versions
# SSLProtocol All -SSLv2 -SSLv3 -TLSv1 -TLSv1.1
SSLHonorCipherOrder On
Header always set Strict-Transport-Security "max-age=63072000; includeSubDomains; preload"
Header always set X-Frame-Options DENY
Header always set X-Content-Type-Options nosniff
# Requires Apache >= 2.4
SSLCompression off
# Requires Apache >= 2.4.11
SSLSessionTickets Off
SSLProxyEngine on
SSLProxyVerify none
SSLProxyCheckPeerCN off
SSLProxyCheckPeerName off
SSLProxyCheckPeerExpire off
<LocationMatch "^/context">
RequestHeader set X-Forwarded-Proto https
RequestHeader set X-Forwarded-Port 443
ProxyPreserveHost On
ProxyPass http://example.com/context retry=0 connectiontimeout=300 timeout=300
ProxyPassReverse http://example.com/context
</LocationMatch>
</VirtualHost>
My question is, should <LocationMatch "^/context"> match URLs starting with /context? For example, https://mydomain/context? And if this should match, any idea what else could be interfering? I'm on version 2.4.41, but I've seen this behavior since at least 2.4.6. Thanks

Answer 1

According to the Apache docs on the ProxyPass directive:
When used inside a <Location> section, the first argument is omitted
and the local directory is obtained from the <Location>. The same will
occur inside a <LocationMatch> section; however, ProxyPass does not
interpret the regexp as such, so it is necessary to use ProxyPassMatch
in this situation instead.
If I understand this correctly, it's not that your <Location> regex is invalid, it's just that your <ProxyPass> doesn't interpret it as a regex. So use <ProxyPassMatch> instead.
Also, this SO question led me to some other pages which support the idea that <LocationMatch> and <ProxyPass> are incompatible with each other:
As indicated by this comment and this page, I need to replace
ProxyPass [with] ProxyPassMatch when using that inside a LocationMatch block