[ops] Add nginx placeholders for unfurlbot configuration

production/nginx/server-common.conf

@@ -59,7 +59,7 @@ location = / {
 # cache /resources/** for 1 week since they don't change often
 location ~ ^/[a-z][a-z]/resources/(.*) {
 	try_files $uri /en-US/resources/$1 =404;
-        expires 1w;
+	expires 1w;
 }
 # cache /<lang>/main.f40e91d908a068a2.js forever since they never change
 location ~ ^/([a-z][a-z])/(.+\..+\.(js|css)) {
@@ -69,11 +69,14 @@ location ~ ^/([a-z][a-z])/(.+\..+\.(js|css)) {
 # cache everything else for 5 minutes
 location ~ ^/([a-z][a-z])$ {
 	try_files $uri /$1/index.html /en-US/index.html =404;
-        expires 5m;
+	expires 5m;
 }
 location ~ ^/([a-z][a-z])/ {
+	if ($unfurlbot) {
+		proxy_pass $mempoolSpaceUnfurler;
+	}
 	try_files $uri /$1/index.html /en-US/index.html =404;
-        expires 5m;
+	expires 5m;
 }
 
 # cache /resources/** for 1 week since they don't change often
@@ -89,6 +92,9 @@ location ~* ^/.+\..+\.(js|css) {
 # catch-all for all URLs i.e. /address/foo /tx/foo /block/000
 # cache 5 minutes since they change frequently
 location / {
+	if ($unfurlbot) {
+		proxy_pass $mempoolSpaceUnfurler;
+	}
 	try_files /$lang/$uri $uri /en-US/$uri /en-US/index.html =404;
 	expires 5m;
 }