NGINX and Lua scripting: conditional use in content_by_lua - nginx

Question

I'm trying to create a conditional content_by_lua script, where the content should be set by lua only under a turthy condition.
example:
nginx.conf
location / {
content_by_lua_file /nginx/lua/nginx.lua;
root /nginx/www;
index index.html;
location ~* \.(?:ico|css|js|gif|jpe?g|png|woff|ttf)$ {
expires max;
add_header Pragma public;
add_header Cache-Control "public, must-revalidate, proxy-revalidate";
}
}
nginx.lua
if condition then
ngx.header["Content-type"] = "text/html"
ngx.say('<H1>Hello World.</H1>');
ngx.exit(0)
else
-- serve the original content (index.html)
end
the problem is - lua scripting under nginx doesnt support 2 content directive within the same route, is there a workaround I can do?
with the current usage when the condition false I expect the index.html to be shown but receive a blank page instead

Answer 1

You can do a ngx.exec call which does an internal call.
nginx.conf
location / {
content_by_lua_file /nginx/lua/nginx.lua;
root /nginx/www;
index index.html;
location ~* \.(?:ico|css|js|gif|jpe?g|png|woff|ttf)$ {
expires max;
add_header Pragma public;
add_header Cache-Control "public, must-revalidate, proxy-revalidate";
}
}
location /default_index {
root /nginx/www;
index index.html;
}
nginx.lua
if condition then
ngx.header["Content-type"] = "text/html"
ngx.say('<H1>Hello World.</H1>');
ngx.exit(0)
else
-- serve the original content (index.html)
ngx.exec("/default_index", ngx.var.args)
end