Nginx pass upstream headers to the remote request

Question

This question is similar to this one but doing x-accel-redirect on aws s3 resource. The former tried to set the upstream headers to the local request. This works fine. But now i have moved my contents to the amazon s3 and i wanted to implement the same restricted download to the s3 objects.

This is my nginx config

proxy_pass_header X-Accel-Redirect;
passenger_pass_header X-Accel-Redirect;

location ~* ^/download_zip/(.*) {
    internal;
    resolver 8.8.8.8 valid=300s;



    proxy_buffering off;
    proxy_set_header Content-Length ""; 
    proxy_set_header Cookie ""; 

    proxy_hide_header x-amz-request-id;
    proxy_hide_header x-amz-meta-uid;
    proxy_hide_header x-amz-id-2;
    proxy_hide_header x-amz-meta-mode;
    proxy_hide_header x-amz-meta-mtime;
    proxy_hide_header x-amz-meta-gid;
    proxy_hide_header x-amz-version-id;
    proxy_hide_header accept-ranges;

    # Do not touch local disks when proxying
    # content to clients
    proxy_method GET;
    proxy_pass_request_body off;
    proxy_max_temp_file_size 0;

    proxy_pass_header Content-MD5;
    add_header Content-MD5 $upstream_http_content_md5; 

   #  proxy_set_header Content-MD5 "123123123123123";


     proxy_pass https://a_b_c_assets.s3-east.amazonaws.com/$1$is_args$args; 


     }

and the rails part is

headers['X-Accel-Redirect'] = '/download_zip/uploads/' + params[:story_id] +'/' +    params[:story_id] + '.zip?' + secure_part
headers['X-Accel-Expires'] = 'max'
headers['Content-MD5'] = checksum

Everything works fine except the Content-MD5 is not passed to the proxied request.

Any help is really appreciated.

Another similar question here

Jariah

Here upstream headers are from amazon. You could use intermediate location to store first upstream header – Laurentia

hi @Alexey, right, i suspect that. Could you elaborate more on the intermediate location. – Jariah

Answer 1

proxy_pass_header X-Accel-Redirect;
passenger_pass_header X-Accel-Redirect;

# this is intermediate location that stores header
# to variable and rewrites to another location
location ^~ /download_zip/ {
    internal;
    set $Content_MD5 $upstream_http_content_md5;
    rewrite ^/(.+) /amazon_$1;
}

location ^~ /amazon_download_zip/ {
    internal;
    resolver 8.8.8.8 valid=300s;

    proxy_buffering off;
    proxy_set_header Content-Length ""; 
    proxy_set_header Cookie ""; 

    proxy_hide_header x-amz-request-id;
    proxy_hide_header x-amz-meta-uid;
    proxy_hide_header x-amz-id-2;
    proxy_hide_header x-amz-meta-mode;
    proxy_hide_header x-amz-meta-mtime;
    proxy_hide_header x-amz-meta-gid;
    proxy_hide_header x-amz-version-id;
    proxy_hide_header accept-ranges;

    # Do not touch local disks when proxying
    # content to clients
    proxy_method GET;
    proxy_pass_request_body off;
    proxy_max_temp_file_size 0;

    proxy_pass_header Content-MD5;
    add_header Content-MD5 $Content_MD5; 

    proxy_pass https://a_b_c_assets.s3-east.amazonaws.com/;
}

Laurentia

user could explain what changed from OPs code to his/hers – Claycomb