mod_zip assembles ZIP archives dynamically. It can stream component files from upstream servers with nginx's native proxying code, so that the process never takes up more than a few KB of RAM at a time, even while assembling archives that are (potentially) hundreds of megabytes.

To install, compile nginx with the following option:

--add-module=/path/to/this/directory

nginx 0.7.25 or later is required. If libiconv is present, support for the "X-Archive-Charset" header is enabled; see below.

The module is activated when the original response (presumably from an upstream) includes the following HTTP header:

X-Archive-Files: zip

It then scans the response body for a list of files. The syntax is a space-separated list of the file checksum (CRC-32), size (in bytes), location (properly URL-encoded), and file name. One file per line. The file location corresponds to a location in your nginx.conf; the file can be on disk, from an upstream, or from another module. The file name can include a directory path, and is what will be extracted from the ZIP file. Example:

1034ab38 428    /foo.txt   My Document1.txt
83e8110b 100339 /bar.txt   My Other Document1.txt

Files are retrieved and encoded in order. If a file cannot be found or the file request returns any sort of error, the download is aborted.

The CRC-32 is optional. Put "-" if you don't know the CRC-32; note that in this case mod_zip will disable support for the "Range" header.

To re-encode the filenames as UTF-8, add the following header to the upstream response:

X-Archive-Charset: [original charset name]

The original charset name should be something that iconv understands. (This feature only works if iconv is present.)

Tip: Add a header "Content-Disposition: attachment; filename=foobar.zip" in the upstream response if you would like the client to name the file "foobar.zip"

Tip 2: To save bandwidth, add a "Last-Modified" header in the upstream response; mod_zip will then honor the "If-Range" header from clients.

Tip 3: To wipe the X-Archive-Files header from the response sent to the client, use the headers_more module: http://wiki.nginx.org/NginxHttpHeadersMoreModule

Tip 4: Using mod_zip with SSL will not work if the backend response has a Set-Cookie header. Wipe it with the headers_more module (see tip 3).

Questions/patches may be directed to Evan Miller, [email protected].