File upload and store with lighttpd

Question

I am running lighthttpd in Linux on an embedded platform.

Now i want to make it possible to transfer a file to the system, with an upload web page containing a file selector and "Upload" button (with HTML tags and ). The selected file is transferred as a POST HTTP request containing multipart/form-data. The file should then simply be stored as a regular file in the file system.

I'm already having a CGI interface, a bash script which receives the request and which passes it to the backend C++ application. And because it is an embedded platform, i would like to avoid using php, python etc. only for this case.

As far as i see, lighttpd is not able to save the received files directly from multipart-encoded request body to pure files, correct?

To decode the body i found 'munpack' tool from the mpack package, which writes the encoded body to files on disk, but is intended for mime encoded emails. Nevertheless i can call it in the CGI bash script, and it works almost like expected, except that it can't handle the terminating boundary id (the boundary id given in 'Content-Type' appended by two dashes), resulting in the last file still containing the final boundary. Update: This munpack behaviour came from a faulty script, but still it doesn't work, munpack produces wrong files when the body contains CRLF line endings; only LF produces the correct result.

Is there any other direct request-to-file-on-disk approach? Or do i really have to filter out the terminating boundary manually in the script, or write a multipart-message parser in my C++ application?

To make the use case clear: A user should be able to upload a firmware file to my system. So he connects to my system with a web browser, receives an upload page where he can select the file and send it with an "Upload" button. This transferred file should then simply be stored on my system. The CGI script for receiving the request does already exist (as well as a C++ backend where i could handle the request, too), the only problem is converting the multipart/form-data encoded file to a plain file on disk.

Answer 1

Now i want to make it possible to transfer a file to the system, through a POST HTTP request. The file should simply be stored as a regular file in the file system.

That sounds more like it should be an HTTP PUT rather than an HTTP POST.

As far as i see, lighttpd is not able to save the received files directly from multipart-encoded request body to pure files, correct?

Do you mean application/x-www-form-urlencoded with the POST? Why multipart-encoded? Are there multiple files being uploaded?

lighttpd mod_webdav supports PUT. Otherwise, you need your own program to handle the request body, be it a shell script or a compiled program. You can use libfcgi with your C++, or you can look at the C programs that lighttpd uses for testing, which implement FastCGI and SCGI in < 300 lines of C each.