On 06-Dec-22 09:24, Patrick Monnerat via curl-library wrote:
On 12/6/22 13:08, Daniel Stenberg wrote:On Tue, 6 Dec 2022, Patrick Monnerat via curl-library wrote:Please find the source code and use examples of functions curl_fopen() and curl_fdopen() in attachement.These allow associating an URL or a curl handle with a standard C FILE pointer and use the standard C IO API on it.Fun!Also a quick reminder to readers that if you want an fopen/fread/frite style API for libcurl, there is also this start => https://github.com/curl/fcurlThanks for your feedback. And the reminder was a good idea.Although the goal is the same, I targetted something really compatible with C FILE. This allows to easily insert libcurl use in existing programs as old as C iitself and use on a handle a much wider range of API without having to write wrappers. The real challenge was "FILE *" !I know fcurl is not complete yet, but noted the method is a bit different: curl_fopen plays with the pause flags and unpause only when enough buffer is available (that is: when in read or write). I did it this way because I support writes too and to prevent buffer overflows.If you try my code on an Apache+PHP-FPM web service, you might experience problems while posting: there currently is an Apache bug on handling chunked post input. It works perfectly with nginx.Patrick
It's a good idea.I don't think your seek() semantics are correct. seek(SEEK_END) terminates connection, which isn't what seek does, or what a C program would expect. seek just positions. I think that what you're doing maps to fclose().
seek should return errno = EBADF if not implemented. EINVAL is for a bad 'whence' .
The idea of doing range requests based on seek from fcurll's issues has merit. May need some support in the library.
You might also provide these as curl_xxx(), using curl handles. While transparency is nice, you can't always hook the C RTL. curl_xxx could be the portable version - it's a pretty simple search-and-replace for users. And your hooked version, if available at configure time, can be used where it's available.
I think that would give you the best of both approaches. curl_portable API that looks like FILE *, or transparent FILE * handles where they are available. The internals will be largely the same.
You may also want to consider other key functions, including delete and rename. With ftp, at least: chmod, chown...
There's quite a bit to making network operations look exactly like local files. But you're definitely on to a useful subset.
Timothe Litt ACM Distinguished Engineer -------------------------- This communication may not represent the ACM or my employer's views, if any, on the matters discussed.
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