FTP wildcard matching
libcurl supports FTP wildcard matching. You use this feature by settingCURLOPT_WILDCARDMATCH to1L and then use a "wildcard pattern" in the inthe filename part of the URL.
Wildcard patterns
The default libcurl wildcard matching function supports:
* - ASTERISK
ftp://example.com/some/path/*.txtTo match all txt files in the directorysome/path. Only two asterisks areallowed within the same pattern string.
? - QUESTION MARK"
A question mark matches any (exactly one) character. Like if you have filescalledphoto1.jpeg andphoto7.jpeg this pattern could match them:
ftp://example.com/some/path/photo?.jpeg[ - BRACKET EXPRESSION
The left bracket opens a bracket expression. The question mark and asteriskhave no special meaning in a bracket expression. Each bracket expression endsby the right bracket (]) and matches exactly one character. Some examplesfollow:
[a-zA-Z0-9] or[f-gF-G] - character intervals
[abc] - character enumeration
[^abc] or[!abc] - negation
[[:name:]] class expression. Supported classes are alnum, lower, space,alpha, digit, print, upper, blank, graph, xdigit.
[][-!^] - special case, matches only\-,],[,! or^.
[\\[\\]\\\\] - escape syntax. Matches[,] or\\.
Using the rules above, a filename pattern can be constructed:
ftp://example.com/some/path/[a-z[:upper:]\\\\].jpegFTP chunk callbacks
When FTP wildcard matching is used, theCURLOPT_CHUNK_BGN_FUNCTION callbackis called before a transfer is initiated for a file that matches.
The callback can then opt to return one of these return codes to tell libcurlwhat to do with the file:
CURL_CHUNK_BGN_FUNC_OKtransfer the fileCURL_CHUNK_BGN_FUNC_SKIPCURL_CHUNK_BGN_FUNC_FAILstop because of error
After the matched file has been transferred or skipped, theCURLOPT_CHUNK_END_FUNCTION callback is called.
The end chunk callback can only return success or error.
FTP matching callback
If the default pattern matching function is not to your liking, you can provideyour own replacement function by setting theCURLOPT_FNMATCH_FUNCTION optionto your alternative.