repo/core/curl/files/curl_easy_escape.3

.\" generated by cd2nroff 0.1 from curl_easy_escape.md
.TH curl_easy_escape 3 "2024-07-29" libcurl
.SH NAME
curl_easy_escape \- URL encode a string
.SH SYNOPSIS
.nf
#include <curl/curl.h>

char *curl_easy_escape(CURL *curl, const char *string, int length);
.fi
.SH DESCRIPTION
This function converts the given input \fIstring\fP to a URL encoded string and
returns that as a new allocated string. All input characters that are not a\-z,
A\-Z, 0\-9, \(aq\-\(aq, \(aq.\(aq, \(aq_\(aq or \(aq~\(aq are converted to their "URL escaped" version
(\fB%NN\fP where \fBNN\fP is a two\-digit hexadecimal number).

If \fIlength\fP is set to 0 (zero), \fIcurl_easy_escape(3)\fP uses strlen() on the input
\fIstring\fP to find out the size. This function does not accept input strings
longer than \fBCURL_MAX_INPUT_LENGTH\fP (8 MB).

You must \fIcurl_free(3)\fP the returned string when you are done with it.
.SH ENCODING
libcurl is typically not aware of, nor does it care about, character
encodings. \fIcurl_easy_escape(3)\fP encodes the data byte\-by\-byte into the
URL encoded version without knowledge or care for what particular character
encoding the application or the receiving server may assume that the data
uses.

The caller of \fIcurl_easy_escape(3)\fP must make sure that the data passed in
to the function is encoded correctly.
.SH URLs
URLs are by definition \fIURL encoded\fP. To create a proper URL from a set of
components that may not be URL encoded already, you cannot just URL encode the
entire URL string with \fIcurl_easy_escape(3)\fP, because it then also converts
colons, slashes and other symbols that you probably want untouched.

To create a proper URL from strings that are not already URL encoded, we
recommend using libcurl\(aqs URL API: set the pieces with \fIcurl_url_set(3)\fP and get
the final correct URL with \fIcurl_url_get(3)\fP.
.SH PROTOCOLS
This functionality affects all supported protocols
.SH EXAMPLE
.nf
int main(void)
{
  CURL *curl = curl_easy_init();
  if(curl) {
    char *output = curl_easy_escape(curl, "data to convert", 15);
    if(output) {
      printf("Encoded: %s\\n", output);
      curl_free(output);
    }
    curl_easy_cleanup(curl);
  }
}
.fi
.SH HISTORY
Since 7.82.0, the \fBcurl\fP parameter is ignored. Prior to that there was
per\-handle character conversion support for some old operating systems such as
TPF, but it was otherwise ignored.
.SH AVAILABILITY
Added in curl 7.15.4
.SH RETURN VALUE
A pointer to a null\-terminated string or NULL if it failed.
.SH SEE ALSO
.BR curl_easy_unescape (3),
.BR curl_url_get (3),
.BR curl_url_set (3)