curl/docs/libcurl/curl_mime_encoder.md
Daniel Stenberg b935fd4a07
docs: make each libcurl man specify protocol(s)
The mandatory header now has a mandatory list of protocols for which the
manpage is relevant.

Most man pages already has a "PROTOCOLS" section, but this introduces a
stricter way to specify the relevant protocols.

cd2nroff verifies that at least one protocol is mentioned (which can be
`*`).

This information is not used just yet, but A) the PROTOCOLS section can
now instead get generated and get a unified wording across all manpages
and B) this allows us to more reliably filter/search for protocol
specific manpages/options.

Closes #13166
2024-03-21 15:27:06 +01:00

2.7 KiB

c SPDX-License-Identifier Title Section Source See-also Protocol
Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al. curl curl_mime_encoder 3 libcurl
curl_mime_addpart (3)
curl_mime_headers (3)
curl_mime_subparts (3)
HTTP
IMAP
SMTP

NAME

curl_mime_encoder - set a mime part's encoder and content transfer encoding

SYNOPSIS

#include <curl/curl.h>

CURLcode curl_mime_encoder(curl_mimepart *part, const char *encoding);

DESCRIPTION

curl_mime_encoder() requests a mime part's content to be encoded before being transmitted.

part is the part's handle to assign an encoder. encoding is a pointer to a null-terminated encoding scheme. It may be set to NULL to disable an encoder previously attached to the part. The encoding scheme storage may safely be reused after this function returns.

Setting a part's encoder multiple times is valid: only the value set by the last call is retained.

Upon multipart rendering, the part's content is encoded according to the pertaining scheme and a corresponding "Content-Transfer-Encoding" header is added to the part.

Supported encoding schemes are:

"binary": the data is left unchanged, the header is added.

"8bit": header added, no data change.

"7bit": the data is unchanged, but is each byte is checked to be a 7-bit value; if not, a read error occurs.

"base64": Data is converted to base64 encoding, then split in CRLF-terminated lines of at most 76 characters.

"quoted-printable": data is encoded in quoted printable lines of at most 76 characters. Since the resulting size of the final data cannot be determined prior to reading the original data, it is left as unknown, causing chunked transfer in HTTP. For the same reason, this encoder may not be used with IMAP. This encoder targets text data that is mostly ASCII and should not be used with other types of data.

If the original data is already encoded in such a scheme, a custom Content-Transfer-Encoding header should be added with curl_mime_headers(3) instead of setting a part encoder.

Encoding should not be applied to multiparts, thus the use of this function on a part with content set with curl_mime_subparts(3) is strongly discouraged.

EXAMPLE

int main(void)
{
  curl_mime *mime;
  curl_mimepart *part;

  CURL *curl = curl_easy_init();
  if(curl) {
    /* create a mime handle */
    mime = curl_mime_init(curl);

    /* add a part */
    part = curl_mime_addpart(mime);

    /* send a file */
    curl_mime_filedata(part, "image.png");

    /* encode file data in base64 for transfer */
    curl_mime_encoder(part, "base64");
  }
}

AVAILABILITY

As long as at least one of HTTP, SMTP or IMAP is enabled. Added in 7.56.0.

RETURN VALUE

CURLE_OK or a CURL error code upon failure.