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Diffstat (limited to 'docs/libcurl/opts/CURLOPT_TRAILERFUNCTION.3')
| -rw-r--r-- | docs/libcurl/opts/CURLOPT_TRAILERFUNCTION.3 | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/docs/libcurl/opts/CURLOPT_TRAILERFUNCTION.3 b/docs/libcurl/opts/CURLOPT_TRAILERFUNCTION.3 new file mode 100644 index 000000000..8ca132362 --- /dev/null +++ b/docs/libcurl/opts/CURLOPT_TRAILERFUNCTION.3 @@ -0,0 +1,112 @@ +.\" ************************************************************************** +.\" * _ _ ____ _ +.\" * Project ___| | | | _ \| | +.\" * / __| | | | |_) | | +.\" * | (__| |_| | _ <| |___ +.\" * \___|\___/|_| \_\_____| +.\" * +.\" * Copyright (C) 1998 - 2018, Daniel Stenberg, <daniel@haxx.se>, et al. +.\" * +.\" * This software is licensed as described in the file COPYING, which +.\" * you should have received as part of this distribution. The terms +.\" * are also available at https://curl.haxx.se/docs/copyright.html. +.\" * +.\" * You may opt to use, copy, modify, merge, publish, distribute and/or sell +.\" * copies of the Software, and permit persons to whom the Software is +.\" * furnished to do so, under the terms of the COPYING file. +.\" * +.\" * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY +.\" * KIND, either express or implied. +.\" * +.\" ************************************************************************** +.\" +.TH CURLOPT_TRAILERFUNCTION 3 "14 Aug 2018" "libcurl 7.64.0" "curl_easy_setopt options" + +.SH NAME: +CURLOPT_TRAILERFUNCTION \- Set callback for sending trailing headers + +.SH SYNOPSIS: +#include <curl.h> + +int curl_trailer_callback(struct curl_slist ** list, void *userdata); + +CURLcode curl_easy_setopt(CURL *handle, CURLOPT_TRAILERFUNCTION, curl_trailer_callback *func); + +.SH DESCRIPTION: +Pass a pointer to a callback function. + +This callback function will be called once right before sending the final +CR LF in an HTTP chunked transfer to fill a list of trailing headers to be +sent before finishing the HTTP transfer. + +You can set the userdata argument with the CURLOPT_TRAILERDATA option. + +The trailing headers included in the linked list must not be CRLF-terminated, +because libcurl will add the appropriate line termination characters after +each header item. + +If you use curl_slist_append to add trailing headers to the curl_slist then +libcurl will duplicate the strings, and will free the curl_slist and the +duplicates once the trailers have been sent. + +If one of the trailing headers is not formatted correctly +(i.e. HeaderName: headerdata) it will be ignored and an info message +will be emitted. + +The return value can either be CURL_TRAILERFUNC_OK or CURL_TRAILERFUNC_ABORT +which would respectively instruct libcurl to either continue with sending the +trailers or to abort the request. + +If you set this option to NULL, then the transfer proceeds as usual +without any interruptions. + +.SH DEFAULT: +NULL + +.SH PROTOCOLS: +HTTP + +.SH EXAMPLE: +#include <curl/curl.h> + +static int trailer_cb(struct curl_slist **tr, void *data) +{ + /* libcurl will free the list */ + *tr = curl_slist_append(*tr, "My-super-awesome-trailer: trailer-stuff"); + (void)data; + return CURL_TRAILERFUNC_OK; +} + +CURL *curl = curl_easy_init(); +if(curl) { + + /* Set the URL of the request */ + curl_easy_setopt(curl, CURLOPT_URL, "http://example.com/"); + /* Now set it as a put */ + curl_easy_setopt(curl, CURLOPT_PUT, 1L); + + /* Assuming we have a function that will return the data to be pushed + Let that function be read_cb */ + curl_easy_setopt(curl, CURLOPT_READFUNCTION, read_cb); + + struct curl_slist *headers = NULL; + headers = curl_slist_append(headers, "Trailer: My-super-awsome-trailer"); + res = curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers); + + /* Set the trailers filling callback */ + curl_easy_setopt(curl, CURLOPT_TRAILERFUNCTION, (curl_trailer_callback)trailer_cb); + + /* Perform the request, res will get the return code */ + res = curl_easy_perform(curl); + + curl_easy_cleanup(curl); + + curl_slist_free_all(headers); +} + + +.SH AVAILABILITY: +This option was added in curl 7.64.0 and is present if HTTP support is enabled + +.SH "SEE ALSO" +.BR CURLOPT_TRAILERDATA "(3), " |