vendor/curl-sys/curl/docs/libcurl/opts/CURLOPT_HTTPHEADER.3 - toolchain/rustc - Git at Google

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 .\" *                            | (__| |_| |  _ <| |___
 .\" *                             \___|\___/|_| \_\_____|
 .\" *
 .\" * Copyright (C) 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.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.
 .\" *
 .\" * SPDX-License-Identifier: curl
 .\" *
 .\" **************************************************************************
 .\"
 .TH CURLOPT_HTTPHEADER 3 "17 Jun 2014" libcurl libcurl
 .SH NAME
 CURLOPT_HTTPHEADER \- set of HTTP headers
 .SH SYNOPSIS
 .nf
 #include <curl/curl.h>

 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTPHEADER,
                           struct curl_slist *headers);
 .fi
 .SH DESCRIPTION
 Pass a pointer to a linked list of HTTP headers to pass to the server and/or
 proxy in your HTTP request. The same list can be used for both host and proxy
 requests!

 When used within an IMAP or SMTP request to upload a MIME mail, the given
 header list establishes the document-level MIME headers to prepend to the
 uploaded document described by \fICURLOPT_MIMEPOST(3)\fP. This does not affect
 raw mail uploads.

 The linked list should be a fully valid list of \fBstruct curl_slist\fP
 structs properly filled in. Use \fIcurl_slist_append(3)\fP to create the list
 and \fIcurl_slist_free_all(3)\fP to clean up an entire list. If you add a
 header that is otherwise generated and used by libcurl internally, your added
 header is used instead. If you add a header with no content as in 'Accept:'
 (no data on the right side of the colon), the internally used header is
 disabled/removed. With this option you can add new headers, replace internal
 headers and remove internal headers. To add a header with no content (nothing
 to the right side of the colon), use the form 'name;' (note the ending
 semicolon).

 The headers included in the linked list \fBmust not\fP be CRLF-terminated,
 because libcurl adds CRLF after each header item itself. Failure to comply
 with this might result in strange behavior.

 The first line in an HTTP request (containing the method, usually a GET or
 POST) is not a header and cannot be replaced using this option. Only the lines
 following the request-line are headers. Adding this method line in this list
 of headers only causes your request to send an invalid header. Use
 \fICURLOPT_CUSTOMREQUEST(3)\fP to change the method.

 When this option is passed to \fIcurl_easy_setopt(3)\fP, libcurl does not copy
 the entire list so you \fBmust\fP keep it around until you no longer use this
 \fIhandle\fP for a transfer before you call \fIcurl_slist_free_all(3)\fP on
 the list.

 Pass a NULL to this option to reset back to no custom headers.

 The most commonly replaced HTTP headers have "shortcuts" in the options
 \fICURLOPT_COOKIE(3)\fP, \fICURLOPT_USERAGENT(3)\fP and
 \fICURLOPT_REFERER(3)\fP. We recommend using those.

 There is an alternative option that sets or replaces headers only for requests
 that are sent with CONNECT to a proxy: \fICURLOPT_PROXYHEADER(3)\fP. Use
 \fICURLOPT_HEADEROPT(3)\fP to control the behavior.
 .SH SPECIFIC HTTP HEADERS
 Setting some specific headers causes libcurl to act differently.
 .IP "Host:"
 The specified host name is used for cookie matching if the cookie engine is
 also enabled for this transfer. If the request is done over HTTP/2 or HTTP/3,
 the custom host name is instead used in the ":authority" header field and
 Host: is not sent at all over the wire.
 .IP "Transfer-Encoding: chunked"
 Tells libcurl the upload is to be done using this chunked encoding instead of
 providing the Content-Length: field in the request.
 .SH SPECIFIC MIME HEADERS
 When used to build a MIME e-mail for IMAP or SMTP, the following
 document-level headers can be set to override libcurl-generated values:
 .IP "Mime-Version:"
 Tells the parser at the receiving site how to interpret the MIME framing.
 It defaults to "1.0" and should normally not be altered.
 .IP "Content-Type:"
 Indicates the document's global structure type. By default, libcurl sets it
 to "multipart/mixed", describing a document made of independent parts. When a
 MIME mail is only composed of alternative representations of the same data
 (i.e.: HTML and plain text), this header must be set to "multipart/alternative".
 In all cases the value must be of the form "multipart/*" to respect the
 document structure and may not include the "boundary=" parameter.
 .P
 Other specific headers that do not have a libcurl default value but are
 strongly desired by mail delivery and user agents should also be included.
 These are "From:", "To:", "Date:" and "Subject:" among others and their
 presence and value is generally checked by anti-spam utilities.
 .SH SECURITY CONCERNS
 By default, this option makes libcurl send the given headers in all HTTP
 requests done by this handle. You should therefore use this option with
 caution if you for example connect to the remote site using a proxy and a
 CONNECT request, you should to consider if that proxy is supposed to also get
 the headers. They may be private or otherwise sensitive to leak.

 Use \fICURLOPT_HEADEROPT(3)\fP to make the headers only get sent to where you
 intend them to get sent.

 Custom headers are sent in all requests done by the easy handle, which implies
 that if you tell libcurl to follow redirects
 (\fICURLOPT_FOLLOWLOCATION(3)\fP), the same set of custom headers is sent in
 the subsequent request. Redirects can of course go to other hosts and thus
 those servers get all the contents of your custom headers too.

 Starting in 7.58.0, libcurl specifically prevents "Authorization:" headers
 from being sent to other hosts than the first used one, unless specifically
 permitted with the \fICURLOPT_UNRESTRICTED_AUTH(3)\fP option.

 Starting in 7.64.0, libcurl specifically prevents "Cookie:" headers from being
 sent to other hosts than the first used one, unless specifically permitted
 with the \fICURLOPT_UNRESTRICTED_AUTH(3)\fP option.
 .SH DEFAULT
 NULL
 .SH PROTOCOLS
 HTTP, IMAP and SMTP
 .SH EXAMPLE
 .nf
 CURL *curl = curl_easy_init();

 struct curl_slist *list = NULL;

 if(curl) {
   curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

   list = curl_slist_append(list, "Shoesize: 10");
   list = curl_slist_append(list, "Accept:");

   curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);

   curl_easy_perform(curl);

   curl_slist_free_all(list); /* free the list */
 }
 .fi

 .SH AVAILABILITY
 As long as HTTP is enabled. Use in MIME mail added in 7.56.0.
 .SH RETURN VALUE
 Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.
 .SH "SEE ALSO"
 .BR curl_mime_init (3),
 .BR CURLOPT_CUSTOMREQUEST (3),
 .BR CURLOPT_HEADER (3),
 .BR CURLOPT_HEADEROPT (3),
 .BR CURLOPT_MIMEPOST (3),
 .BR CURLOPT_PROXYHEADER (3)
	.\" **************************************************************************
	.\" * _ _ ____ _
	.\" * Project ___\| \| \| \| _ \\| \|
	.\" * / __\| \| \| \| \|_) \| \|
	.\" * \| (__\| \|_\| \| _ <\| \|___
	.\" * \___\|\___/\|_\| \_\_____\|
	.\" *
	.\" * Copyright (C) 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.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.
	.\" *
	.\" * SPDX-License-Identifier: curl
	.\" *
	.\" **************************************************************************
	.\"
	.TH CURLOPT_HTTPHEADER 3 "17 Jun 2014" libcurl libcurl
	.SH NAME
	CURLOPT_HTTPHEADER \- set of HTTP headers
	.SH SYNOPSIS
	.nf
	#include <curl/curl.h>

	CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTPHEADER,
	struct curl_slist *headers);
	.fi
	.SH DESCRIPTION
	Pass a pointer to a linked list of HTTP headers to pass to the server and/or
	proxy in your HTTP request. The same list can be used for both host and proxy
	requests!

	When used within an IMAP or SMTP request to upload a MIME mail, the given
	header list establishes the document-level MIME headers to prepend to the
	uploaded document described by \fICURLOPT_MIMEPOST(3)\fP. This does not affect
	raw mail uploads.

	The linked list should be a fully valid list of \fBstruct curl_slist\fP
	structs properly filled in. Use \fIcurl_slist_append(3)\fP to create the list
	and \fIcurl_slist_free_all(3)\fP to clean up an entire list. If you add a
	header that is otherwise generated and used by libcurl internally, your added
	header is used instead. If you add a header with no content as in 'Accept:'
	(no data on the right side of the colon), the internally used header is
	disabled/removed. With this option you can add new headers, replace internal
	headers and remove internal headers. To add a header with no content (nothing
	to the right side of the colon), use the form 'name;' (note the ending
	semicolon).

	The headers included in the linked list \fBmust not\fP be CRLF-terminated,
	because libcurl adds CRLF after each header item itself. Failure to comply
	with this might result in strange behavior.

	The first line in an HTTP request (containing the method, usually a GET or
	POST) is not a header and cannot be replaced using this option. Only the lines
	following the request-line are headers. Adding this method line in this list
	of headers only causes your request to send an invalid header. Use
	\fICURLOPT_CUSTOMREQUEST(3)\fP to change the method.

	When this option is passed to \fIcurl_easy_setopt(3)\fP, libcurl does not copy
	the entire list so you \fBmust\fP keep it around until you no longer use this
	\fIhandle\fP for a transfer before you call \fIcurl_slist_free_all(3)\fP on
	the list.

	Pass a NULL to this option to reset back to no custom headers.

	The most commonly replaced HTTP headers have "shortcuts" in the options
	\fICURLOPT_COOKIE(3)\fP, \fICURLOPT_USERAGENT(3)\fP and
	\fICURLOPT_REFERER(3)\fP. We recommend using those.

	There is an alternative option that sets or replaces headers only for requests
	that are sent with CONNECT to a proxy: \fICURLOPT_PROXYHEADER(3)\fP. Use
	\fICURLOPT_HEADEROPT(3)\fP to control the behavior.
	.SH SPECIFIC HTTP HEADERS
	Setting some specific headers causes libcurl to act differently.
	.IP "Host:"
	The specified host name is used for cookie matching if the cookie engine is
	also enabled for this transfer. If the request is done over HTTP/2 or HTTP/3,
	the custom host name is instead used in the ":authority" header field and
	Host: is not sent at all over the wire.
	.IP "Transfer-Encoding: chunked"
	Tells libcurl the upload is to be done using this chunked encoding instead of
	providing the Content-Length: field in the request.
	.SH SPECIFIC MIME HEADERS
	When used to build a MIME e-mail for IMAP or SMTP, the following
	document-level headers can be set to override libcurl-generated values:
	.IP "Mime-Version:"
	Tells the parser at the receiving site how to interpret the MIME framing.
	It defaults to "1.0" and should normally not be altered.
	.IP "Content-Type:"
	Indicates the document's global structure type. By default, libcurl sets it
	to "multipart/mixed", describing a document made of independent parts. When a
	MIME mail is only composed of alternative representations of the same data
	(i.e.: HTML and plain text), this header must be set to "multipart/alternative".
	In all cases the value must be of the form "multipart/*" to respect the
	document structure and may not include the "boundary=" parameter.
	.P
	Other specific headers that do not have a libcurl default value but are
	strongly desired by mail delivery and user agents should also be included.
	These are "From:", "To:", "Date:" and "Subject:" among others and their
	presence and value is generally checked by anti-spam utilities.
	.SH SECURITY CONCERNS
	By default, this option makes libcurl send the given headers in all HTTP
	requests done by this handle. You should therefore use this option with
	caution if you for example connect to the remote site using a proxy and a
	CONNECT request, you should to consider if that proxy is supposed to also get
	the headers. They may be private or otherwise sensitive to leak.

	Use \fICURLOPT_HEADEROPT(3)\fP to make the headers only get sent to where you
	intend them to get sent.

	Custom headers are sent in all requests done by the easy handle, which implies
	that if you tell libcurl to follow redirects
	(\fICURLOPT_FOLLOWLOCATION(3)\fP), the same set of custom headers is sent in
	the subsequent request. Redirects can of course go to other hosts and thus
	those servers get all the contents of your custom headers too.

	Starting in 7.58.0, libcurl specifically prevents "Authorization:" headers
	from being sent to other hosts than the first used one, unless specifically
	permitted with the \fICURLOPT_UNRESTRICTED_AUTH(3)\fP option.

	Starting in 7.64.0, libcurl specifically prevents "Cookie:" headers from being
	sent to other hosts than the first used one, unless specifically permitted
	with the \fICURLOPT_UNRESTRICTED_AUTH(3)\fP option.
	.SH DEFAULT
	NULL
	.SH PROTOCOLS
	HTTP, IMAP and SMTP
	.SH EXAMPLE
	.nf
	CURL *curl = curl_easy_init();

	struct curl_slist *list = NULL;

	if(curl) {
	curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");

	list = curl_slist_append(list, "Shoesize: 10");
	list = curl_slist_append(list, "Accept:");

	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);

	curl_easy_perform(curl);

	curl_slist_free_all(list); /* free the list */
	}
	.fi

	.SH AVAILABILITY
	As long as HTTP is enabled. Use in MIME mail added in 7.56.0.
	.SH RETURN VALUE
	Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.
	.SH "SEE ALSO"
	.BR curl_mime_init (3),
	.BR CURLOPT_CUSTOMREQUEST (3),
	.BR CURLOPT_HEADER (3),
	.BR CURLOPT_HEADEROPT (3),
	.BR CURLOPT_MIMEPOST (3),
	.BR CURLOPT_PROXYHEADER (3)