doc/man3/OSSL_HTTP_REQ_CTX.pod - third_party/openssl - Git at Google

 =pod

 =head1 NAME

 OSSL_HTTP_REQ_CTX,
 OSSL_HTTP_REQ_CTX_new,
 OSSL_HTTP_REQ_CTX_free,
 OSSL_HTTP_REQ_CTX_set_request_line,
 OSSL_HTTP_REQ_CTX_add1_header,
 OSSL_HTTP_REQ_CTX_set1_req,
 OSSL_HTTP_REQ_CTX_nbio,
 OSSL_HTTP_REQ_CTX_sendreq_d2i,
 OSSL_HTTP_REQ_CTX_get0_mem_bio,
 OSSL_HTTP_REQ_CTX_set_max_response_length
 - HTTP client low-level functions

 =head1 SYNOPSIS

  #include <openssl/http.h>

  typedef struct ossl_http_req_ctx_st OSSL_HTTP_REQ_CTX;

  OSSL_HTTP_REQ_CTX *OSSL_HTTP_REQ_CTX_new(BIO *wbio, BIO *rbio,
                                           int maxline, unsigned long max_resp_len,
                                           int timeout,
                                           const char *expected_content_type,
                                           int expect_asn1);
  void OSSL_HTTP_REQ_CTX_free(OSSL_HTTP_REQ_CTX *rctx);

  int OSSL_HTTP_REQ_CTX_set_request_line(OSSL_HTTP_REQ_CTX *rctx, int method_POST,
                                         const char *server, const char *port,
                                         const char *path);
  int OSSL_HTTP_REQ_CTX_add1_header(OSSL_HTTP_REQ_CTX *rctx,
                                    const char *name, const char *value);

  int OSSL_HTTP_REQ_CTX_set1_req(OSSL_HTTP_REQ_CTX *rctx, const char *content_type,
                                 const ASN1_ITEM *it, ASN1_VALUE *req);
  int OSSL_HTTP_REQ_CTX_nbio(OSSL_HTTP_REQ_CTX *rctx);
  ASN1_VALUE *OSSL_HTTP_REQ_CTX_sendreq_d2i(OSSL_HTTP_REQ_CTX *rctx,
                                            const ASN1_ITEM *it);

  BIO *OSSL_HTTP_REQ_CTX_get0_mem_bio(const OSSL_HTTP_REQ_CTX *rctx);
  void OSSL_HTTP_REQ_CTX_set_max_response_length(OSSL_HTTP_REQ_CTX *rctx,
                                                 unsigned long len);

 =head1 DESCRIPTION

 B<OSSL_HTTP_REQ_CTX> is a context structure for an HTTP request, used to
 collect all the necessary data to perform that request.

 This file documents low-level HTTP functions rarely used directly.  High-level
 HTTP client functions like L<OSSL_HTTP_get(3)> and L<OSSL_HTTP_transfer(3)>
 should be preferred.

 OSSL_HTTP_REQ_CTX_new() allocates a new HTTP request context structure,
 which gets populated with the B<BIO> to send the request to (I<wbio>),
 the B<BIO> to read the response from (I<rbio>, which may be equal to I<wbio>),
 the maximum expected response header line length (I<maxline>, where a value <= 0
 indicates that the B<HTTP_DEFAULT_MAX_LINE_LENGTH> of 4KiB should be used;
 this length is also used as the number of content bytes read at a time),
 the maximum allowed response content length (I<max_resp_len>, where 0 means
 that the B<HTTP_DEFAULT_MAX_RESP_LEN> is used, which currently is 100 KiB),
 a response timeout measure in seconds (I<timeout>,
 where 0 indicates no timeout, i.e., waiting indefinitely),
 the expected MIME content type of the response (I<expected_content_type>,
 which may be NULL for no expectation),
 and a flag indicating that the response is expected to be
 a DER encoded ASN.1 structure (I<expect_asn1>).
 The allocated context structure is also populated with an internal allocated
 memory B<BIO>, which collects the HTTP request and additional headers as text.
 The returned context should only be used for a single HTTP request/response.

 OSSL_HTTP_REQ_CTX_free() frees up the HTTP request context I<rctx>.
 The I<wbio> and I<rbio> are not free'd and it is up to the application
 to do so.

 OSSL_HTTP_REQ_CTX_set_request_line() adds the HTTP request line to the context.
 The HTTP method is determined by I<method_POST>,
 which should be 1 to indicate C<POST> or 0 to indicate C<GET>.
 I<server> and I<port> may be set to indicate a proxy server and port
 that the request should go through, otherwise they should be left NULL.
 I<path> is the HTTP request path; if left NULL, C</> is used.

 OSSL_HTTP_REQ_CTX_add1_header() adds header I<name> with value I<value> to the
 context I<rctx>. It can be called more than once to add multiple headers.
 For example, to add a C<Host> header for C<example.com> you would call:

  OSSL_HTTP_REQ_CTX_add1_header(ctx, "Host", "example.com");

 OSSL_HTTP_REQ_CTX_set1_req() is to be used if and only if the I<method_POST>
 parameter in the OSSL_HTTP_REQ_CTX_set_request_line() call was 1.
 It finalizes the HTTP request context by adding the DER encoding of I<req>,
 using the ASN.1 template I<it> to do the encoding.
 The HTTP header C<Content-Length> is filled out with the length of the request.
 If I<content_type> isn't NULL,
 the HTTP header C<Content-Type> is also added with its content as value.
 All of this ends up in the internal memory B<BIO>.

 OSSL_HTTP_REQ_CTX_nbio() attempts to send the request prepared I<rctx>
 and gathering the response via HTTP, using the I<rbio> and I<wbio>
 that were given when calling OSSL_HTTP_REQ_CTX_new().
 When successful, the contents of the internal memory B<BIO> contains
 the contents of the HTTP response, without the response headers.
 It may need to be called again if its result is -1, which indicates
 L<BIO_should_retry(3)>.  In such a case it is advisable to sleep a little in
 between using L<BIO_wait(3)> on the read BIO to prevent a busy loop.

 OSSL_HTTP_REQ_CTX_sendreq_d2i() calls OSSL_HTTP_REQ_CTX_nbio(), possibly
 several times until a timeout is reached, and DER decodes the received
 response using the ASN.1 template I<it>.

 OSSL_HTTP_REQ_CTX_get0_mem_bio() returns the internal memory B<BIO>.
 Before sending the request, this could used to modify the HTTP request text.
 I<Use with caution!>
 After receiving a response via HTTP, the BIO represents
 the current state of reading the response headers and contents.

 OSSL_HTTP_REQ_CTX_set_max_response_length() sets the maximum allowed
 response content length for I<rctx> to I<len>. If not set or I<len> is 0
 then the B<HTTP_DEFAULT_MAX_RESP_LEN> is used, which currently is 100 KiB.
 If the C<Content-Length> header is present and exceeds this value or
 the content is an ASN.1 encoded structure with a length exceeding this value
 or both length indications are present but disagree then an error occurs.

 =head1 WARNINGS

 The server's response may be unexpected if the hostname that was used to
 create the I<wbio>, any C<Host> header, and the host specified in the
 request URL do not match.

 Many of these functions must be called in a certain order.

 First, the HTTP request context must be allocated:
 OSSL_HTTP_REQ_CTX_new().

 Then, the HTTP request must be prepared with request data:

 =over 4

 =item 1.

 Calling OSSL_HTTP_REQ_CTX_set_request_line().  This must be done exactly once.

 =item 2.

 Adding extra headers with OSSL_HTTP_REQ_CTX_add1_header().
 This is optional and may be done multiple times with different names.

 =item 3.

 Add C<POST> data with OSSL_HTTP_REQ_CTX_set1_req().  This may only be done if
 I<method_POST> was 1 in the OSSL_HTTP_REQ_CTX_set_request_line() call,
 and must be done exactly once in that case.

 =back

 When the request context is fully prepared, the HTTP exchange may be performed
 with OSSL_HTTP_REQ_CTX_nbio() or OSSL_HTTP_REQ_CTX_sendreq_d2i().

 =head1 RETURN VALUES

 OSSL_HTTP_REQ_CTX_new() returns a pointer to a B<OSSL_HTTP_REQ_CTX>, or NULL
 on error.

 OSSL_HTTP_REQ_CTX_free() and OSSL_HTTP_REQ_CTX_set_max_response_length()
 do not return values.

 OSSL_HTTP_REQ_CTX_set_request_line(), OSSL_HTTP_REQ_CTX_add1_header(),
 OSSL_HTTP_REQ_CTX_set1_req() and OSSL_HTTP_REQ_CTX_nbio
 return 1 for success and 0 for failure.

 OSSL_HTTP_REQ_CTX_sendreq_d2i() returns a pointer to an B<ASN1_VALUE> for
 success and NULL for failure.

 OSSL_HTTP_REQ_CTX_get0_mem_bio() returns the internal memory B<BIO>.

 =head1 SEE ALSO

 L<BIO_should_retry(3)>,
 L<BIO_wait(3)>,
 L<OSSL_HTTP_get(3)>,
 L<OSSL_HTTP_transfer(3)>

 =head1 COPYRIGHT

 Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.

 Licensed under the Apache License 2.0 (the "License").  You may not use
 this file except in compliance with the License.  You can obtain a copy
 in the file LICENSE in the source distribution or at
 L<https://www.openssl.org/source/license.html>.

 =cut
	=pod

	=head1 NAME

	OSSL_HTTP_REQ_CTX,
	OSSL_HTTP_REQ_CTX_new,
	OSSL_HTTP_REQ_CTX_free,
	OSSL_HTTP_REQ_CTX_set_request_line,
	OSSL_HTTP_REQ_CTX_add1_header,
	OSSL_HTTP_REQ_CTX_set1_req,
	OSSL_HTTP_REQ_CTX_nbio,
	OSSL_HTTP_REQ_CTX_sendreq_d2i,
	OSSL_HTTP_REQ_CTX_get0_mem_bio,
	OSSL_HTTP_REQ_CTX_set_max_response_length
	- HTTP client low-level functions

	=head1 SYNOPSIS

	#include <openssl/http.h>

	typedef struct ossl_http_req_ctx_st OSSL_HTTP_REQ_CTX;

	OSSL_HTTP_REQ_CTX OSSL_HTTP_REQ_CTX_new(BIO wbio, BIO *rbio,
	int maxline, unsigned long max_resp_len,
	int timeout,
	const char *expected_content_type,
	int expect_asn1);
	void OSSL_HTTP_REQ_CTX_free(OSSL_HTTP_REQ_CTX *rctx);

	int OSSL_HTTP_REQ_CTX_set_request_line(OSSL_HTTP_REQ_CTX *rctx, int method_POST,
	const char server, const char port,
	const char *path);
	int OSSL_HTTP_REQ_CTX_add1_header(OSSL_HTTP_REQ_CTX *rctx,
	const char name, const char value);

	int OSSL_HTTP_REQ_CTX_set1_req(OSSL_HTTP_REQ_CTX rctx, const char content_type,
	const ASN1_ITEM it, ASN1_VALUE req);
	int OSSL_HTTP_REQ_CTX_nbio(OSSL_HTTP_REQ_CTX *rctx);
	ASN1_VALUE OSSL_HTTP_REQ_CTX_sendreq_d2i(OSSL_HTTP_REQ_CTX rctx,
	const ASN1_ITEM *it);

	BIO OSSL_HTTP_REQ_CTX_get0_mem_bio(const OSSL_HTTP_REQ_CTX rctx);
	void OSSL_HTTP_REQ_CTX_set_max_response_length(OSSL_HTTP_REQ_CTX *rctx,
	unsigned long len);

	=head1 DESCRIPTION

	B<OSSL_HTTP_REQ_CTX> is a context structure for an HTTP request, used to
	collect all the necessary data to perform that request.

	This file documents low-level HTTP functions rarely used directly. High-level
	HTTP client functions like L<OSSL_HTTP_get(3)> and L<OSSL_HTTP_transfer(3)>
	should be preferred.

	OSSL_HTTP_REQ_CTX_new() allocates a new HTTP request context structure,
	which gets populated with the B<BIO> to send the request to (I<wbio>),
	the B<BIO> to read the response from (I<rbio>, which may be equal to I<wbio>),
	the maximum expected response header line length (I<maxline>, where a value <= 0
	indicates that the B<HTTP_DEFAULT_MAX_LINE_LENGTH> of 4KiB should be used;
	this length is also used as the number of content bytes read at a time),
	the maximum allowed response content length (I<max_resp_len>, where 0 means
	that the B<HTTP_DEFAULT_MAX_RESP_LEN> is used, which currently is 100 KiB),
	a response timeout measure in seconds (I<timeout>,
	where 0 indicates no timeout, i.e., waiting indefinitely),
	the expected MIME content type of the response (I<expected_content_type>,
	which may be NULL for no expectation),
	and a flag indicating that the response is expected to be
	a DER encoded ASN.1 structure (I<expect_asn1>).
	The allocated context structure is also populated with an internal allocated
	memory B<BIO>, which collects the HTTP request and additional headers as text.
	The returned context should only be used for a single HTTP request/response.

	OSSL_HTTP_REQ_CTX_free() frees up the HTTP request context I<rctx>.
	The I<wbio> and I<rbio> are not free'd and it is up to the application
	to do so.

	OSSL_HTTP_REQ_CTX_set_request_line() adds the HTTP request line to the context.
	The HTTP method is determined by I<method_POST>,
	which should be 1 to indicate C<POST> or 0 to indicate C<GET>.
	I<server> and I<port> may be set to indicate a proxy server and port
	that the request should go through, otherwise they should be left NULL.
	I<path> is the HTTP request path; if left NULL, C</> is used.

	OSSL_HTTP_REQ_CTX_add1_header() adds header I<name> with value I<value> to the
	context I<rctx>. It can be called more than once to add multiple headers.
	For example, to add a C<Host> header for C<example.com> you would call:

	OSSL_HTTP_REQ_CTX_add1_header(ctx, "Host", "example.com");

	OSSL_HTTP_REQ_CTX_set1_req() is to be used if and only if the I<method_POST>
	parameter in the OSSL_HTTP_REQ_CTX_set_request_line() call was 1.
	It finalizes the HTTP request context by adding the DER encoding of I<req>,
	using the ASN.1 template I<it> to do the encoding.
	The HTTP header C<Content-Length> is filled out with the length of the request.
	If I<content_type> isn't NULL,
	the HTTP header C<Content-Type> is also added with its content as value.
	All of this ends up in the internal memory B<BIO>.

	OSSL_HTTP_REQ_CTX_nbio() attempts to send the request prepared I<rctx>
	and gathering the response via HTTP, using the I<rbio> and I<wbio>
	that were given when calling OSSL_HTTP_REQ_CTX_new().
	When successful, the contents of the internal memory B<BIO> contains
	the contents of the HTTP response, without the response headers.
	It may need to be called again if its result is -1, which indicates
	L<BIO_should_retry(3)>. In such a case it is advisable to sleep a little in
	between using L<BIO_wait(3)> on the read BIO to prevent a busy loop.

	OSSL_HTTP_REQ_CTX_sendreq_d2i() calls OSSL_HTTP_REQ_CTX_nbio(), possibly
	several times until a timeout is reached, and DER decodes the received
	response using the ASN.1 template I<it>.

	OSSL_HTTP_REQ_CTX_get0_mem_bio() returns the internal memory B<BIO>.
	Before sending the request, this could used to modify the HTTP request text.
	I<Use with caution!>
	After receiving a response via HTTP, the BIO represents
	the current state of reading the response headers and contents.

	OSSL_HTTP_REQ_CTX_set_max_response_length() sets the maximum allowed
	response content length for I<rctx> to I<len>. If not set or I<len> is 0
	then the B<HTTP_DEFAULT_MAX_RESP_LEN> is used, which currently is 100 KiB.
	If the C<Content-Length> header is present and exceeds this value or
	the content is an ASN.1 encoded structure with a length exceeding this value
	or both length indications are present but disagree then an error occurs.

	=head1 WARNINGS

	The server's response may be unexpected if the hostname that was used to
	create the I<wbio>, any C<Host> header, and the host specified in the
	request URL do not match.

	Many of these functions must be called in a certain order.

	First, the HTTP request context must be allocated:
	OSSL_HTTP_REQ_CTX_new().

	Then, the HTTP request must be prepared with request data:

	=over 4

	=item 1.

	Calling OSSL_HTTP_REQ_CTX_set_request_line(). This must be done exactly once.

	=item 2.

	Adding extra headers with OSSL_HTTP_REQ_CTX_add1_header().
	This is optional and may be done multiple times with different names.

	=item 3.

	Add C<POST> data with OSSL_HTTP_REQ_CTX_set1_req(). This may only be done if
	I<method_POST> was 1 in the OSSL_HTTP_REQ_CTX_set_request_line() call,
	and must be done exactly once in that case.

	=back

	When the request context is fully prepared, the HTTP exchange may be performed
	with OSSL_HTTP_REQ_CTX_nbio() or OSSL_HTTP_REQ_CTX_sendreq_d2i().

	=head1 RETURN VALUES

	OSSL_HTTP_REQ_CTX_new() returns a pointer to a B<OSSL_HTTP_REQ_CTX>, or NULL
	on error.

	OSSL_HTTP_REQ_CTX_free() and OSSL_HTTP_REQ_CTX_set_max_response_length()
	do not return values.

	OSSL_HTTP_REQ_CTX_set_request_line(), OSSL_HTTP_REQ_CTX_add1_header(),
	OSSL_HTTP_REQ_CTX_set1_req() and OSSL_HTTP_REQ_CTX_nbio
	return 1 for success and 0 for failure.

	OSSL_HTTP_REQ_CTX_sendreq_d2i() returns a pointer to an B<ASN1_VALUE> for
	success and NULL for failure.

	OSSL_HTTP_REQ_CTX_get0_mem_bio() returns the internal memory B<BIO>.

	=head1 SEE ALSO

	L<BIO_should_retry(3)>,
	L<BIO_wait(3)>,
	L<OSSL_HTTP_get(3)>,
	L<OSSL_HTTP_transfer(3)>

	=head1 COPYRIGHT

	Copyright 2015-2021 The OpenSSL Project Authors. All Rights Reserved.

	Licensed under the Apache License 2.0 (the "License"). You may not use
	this file except in compliance with the License. You can obtain a copy
	in the file LICENSE in the source distribution or at
	L<https://www.openssl.org/source/license.html>.

	=cut