287 lines
13 KiB
Plaintext
287 lines
13 KiB
Plaintext
=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_set_expected,
|
|
OSSL_HTTP_REQ_CTX_set1_req,
|
|
OSSL_HTTP_REQ_CTX_nbio,
|
|
OSSL_HTTP_REQ_CTX_nbio_d2i,
|
|
OSSL_HTTP_REQ_CTX_exchange,
|
|
OSSL_HTTP_REQ_CTX_get0_mem_bio,
|
|
OSSL_HTTP_REQ_CTX_get_resp_len,
|
|
OSSL_HTTP_REQ_CTX_set_max_response_length,
|
|
OSSL_HTTP_is_alive
|
|
- 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 buf_size);
|
|
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_set_expected(OSSL_HTTP_REQ_CTX *rctx,
|
|
const char *content_type, int asn1,
|
|
int timeout, int keep_alive);
|
|
int OSSL_HTTP_REQ_CTX_set1_req(OSSL_HTTP_REQ_CTX *rctx, const char *content_type,
|
|
const ASN1_ITEM *it, const ASN1_VALUE *req);
|
|
int OSSL_HTTP_REQ_CTX_nbio(OSSL_HTTP_REQ_CTX *rctx);
|
|
int OSSL_HTTP_REQ_CTX_nbio_d2i(OSSL_HTTP_REQ_CTX *rctx,
|
|
ASN1_VALUE **pval, const ASN1_ITEM *it);
|
|
BIO *OSSL_HTTP_REQ_CTX_exchange(OSSL_HTTP_REQ_CTX *rctx);
|
|
|
|
BIO *OSSL_HTTP_REQ_CTX_get0_mem_bio(const OSSL_HTTP_REQ_CTX *rctx);
|
|
size_t OSSL_HTTP_REQ_CTX_get_resp_len(const OSSL_HTTP_REQ_CTX *rctx);
|
|
void OSSL_HTTP_REQ_CTX_set_max_response_length(OSSL_HTTP_REQ_CTX *rctx,
|
|
unsigned long len);
|
|
|
|
int OSSL_HTTP_is_alive(const OSSL_HTTP_REQ_CTX *rctx);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
B<OSSL_HTTP_REQ_CTX> is a context structure for an HTTP request and response,
|
|
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 write/send the request to (I<wbio>),
|
|
the B<BIO> to read/receive the response from (I<rbio>, which may be equal to
|
|
I<wbio>), and the maximum expected response header line length I<buf_size>.
|
|
A value <= 0 indicates that
|
|
the B<OSSL_HTTP_DEFAULT_MAX_LINE_LEN> of 4KiB should be used.
|
|
I<buf_size> is also used as the number of content bytes that are read at a time.
|
|
The allocated context structure includes an internal memory B<BIO>,
|
|
which collects the HTTP request header lines.
|
|
|
|
OSSL_HTTP_REQ_CTX_free() frees up the HTTP request context I<rctx>.
|
|
The I<rbio> is not free'd, I<wbio> will be free'd if I<free_wbio> is set.
|
|
|
|
OSSL_HTTP_REQ_CTX_set_request_line() adds the 1st HTTP request line to I<rctx>.
|
|
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 give the server and the optional port that
|
|
an HTTP proxy shall forward the request to, otherwise they must be left NULL.
|
|
I<path> provides the HTTP request path; if left NULL, C</> is used.
|
|
For backward compatibility, I<path> may begin with C<http://> and thus convey
|
|
an absoluteURI. In this case it indicates HTTP proxy use and provides also the
|
|
server (and optionally the port) that the proxy shall forward the request to.
|
|
In this case the I<server> and I<port> arguments must be NULL.
|
|
|
|
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 header lines.
|
|
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_set_expected() optionally sets in I<rctx> some expectations
|
|
of the HTTP client on the response.
|
|
Due to the structure of an HTTP request, if the I<keep_alive> argument is
|
|
nonzero the function must be used before calling OSSL_HTTP_REQ_CTX_set1_req().
|
|
|
|
If the I<content_type> argument is not NULL,
|
|
the client will check that the specified content-type string
|
|
is included in the HTTP header of the response and return an error if not.
|
|
In the content-type header line the specified string should be present either
|
|
as a whole, or in case the specified string does not include a C<;> character,
|
|
it is sufficient that the specified string appears as a prefix
|
|
in the header line, followed by a C<;> character and any further text.
|
|
For instance, if the I<content_type> argument specifies C<text/html>,
|
|
this is matched by C<text/html>, C<text/html; charset=UTF-8>, etc.
|
|
|
|
If the I<asn1> parameter is nonzero a structure in ASN.1 encoding will be
|
|
expected as the response content and input streaming is disabled. This means
|
|
that an ASN.1 sequence header is required, its length field is checked, and
|
|
OSSL_HTTP_REQ_CTX_get0_mem_bio() should be used to get the buffered response.
|
|
Otherwise (by default) any input format is allowed without length checks.
|
|
In this case the BIO given as I<rbio> argument to OSSL_HTTP_REQ_CTX_new() should
|
|
be used directly to read the response contents, which may support streaming.
|
|
If the I<timeout> parameter is > 0 this indicates the maximum number of seconds
|
|
the subsequent HTTP transfer (sending the request and receiving a response)
|
|
is allowed to take.
|
|
I<timeout> == 0 enables waiting indefinitely, i.e., no timeout can occur.
|
|
This is the default.
|
|
I<timeout> < 0 takes over any value set via the I<overall_timeout> argument of
|
|
L<OSSL_HTTP_open(3)> with the default being 0, which means no timeout.
|
|
If the I<keep_alive> parameter is 0, which is the default, the connection is not
|
|
kept open after receiving a response. This is the default behavior for HTTP 1.0.
|
|
If the value is 1 or 2 then a persistent connection is requested.
|
|
If the value is 2 then a persistent connection is required,
|
|
i.e., an error occurs in case the server does not grant it.
|
|
|
|
OSSL_HTTP_REQ_CTX_set1_req() finalizes the HTTP request context.
|
|
It is needed if the I<method_POST> parameter in the
|
|
OSSL_HTTP_REQ_CTX_set_request_line() call was 1
|
|
and an ASN.1-encoded request should be sent.
|
|
It must also be used when requesting "keep-alive",
|
|
even if a GET request is going to be sent, in which case I<req> must be NULL.
|
|
Unless I<req> is NULL, the function adds the DER encoding of I<req> using
|
|
the ASN.1 template I<it> to do the encoding (which does not support streaming).
|
|
The HTTP header C<Content-Length> is filled out with the length of the request.
|
|
I<content_type> must be NULL if I<req> is NULL.
|
|
If I<content_type> isn't NULL,
|
|
the HTTP header C<Content-Type> is also added with the given string value.
|
|
The header lines are added to the internal memory B<BIO> for the request header.
|
|
|
|
OSSL_HTTP_REQ_CTX_nbio() attempts to send the request prepared in I<rctx>
|
|
and to gather the response via HTTP, using the I<wbio> and I<rbio>
|
|
that were given when calling OSSL_HTTP_REQ_CTX_new().
|
|
The function 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_nbio_d2i() is like OSSL_HTTP_REQ_CTX_nbio() but on success
|
|
in addition parses the response, which must be a DER-encoded ASN.1 structure,
|
|
using the ASN.1 template I<it> and places the result in I<*pval>.
|
|
|
|
OSSL_HTTP_REQ_CTX_exchange() calls OSSL_HTTP_REQ_CTX_nbio() as often as needed
|
|
in order to exchange a request and response or until a timeout is reached.
|
|
On success it returns a pointer to the BIO that can be used to read the result.
|
|
If an ASN.1-encoded response was expected, this is the BIO
|
|
returned by OSSL_HTTP_REQ_CTX_get0_mem_bio() when called after the exchange.
|
|
This memory BIO does not support streaming.
|
|
Otherwise the returned BIO is the I<rbio> given to OSSL_HTTP_REQ_CTX_new(),
|
|
which may support streaming.
|
|
When this BIO is returned, it has been read past the end of the response header,
|
|
such that the actual response body can be read from it.
|
|
The returned BIO pointer MUST NOT be freed by the caller.
|
|
|
|
OSSL_HTTP_REQ_CTX_get0_mem_bio() returns the internal memory B<BIO>.
|
|
Before the HTTP request is sent, this could be used to adapt its header lines.
|
|
I<Use with caution!>
|
|
After receiving a response via HTTP, the BIO represents the current state of
|
|
reading the response header. If the response was expected to be ASN.1 encoded,
|
|
its contents can be read via this BIO, which does not support streaming.
|
|
The returned BIO pointer must not be freed by the caller.
|
|
|
|
OSSL_HTTP_REQ_CTX_get_resp_len() returns the size of the response contents
|
|
in I<rctx> if provided by the server as <Content-Length> header field, else 0.
|
|
|
|
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<OSSL_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.
|
|
|
|
OSSL_HTTP_is_alive() can be used to query if the HTTP connection
|
|
given by I<rctx> is still alive, i.e., has not been closed.
|
|
It returns 0 if I<rctx> is NULL.
|
|
|
|
If the client application requested or required a persistent connection
|
|
and this was granted by the server, it can keep I<rctx> as long as it wants
|
|
to send further requests and OSSL_HTTP_is_alive() returns nonzero,
|
|
else it should call I<OSSL_HTTP_REQ_CTX_free(rctx)> or L<OSSL_HTTP_close(3)>.
|
|
In case the client application keeps I<rctx> but the connection then dies
|
|
for any reason at the server side, it will notice this obtaining an
|
|
I/O error when trying to send the next request via I<rctx>.
|
|
|
|
=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().
|
|
|
|
=item 2.
|
|
|
|
Adding extra header lines with OSSL_HTTP_REQ_CTX_add1_header().
|
|
This is optional and may be done multiple times with different names.
|
|
|
|
=item 3.
|
|
|
|
Finalize the request using OSSL_HTTP_REQ_CTX_set1_req().
|
|
This may be omitted if the GET method is used and "keep-alive" is not requested.
|
|
|
|
=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_exchange().
|
|
|
|
=head1 NOTES
|
|
|
|
When built with tracing enabled, OSSL_HTTP_REQ_CTX_nbio() and all functions
|
|
using it, such as OSSL_HTTP_REQ_CTX_exchange() and L<OSSL_HTTP_transfer(3)>,
|
|
may be traced using B<OSSL_TRACE_CATEGORY_HTTP>.
|
|
See also L<OSSL_trace_enabled(3)> and L<openssl(1)/ENVIRONMENT>.
|
|
|
|
=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_set_expected()
|
|
return 1 for success and 0 for failure.
|
|
|
|
OSSL_HTTP_REQ_CTX_nbio() and OSSL_HTTP_REQ_CTX_nbio_d2i()
|
|
return 1 for success, 0 on error or redirection, -1 if retry is needed.
|
|
|
|
OSSL_HTTP_REQ_CTX_exchange() and OSSL_HTTP_REQ_CTX_get0_mem_bio()
|
|
return a pointer to a B<BIO> on success as described above or NULL on failure.
|
|
The returned BIO must not be freed by the caller.
|
|
|
|
OSSL_HTTP_REQ_CTX_get_resp_len() returns the size of the response contents
|
|
or 0 if not available or an error occurred.
|
|
|
|
OSSL_HTTP_is_alive() returns 1 if its argument is non-NULL
|
|
and the client requested a persistent connection
|
|
and the server did not disagree on keeping the connection open, else 0.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<BIO_should_retry(3)>,
|
|
L<BIO_wait(3)>,
|
|
L<ASN1_item_d2i_bio(3)>,
|
|
L<ASN1_item_i2d_mem_bio(3)>,
|
|
L<OSSL_HTTP_open(3)>,
|
|
L<OSSL_HTTP_get(3)>,
|
|
L<OSSL_HTTP_transfer(3)>,
|
|
L<OSSL_HTTP_close(3)>,
|
|
L<OSSL_trace_enabled(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
The functions described here were added in OpenSSL 3.0.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2015-2023 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
|