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.\" Author: Archie Cobbs <archie@freebsd.org>
.\"
.\" $Id: http_request.3,v 1.1.1.1 2012/02/21 23:25:53 misho Exp $
.\"
.Dd April 22, 2002
.Dt HTTP_REQUEST 3
.Os
.Sh NAME
.Nm http_request
.Nd HTTP request object
.Sh LIBRARY
PDEL Library (libpdel, \-lpdel)
.Sh SYNOPSIS
.In sys/types.h
.In stdio.h
.In netinet/in.h
.In openssl/ssl.h
.In pdel/http/http_defs.h
.In pdel/http/http_server.h
.\"
.Ss Accessors
.\"
.Ft "const char *"
.Fn http_request_get_method "struct http_request *req"
.Ft "int"
.Fn http_request_set_method "struct http_request *req" "const char *method"
.Ft "const char *"
.Fn http_request_get_uri "struct http_request *req"
.Ft "const char *"
.Fn http_request_get_path "struct http_request *req"
.Ft "int"
.Fn http_request_set_path "struct http_request *req" "const char *path"
.Ft "const char *"
.Fn http_request_get_version "struct http_request *req"
.Ft "const char *"
.Fn http_request_get_query_string "struct http_request *req"
.Ft "const char *"
.Fn http_request_get_host "struct http_request *req"
.Ft "struct in_addr"
.Fn http_request_get_remote_ip "struct http_request *req"
.Ft "u_int16_t"
.Fn http_request_get_remote_port "struct http_request *req"
.Ft "SSL_CTX *"
.Fn http_request_get_ssl "struct http_request *req"
.\"
.Ss "HTTP Headers"
.\"
.Ft "const char *"
.Fn http_request_get_header "struct http_request *req" "const char *name"
.Ft "int"
.Fn http_request_num_headers "struct http_request *req"
.Ft "int"
.Fn http_request_get_header_by_index "struct http_request *req" "u_int index" "const char **namep" "const char **valuep"
.Ft "int"
.Fn http_request_set_header "struct http_request *req" "int append" "const char *name" "const char *valfmt" "..."
.Ft "int"
.Fn http_request_remove_header "struct http_request *req" "const char *name"
.Ft "int"
.Fn http_request_send_headers "struct http_request *req"
.\"
.Ss "HTTP Body"
.\"
.Ft "FILE *"
.Fn http_request_get_input "struct http_request *req"
.Ft "FILE *"
.Fn http_request_get_output "struct http_request *req" "int buffer"
.\"
.Ss "HTTP Basic Authorization"
.\"
.Ft "const char *"
.Fn http_request_get_username "struct http_request *req"
.Ft "const char *"
.Fn http_request_get_password "struct http_request *req"
.Ft "char *"
.Fn http_request_encode_basic_auth "const char *mtype" "const char *username" "const char *password"
.\"
.Ss "Name/Value Pairs"
.\"
.Ft "const char *"
.Fn http_request_get_value "struct http_request *req" "const char *name" "int instance"
.Ft "int"
.Fn http_request_set_value "struct http_request *req" "const char *name" "const char *value"
.Ft int
.Fn http_request_get_num_values "struct http_request *req"
.Ft int
.Fn http_request_get_value_by_index "struct http_request *req" "int index" "const char **name" "const char **value"
.Ft "int"
.Fn http_request_set_query_from_values "struct http_request *req"
.Ft "int"
.Fn http_request_read_url_encoded_values "struct http_request *req"
.Ft "int"
.Fn http_request_write_url_encoded_values "struct http_request *req"
.\"
.Ss "MIME Multi-Part Support"
.\"
.Ft int
.Fn http_request_get_mime_multiparts "struct http_request *req" "http_mime_handler_t *handler" "void *arg"
.Ft "struct mime_multipart *"
.Fn http_request_read_mime_multipart "struct http_request *req"
.Ft "int"
.Fn http_request_file_upload "struct http_request *req" "const char *field" "FILE *fp" "size_t max"
.\"
.Ss Miscellaneous
.\"
.Ft "char *"
.Fn http_request_url_encode "const char *mtype" "const char *string"
.Ft "void"
.Fn http_request_url_decode "const char *s" "char *t"
.Ft "time_t"
.Fn http_request_parse_time "const char *string"
.Ft "void "
.Fn http_request_set_proxy "struct http_request *req" "int whether"
.Ft "int"
.Fn http_request_get_raw_socket "struct http_request *req"
.\"
.Sh DESCRIPTION
.\"
The
.Nm http_request
object is used by the PDEL HTTP library to represent an HTTP request.
An HTTP request may be associated with an HTTP client (the request is
generated locally) or an HTTP server (the request is generated remotely).
Some of the functions and values defined below only make sense in one
of these cases.
.Pp
.Nm http_request
objects are not created directly; rather, they are obtained from another
object which is associated with the HTTP connection.
They are freed automatically (and become invalid) when the corresponding
HTTP connection object is closed.
.\"
.Ss Accessors
.\"
.Fn http_request_get_method
returns the HTTP method, typically "GET" or "POST" but others are possible.
.Pp
.Fn http_request_set_method
sets the method for a request when the local side is the client.
.Pp
.Fn http_request_get_uri
gets the URI from the request.
This is the requested resource exactly as the client requested it,
before any URL-decoding.
The first character of this string will always be '/' for non-proxy requests.
.Pp
.Fn http_request_get_path
returns the path part of the URI, after URL-decoding has taken place.
This does not include the '?' and query string part, if any.
The first character of this string will always be '/'.
.Pp
.Fn http_request_set_path
sets the path for a request.
The first character must be '/'.
.Pp
.Fn http_request_get_version
returns the version string for this request.
Typically one of "HTTP/0.9", "HTTP/1.0", or "HTTP/1.1".
.Pp
.Fn http_request_get_query_string
returns the HTTP query string (which optionally appears at the end of
an URL after a '?' character), or the empty string if there is no query string.
The returned string is exactly as it was submitted by the client,
i.e., no URL-decoding has been performed on it.
.Pp
.Fn http_request_get_host
returns the hostname specified in the request.
This may be
.Dv NULL
for a non-proxy request if the client fails to send the "Host" header
(typically older browsers).
This value can be used to implement "virtual hosting".
.Pp
.Fn http_request_get_remote_ip
returns the IP address of the remote side.
.Pp
.Fn http_request_get_remote_port
returns the TCP port of the remote side.
.Pp
.Fn http_request_get_ssl
returns the SSL context for the HTTP connection, or
.Dv NULL
if the connection is not over SSL.
.\"
.Ss "HTTP Headers"
.\"
.Fn http_request_get_header
returns the value of the named header, or
.Dv NULL
if the header is not defined for the request.
HTTP header names are case-insensitive.
.Pp
.Fn http_request_num_headers
returns the number of headers in the request.
.Pp
.Fn http_request_get_header_by_index
points
.Fa "*namep"
at the name and
.Fa "*valuep"
at the value of the header with index
.Fa index ,
which must be less than the value returned by
.Fn http_request_num_headers .
.Pp
.Fn http_request_set_header
formats and sets a header value.
If
.Fa append
is non-zero, the value is appended to any existing value
(after adding a ",\ " separator) rather than replacing it.
.Pp
.Fn http_request_remove_header
removes a header from the request.
.Pp
.Fn http_request_send_headers
causes the client request headers to be sent to the server if they
haven't already been sent.
This causes the URI to be constructed from the request path (see
.Fn http_request_set_path
above) and the name/value pairs (see
.Fn http_request_set_value
below) added as the query string.
.\"
.Ss "HTTP Body"
.\"
.Fn http_request_get_input
returns the body of the request as an input stream.
The local side must be the server for this HTTP connection.
.Pp
.Fn http_request_get_output
returns an output stream that writes into the body of the request.
The local side must be the client for this HTTP connection.
.Fa buffer
determines whether the entire output should be buffered before sending, or
should writes to the stream translate immediately into writes to the server.
The latter option will force the headers to be sent (if they haven't been
sent already) when the first byte is written to the stream.
Setting
.Fa buffer
to zero is also incompatible with keep-alive, unless the user code manually
sets the "Content-Length" header (in which case it takes responsibility
for writing the correct number of bytes).
If
.Fa buffer
is non-zero, the output will be buffered entirely in memory until the output
stream is closed, at which point "Content-Length" is computed automatically.
.\"
.Ss "HTTP Basic Authorization"
.\"
.Fn http_request_get_username
returns the username from the "Authorization" header, or
.Dv NULL
if none was specified.
This works for "Basic" authentication only.
.Pp
.Fn http_request_get_password
returns the password from the "Authorization" header, or
.Dv NULL
if none was specified.
This works for "Basic" authentication only.
.Pp
.Fn http_request_encode_basic_auth
formats and base-64 encodes the
.Fa username
and
.Fa password
into a form suitable for the HTTP "Basic" authentication header.
The returned buffer is allocated with
.Xr typed_mem 3
type
.Fa mtype ;
the caller must eventually free it.
.\"
.Ss "Name/Value Pairs"
.\"
Requests have an internal list of name, value pairs.
The names need not be unique.
For servers, this list is automatically initialized from the request
by parsing the URI query string.
For clients, this list is used to automatically generate the URI query
string when the request headers are sent for "GET" queries only.
.Pp
.Fn http_request_get_value
returns the value associated with with
.Fa name .
Since the same name may exist multiple times,
.Fa instance
should be 0 to retrieve the first value, 1 for the second, etc.
.Dv NULL
is returned if the value is not found.
.Pp
.Fn http_request_set_value
adds a name, value pair to the internal database.
.Pp
.Fn http_request_get_num_values
returns the number of name, value pairs.
.Pp
.Fn http_request_get_value_by_index
retrieves name, value pair that is at position
.Fa index
in the list.
Note that the list is kept sorted by name.
.Pp
.Fn http_request_set_query_from_values
generates a query string for the request based on the
name, value pairs.
This is useful if a query string is desired with a non-GET request.
.Pp
.Fn http_request_read_url_encoded_values
reads the request body, interprets it as an URL-encoded query string,
and sets the request's name, value pairs from string.
This is typically used by a server to input HTML form data that
was submitted using the "POST" method.
.Pp
.Fn http_request_write_url_encoded_values
writes out the name, value pairs as URL-encoded query string data.
This is typically used by a client to output HTML form data using
the "POST" method.
.Pp
.\"
.Ss "MIME Multi-Part Support"
.\"
These functions operate on requests whose body contains multi-part MIME data.
The request must have content type "multipart/form-data" and
the body must be properly formatted for multi-part MIME or else these
functions will return an error.
.Pp
.Fn http_request_get_mime_multiparts
reads the request body as a multi-part MIME document and invokes the
.Fa handler
for each part:
.Pp
.Bd -literal -compact
    typedef int http_mime_handler_t(void *arg,
                struct mime_part *part, FILE *fp);
.Ed
.Pp
The
.Fa arg
is passed untouched to the handler.
.Fa fp
is an input stream that reads only the MIME part being processed.
The handler should read as much of the MIME part as desired and then return
0 to continue with subsequent parts, or else
-1 (with
.Va errno
set) to abort processing.
In the latter case,
.Fn http_request_get_mime_multiparts
will return -1.
In no case should
the handler close the stream
.Fa fp
or free
.Fa part .
See
.Xr http_mime 3
for a description of how to use
.Fa part .
.Pp
.Fn http_request_read_mime_multipart
reads an entire multi-part MIME request body into memory and returns
the result, which the caller is responsible for eventually freeing.
See
.Xr http_mime 3
for a description of how to use the return value.
.Pp
.Fn http_request_file_upload
reads only the value of the field
.Fa field
from a multi-part MIME request body and writes it to the output stream
.Fa fp .
The data is transferred in an on-line fasion so that the entire value
does not need to fit in memory at once.
This is useful for HTML form file uploads of large files.
All MIME parts other than the first part with name
.Fa field
are discarded.
If
.Fa max
is non-zero and the length of the field is more than
.Fa max
bytes, an error is generated with
.Va errno
set to
.Er EFBIG.
This is useful for avoiding disk-filling attacks.
.\"
.Ss Miscellaneous
.\"
.Fn http_request_url_encode
URL-encodes the string
.Fa s
into a buffer allocated with
.Xr typed_mem 3
type
.Fa mtype 
and returns the result, which the caller must eventually free.
.Pp
.Fn http_request_url_decode
URL-decodes the string
.Fa s
and puts the result in the buffer
.Fa t ,
which must have length at least
.Li "strlen(s) + 1" .
.Pp
.Fn http_request_parse_time
parses an HTTP time string and returns the result, or -1 on failure.
.Pp
.Fn http_request_set_proxy
sets or clears the proxy bit for a client request.
When this bit is set, the client will make a proxy HTTP request instead
of a normal HTTP request.
.Pp
.Fn http_request_get_raw_socket
returns the underlying file descriptor for the HTTP connection.
This is a huge layering violation fraught with danger, but necessary
for implementing a proxy server that supports the "CONNECT" method.
This function will fail for SSL connections.
The returned file descriptor should not be closed.
.Sh RETURN VALUES
All of the above routines that can return an error return
.Dv NULL
or -1 to indicate this and set
.Va errno
to an appropriate value.
Success is indicated by a normal return value or zero.
.Sh SEE ALSO
.Xr http_client 3 ,
.Xr http_mime 3 ,
.Xr http_response 3 ,
.Xr http_server 3 ,
.Xr http_servlet 3 ,
.Xr libpdel 3 ,
.Xr typed_mem 3
.Rs
.%A R. Fielding
.%A J. Gettys
.%A J. Mogul
.%A H. Frystyk
.%A L. Masinter
.%A P. Leach
.%A T. Berners-Lee
.%T "Hypertext Transfer Protocol -- HTTP/1.1"
.%O RFC 2616
.Re
.Rs
.%A N. Freed
.%A N. Borenstein
.%T "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types"
.%O RFC 2046
.Re
.Sh HISTORY
The PDEL library was developed at Packet Design, LLC.
.Dv "http://www.packetdesign.com/"
.Sh AUTHORS
.An Archie Cobbs Aq archie@freebsd.org