ne_request_create, ne_request_dispatch, ne_request_destroy — low-level HTTP request handling
#include <ne_request.h>
ne_request *ne_request_create( | ne_session *session, |
const char *method, | |
const char *target) ; |
int ne_request_dispatch( | ne_request *req) ; |
void ne_request_destroy( | ne_request *req) ; |
The ne_request object represents an HTTP
request and the associated response. The
ne_request_create
function creates a new
request object for the given session
.
The target resource for the request is identified by the
target
, parameter, and the method to be
performed on that resource via the
method
parameter.
The target
string used must conform to
the request-target
definition given in RFC 9112. Usually
this will take the abolute-path
form, which
optionally includes a query string.
To dispatch a request, and process the response, the
ne_request_dispatch
function can be used. An
alternative is to use the (more complex, but more flexible)
combination of the ne_begin_request
,
ne_end_request
, and
ne_read_response_block
functions; see
ne_begin_request
. Dispatching a request may require
multiple iterations of a request being sent and response received, for example
if authentication is used (see ne_set_server_auth), or if a persistent
connection times out; this is handled internally by ne_request_dispatch
.
To add extra headers in the request, the functions ne_add_request_header and ne_print_request_header can be used. To include a message
body with the request, one of the functions
ne_set_request_body_buffer
, ne_set_request_body_fd
, or
ne_set_request_body_provider
can be used.
The return value of
ne_request_dispatch
indicates merely whether the
request was sent and the response read successfully. To discover the
result of the operation, ne_get_status, along with
any processing of the response headers and message body.
A request can only be dispatched once: calling
ne_request_dispatch
more than once on a
single ne_request object produces undefined
behaviour. Once all processing associated with the request
object is complete, use the
ne_request_destroy
function to destroy
the resources associated with it. Any subsequent use of the
request object produces undefined behaviour.
Request methods are assumed to be idempotent
by default. For a request using a non-idempotent method such
as POST
, the
NE_REQFLAG_IDEMPOTENT
flag must be
disabled using ne_set_request_flag.
The ne_request_create
function
returns a pointer to a request object (and never NULL
).
The ne_request_dispatch
function
returns zero if the request was dispatched successfully, and a
non-zero error code otherwise.
The path
,
method
and
target
parameters of
ne_request_create
are used directly in
request data without validation, so must not be taken from
untrusted sources. For example, allowing insertion of
unescaped CR, LF or other control characters in these
parameters may result in unexpected or insecure behaviour.
neon does not impose any length restrictions on request input data.
NE_ERROR | Request failed (see session error string) |
NE_LOOKUP | The DNS lookup for the server (or proxy server) failed. |
NE_AUTH | Authentication failed on the server. |
NE_PROXYAUTH | Authentication failed on the proxy server. |
NE_CONNECT | A connection to the server could not be established. |
NE_TIMEOUT | A timeout occurred while waiting for the server to respond. |
An example of applying a MKCOL
operation to the resource at the location
http://www.example.com/foo/bar/
:
ne_session *sess = ne_session_create("http", "www.example.com", 80); ne_request *req = ne_request_create(sess, "MKCOL", "/foo/bar/"); if (ne_request_dispatch(req)) { printf("Request failed: %s\n", ne_get_error(sess)); } ne_request_destroy(req);