NE_REQUEST_CREATE(3)

NAME
ne_request_create, ne_request_dispatch, ne_request_destroy - low-level HTTP request handling

SYNOPSIS

#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);

DESCRIPTION

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[1]. 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[2] 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.

RETURN VALUE

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.

NOTES

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.

ERRORS

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.

EXAMPLE

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);

SEE ALSO

ne_get_error, ne_set_error, ne_get_status, ne_add_request_header, ne_set_request_body_buffer, ne_set_request_flag.

COPYRIGHT
Copyright © 2001-2024 Joe Orton

REFERENCES

1.  RFC 9112
    https://www.rfc-editor.org/rfc/rfc9112

2.  idempotent
    https://www.rfc-editor.org/rfc/rfc9110.html#name-idempotent-methods