NAME

       globus_gass_transfer_server - Implementing Servers

        - GASS Server Implementation.

SYNOPSIS

   Typedefs
       typedef void(* globus_gass_transfer_close_callback_t) (void *callback_arg,
           globus_gass_transfer_listener_t listener)
       typedef void(* globus_gass_transfer_listen_callback_t) (void *callback_arg,
           globus_gass_transfer_listener_t listener)

   Functions
       int globus_gass_transfer_create_listener (globus_gass_transfer_listener_t *listener,
           globus_gass_transfer_listenerattr_t *attr, char *scheme)
       int globus_gass_transfer_close_listener (globus_gass_transfer_listener_t listener,
           globus_gass_transfer_close_callback_t callback, void *user_arg)
       int globus_gass_transfer_register_listen (globus_gass_transfer_listener_t listener,
           globus_gass_transfer_listen_callback_t callback, void *user_arg)
       int globus_gass_transfer_register_accept (globus_gass_transfer_request_t *request,
           globus_gass_transfer_requestattr_t *attr, globus_gass_transfer_listener_t listener,
           globus_gass_transfer_callback_t callback, void *user_arg)
       void * globus_gass_transfer_listener_get_user_pointer (globus_gass_transfer_listener_t
           listener)
       int globus_gass_transfer_listener_set_user_pointer (globus_gass_transfer_listener_t
           listener, void *user_pointer)
       char * globus_gass_transfer_listener_get_base_url (globus_gass_transfer_listener_t
           listener)
       int globus_gass_transfer_refer (globus_gass_transfer_request_t request, char **urls,
           globus_size_t num_urls)
       int globus_gass_transfer_authorize (globus_gass_transfer_request_t request, globus_size_t
           total_length)
       int globus_gass_transfer_deny (globus_gass_transfer_request_t request, int reason, char
           *message)

Detailed Description

       GASS Server Implementation.

       Implementing Servers

       Another mode of using the GASS Transfer API is to implement data servers. The primary
       difference between the client and server parts of the GASS Transfer API are how requests
       are generated.

       To implement a server, the user would call globus_gass_transfer_create_listener() to
       create a new server port on which a specific protocol will be used to request file
       transfer operations. The user may obtain the URL that the listener is bound to by calling
       globus_gass_transfer_listener_get_base_url().

       Once the listener is created, the user can call globus_gass_transfer_register_listen() to
       wait for clients to connect to it. Once the server has detected an attempt to connect by a
       client, the use can call globus_gass_transfer_register_accept() to accept the connection
       from the client and parse the request.

       In the callback associated with globus_gass_transfer_register_accept(), the server can
       decide how to process the request. The user may choose to authorize the request by calling
       globus_gass_transfer_authorize(), refer it to another URL or URLs by calling
       globus_gass_transfer_refer() or deny the client access to the URL by calling
       globus_gass_transfer_deny().

Typedef Documentation

   typedef void(* globus_gass_transfer_close_callback_t) (void *callback_arg,
       globus_gass_transfer_listener_t listener)
       Listener close callback

       Parameters
           callback_arg
           listener

   typedef void(* globus_gass_transfer_listen_callback_t) (void *callback_arg,
       globus_gass_transfer_listener_t listener)
       Listen callback.

       Parameters
           callback_arg
           listener

Function Documentation

   int globus_gass_transfer_authorize (globus_gass_transfer_request_t request, globus_size_t
       total_length)
       Authorize a request.

       This function causes the request to be authorized for processing. It should be called in
       response to a request accept callback when the server wants to agree to process this
       request. After calling this function, the server implementation should call
       globus_gass_transfer_send_bytes() or globus_gass_transfer_receive_bytes() to send or
       receive the data associated with the URL.

       Parameters
           request A new request handle, passed to the server in an accept callback.
           total_length For a 'get' request, the total_length of the file to be retrieved if
           known. This value may be GLOBUS_GASS_LENGTH_UNKNOWN if the protocol supports
           transferring arbitrarily-sized files.

       Return values
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE The request handle was not valid, not created
           by calling globus_gass_transfer_register_accept(), or has already been denied or
           authorized.
           GLOBUS_GASS_TRANSFER_ERROR_NOT_IMPLEMENTED The protocol module does not support
           authorizing requests.

       See also
           globus_gass_transfer_refer(), globus_gass_transfer_deny()

   int globus_gass_transfer_close_listener (globus_gass_transfer_listener_t listener,
       globus_gass_transfer_close_callback_t callback, void * user_arg)
       Close a GASS listener.

       This function calls the protocol specific function needed to close a GASS server listener
       port. Callbacks for any outstanding accepts will be called before the close callback is
       invoked.

       Parameters
           listener Listener handle created by calling globus_gass_transfer_create_listener().
           callback Function to call once the listener handle has been closed.
           user_arg Argument to be passed to the callback function.

       Return values
           GLOBUS_SUCCESS The close operation was successfully registered on the listener.
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE The listener handle was invalid.
           GLOBUS_GASS_TRANSFER_ERROR_NOT_INITIALIZED The listener handle was not properly
           initialized.
           GLOBUS_GASS_TRANSFER_ERROR_DONE A close has already been registered on the listener.

   int globus_gass_transfer_create_listener (globus_gass_transfer_listener_t * listener,
       globus_gass_transfer_listenerattr_t * attr, char * scheme)
       Create a new protocol-specific listener socket for a GASS server.

       This function creates a new socket to listen for client connections as a GASS server. The
       listener handle pointer is initialized to contain the a new handle which can be used in
       subsequent server operations.

       After calling this function, a user may call the globus_gass_transfer_register_listen() or
       globus_gass_transfer_close_listener() functions with this listener handle.

       Parameters
           listener A new listener handle to initialize.
           attr Protocol-specific attributes for the new listener.
           scheme The protocol scheme to implement for the listener.

       Return values
           GLOBUS_SUCCESS The listener was successfully created.
           GLOBUS_GASS_TRANSFER_ERROR_NULL_POINTER The listener or scheme parameter was NULL
           GLOBUS_GASS_TRANSFER_ERROR_NOT_IMPLEMENTED The scheme is not supported by any protocol
           module.
           GLOBUS_GASS_TRANSFER_ERROR_MALLOC_FAILED Data structures associated with the transfer
           could not be allocated.

   int globus_gass_transfer_deny (globus_gass_transfer_request_t request, int reason, char *
       message)
       Deny a request.

       This function causes the request to be denied for further processing. It should be called
       in response to a request ccept callback when the server wants to refuse processing this
       request for the client. After calling this function, the server implementation need do
       nothing further with the request handle.

       Parameters
           request A new request handle, passed to the server in an accept callback.
           reason A protocol-specific reason code.
           message An informational message to be sent to the client.

       Return values
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE The request handle was not valid, not created
           by calling globus_gass_transfer_register_accept(), or has already been denied or
           authorized.
           GLOBUS_GASS_TRANSFER_ERROR_NOT_IMPLEMENTED The protocol module does not support
           denying requests.

       See also
           globus_gass_transfer_refer(), globus_gass_transfer_authorize()

   char* globus_gass_transfer_listener_get_base_url (globus_gass_transfer_listener_t listener)
       Get the base URL of a listener.

       This function queries a listener handle for the base URL which the server is listening on.
       For most protocols, this contains the protocol scheme, host, and port that the listener
       has registered itself on.

       Parameters
           listener The listener handle to query.

       Returns
           This function returns a pointer to a string containing the base URL. This string must
           not be freed or modified by the caller. It may not be referred to after the function
           globus_gass_transfer_listener_close() has been called.

   void* globus_gass_transfer_listener_get_user_pointer (globus_gass_transfer_listener_t
       listener)
       Get the user pointer associated with a listener.

       This function will query the listener's user_pointer field and return it's value.

       Parameters
           listener The listener handle.

       Returns
           If the listener handle is invalid or the user_pointer's value has not been set, then
           GLOBUS_NULL will be returned. Otherwise, the value of the user pointer will be
           returned.

       See also
           globus_gass_transfer_listener_set_user_pointer()

   int globus_gass_transfer_listener_set_user_pointer (globus_gass_transfer_listener_t listener,
       void * user_pointer)
       Set the user pointer associated with a listener.

       This function will set the listener's user_pointer field. The pointer may be used to
       associate any pointer-sized data with a listener handle.

       Parameters
           listener The listener handle.
           user_pointer The value of the user pointer.

       Return values
           GLOBUS_SUCCESS The user pointer was successfully set.
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE The listener handle was invalid.

       See also
           globus_gass_transfer_listener_get_user_pointer()

   int globus_gass_transfer_refer (globus_gass_transfer_request_t request, char ** urls,
       globus_size_t num_urls)
       Refer a request.

       This function causes the request to be referred to another URL or list of URLs. It should
       be called in response to a request accept callback when the server wants to refer the
       client to another server or servers to process the request.

       Parameters
           request A new request handle, passed to the server in an accept callback.
           urls An array of strings, each being a URL pointing to sources of the same data as the
           original URL.
           num_urls The length of the urls array.

       Return values
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE The request handle was not valid, not created
           by calling globus_gass_transfer_register_accept(), or has already been denied or
           authorized.
           GLOBUS_GASS_TRANSFER_ERROR_NOT_IMPLEMENTED The protocol module does not support
           referrals.

       See also
           globus_gass_transfer_deny(), globus_gass_transfer_authorize()

   int globus_gass_transfer_register_accept (globus_gass_transfer_request_t * request,
       globus_gass_transfer_requestattr_t * attr, globus_gass_transfer_listener_t listener,
       globus_gass_transfer_callback_t callback, void * user_arg)
       Accept new client connections.

       This function causes the listener handle to accept a new connection on the listener and
       parse the file request. Once the file request has been parsed, the specified callback
       function will be called. The server implementation must then either authorize, deny, or
       refer this request.

       Parameters
           request A pointer to a new request handle. This request handle will be initialized
           when the callback function is invoked.
           attr Request attributes.
           listener The listener handle to register for the new request.
           callback Function to call when the protocol module has parsed the file request.
           user_arg Argument to be passed to the callback function.

       Return values
           GLOBUS_SUCCESS The listen callback has been registered with the protocol module.
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE An invalid listener handle was passed to this
           function.
           GLOBUS_GASS_TRANSFER_ERROR_NOT_INITIALIZED An uninitialized listener handle was passed
           to this function.
           GLOBUS_GASS_TRANSFER_ERROR_INTERNAL_ERROR The request could not be initialized due to
           some internal resource depletion.
           GLOBUS_GASS_NOT_REGISTERED. The globus_gass_transfer_register_listen() function has
           not yet been called.
           GLOBUS_GASS_ALREADY_REGISTERED. The listener is already processing a new request.
           GLOBUS_GASS_TRANSFER_ERROR_DONE The listener has been registered for closing.

       See also
           globus_gass_transfer_register_listen();

   int globus_gass_transfer_register_listen (globus_gass_transfer_listener_t listener,
       globus_gass_transfer_listen_callback_t callback, void * user_arg)
       Listen for new client connections.

       This function causes the listener handle to listen for new client connections. When one is
       ready, it calls the specified callback function, letting the server implementer continue
       to accept the connection and process the request.

       Parameters
           listener The listener handle to register for new connections.
           callback Function to call when a new connection may be accepted.
           user_arg Argument to be passed to the callback function.

       Return values
           GLOBUS_SUCCESS The listen callback has been registered with the protocol module.
           GLOBUS_GASS_TRANSFER_ERROR_INVALID_USE An invalid listener handle was passed to this
           function.
           GLOBUS_GASS_TRANSFER_ERROR_NOT_INITIALIZED An uninitialized listener handle was passed
           to this function.
           GLOBUS_GASS_TRANSFER_ERROR_ALREADY_REGISTERED The listener has already been registered
           for a new connection.
           GLOBUS_GASS_TRANSFER_ERROR_DONE The listener has been registered for closing.

       See also
           globus_gass_transfer_register_accept();

Author

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