Function demoprot_export

contrib/extprotocol/gpextprotocol.c:162–240

* Export data out of GPDB. */

 * Export data out of GPDB.
 */
Datum 
demoprot_export(PG_FUNCTION_ARGS)
{
	extprotocol_t   *myData;
	char			*data;
	int				 datlen;
	size_t			 wrote = 0;

	/* Must be called via the external table format manager */
	if (!CALLED_AS_EXTPROTOCOL(fcinfo))
		elog(ERROR, "extprotocol_export: not called by external protocol manager");

	/* Get our internal description of the protocol */
	myData = (extprotocol_t *) EXTPROTOCOL_GET_USER_CTX(fcinfo);

	if(EXTPROTOCOL_IS_LAST_CALL(fcinfo))
	{
		/* we're done sending data. close our connection */
		if(myData && myData->file)
			if(fclose(myData->file))
				ereport(ERROR,
						(errcode_for_file_access(),
						 errmsg("could not close file \"%s\": %m",
								 myData->filename)));
		
		PG_RETURN_INT32(0);
	}	

	if (myData == NULL)
	{
		/* first call. do any desired init */
		
		const char	*p_name = "demoprot";
		DemoUri		*parsed_url;
		char		*url = EXTPROTOCOL_GET_URL(fcinfo);
			
		myData 			 = palloc(sizeof(extprotocol_t));
				
		myData->url 	 = pstrdup(url);
		parsed_url 		 = ParseDemoUri(myData->url);
		myData->filename = pstrdup(parsed_url->path);
	
		if(strcasecmp(parsed_url->protocol, p_name) != 0)
			elog(ERROR, "internal error: demoprot called with a different protocol (%s)",
						parsed_url->protocol);

		FreeDemoUri(parsed_url);
		
		/* open the destination file (or connect to remote server in other cases) */
		myData->file = fopen(myData->filename, "a");
		
		if (myData->file == NULL)
			ereport(ERROR,
					(errcode_for_file_access(),
					 errmsg("demoprot_export: could not open file \"%s\" for writing: %m",
							myData->filename)));
		
		EXTPROTOCOL_SET_USER_CTX(fcinfo, myData);