According to the XMLRPC docs, a post using XMLRPC and a post using the wordpress backend are exactly the same with the exception of the returned data which is set for output to an XMLRPC client instead of a web browser.
Since these functions are presented to the server in a commandline as a single PHP POST value aproximating an XML input text stream, and output data is passed passed back as an actual XML output text stream, aditional PHP POST and GET functions are not available.
The functions of XMLRPC actually use this method of communication to provide an offline type interface for these menu items in the wordpress backend.
- POSTS -> MANAGE, ADD NEW, TAGS, CATEGORIES
- PAGES -> EDIT, ADD NEW
- MEDIA -> ADD NEW
- LINKS -> EDIT, ADD NEW, LINK CATAGORIES
- USERS -> ADD NEW
not all third party XMLRPC tools use or provide users with all of these features, but most good tools do provide some function.
XMLRPC can NOT process GET or POST data from forms. XMLRPC uses passed values as database table data. All filters are applied the passed values, and then XMLRPC uses the filtered data only to add, remove, manage database content, no forms processing is available.
Can Not absolutely verify, but my understanding is that posting by ATOM protocal or E-Mail use the same wordpress interconnects as XMLRPC, so if you can do it with XMLRPC,you can also do it with those tools.