On May 22, 2015, at 3:53 AM, Stuart Dallas wrote:
On Fri, 22 May 2015 at 07:20 Jeffry Killen <jekillen@xxxxxxxxxxx>
wrote:
This may be a bit off topic but I begin with understanding of
php and doing synchronous and async queries generated by
javascript on the client side.
Recently I resurrected a home built server and installed FreeBSD.
Since I have been doing probably as much javascript as php, I have
been interested in exploring node.js.
My question is academic
How is a simple query from a client like Firefox to an http server
using
php to process the request different from RPC?
(I have been looking at Wikipedia article on RPC: http://en.wikipedia.org/wiki/Remote_procedure_call)
I have written call back functions that are invoke from a window
opened
in javascript that call functions in the opening window. And as well,
calling
a server side script generally involves calling functions and methods
and
sending a result back to the client.
For instance, there may be a form that is used to compose and
execute a
query of the server's data base server (MySQL, Postgres, etc) and the
result is assembled and sent back to the client for display.
How is this different from formal RPC?
Now there is Apache Thrift with bindings to node.js (and other
languages),
which seems to imply that php can hand off requests to a node.js
server,
that might in turn satisfy a client request. (node.js is server side
javascript)
Right now I wouldn't do anything outside of localhost with node.js
because
it looks like asking for a whole lot of trouble if used over public
network.
Are there any academic thoughts on this?
Generally speaking, RPC (as a concept) is simply "making a request
to a remote server and receiving the results." The term originated
with distributed systems with technologies such as CORBA.
Essentially RPC describes the format of the request before it hits
the transport mechanism (HTTP, 0MQ, TCP, whatever), and there are
several different standards. XMLRPC is another technology that does
RPC defined using XML over HTTP: http://en.wikipedia.org/wiki/XML-RPC.
The main distinguishing feature of an RPC against simply using, for
example, a REST service is that the client does not necessarily know
that it's calling a remote procedure. That fact is hidden by a class
or library that wraps the remote call in a local function.
Doing RPC over public networks is acceptable so long as you use SSL
to protect the data and authentication to prevent unauthorised
access. This is generally not a bad idea even within a private
network, because there really is no such thing as a private network!
I hope that helps expand on what RPC is and why it's different from
submitting a form on a web page.
-Stuart
So, the class or library would be local to but separate from the
client itself?
As if, say, javascript had to call a function in another application
to make an
async request to a server. This is a bit subtile for me. It appears to
be another
layer between the application layer and the transport layer.
Thank you for your reply
JK
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