LiveCode Server, can it read local (on the server) drives?

[Richard Gaskin]

Roger Eller wrote:

 > A direct SQL query followed by a FTP command to check existence,
 > on a per file basis takes about 150 millisecs.
 > The same query performed by LC Server, and FTP existence check,
 > takes about 500 millisecs.

FTP is notoriously slow.  All things considered, that's not bad, though 
on a server with any appreciable traffic a half-second for a single 
transaction may become problematic.

 > I doubt that all of the data (the list) could be carried in a GET
 > parameter of the URL.  I don't know the URL length limitations, or
 > if there is a limit.

It does, and there is no standard.  POST can carry much more data, and 
although it's also implemented with no consistent limitation at least it 
should be big enough to handle a list of the size you describe.

In your original post you wrote:

 > I wish to have the server perform a SQL query to a database of file
 > paths, and follow that request with an existence verification to a
 > local drive of that same server.

Rather than FTP between servers, I wonder if it may be more efficient, 
and possible simpler in terms of the number of moving parts, to call 
another LC Server routine (or PHP or whatever else could do this) on 
that DB server to both query the DB and check for the existence of the 
corresponding file there.

In LC, "if there is a file <path>" is darn fast, many times faster than 
checking a file's existence via FTP (probably by at least an order of 
magnitude).

Another possible benefit of this approach is that the addition of an LC 
script as a sort of "middleware" on the other server turns that server 
into a service, one that could be extended in other useful directions 
down the road as your needs grow.

In cases like this I'm often reminded of Jeff Bezos' requirement for his 
engineering team:  "Don't give me code, give me APIs".  With that 
mandate they were able to implement a system that no only grew well 
enough to make Amazon the largest retailer on earth, but also later 
became a product in itself, known today as Amazon Web Services.

--
  Richard Gaskin
  Fourth World
  LiveCode training and consulting: http://www.fourthworld.com
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