The 'submit' button on a page will do one of two things. Either
send a GET string
send a POST message
The USPS page uses "
The GET is a simple method of send a web page address & the data pairs.
- this method has a limit of about 1000 chars and is sent so that a
program sniffing packets can see the entire string
The POST is a more capable method that sends the web page address &
another message that can contain a variety of encoded data.
- this method does not have a limit and the variables cannot be sniffed
In your case, the LC 'post' command is the 'submit' button action.
In the LC library, the web page address and the message are formatted
for you
Think of the receiving web page as a hander in LC.
The post message calls the handler and passes the variables defined by
pVar1=string&pVar2=integer&pVar3=state&pVar4=city
Now the server program gets called, crunches, and returns what it is
programmed to return, just like a LC handler or function.
The POST command can also send images (as binary endoded as a text
block), sounds, videos, files, etc.
The key is to format the message so that the sever program can know
how to decode the text and where the parts begin and end, if multiple
parts are sent in one message. This is the function of 'multi-part
boundaries' (long random strings that divide the parts)
On Nov 27, 2010, at 3:46 PM, James Hurley wrote:
Richard,
I'm beginning to get it. I should put
visited
=1&pagenumber=0&firmname=&address2=620+moulton&address1=&city=los
+
angeles
&state=ca&urbanization=&zip5=90031&submit.x=48&submit.y=8&submit=Fin
into field 1--or, of course, the data appropriate to my addresses.
But where did this "visited" line come from? Where in the process of
sending the "submit" does this line present itself?
Jim
Richard,
Thanks. I am astonished that this is possible.
I'm afraid I am missing something. I tried entering my data (my
home address--it appears that is what you did) in the USPS page
http://zip4.usps.com/zip4/
I then copied and pasted that source code into field 1 in LiveCode.
(I didn't see any reference to my data--my address--in that html
text.)
I used your script in a button and obtained some html text in field
2. But there is no reference in field 2 to my street address.
I don't mind working on the parsing to do the put and get, but I'm
sure I missing the ingredient where my data (address, city and St)
goes into field 1. I think that is what I am missing.
I don't see "visited=1&pagenumber=0 etc. anywhere in field 1 or 2.
Floundering,
Jim
James Hurley wrote:
> At the USPS web site (http://zip4.usps.com/zip4/) it is possible
by
> entering the street address, the city and the state to obtain
the 9
> digit zip code for that address.
>
> This may be naive, but is it possible to do this from within
LiveCode
> by script?
Good news: you can use the post command for that.
Bad news: the result is HTML, so you'll need to parse out the
relevant
parts.
To test I made a stack with a button and two fields - here's the
script
for the button, using the URL derived from the HTML source of the
form
element in that page:
on mouseUp
post fld 1 to url "http://zip4.usps.com/zip4/zcl_0_results.jsp";
set the htmlText of fld 2 to it
end mouseUp
Field 1 contains form element names and values, packaged up in the
name=value format used by both POST and GET:
visited
=1&pagenumber=0&firmname=&address2=620+moulton&address1=&city=los
+
angeles
&state=ca&urbanization=&zip5=90031&submit.x=48&submit.y=8&submit=Fin
Field 2 will contain the HTML once the request is returned. Now
for the
tedious parsing to get the parts you want....
--
Richard Gaskin
Fourth World
LiveCode training and consulting: http://www.fourthworld.com
Webzine for LiveCode developers: http://www.LiveCodeJournal.com
LiveCode Journal blog: http://LiveCodejournal.com/blog.irv
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Las Vegas
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