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One of the greatest things about the internet is the wealth of free
information and content available. Their are thousands of websites that
allow you to use content from their websites and databases - and display it on
yours. Some examples of this are stock quotes, Weather data, News stories,
Search engine results, Auction listings, etc - the list goes on and on.
Another important aspect of the internet are application service providers, some
examples of these services could include CRM's (customer relationship
management), Info sharing, sales tracking, e-business, Human resource's, desktop
applications, etc - the list again goes on and on.
What do all of these have in Common? - All this data and all these services
are not accessible directly by your Flash Movie. What if you wanted to
include constantly changing and updated weather reports from noaa - or
stock quotes from Yahoo financial - or News feeds from Moreover - or send a new
Lead to a CRM service - or send payment information to Authorize.net for
processing - or send and retrieve data from a database not located on your
server. Well this tutorial goes into one method which allows you to do all
of this in Flash - with the User Never leaving your Site!
Macromedia suggests two solutions or work arounds to this security feature,
the first one is Proxy scripting the second involves DNS aliasing. This
article/tutorial will go over two examples of Proxy Scripting and how it can be
used to create a more diverse and changing Flash movie/experience. I also put together an
example of a search engine for a visual example of what this is all about.
The search engine is based on Yahoo, but with the results
of the search
query sent from and displayed in Flash (included in the download) - For a
working version/example of the search engine visit - http://www.flash-db.com/Search/.
This is just one of many useful applications of this article. Their is
also an example of using this method with moreover news at www.flash-db.com/News/.
This tutorial is not for everyone and it will not be possible for everyone to
use this. 1) Since a server side script is needed, this script must
be run on a server. 2) Some servers do not allow outgoing
connections, if your server has this restriction then it will not be possible to
run this script. (Some free and really large inexpensive commercial
hosting companies will have this restriction due to their firewall settings). 3)
These scripts are not needed with Stand-Alone (exe) flash presentations - this
is only needed for SWF files embedded in a Browser on the internet.
Overview
First it's necessary to define two types of Data/Content that we will be
accessing. 1) Static - this involves web pages that are not changing and
are not based on information (query terms) that are passed to them. Examples
of this would be Text files, HTML pages, and XML content - that
reside on a server/domain outside of your own. 2) Dynamic - this
involves web pages, database's, and other scripts that look up or perform
queries based on the information you send to them.
Static: Loading static content/data from other servers is easier
then loading dynamic content. This is because you will not have to build a
request method such as "GET" or "POST". This is
just fetching or grabbing static content from else where on the web and bringing
it back to your flash movie. An
example. If you wanted to you could also return Images, SWF's, mp3's,
movies etc with this method - although since LoadMovie does not have this
restriction their would be no sense in doing this with these types of files.
Dynamic: Dynamic content/data requires that a request be sent
via "GET" or "POST". Then depending on the Data you
send the page - it reacts and produces results based on your request Data.
A good example of this is sending a Search engine a Search Term. If you
wanted to search Google for "Flash" you would have to tell it to
search for "Flash".
Another example would be if you wanted to add a Sales Lead to a service that
tracks this information for you. Or if you wanted to send Credit card info
to a credit card transaction processor. Or maybe add information to a
database on a different server. Basically any time you have to send
information to get information in return.
Tying it together: Basic Flow of data: From
Flash -> to the Script -> To the external source -> Back to the script
-> Back to Flash. The hardest part of all of this (because most data is
not returned in nicely formatted XML) is parsing and formatting the data that is
returned from the external source to a format Flash can easily display. Easy
returned formats to work with include CSV (comma seperated values) TSV (Tab
seperated values) - and of course XML (which does not require any parsing since
Flash can already read XML). A lot of times you'll have to work
with complex HTML stuff coming back which is the hardest to format and parse for
use in Flash. This is
the real art behind all of this.
Thoughts: Macromedia added this security restriction (external
data is not accessible) because Flash can Loop and no user action is needed to
send out a request via "GET" or "POST". So at first
you might think "Big deal" - but if you look at this further and keep
in mind past DOS (denial of service) attacks, you'll see that Macromedia was
right by adding this security feature and did so with good reason. What if
someone put up hundreds/thousands of really simple Flash movies all over on free web
servers that sent out hundreds/thousands/millions of requests to someone's
database or site every second. This could become a problem and
reduce the performance (or crash) the website that was being targeted.
(This last paragraph is just an thought - and may or may not be plausible).
Jeffrey Hill is a freelance web developer from Boulder, Colorado. He specializes in creating and developing dynamic database driven Flash content, applications, and content management systems. Specialty's include SQL, PHP, Perl, and XML.
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Proxy Scripting in Flash - Loading External Data
