DIGG IT! HTTPService is a very powerful tag in MXML. I overlooked it for a while until I found some tricks to using it. Here is my list:&
1. HTTPService processes the data returned.
If you load XML using HTTPService, by default it will return an object heirachy even when useProxy='false'. Once the data had returned you can use dot notation to retrieve nodes by name.
myXMLService.result.frog.dog.blog
A handy use of this is to set dataProviders directly. Using any List based control, you can set the dataProvider from an XML file. This is super handy given with one HTTPService XML request and setting one variable you can add complex data into a control.
Warning: There is a gotcha in here. When XML is parsed to Object, similar node names at the same level are turned into an array. To access nodes of a common name you use name[1]. The problem is that names do not become nested unless there is more than one. If you set dataProvider values this way, when 1 element is set, it will mess-up. Although you can filter for this using the length property, it will be undefined when there is only 1 node.
There are some other formats supported but I have yet to explore them. You can set the HTTPService.resultFormat property to either "object" (the default!), "xml" , "flashvars" or "text". Depending on what your doing these can be very useful.
2. Use Databinding with the URL property.
This one is really handy and can dynamically generate GET URLS for you based on local variables.
<mx:HTTPService id="documentService" useProxy="false" url="{ 'http://server/' + docPath + '/data.xml' }" result="documentData=documentService.result" />
This defines the documentService. When documentService.send() is called, the URL is calculated based on the current value of docPath and the request is made. When data returns, the returned object is saved to the variable 'documentData'.
In using this, I would do this a ton:
docPath = "frog/dog"
documentService.send()
3. Caching data between requests.
<mx:HTTPService id="documentService" useProxy="false" url="{ 'http://server/document.cfm?id='+ docID }" result="documentCache[docID]=documentService.result;documentServiceResult()" />
In this case, I use a variable called docID to vary the data returned from the HTTPService. With each request, I save a local copy according to the docID value. When calling this I use the following code:
if( documentCache[docID] == undefined or ){
documentService.send()
}else{
documentServiceResult()
}
Instead of retrieving the data every time from the server, this only fetches the data once and caches it inside the player locally. Subsequent requests are pulled form the local cache.
4. useProxy='false'
This is a big deal since it allows Flash to use the players security model for loading data from another server. Just add a crossdomain.xml security file to the root of all servers you want to access and you can exchange data with another domain. Here is a sample crossdomain.xml file:
http://www.macromedia.com/crossdomain.xml
http://www.yahoo.com/crossdomain.xml
As I dig deeper into the practical side of Flex development, I will post some more.
Using these you can exchange data with the best of them!
Cheers,
ted ;)
where have you declared the object "documentData" ?
I didn't post the full code, just snips. Sorry for the exclusion.
In an mx:Script element, do this:
var documentData:Object = {}
And for 'documentCache' do this:
var documentCache:Object = {}
Cheers,
ted ;)
For point number one you can avoid this by always using mx.utils.ArrayUtil.toArray when passing an httpservice result as a dataProvider.
Is it possible to access http session from HTTPService on the server side?Can someone please help me on how to do this?
How would you pass some search criteria in httpservice to a jsp page or alike script that is on a servlet
To handle situations with only one result I used the following code in the ResultEvent handler:
if (event.result.items.item is ArrayCollection) searchResults = event.result.items.item;
else if (event.result.items.item) searchResults = new ArrayCollection([event.result.items.item]);
if (searchResults)
{
/* handle search result */
}
Is there a shorter/better way to do this?
How much data can I cache? Is it the 100k restriction from the Flash plugin?
Pat
Damn - you just made me want to kick myself. The caching is just brilliant.
Hi,
i have a problem set a variable in the url tec of the httpservice like this:
public var foo:String = "http://__domain.de";
mx:HTTPService id="getNav" result="create_nav(event)" method="POST" url="{Application.application.foo}/airInfo/modules.air.php" useProxy="false"
I always get the error that i have to set the url but it is set.
I donīt understand this. The variable in a label is working but not in the url of the httpservice
now it works.
i have the wrong syntax
url="{Application.application.foo + '/airInfo/modules.air.php'}"
Any reason for flex transform nodes that contain for example 1.0, 2.0 in strings? i'm struggling myself to find out how to tell flex to not transform the data in integer because it's suppose to be a string.
What should i do?! :P
Can you please help me for the problem described here ?
http://board.flashkit.com/board/showthread.php?t=772909
Thanks
I have a question :
You Said "If you load XML using HTTPService, by default it will return an object heirachy even when useProxy='false'. Once the data had returned you can use dot notation to retrieve nodes by name."
Is there a way by which we can understand that the data is returned ? In most of the cases , I have noticed that if on line 10 i write httpserv.send(); and on line 11 i write mytxt.text=httpserv.lastresult.node.child[1]
Than usually the pointer at line 11 moves away before the data is returned from the httpserv
please help me ASAP, I've already ruined two days to fix this problem but no luck yet :s
i have many HTTPService objects in my app and I`m using them to retrieve data from aspx pages. this is ok locally and i used crossdomain.xml to make it work on the net. But some HTTPService objects delay the data or do not return it in some cases. can you help me please? lejdikoci-@-yahoo.com.
(remove minuses)