[OpenLayers-Users] Questions on using Protocol.HTTP and custom XML to load/edit features

[Stephen Woodbridge]

OK, to partially answer some of my own questions ... inline below.

Stephen Woodbridge wrote:
> Hi all,
> 
> I am trying to implement a vector layer that will allow editing point 
> data. The data is accessed via a PHP script that serves some arbitrary 
> XML. The layer looks like this so far:
> 
>              vector = new OpenLayers.Layer.Vector("POI", {
>                  maxResolution: 360.0/16777216/2, // zoom 15
>                  styleMap: styleMap,
>                  protocol: new OpenLayers.Protocol.HTTP({
>                      url: "poi-server.php",
>                      params: {
>                          m: 'r',
>                          srs: 'EPSG:4326'
>                      },
>                      format: new OpenLayers.Format.XML()
>                  }),
>                  strategies: [
>                      new OpenLayers.Strategy.BBOX({ratio: 1}),
>                      new OpenLayers.Strategy.Save({
>                          auto: true//,
>                          //save: function() { alert("Save called."); }
>                      }),
>                  ]
>              });
> 
> This seems like it almost works. But has the following problems, so 
> maybe I'm just taking the wrong approach all together. Here is a live 
> example:
> 
> http://imaptools.com:8080/tilecache/test.html?zoom=17&lat=33.89595&lon=35.49935&layers=BT
> 
> Issue:
> 
> 1) the feature request does not seem to load on page load, but fires if 
> you pan the map slightly
> 
> 2) when the features load, I get an error on line 128 of 
> OpenLayers/Format/XML.js because test.indexOf() is not a method. This is 
> because text is type Document not string?

This appears to be because I need to write my own class like 
OpenLayers.Format.MyXML that parses the XML document the PHP returns and 
  returns an array of features. Working on writing this.

> 3) I assume the the XML parser will parse the response into an 
> appropriate tree object, then I need to add some code that reads the 
> tree and constructs feature objects that I then add to the layer. So is 
> the problem above because the text object passed to read IS my tree and 
> I need to pass a my own read() function to some code to do that? Where 
> do I do that?

See 2) above.

> 4) If I add a point using the toolbar add point button, I get
> 
> Security error"  code: "1000
> http://imaptools.com:8080/ol28/lib/OpenLayers/Format/XML.js
> Line 198
> 
> data = serializer.serializeToString(node);
> 
> What is this error and why am I getting it? I assumed that a default 
> serializer exists, I probably need to add my own it write the expected 
> XML the the PHP needs. Where would I add this and what are the exected 
> inputs and outputs?

I'm hoping this is probably related to the above. will report back after 
I get my XML parser working.

> 5) I eventually need to issue the Ajax requests by sending XML documents 
> to the server instead of issuing GET requests. So to do this I assume I 
> need to a) write code to serialize some params into a document, then b) 
> get HTTP protocol to send the document. How do I do this? The PHP code 
> is only temporary for testing and developing in my environment.
> 
> I learned a lot today, just by reading lots of OL code but I still have 
> a ways to go.
> 
> I would appreciate and help and guidance.

Any thoughts on 1) or 5)? Just a pointer would be helpful :)

Perseverance pays off,
   -Steve

> Thanks,
>    -Steve
> _______________________________________________
> Users mailing list
> Users at openlayers.org
> http://openlayers.org/mailman/listinfo/users