What is the way to parse XML in a Worklight Adapte

问题:

In a notification Worklight adapter - I invoke the adapter passing a very long XML string from the backend service.

The backend service cannot be altered or changed.

I want to be able to turn the javascript String object into something I can parse and use useful functions on such as :

var custNum = doc.getElementsByTagName("data:custNum")[0];

However all attempts so far at creating the 'doc' variable have failed. Standard DOMParser and window methods are undefined and out of scope in adapters. I would rather not resort to lengthy string splitting to find my nodes!

Many thanks

回答1:

Set returnedContentType: "xml". This will force WL platform to parse XML for you automatically and convert it to JSON you can manipulate.

E.g.

<a>
  <b>
     c
  </b>
</a>

Will be converted to

{"a": 
     {"b":"c"}
}

so you can get values with syntax like response.a.b

回答2:

You should use XSL Transformation Filtering to get rid of all unneeded data from the XML.
Something like this should be your adapter JavaScript function:

function getFeedsFiltered() {

    var input = {
        method : 'get',
        returnedContentType : 'xml',
        path : "rss.xml",
        transformation : {
            type : 'xslFile',
            xslFile : 'filtered.xsl'
        }
    };

    return WL.Server.invokeHttp(input);
}

and something like this should be in your XSL file

<xsl:stylesheet version="1.0"
                xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
                xmlns:h="http://www.w3.org/1999/xhtml"
                xmlns:dc="http://purl.org/dc/elements/1.1/" >
    <xsl:output method="text"/>

    <xsl:template match="/">
        {
            'Items': [
                <xsl:for-each select="//item">
                    {
                        'title': '<xsl:value-of select="title"/>',
                        'creator': '<xsl:value-of select="dc:creator"/>',
                        'link': '<xsl:value-of select="link"/>',
                        'pubDate': '<xsl:value-of select="pubDate"/>'
                    },
                </xsl:for-each>
            ]
        }
    </xsl:template>

</xsl:stylesheet>

Please check Getting started with IBM Worklight (http://www.ibm.com/developerworks/mobile/worklight/getting-started.html) module 5.2 - Creating HTTP Adapters(ftp://public.dhe.ibm.com/software/mobile-solutions/worklight/docs/v505/Module_05_2_-_Creating_HTTP_Adapters.pdf) and its exercise and code sample(ftp://public.dhe.ibm.com/software/mobile-solutions/worklight/docs/v505/module_05_2_HTTP_Adapter.zip).

回答3:

In the end I wrote a function like this :

function findNode(node,string){

    var nodeEnd = node.slice(0, 1) + "/" + node.slice(1);
    var chunk = string.split(node)[1];
    var chunk2 = chunk.split(nodeEnd)[0];

    return chunk2;

}

Which I use - nice and simple.