Convert Atom (XML) to JSON

Question 1

"Convert XML to JSON" is simple to say, but XML and JSON are different structural paradigms. If your XML document looks like:

<a>
    <b>foo</b>
    <c prop="value">bar</c>
</a>

... how do you represent that in JSON? There are lots of questions, like:

Does ordering matter? (Object properties in JSON are unordered, so after conversion there is no way to tell if <c> came before or after <b>)
If there is only one <b>, does that mean it's a single-item array, or just an object?
How do you represent attributes? Does the convertor flip between plain strings (for "b") and objects with extra properties (for "c") depending on whether attributes are defined?

Each "XML to JSON convertor" I've seen has taken a slightly different approach to this, so there is no "standard" behaviour to rely on.

So, for a complete answer, I think you need to give a clearer idea of what you want your JSON ATOM format to look like.

If you just want something, and you'll work around whatever you get, then you might be able to do this with a service like Yahoo Pipes (example here, I'm sure there are more).

However, you are at the whim of whatever actual convertor is being used behind the scenes, which might have odd behaviours (e.g. one day your source feed adds an attribute, and your output changes dramatically).

Question 2

We found an XSLT here:

http://www.bjelic.net/2012/08/01/coding/convert-xml-to-json-using-xslt/#code

and slightly modified it to handle the links & categories elements of Atom Document to the way we want to show it.

<?xml version="1.0" encoding="UTF-8" ?>
<xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
    <xsl:output method="text" encoding="utf-8"/>

    <xsl:template match="/*[node()]">
        <xsl:text>{</xsl:text>
        <xsl:apply-templates select="." mode="detect" />
        <xsl:text>}</xsl:text>
    </xsl:template>

    <xsl:template match="*" mode="detect">
        <xsl:choose>
            <xsl:when test="name(preceding-sibling::*[1]) = name(current()) and name(following-sibling::*[1]) != name(current())">
                    <xsl:apply-templates select="." mode="obj-content" />
                <xsl:text>]</xsl:text>
                <xsl:if test="count(following-sibling::*[name() != name(current())]) &gt; 0">, </xsl:if>
            </xsl:when>
            <xsl:when test="name(preceding-sibling::*[1]) = name(current())">
                    <xsl:apply-templates select="." mode="obj-content" />
                    <xsl:if test="name(following-sibling::*) = name(current())">, </xsl:if>
            </xsl:when>
            <xsl:when test="following-sibling::*[1][name() = name(current())]">
                <xsl:text>"</xsl:text><xsl:value-of select="name()"/><xsl:text>" : [</xsl:text>
                    <xsl:apply-templates select="." mode="obj-content" /><xsl:text>, </xsl:text>
            </xsl:when>
            <xsl:when test="count(./child::*) > 0 or count(@*) > 0">
                <xsl:text>"</xsl:text><xsl:value-of select="name()"/>" : <xsl:apply-templates select="." mode="obj-content" />
                <xsl:if test="count(following-sibling::*) &gt; 0">, </xsl:if>
            </xsl:when>
            <xsl:when test="count(./child::*) = 0">
                <xsl:text>"</xsl:text><xsl:value-of select="name()"/>" : "<xsl:apply-templates select="."/><xsl:text>"</xsl:text>
                <xsl:if test="count(following-sibling::*) &gt; 0">, </xsl:if>
            </xsl:when>
        </xsl:choose>
    </xsl:template>

    <xsl:template match="*" mode="obj-content">
        <xsl:text>{</xsl:text>
            <xsl:apply-templates select="@*" mode="attr" />
            <xsl:if test="count(@*) &gt; 0 and (count(child::*) &gt; 0 or text())">, </xsl:if>
            <xsl:apply-templates select="./*" mode="detect" />
            <xsl:if test="count(child::*) = 0 and text() and not(@*)">
                <xsl:text>"</xsl:text><xsl:value-of select="name()"/>" : "<xsl:value-of select="text()"/><xsl:text>"</xsl:text>
            </xsl:if>
            <xsl:if test="count(child::*) = 0 and text() and @*">
                <xsl:text>"text" : "</xsl:text><xsl:value-of select="text()"/><xsl:text>"</xsl:text>
            </xsl:if>
        <xsl:text>}</xsl:text>
        <xsl:if test="position() &lt; last()">, </xsl:if>
    </xsl:template>

    <xsl:template match="@*" mode="attr">
        <xsl:text>"</xsl:text><xsl:value-of select="name()"/>" : "<xsl:value-of select="."/><xsl:text>"</xsl:text>
        <xsl:if test="position() &lt; last()">,</xsl:if>
    </xsl:template>

    <xsl:template match="node/@TEXT | text()" name="removeBreaks">
        <xsl:param name="pText" select="normalize-space(.)"/>
        <xsl:choose>
            <xsl:when test="not(contains($pText, '&#xA;'))"><xsl:copy-of select="$pText"/></xsl:when>
            <xsl:otherwise>
                <xsl:value-of select="concat(substring-before($pText, '&#xD;&#xA;'), ' ')"/>
                <xsl:call-template name="removeBreaks">
                    <xsl:with-param name="pText" select="substring-after($pText, '&#xD;&#xA;')"/>
                </xsl:call-template>
            </xsl:otherwise>
        </xsl:choose>
    </xsl:template>

</xsl:stylesheet>

Hope that helps!