XMLStarlet 和 RSS

本文介绍了XMLStarlet 和 RSS的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！

问题描述

我似乎无法通过 xmlstarlet 获得这个基本的 xslt 查询.

I can't seem to get this basic xslt query working via xmlstarlet.

我确定我遗漏了一些明显的东西，但对于我的一生，我无法弄清楚这个语法，所以请有人照亮我.

I'm sure I'm missing something obvious, but for the life of me I cannot figure out this syntax, so someone please illuminate me.

XML Starlet 命令:

XML Starlet Command:

xml sel -t -m "//rdf:RDF/item" -v link -v description -v link ./sss.rdf

sss.rdf:

<?xml version="1.0" encoding="UTF-8"?>
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns="http://purl.org/rss/1.0/" xmlns:admin="http://webns.net/mvcb/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:ev="http://purl.org/rss/1.0/modules/event/" xmlns:syn="http://purl.org/rss/1.0/modules/syndication/" xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/">
    <channel rdf:about="http://baltimore.craigslist.org/search/sss?catAbb=sss&amp;amp;format=rss&amp;amp;maxAsk=150&amp;amp;minAsk=50&amp;amp;query=ipod%20touch%205g&amp;amp;srchType=A">
        <title>craigslist baltimore | all for sale / wanted search "ipod touch 5g"</title>
        <link>http://baltimore.craigslist.org/search/sss?catAbb=sss&amp;amp;maxAsk=150&amp;amp;minAsk=50&amp;amp;query=ipod%20touch%205g&amp;amp;srchType=A</link>
        <description />
        <dc:language>en-us</dc:language>
        <dc:rights>&amp;copy; 2013 craigslist</dc:rights>
        <dc:publisher>[email protected]</dc:publisher>
        <dc:creator>[email protected]</dc:creator>
        <dc:source>http://baltimore.craigslist.org/search/sss?catAbb=sss&amp;amp;format=rss&amp;amp;maxAsk=150&amp;amp;minAsk=50&amp;amp;query=ipod%20touch%205g&amp;amp;srchType=A</dc:source>
        <dc:title>craigslist baltimore | all for sale / wanted search "ipod touch 5g"</dc:title>
        <dc:type>Collection</dc:type>
        <syn:updateBase>2013-09-20T09:23:41-07:00</syn:updateBase>
        <syn:updateFrequency>1</syn:updateFrequency>
        <syn:updatePeriod>hourly</syn:updatePeriod>
        <items>
            <rdf:Seq>
                <rdf:li rdf:resource="http://baltimore.craigslist.org/ele/4039527375.html" />
            </rdf:Seq>
        </items>
    </channel>
    <item rdf:about="http://baltimore.craigslist.org/ele/4039527375.html">
        <title><![CDATA[Unlocked Optimus Lg Phone (Baltimore) $150]]></title>
        <link>http://baltimore.craigslist.org/ele/4039527375.html</link>
        <description>OR WE CAN HAVE A SWAP FOR AN IPOD TOUCH 5g<![CDATA[
&#9679;Optimus Lg Phone For Sale At 150.00 The Original Price Was $180.00
&#9679;It Does Not Include The Charger, But You Can Find It At Walmart For $4.00
&#9679;The Phone Was Only Used For 2-3 Months
&# [...]]]></description>
        <dc:date>2013-09-01T10:14:06-07:00</dc:date>
        <dc:language>en-us</dc:language>
        <dc:rights>&amp;copy; 2013 craigslist</dc:rights>
        <dc:source>http://baltimore.craigslist.org/ele/4039527375.html</dc:source>
        <dc:title><![CDATA[Unlocked Optimus Lg Phone (Baltimore) $150]]></dc:title>
        <dc:type>text</dc:type>
        <dcterms:issued>2013-09-01T10:14:06-07:00</dcterms:issued>
    </item>
</rdf:RDF>

我想要的输出:

Unlocked Optimus Lg Phone (Baltimore) $150
OR WE CAN HAVE A SWAP FOR AN IPOD TOUCH 5g
    &#9679;Optimus Lg Phone For Sale At 150.00 The Original Price Was $180.00
    &#9679;It Does Not Include The Charger, But You Can Find It At Walmart For $4.00
    &#9679;The Phone Was Only Used For 2-3 Months
    &# [...]
http://baltimore.craigslist.org/ele/4039527375.html

推荐答案

这个 XmlStarlet 命令:

xml sel -N purl="http://purl.org/rss/1.0/" -t -m "//rdf:RDF/purl:item" -v purl:title -n -v purl:description -n -v purl:link -n ./sss.rdf

产生所需的输出:

Unlocked Optimus Lg Phone (Baltimore) $150
OR WE CAN HAVE A SWAP FOR AN IPOD TOUCH 5g
&amp;#9679;Optimus Lg Phone For Sale At 150.00 The Original Price Was $180.00
&amp;#9679;It Does Not Include The Charger, But You Can Find It At Walmart For $4.00
&amp;#9679;The Phone Was Only Used For 2-3 Months
&amp;# [...]
http://baltimore.craigslist.org/ele/4039527375.html

说明:

关键是要注意输入文档有一个默认的命名空间，这会导致item、title、description和链接 位于 http://purl.org/rss/1.0/ 命名空间中.定义 -N purl="http://purl.org/rss/1.0/" 允许我们在 XPath 中指定这些元素时使用 purl 前缀.如果没有 purl 命名空间前缀，XPath 将不匹配.

The key is to notice that the input document has a default namespace, which causes item, title, description, and link to be in the http://purl.org/rss/1.0/ namespace. Defining -N purl="http://purl.org/rss/1.0/" allows us to use the purl prefix when specifying these elements in the XPaths. Without the purl namespace prefixes, the XPaths weren't matching.

这篇关于XMLStarlet 和 RSS的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！