xml - 使用clj-xpath在带有任意标签的clojure中解析xml

Question

我正在尝试使用 clj-xpath 解析一些 xml，基本上我想制作一个看起来像这样的函数

(map
         (fn [item]
           {:title ($x:text "./title" item)
            :url  ($x:text "./url" item)})
         (take 5
               ($x "/search/events/event" (xmldoc))))

但是带有任意标签。 到目前为止，我有这个

ns mashup-dsl.datamodel
(:use
    [clj-xpath.core])
(def data-url "http://api.eventful.com/rest/events/search?  app_key=4H4Vff4PdrTGp3vV&keywords=music&location=Belgrade&date=Future")

(def events-xml
 (fn [] (slurp data-url)))

(def xmldoc
  (fn [] (xml->doc (events-xml))))

(def item (take 5 ($x "/search/events/event" (xmldoc))))

(defn create-xpath [tag] (str "./" tag))

(def tags ["title" "url"])

(defn parse [item]
    (doseq [tag tags])(into {} (keyword tag) ($x:text (create-xpath tag) item)))

但我收到此错误，TransformerException Extra illegal tokens: '$', 'tag', '@', '64516c52' org.apache.xpath.compiler.XPathParser.error (XPathParser.java:610)。所以问题出在解析函数中。有什么想法吗？

Answer 1

以下是提取前 5 个标题的方法:

user=> (map #($x:text "./title" %) (take 5 ($x "//event" (xmldoc))))
("9th International Belgrade Early Music Festival" "Belgrade Baroque Academy, Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'Incoronazione di Poppea\"" "Belgrade Baroque Academy, Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'Incoronazione di Poppea\"" "ICTM Study Group on Music and Dance in Southeastern Europe Conference" "New Belgrade Opera, Madlenianum Opera-Theatre, New Trinity Baroque; Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'incoronazione di Poppea\"")

您的示例 doseq 未正确关闭，您需要编译表达式以针对 xml->doc 结果使用。

您可以创建一个辅助函数，该函数将返回函数以从标签中提取文本:

(defn tag-fn [tag] (partial $x:text tag))

现在，您可以为“title”和“url”生成函数:

user=> (tag-fn "title")
#<core$partial$fn__4190 clojure.core$partial$fn__4190@71cc2b7a>

和

user=> (map (tag-fn "title") (take 5 ($x "//event" (xmldoc))))
("9th International Belgrade Early Music Festival" "Belgrade Baroque Academy, Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'Incoronazione di Poppea\"" "Belgrade Baroque Academy, Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'Incoronazione di Poppea\"" "ICTM Study Group on Music and Dance in Southeastern Europe Conference" "New Belgrade Opera, Madlenianum Opera-Theatre, New Trinity Baroque; Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'incoronazione di Poppea\"")

或网址和标题:

user=> (map (juxt (tag-fn "url") (tag-fn "title")) (take 2 ($x "//event" (xmldoc))))
(["http://eventful.com/belgrade/events/9th-international-belgrade-/E0-001-064654999-7@2014061420?utm_source=apis&utm_medium=apim&utm_campaign=apic" "9th International Belgrade Early Music Festival"] ["http://eventful.com/belgrade/events/belgrade-baroque-academy-mijanovic-gosta-9th-belg-/E0-001-059734872-8?utm_source=apis&utm_medium=apim&utm_campaign=apic" "Belgrade Baroque Academy, Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'Incoronazione di Poppea\""])

或者 url 和 title:

user=> (map (apply juxt (map tag-fn ["url" "title"])) (take 2 ($x "//event" (xmldoc))))
(["http://eventful.com/belgrade/events/9th-international-belgrade-/E0-001-064654999-7@2014061420?utm_source=apis&utm_medium=apim&utm_campaign=apic" "9th International Belgrade Early Music Festival"] ["http://eventful.com/belgrade/events/belgrade-baroque-academy-mijanovic-gosta-9th-belg-/E0-001-059734871-9?utm_source=apis&utm_medium=apim&utm_campaign=apic" "Belgrade Baroque Academy, Mijanovic, Gosta / 9th Belgrade Early Music Festival / Monteverdi: \"L'Incoronazione di Poppea\""])