It turns out, the presence of heavily namespaced xml in this makes the prior answer a bit harder to munge to xml. Normally you could just call xml/emit-str on the returned element and get a formatted xml string back, but since namespaces are involved (they show up in the xml element for the entry under the map #:m{:type …} which translates to {:m/type …} where data.xml doesn’t know what alias the namespace m refers to) if you want to preserve the exact xml from the input, you need to include these aliases or bake the namespaces into the keywords in the xml element. So xml/emit-str (under data.xml 0.0.8) will complain about not knowing what alias ‘m’ means in that context. You can still trivially munge the data, you just have unknown namespace aliases that have to be provided (for every one) when you emit the xml, and data.xml v 0.0.8 doesn’t support namespaces directly (although the underlying java reader/writer does).
user=> (-> xs latest-entry second xml/emit-str)
Execution error (StreamExceptionBase) at com.fasterxml.aalto.out.StreamWriterBase/throwOutputError (StreamWriterBase.java:1662).
Unbound namespace URI 'm'
We can do one of two things: walk the xml tree and coerce all qualified (e.g. namespaced) tags to unqualified tags, which should avoid any namespacing altogether (at the expense of changing the output, e.g. eliding m: xmlns stuff) which may or may not matter, or we can upgrade to the 0.2.0-alpha which supports xmlns directly.
Using 0.2.0-alpha violates a few assumptions since the namespacing is accomplished again by qualified keywords, except this time they are fully baked into the tag:
{:tag :entry ...} ;;v 0.0.8
{:tag :xmlns.http%3A%2F%2Fwww.w3.org%2F2005%2FAtom/entry ...} ;;v 0.2.0-alpha
So we need to change tag? accordingly to compare the namespace keywords with the submitted unqualified tag:
(defn tag? [k]
(fn [e]
(when
(and (not (string? e)) ;;data.xml 0.2.0 pulls in a bunch of \n strings now.
(= (name (:tag e)) (name k)))
e)))
An added surprise in 0.2.0-alpha, is that content may now return space items directly, so we get values like “\n” where before we had xml nodes. So we define a function to help querying instead of using the raw :content key:
(defn child-elements [xs]
(->> xs :content (filter #(instance? clojure.data.xml.node.Element %))))
and update the other functions to use it:
(defn entries [xs]
(->> xs child-elements (filter (tag? :entry))))
(defn entry->date [e]
(some->> e
child-elements
(some (tag? :content))
child-elements
first
child-elements
(some (tag? :NEW_DATE))
:content
first
clojure.instant/read-instant-date))
For completeness, the other functions don’t change but here they are, with an added function to get an xml string:
(defn ordered-entries [root]
(->> (for [e (entries root)]
[(entry->date e) e])
(sort-by first)))
(defn latest-entry [root]
(->> root ordered-entries last))
(defn latest-entry-xml [root]
(->> root latest-entry second xml/emit-str))
(def xs
(->> url
slurp
xml/parse-str))
user=> (latest-entry-xml xs)
"<?xml version='1.0' encoding='UTF-8'?><entry xmlns:d=\"http://schemas.microsoft.com/ado/2007/08/dataservices\" xmlns:m=\"http://schemas.microsoft.com/ado/2007/08/dataservices/metadata\" xmlns=\"http://www.w3.org/2005/Atom\">\n<title type=\"text\"/>\n<updated>2022-11-15T15:54:28Z</updated>\n<author><name/></author>\n<category term=\"TreasuryDataWarehouseModel.DailyTreasuryYieldCurveRateDatum\" scheme=\"http://schemas.microsoft.com/ado/2007/08/dataservices/scheme\"/>\n<content type=\"application/xml\">\n<m:properties>\n<d:NEW_DATE m:type=\"Edm.DateTime\">2022-11-15T00:00:00</d:NEW_DATE>\n<d:BC_1MONTH m:type=\"Edm.Double\">3.77</d:BC_1MONTH>\n<d:BC_2MONTH m:type=\"Edm.Double\">4.10</d:BC_2MONTH>\n<d:BC_3MONTH m:type=\"Edm.Double\">4.31</d:BC_3MONTH>\n<d:BC_4MONTH m:type=\"Edm.Double\">4.40</d:BC_4MONTH>\n<d:BC_6MONTH m:type=\"Edm.Double\">4.54</d:BC_6MONTH>\n<d:BC_1YEAR m:type=\"Edm.Double\">4.60</d:BC_1YEAR>\n<d:BC_2YEAR m:type=\"Edm.Double\">4.37</d:BC_2YEAR>\n<d:BC_3YEAR m:type=\"Edm.Double\">4.17</d:BC_3YEAR>\n<d:BC_5YEAR m:type=\"Edm.Double\">3.93</d:BC_5YEAR>\n<d:BC_7YEAR m:type=\"Edm.Double\">3.88</d:BC_7YEAR>\n<d:BC_10YEAR m:type=\"Edm.Double\">3.80</d:BC_10YEAR>\n<d:BC_20YEAR m:type=\"Edm.Double\">4.20</d:BC_20YEAR>\n<d:BC_30YEAR m:type=\"Edm.Double\">3.98</d:BC_30YEAR>\n<d:BC_30YEARDISPLAY m:type=\"Edm.Double\">3.98</d:BC_30YEARDISPLAY>\n</m:properties>\n</content>\n</entry>"
