[xquery-talk] Recursion or not - how to (re)query an API

[Christian Grün]

Hi Bridger,

I know too little about the API you are working, and your query
processor (parts of the semantics of fn:doc are
implementation-defined), but I noticed that the URL construction might
need to be revised:

OLD:
  local:getPID(doc("$in" || "&sessionToken=" || "$rQ"))

NEW:
  local:getPID(doc($in || "&sessionToken=" || encode-for-uri($rQ)))

Possibly, $in (or a part of it) needs to be encoded as well.

Hope this helps,
Christian



On Mon, Jan 18, 2016 at 5:09 PM, Bridger Dyson-Smith
<bdysonsmith at gmail.com> wrote:
> Hi all,
>
> I'm struggling with getting a working example of the following problem: I'm
> sending a query to an API that returns some data and, if the data set is
> large enough, a resumption token to requery the API.
>
> I'm stuck at the point of how to generate the new query URL, while still
> processing the new data. Is the best idea to create a function that will
> update a new request to the API, or is there a different approach that can
> be used?
>
> I've made several attempts with functions -- the latest non-working examples
> are below -- and I'm missing... something, but I don't know what.
>
> Thanks for any guidance you can provide.
> Cheers,
> Bridger
>
> (: sample query :)
> (:
> http://server:8080/fedora/objects?query=pid~{$collection}*&resultFormat=xml&pid=true
> :)
>
> declare variable $query external :=
> 'http://our.server:8080/fedora/objects?query=pid~gamble*&resultFormat=xml&pid=true';
> declare variable $sessionToken := '&sessionToken=';
> declare variable $resToken := '';
>
> (:functions:)
> (:doesn't work:)
> declare function local:getPID($in as document-node()) as xs:anyAtomicType*
> {
>   data($in/*:resultList/*:objectFields/*:pid)
> };
>
> (:doesn't work:)
> declare function local:reQuery(
>   $in as document-node(),
>   $rQ as xs:untypedAtomic*) as document-node()
> {
>   let $rQ := $in/*:listSession/*:token/text()
>   return (
>     if ($rQ) then
>       local:getPID(doc("$in" || "&sessionToken=" || "$rQ"))
>     else ()
>   )
> };
>
> (: this works processing the descendant elements but doesn't recurse :)
> for $result in fn:doc($query)/*:result
> let $resToken := $result/*:listSession/*:token/text()
> let $pid := $result/*:resultList/*:objectFields/*:pid/text()
> return (
>   $result,
>   $resToken,
>   $pid
> )
>
> (: sample returned from query; e.g. $result :)
> <result xmlns="http://www.fedora.info/definitions/1/0/types/"
> xmlns:types="http://www.fedora.info/definitions/1/0/types/"
> xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
> xsi:schemaLocation="http://www.fedora.info/definitions/1/0/types/
> http://localhost:8080/fedora/schema/findObjects.xsd">
>   <listSession>
>     <token>63c0762b5eb3d4b46c58add843b7b3e6</token>
>     <cursor>0</cursor>
>     <expirationDate>2016-01-18T01:40:05.381Z</expirationDate>
>   </listSession>
>   <resultList>
>     <objectFields>
>       <pid>gamble:1</pid>
>     </objectFields>
>     <objectFields>
>       <pid>gamble:10</pid>
>     </objectFields>
>   </resultList>
> </result>
>
>
>
>
>
>
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