diff -r d97eda8bc8ec -r 821253d361d1 server/src/app/Services/BnfResolver.php
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/server/src/app/Services/BnfResolver.php	Thu Feb 25 21:26:15 2016 +0100
@@ -0,0 +1,109 @@
+<?php
+namespace CorpusParole\Services;
+
+use Cache;
+use CorpusParole\Services\BnfResolverInterface;
+
+class BnfResolver implements BnfResolverInterface {
+
+    public function __construct($sparqlClient) {
+        $this->sparqlClient = $sparqlClient;
+    }
+
+    private function checkBnfId($id) {
+        $bnfid = $id;
+
+        if(strpos($id, config('corpusparole.bnf_ark_base_url')) === 0) {
+            $bnfid = config('corpusparole.bnf_base_url').substr($id, strlen(config('corpusparole.bnf_ark_base_url')));
+        }
+        elseif(strpos($id, config('corpusparole.bnf_base_url')) !== 0) {
+            $bnfid = config('corpusparole.bnf_base_url').$id;
+        }
+        $bnfid = rtrim($bnfid, '/');
+        if(preg_match("/^".preg_quote(config('corpusparole.bnf_base_url'),"/")."ark\:\/12148\/[[:alnum:]]/", $bnfid) !== 1) {
+            throw new BnfResolverException("the provided id \"$id\" is not a BNF id");
+        }
+        return $bnfid;
+    }
+
+    /**
+     * Get label from BNF id
+     * @param string $id The id to resolve. Can be an url starting with http://data.bnf.fr/ or http://ark.bnf.fr/
+     * @return a string with the name
+     */
+    public function getLabel($id) {
+        $res = $this->getlabels([$id,]);
+        assert(array_key_exists($id,$res), "the result must contains $id");
+        return $res[$id];
+    }
+
+    /**
+     * Get a list of names from an array of viaf ids.
+     * @param array $ids The array of ids to resolve.
+     *                   Each id can be an url starting with http://data.bnf.fr/ or http://ark.bnf.fr/
+     */
+    public function getLabels(array $ids) {
+
+        if(count($ids) > config('corpusparole.bnf_max_ids')) {
+            throw new BnfResolverException("Too manys ids provided");
+        }
+
+        $bnfids = array_map([$this, 'checkBnfId'], $ids);
+        $bnfidsMap = array_combine($bnfids, $ids);
+
+        $results = [];
+        $missingBnfids = [];
+
+        foreach ($bnfidsMap as $bnfid => $bnfidSource) {
+            $cachedValue = Cache::get("bnf:$bnfid");
+            if(is_null($cachedValue)) {
+                array_push($missingBnfids, $bnfid);
+            } else {
+                $results[$bnfidSource] = $cachedValue;
+            }
+        }
+
+        if(count($missingBnfids) == 0) {
+            return $results;
+        }
+
+        $query = "SELECT ?s ?o WHERE {";
+        foreach ($missingBnfids as $index => $bid) {
+            if($index > 0) {
+                $query .= " UNION ";
+            }
+            $query .= "{ <$bid> <http://www.w3.org/2004/02/skos/core#prefLabel> ?o. ?s <http://www.w3.org/2004/02/skos/core#prefLabel> ?o. FILTER(?s = <$bid> && lang(?o) = \"fr\")}";
+        }
+        $query .= "}";
+
+        $docs = $this->sparqlClient->query($query);
+
+        $resultsRaw = [];
+
+        foreach ($docs as $doc) {
+            $bnfid = $doc->s->getUri();
+            $bnflabel = $doc->o;
+
+            $value = $bnflabel->getValue();
+
+            if(!empty($value)) {
+                $resultsRaw[$bnfid] = $bnflabel;
+            }
+        }
+
+        foreach ($missingBnfids as $bnfid) {
+            $bnfidSource = $bnfidsMap[$bnfid];
+            $missingValue = (array_key_exists($bnfid,$resultsRaw) && $resultsRaw[$bnfid])?mb_strtolower($resultsRaw[$bnfid]->getValue()):"";
+            if (mb_strlen($missingValue)>0) {
+                Cache::put("bnf:$bnfid", $missingValue, config('corpusparole.bnf_cache_expiration'));
+                $results[$bnfidSource] = $missingValue;
+            }
+            else {
+                $results[$bnfidSource] = null;
+            }
+        }
+
+        return $results;
+    }
+
+}