diff --git a/src/cache/CacheData.php b/src/cache/CacheData.php
new file mode 100644
index 0000000..5ce5b83
--- /dev/null
+++ b/src/cache/CacheData.php
@@ -0,0 +1,46 @@
+<?php
+namespace nulib\cache;
+
+use nulib\cl;
+use nulib\php\func;
+use Traversable;
+
+/**
+ * Interface CacheData: gestion d'une donnée mise en cache
+ */
+abstract class CacheData {
+  function __construct(?string $name, $compute) {
+    $this->name = $name ?? "";
+    $this->compute = func::withn($compute ?? static::COMPUTE);
+  }
+
+  protected string $name;
+
+  function getName() : string {
+    return $this->name;
+  }
+
+  protected ?func $compute;
+
+  /** calculer la donnée */
+  function compute() {
+    $compute = $this->compute;
+    $data = $compute !== null? $compute->invoke(): null;
+    return $data;
+  }
+
+  /** spécifier le chemin du cache à partir du fichier de base */
+  abstract function setDatafile(?string $basefile): void;
+
+  /** indiquer si le cache existe */
+  abstract function exists(): bool;
+
+  /** charger la donnée depuis le cache */
+  abstract function load();
+
+  /** sauvegarder la donnée dans le cache et la retourner */
+  abstract function save($data);
+
+  /** supprimer le cache */
+  abstract function delete();
+}
diff --git a/src/cache/CacheFile.php b/src/cache/CacheFile.php
index 01ea78a..f40ed80 100644
--- a/src/cache/CacheFile.php
+++ b/src/cache/CacheFile.php
@@ -22,21 +22,21 @@ class CacheFile extends SharedFile {
     else return new static($file, $data);
   }
 
-  protected static function ensure_source($data, ?IDataCache &$source, bool $allowArray=true): bool {
-    if ($data === null || $data instanceof IDataCache) {
+  protected static function ensure_source($data, ?CacheData &$source, bool $allowArray=true): bool {
+    if ($data === null || $data instanceof CacheData) {
       $source = $data;
-    } elseif (is_subclass_of($data, IDataCache::class)) {
+    } elseif (is_subclass_of($data, CacheData::class)) {
       $source = new $data();
     } elseif (func::is_callable($data)) {
-      $source = new DataCache(null, $data);
+      $source = new DataCacheData(null, $data);
     } elseif (is_array($data) && $allowArray) {
       return false;
     } elseif (is_iterable($data)) {
-      $source = new DataCache(null, static function() use ($data) {
+      $source = new DataCacheData(null, static function() use ($data) {
         yield from $data;
       });
     } else {
-      throw ValueException::invalid_type($source, IDataCache::class);
+      throw ValueException::invalid_type($source, CacheData::class);
     }
     return true;
   }
@@ -53,13 +53,8 @@ class CacheFile extends SharedFile {
     $data ??= $params["data"] ?? null;
     $this->sources = null;
     if (self::ensure_source($data, $source)) {
-      if ($source !== null) {
-        $source->setDatafile($basefile);
-        $key = $source->getName();
-      } else {
-        $key = "";
-      }
-      $this->sources = [$key => $source];
+      if ($source !== null) $source->setDatafile($basefile);
+      $this->sources = ["" => $source];
     } else {
       $sources = [];
       $index = 0;
@@ -89,7 +84,7 @@ class CacheFile extends SharedFile {
 
   protected bool $cacheNull;
 
-  /** @var ?IDataCache[] */
+  /** @var ?CacheData[] */
   protected ?array $sources;
 
   /**
@@ -268,7 +263,7 @@ class CacheFile extends SharedFile {
           $data = $source->load();
         }
         if ($this->shouldCache($data)) {
-          $source->save($data);
+          $data = $source->save($data);
         } else {
           # ne pas garder le fichier s'il ne faut pas mettre en cache
           $source->delete();
diff --git a/src/cache/CursorCacheData.php b/src/cache/CursorCacheData.php
new file mode 100644
index 0000000..bcfdd33
--- /dev/null
+++ b/src/cache/CursorCacheData.php
@@ -0,0 +1,36 @@
+<?php
+namespace nulib\cache;
+
+class CursorCacheData extends CacheData {
+  function __construct(array $cursorId, $compute=null, ?CursorChannel $channel=null) {
+    $name = $cursorId["group_id"];
+    if ($name) $name .= "_";
+    $name .= $cursorId["id"];
+    parent::__construct($name, $compute);
+    $channel ??= (new CursorChannel($cursorId))->initStorage(cache::storage());
+    $this->channel = $channel;
+  }
+
+  function setDatafile(?string $basefile): void {
+  }
+
+  protected CursorChannel $channel;
+
+  function exists(): bool {
+    return $this->channel->count() > 0;
+  }
+
+  function load() {
+    return $this->channel;
+  }
+
+  function save($data) {
+    if (!is_iterable($data)) $data = [$data];
+    $this->channel->rechargeAll($data);
+    return $this->channel;
+  }
+
+  function delete() {
+    $this->channel->delete(null);
+  }
+}
diff --git a/src/cache/DataCache.php b/src/cache/DataCacheData.php
similarity index 74%
rename from src/cache/DataCache.php
rename to src/cache/DataCacheData.php
index cf2775b..7ada552 100644
--- a/src/cache/DataCache.php
+++ b/src/cache/DataCacheData.php
@@ -7,7 +7,7 @@ use nulib\os\path;
 use nulib\php\func;
 use Traversable;
 
-class DataCache implements IDataCache {
+class DataCacheData extends CacheData {
   /** @var string identifiant de cette donnée */
   const NAME = null;
 
@@ -15,22 +15,14 @@ class DataCache implements IDataCache {
   const COMPUTE = null;
 
   function __construct(?string $name=null, $compute=null, ?string $basefile=null) {
-    $this->name = $name ?? static::NAME ?? "";
-    $this->compute = func::withn($compute ?? static::COMPUTE);
+    $name ??= static::NAME ?? "";
+    $compute ??= static::COMPUTE;
+    parent::__construct($name, $compute);
     $this->setDatafile($basefile);
   }
 
-  protected string $name;
-
-  function getName() : string {
-    return $this->name;
-  }
-
-  protected ?func $compute;
-
   function compute() {
-    $compute = $this->compute;
-    $data = $compute !== null? $compute->invoke(): null;
+    $data = parent::compute();
     if ($data instanceof Traversable) $data = cl::all($data);
     return $data;
   }
@@ -56,8 +48,9 @@ class DataCache implements IDataCache {
     return file::reader($this->datafile)->unserialize();
   }
 
-  function save($data): void {
+  function save($data) {
     file::writer($this->datafile)->serialize($data);
+    return $data;
   }
 
   function delete(): void {
diff --git a/src/cache/IDataCache.php b/src/cache/IDataCache.php
deleted file mode 100644
index e25424d..0000000
--- a/src/cache/IDataCache.php
+++ /dev/null
@@ -1,27 +0,0 @@
-<?php
-namespace nulib\cache;
-
-/**
- * Interface IDataCache: gestion d'une donnée mise en cache
- */
-interface IDataCache {
-  function getName(): string;
-
-  /** calculer la donnée */
-  function compute();
-
-  /** spécifier le chemin du cache à partir du fichier de base */
-  function setDatafile(?string $basefile): void;
-
-  /** indiquer si le cache existe */
-  function exists(): bool;
-
-  /** charger la donnée depuis le cache */
-  function load();
-
-  /** sauvegarder la donnée dans le cache */
-  function save($data): void;
-
-  /** supprimer le cache */
-  function delete();
-}
diff --git a/src/cache/TODO.md b/src/cache/TODO.md
index 5d181f1..e8c41c0 100644
--- a/src/cache/TODO.md
+++ b/src/cache/TODO.md
@@ -1,21 +1,6 @@
 # nulib\cache
 
-* [ ] CacheChannel: stocker aussi la clé primaire, ce qui permet de récupérer la donnée correspondante dans la source
-
-* Cache:
-  * une méthode calcule + stocke la valeur
-    * valeur scalaire: compute() puis écriture dans un fichier cache
-    * valeur itérable: compute() puis enregistre dans un channel
-  * une méthode récupère la valeur
-    * valeur scalaire: lecture du fichier cache
-    * valeur itérable: parcours des valeurs du channel
-  
-  ainsi, il faudra peut-être deux classes: DataCache et CursorCache qui
-  implémentent ces deux fonctionnalités
-  * cache::get() utilise DataCache
-  * cache::all() utilise CursorCache
-
-peut-être qu'on peut garder CacheFile et le fonctionnement ci-dessus est
-implémenté dans CacheData? à voir
+* [ ] CacheChannel: stocker aussi la clé primaire, ce qui permet de récupérer
+  la donnée correspondante dans la source?
 
 -*- coding: utf-8 mode: markdown -*- vim:sw=4:sts=4:et:ai:si:sta:fenc=utf-8:noeol:binary
\ No newline at end of file
diff --git a/src/cache/cache.php b/src/cache/cache.php
index 3c557c0..ed599fa 100644
--- a/src/cache/cache.php
+++ b/src/cache/cache.php
@@ -72,9 +72,9 @@ class cache {
     return new CacheFile($file, $data, $params);
   }
 
-  static function cache($dataId, callable $compute, ?array $params=null): CacheFile {
+  static function cache($dataId, $data, ?array $params=null): CacheFile {
     self::verifix_id($dataId);
-    return self::new($dataId, null, $compute, $params);
+    return self::new($dataId, null, $data, $params);
   }
 
   static function get($dataId, $data, ?array $params=null) {
@@ -84,10 +84,10 @@ class cache {
     return $cache->get(null, $noCache);
   }
 
-  static function all($cursorId, ?iterable $rows, ?array $params=null): iterable {
-    self::verifix_id($dataId);
-    $noCache = !self::should_cache($dataId["id"], $dataId["group_id"]);
-    $cache = self::new($cursorId, "_rows", new CursorCache($cursorId, $rows), $params);
+  static function all($cursorId, $rows, ?array $params=null): ?iterable {
+    self::verifix_id($cursorId);
+    $noCache = !self::should_cache($cursorId["id"], $cursorId["group_id"]);
+    $cache = self::new($cursorId, "_rows", new CursorCacheData($cursorId, $rows), $params);
     return $cache->get(null, $noCache);
   }
 }
diff --git a/tbin/test-nucache.php b/tbin/test-nucache.php
index 43f06df..f3590c0 100755
--- a/tbin/test-nucache.php
+++ b/tbin/test-nucache.php
@@ -2,7 +2,7 @@
 <?php
 require __DIR__.'/../vendor/autoload.php';
 
-use nulib\cache\DataCache;
+use nulib\cache\DataCacheData;
 use nulib\cache\CacheFile;
 use nulib\ext\yaml;
 use nulib\os\sh;
@@ -43,7 +43,7 @@ if (in_array("one", $what)) {
 }
 
 if (in_array("two", $what)) {
-  $two = new CacheFile("two", new DataCache(null, function () {
+  $two = new CacheFile("two", new DataCacheData(null, function () {
     return 2;
   }), [
     "duration" => $duration,
@@ -52,11 +52,11 @@ if (in_array("two", $what)) {
 }
 
 if (in_array("three", $what)) {
-  $data31 = new DataCache("data31name", function () {
+  $data31 = new DataCacheData("data31name", function () {
     return 31;
   });
 
-  $data32 = new DataCache(null, function () {
+  $data32 = new DataCacheData(null, function () {
     return 32;
   });
 
diff --git a/tests/cache/SourceTest.php b/tests/cache/SourceTest.php
deleted file mode 100644
index b35d3f6..0000000
--- a/tests/cache/SourceTest.php
+++ /dev/null
@@ -1,66 +0,0 @@
-<?php
-namespace nulib\cache;
-
-use nulib\db\Capacitor;
-use nulib\db\sqlite\Sqlite;
-use nulib\db\sqlite\SqliteStorage;
-use nulib\output\msg;
-use nulib\output\std\StdMessenger;
-use nulib\tests\TestCase;
-use Traversable;
-
-class SourceTest extends TestCase {
-  static function setUpBeforeClass(): void {
-    msg::set_messenger_class(StdMessenger::class);
-  }
-
-  /** @param Traversable|iterable $dest */
-  protected static function assertSource($dest): void {
-    self::assertSame([
-      ["pk" => 1, "s" => null, "i" => null, "b" => null],
-      ["pk" => 2, "s" => "false", "i" => 0, "b" => 0],
-      ["pk" => 3, "s" => "first", "i" => 1, "b" => 1],
-      ["pk" => 4, "s" => "second", "i" => 2, "b" => 1],
-    ], iterator_to_array($dest));
-  }
-
-  function testDirect() {
-    $destStorage = new SqliteStorage(new Sqlite(__DIR__.'/dest.db'));
-    new Capacitor($destStorage, $dest = new CursorChannel("source"));
-
-    $sourceDb = new SourceDb();
-    $dest->rechargeAll($sourceDb->all("select * from source"));
-
-    $this->assertSource($dest);
-  }
-
-  function testCache() {
-    $getSource = function() {
-      $db = new SourceDb();
-      msg::info("query source");
-      yield from $db->all("select * from source");
-    };
-
-    $params = [
-      "duration" => 2,
-      "override_duration" => true,
-    ];
-
-    msg::info("initial");
-    cache::nc();
-    $dest = cache::all("source", $getSource(), $params);
-    $this->assertSource($dest);
-
-    msg::info("cached");
-    $dest = cache::all("source", $getSource(), $params);
-    $this->assertSource($dest);
-
-    sleep(4);
-    msg::info("expired");
-    $dest = cache::all("source", $getSource(), $params);
-    $this->assertSource($dest);
-
-    sleep(4);
-    msg::info("end");
-  }
-}
diff --git a/tests/cache/cacheTest.php b/tests/cache/cacheTest.php
index 3833d55..3a16cb0 100644
--- a/tests/cache/cacheTest.php
+++ b/tests/cache/cacheTest.php
@@ -21,38 +21,46 @@ class cacheTest extends _TestCase {
     msg::note("fin gendata");
   }
 
-  function _testRows(iterable $rows) {
+  function _testRows(iterable $rows, int $expectedCount) {
     $count = 0;
     foreach ($rows as $key => $row) {
-      msg::info("got $key => {a={$row["a"]}, b={$row["b"]}}");
+      $parts = ["got $key => {"];
+      $i = 0;
+      foreach ($row as $k => $v) {
+        if ($i++ > 0) $parts[] = ", ";
+        $parts[] = "$k=$v";
+      }
+      $parts[] = "}";
+      msg::info(implode("", $parts));
       $count++;
     }
-    self::assertSame(3, $count);
+    self::assertSame($expectedCount, $count);
   }
-  function _testGet(string $dataId, callable $gencompute) {
+  
+  function _testGet(string $dataId, int $expectedCount, callable $gencompute) {
     msg::section($dataId);
-    cache::nc();
+    cache::nc(true, true);
 
     msg::step("premier");
     $rows = cache::get($dataId, $gencompute());
-    $this->_testRows($rows);
+    $this->_testRows($rows, $expectedCount);
     msg::step("deuxième");
     $rows = cache::get($dataId, $gencompute());
-    $this->_testRows($rows);
+    $this->_testRows($rows, $expectedCount);
 
     msg::step("vider le cache");
     cache::nc(true, true);
 
     msg::step("premier");
     $rows = cache::get($dataId, $gencompute());
-    $this->_testRows($rows);
+    $this->_testRows($rows, $expectedCount);
     msg::step("deuxième");
     $rows = cache::get($dataId, $gencompute());
-    $this->_testRows($rows);
+    $this->_testRows($rows, $expectedCount);
   }
 
   function testGetStatic() {
-    $this->_testGet("getStatic", function() {
+    $this->_testGet("getStatic", 3, function () {
       return static function () {
         msg::note("getdata");
         return self::DATA;
@@ -61,12 +69,40 @@ class cacheTest extends _TestCase {
   }
 
   function testGetGenerator() {
-    $this->_testGet("getGenerator", function() {
+    $this->_testGet("getGenerator", 3, function () {
       return $this->gendata();
     });
   }
 
-  function testAll() {
-    
+  function _testAll(string $cursorId, int $expectedCount, callable $gencompute) {
+    msg::section($cursorId);
+    cache::nc(true, true);
+
+    msg::step("premier");
+    $rows = cache::all($cursorId, $gencompute());
+    $this->_testRows($rows, $expectedCount);
+    msg::step("deuxième");
+    $rows = cache::all($cursorId, $gencompute());
+    $this->_testRows($rows, $expectedCount);
+
+    msg::step("vider le cache");
+    cache::nc(true, true);
+
+    msg::step("premier");
+    $rows = cache::all($cursorId, $gencompute());
+    $this->_testRows($rows, $expectedCount);
+    msg::step("deuxième");
+    $rows = cache::all($cursorId, $gencompute());
+    $this->_testRows($rows, $expectedCount);
+  }
+
+  function testAllGenerator() {
+    $this->_testAll("allGenerator", 4, function() {
+      return static function() {
+        $db = new SourceDb();
+        msg::note("query source");
+        yield from $db->all("select * from source");
+      };
+    });
   }
 }