Merge pull request 'feat: implement download' (#31) from feat/implement-download into main

Reviewed-on: #31

lib/Client/Client.php

@@ -6,8 +6,8 @@ namespace KTXM\ProviderImap\Client;
 
 use KTXM\ProviderImap\Client\Command\CapabilityCommand;
 use KTXM\ProviderImap\Client\Command\CommandInterface;
+use KTXM\ProviderImap\Client\FetchTarget;
 use KTXM\ProviderImap\Client\Command\LoginCommand;
-use KTXM\ProviderImap\Client\Command\StatusCommand;
 use KTXM\ProviderImap\Client\Command\StartTlsCommand;
 use KTXM\ProviderImap\Client\Protocol\CommandExecutor;
 use KTXM\ProviderImap\Client\Protocol\ProtocolReader;
@@ -87,6 +87,15 @@ final class Client implements ClientInterface
         return $this->executor->perform($command, $this->session);
     }
 
+    public function download(FetchTarget $target, string $section, int $chunkSize = 8192): \Generator
+    {
+        if ($this->session === null || $this->executor === null) {
+            throw new ImapException('IMAP client is not connected.');
+        }
+
+        return $this->executor->download($target, $section, $chunkSize, $this->session);
+    }
+
     public function session(): SessionContext
     {
         if ($this->session === null) {

lib/Client/ClientInterface.php

@@ -5,6 +5,7 @@ declare(strict_types=1);
 namespace KTXM\ProviderImap\Client;
 
 use KTXM\ProviderImap\Client\Command\CommandInterface;
+use KTXM\ProviderImap\Client\FetchTarget;
 
 interface ClientInterface
 {
@@ -21,4 +22,11 @@ interface ClientInterface
      * @return TResult
      */
     public function perform(CommandInterface $command): mixed;
+
+    /**
+     * Stream the raw bytes of a single IMAP BODY section without buffering.
+     *
+     * @return \Generator<string>  raw (transfer-encoded) bytes from the socket
+     */
+    public function download(FetchTarget $target, string $section, int $chunkSize = 8192): \Generator;
 }

lib/Client/FetchOptions.php

@@ -89,6 +89,11 @@ final class FetchOptions
         return $this->with('BODY[TEXT]');
     }
 
+    public function withBody(): self
+    {
+        return $this->with('BODY[]');
+    }
+
     public function withBodySection(string $section): self
     {
         $section = strtoupper(trim($section));

lib/Client/Message.php

@@ -156,6 +156,11 @@ final class Message
         return $this->bodySections;
     }
 
+    public function bodyRaw(): ?string
+    {
+        return $this->bodySections[''] ?? null;
+    }
+
     /**
      * @param array<string, string> $bodySections
      */

lib/Client/MessageParser.php

@@ -524,9 +524,6 @@ final class MessageParser
             }
 
             $section = strtoupper(trim($matches[1]));
-            if ($section === '') {
-                continue;
-            }
 
              if (preg_match('/^(\d+(?:\.\d+)*)\.TEXT$/', $section, $partMatches) === 1) {
                 $section = $partMatches[1];

lib/Client/MessagePart.php

@@ -167,8 +167,9 @@ final class MessagePart
     {
         $data = [
             'partId' => $this->partId,
+            'blobId' => $this->partId,
+            'cId' => $this->contentId,
             'type' => $this->mimeType,
-            'blobId' => $this->contentId,
             'charset' => $this->parameters['charset'] ?? null,
             'name' => $this->parameters['name'] ?? $this->dispositionParameters['filename'] ?? null,
             'encoding' => $this->encoding,

lib/Client/Protocol/CommandExecutor.php

@@ -6,9 +6,11 @@ namespace KTXM\ProviderImap\Client\Protocol;
 
 use Generator;
 use KTXM\ProviderImap\Client\Command\CommandInterface;
+use KTXM\ProviderImap\Client\FetchTarget;
 use KTXM\ProviderImap\Client\ImapException;
 use KTXM\ProviderImap\Client\Protocol\Response\TaggedResponse;
 use KTXM\ProviderImap\Client\Protocol\Response\UntaggedResponse;
+use KTXM\ProviderImap\Client\Protocol\RequestFrame;
 use KTXM\ProviderImap\Client\SessionContext;
 use KTXM\ProviderImap\Client\SessionState;
 use Psr\Log\LoggerInterface;
@@ -41,10 +43,42 @@ final class CommandExecutor
         $this->writer->write($tag, $frame);
 
         return $command->handle(new ResponseStream(function () use ($tag, $context): Generator {
-            yield from $this->responsesUntilCompletion($tag, $context);
+            yield from $this->processPerform($tag, $context);
         }), $context);
     }
 
+    /**
+     * Stream the raw bytes of a single IMAP BODY section without buffering.
+     *
+     * Sends a UID FETCH for the given section and yields the literal bytes
+     * directly from the socket in chunks, never assembling a full string.
+     * The caller MUST fully exhaust the returned Generator before issuing
+     * any further IMAP commands.
+     *
+     * @return \Generator<string>  raw (transfer-encoded) bytes from the socket
+     */
+    public function download(FetchTarget $target, string $section, int $chunkSize, SessionContext $context): \Generator
+    {
+        $this->assertState([SessionState::Selected], $context->state(), 'FETCH (download)');
+
+        $tag = $this->tags->next();
+        $this->writer->write($tag, new RequestFrame(sprintf(
+            'UID FETCH %s (UID BODY[%s])',
+            $target->sequenceSet()->toCommand(),
+            $section,
+        )));
+
+        $result = $this->reader->readUntilFetchLiteral($tag);
+
+        if ($result === null) {
+            return; // UID not found or empty FETCH result
+        }
+
+        yield from $this->reader->streamLiteral($result['literalLength'], $chunkSize);
+
+        $this->reader->readToEnd($tag);
+    }
+
     /**
      * @param list<SessionState> $allowedStates
      */
@@ -63,7 +97,7 @@ final class CommandExecutor
         ));
     }
 
-    private function responsesUntilCompletion(string $tag, SessionContext $context): Generator
+    private function processPerform(string $tag, SessionContext $context): Generator
     {
         while (true) {
             $response = $this->reader->readResponse();

lib/Client/Protocol/ProtocolReader.php

@@ -42,7 +42,14 @@ final class ProtocolReader
 
     public function readResponse(): ResponseInterface
     {
-        $raw = $this->readRawResponse();
+        $raw = $this->connection->readLine();
+
+        while (($literalLength = $this->trailingLiteralLength($raw)) !== null) {
+            $raw .= $this->connection->readBytes($literalLength);
+            $raw .= $this->connection->readLine();
+        }
+
+        $raw = $this->trimTrailingLineEnding($raw);
 
         if ($raw === '') {
             throw new ImapException('Received empty IMAP response line.');
@@ -85,16 +92,72 @@ final class ProtocolReader
         return new TaggedResponse($parts[0], $status, $parts[2] ?? '', $raw);
     }
 
-    private function readRawResponse(): string
+    /**
+     * Read responses until an untagged FETCH response containing a literal marker is found,
+     * returning the literal byte count WITHOUT consuming the literal bytes from the socket.
+     * Returns null if the tagged OK/NO/BAD for $tag arrives before any literal is detected.
+     *
+     * ⚠️ After a non-null return the literal bytes MUST be consumed (via streamLiteral())
+     * before any further reads are made on this reader.
+     *
+     * @return array{literalLength: int, prefixLine: string}|null
+     */
+    public function readUntilFetchLiteral(string $tag): ?array
     {
-        $raw = $this->connection->readLine();
+        while (true) {
+            $line = $this->connection->readLine();
+            $trimmed = $this->trimTrailingLineEnding($line);
 
-        while (($literalLength = $this->trailingLiteralLength($raw)) !== null) {
+            // Literal marker at the end of the line — stop before consuming the bytes
-            $raw .= $this->connection->readBytes($literalLength);
+            $literalLength = $this->trailingLiteralLength($line);
-            $raw .= $this->connection->readLine();
+            if ($literalLength !== null) {
+                return ['literalLength' => $literalLength, 'prefixLine' => $trimmed];
             }
 
-        return $this->trimTrailingLineEnding($raw);
+            // Tagged completion for our command
+            if (str_starts_with($trimmed, $tag . ' ')) {
+                $parts = preg_split('/\s+/', $trimmed, 3) ?: [];
+                $status = strtoupper($parts[1] ?? '');
+                if ($status === 'NO' || $status === 'BAD') {
+                    throw new ImapException(sprintf('FETCH command failed: %s', $trimmed));
+                }
+                return null; // Tagged OK without ever finding a literal → UID not found
+            }
+
+            // Any other untagged response — discard and continue
+        }
+    }
+
+    public function readToEnd(string $tag): TaggedResponse
+    {
+        while (true) {
+            $response = $this->readResponse();
+
+            if ($response instanceof TaggedResponse && $response->tag() === $tag) {
+                if (!$response->isOk()) {
+                    throw new ImapException(sprintf('FETCH failed: %s', $response->text()));
+                }
+                return $response;
+            }
+        }
+    }
+
+    /**
+     * Yield the literal bytes already waiting in the socket as chunks.
+     * After the generator is fully exhausted this method reads the one trailing
+     * line that closes the FETCH parenthesised response (e.g. ")\r\n").
+     *
+     * Contract: the caller MUST exhaust this generator before issuing any further
+     * reads on this reader.
+     *
+     * @return \Generator<string>
+     */
+    public function streamLiteral(int $length, int $chunkSize = 8192): \Generator
+    {
+        yield from $this->connection->readBytesChunked($length, $chunkSize);
+
+        // Consume the closing portion of the FETCH parenthesised list (e.g. ")\r\n")
+        $this->connection->readLine();
     }
 
     private function trailingLiteralLength(string $raw): ?int

lib/Client/Transport/ConnectionInterface.php

@@ -20,5 +20,13 @@ interface ConnectionInterface
 
     public function readBytes(int $length): string;
 
+    /**
+     * Yield the literal payload in chunks without buffering the full content.
+     * Reads exactly $length bytes from the socket, never crossing the literal boundary.
+     *
+     * @return \Generator<string>
+     */
+    public function readBytesChunked(int $length, int $chunkSize = 8192): \Generator;
+
     public function upgradeToTls(): void;
 }

lib/Client/Transport/SocketConnection.php

@@ -135,6 +135,26 @@ final class SocketConnection implements ConnectionInterface
         return $buffer;
     }
 
+    public function readBytesChunked(int $length, int $chunkSize = 8192): \Generator
+    {
+        if ($length < 0) {
+            throw new ImapException('IMAP socket cannot read a negative number of bytes.');
+        }
+
+        $remaining = $length;
+
+        while ($remaining > 0) {
+            $chunk = fread($this->stream(), min($chunkSize, $remaining));
+
+            if ($chunk === false || $chunk === '') {
+                throw new ImapException('Failed to read literal payload from IMAP socket.');
+            }
+
+            $remaining -= strlen($chunk);
+            yield $chunk;
+        }
+    }
+
     public function upgradeToTls(): void
     {
         $stream = $this->stream();

lib/Providers/MessageAttachment.php

@@ -9,12 +9,14 @@ declare(strict_types=1);
 
 namespace KTXM\ProviderImap\Providers;
 
+use KTXF\Mail\Object\MessagePartInterface;
+
 /**
  * Mail Attachment Object
  *
  * @since 1.0.0
  */
-class MessageAttachment implements \KTXF\Mail\Object\MessagePartInterface {
+class MessageAttachment implements MessagePartInterface {
 
     protected MessagePart $_meta;
     protected ?string $_contents = null;

lib/Providers/MessagePart.php

@@ -9,10 +9,8 @@ declare(strict_types=1);
 
 namespace KTXM\ProviderImap\Providers;
 
-use Gricob\IMAP\Protocol\Response\Line\Data\Fetch\BodyStructure\MultiPart;
-use Gricob\IMAP\Protocol\Response\Line\Data\Fetch\BodyStructure\Part;
-use Gricob\IMAP\Protocol\Response\Line\Data\Fetch\BodyStructure\SinglePart;
 use KTXF\Mail\Object\MessagePartMutableAbstract;
+use KTXM\ProviderImap\Client\MessagePart as ImapMessagePart;
 
 /**
  * Mail Message Part Implementation
@@ -25,7 +23,7 @@ class MessagePart extends MessagePartMutableAbstract {
      * @param Part $part gricob BodyStructure Part (SinglePart or MultiPart)
      * @param string $partId numeric part identifier (e.g. "1", "1.1", "2")
      */
-    public function fromImap(Part $part, string $partId = '1'): static {
+    public function fromImap(ImapMessagePart $part, string $partId = '1'): static {
 
         $this->data['partId'] = $partId;
 
@@ -104,82 +102,4 @@ class MessagePart extends MessagePartMutableAbstract {
         return $this;
     }
 
-    /**
-     * Convert message part to store array
-     */
-    public function toStore(): array {
-        $data = $this->data;
-        if (count($this->parts) > 0) {
-            $data['subParts'] = [];
-            foreach ($this->parts as $subPart) {
-                if ($subPart instanceof MessagePart) {
-                    $data['subParts'][] = $subPart->toStore();
-                }
-            }
-        } else {
-            $data['subParts'] = null;
-        }
-        return $data;
-    }
-
-    /**
-     * Hydrate message part from store array
-     */
-    public function fromStore(array $data): static {
-        if (isset($data['subParts']) && is_array($data['subParts'])) {
-            foreach ($data['subParts'] as $subPart) {
-                $this->parts[] = (new MessagePart())->fromStore($subPart);
-            }
-            unset($data['subParts']);
-        }
-        $this->data = $data;
-        return $this;
-    }
-
-    /**
-     * Inject decoded body content from a map of IMAP section-ID → raw encoded text.
-     *
-     * Walks the MessagePart tree recursively. For each text/* leaf part whose
-     * partId is present in $sectionMap the raw text is decoded according to the
-     * part's Content-Transfer-Encoding and converted to UTF-8 before being
-     * stored in 'content'. Binary parts (images, PDFs, …) are skipped.
-     *
-     * @param array<string,string> $sectionMap  Keys: IMAP section IDs (e.g. "1", "1.2");
-     *                                           Values: raw (transfer-encoded) body text
-     */
-    public function injectSections(array $sectionMap): void
-    {
-        // MultiPart: recurse into children
-        if (!empty($this->parts)) {
-            foreach ($this->parts as $childPart) {
-                if ($childPart instanceof MessagePart) {
-                    $childPart->injectSections($sectionMap);
-                }
-            }
-            return;
-        }
-
-        // SinglePart: only inject decoded content for text/* MIME types
-        $type = strtolower($this->data['type'] ?? '');
-        if (!str_starts_with($type, 'text/')) {
-            return;
-        }
-
-        $partId = $this->data['partId'] ?? null;
-        if ($partId === null || !array_key_exists($partId, $sectionMap)) {
-            return;
-        }
-
-        $raw = $sectionMap[$partId];
-        $encoding = strtolower($this->data['encoding'] ?? '7bit');
-        $decoded = match ($encoding) {
-            'quoted-printable' => quoted_printable_decode($raw),
-            'base64'           => base64_decode($raw, strict: false),
-            default            => $raw, // 7bit, 8bit, binary
-        };
-
-        $charset = $this->data['charset'] ?? 'us-ascii';
-        $this->data['content'] = MessageProperties::toUtf8($decoded, $charset);
-    }
-
 }

lib/Providers/Provider.php

@@ -194,7 +194,7 @@ class Provider implements ProviderBaseInterface, ProviderServiceMutateInterface,
             // Attempt to authenticate and list mailboxes as a connectivity check
             $client  = RemoteService::freshClient($service);
             $service = RemoteService::mailService($service, $client);
-            $mailboxes = $service->collectionList();
+            $mailboxes = iterator_to_array($service->collectionList());
 
             $latency = (int) round((microtime(true) - $startTime) * 1000);
 
@@ -205,36 +205,9 @@ class Provider implements ProviderBaseInterface, ProviderServiceMutateInterface,
                     . ' (Latency: ' . $latency . ' ms)',
             ];
         } catch (\Throwable $e) {
-            $latency = (int) round((microtime(true) - $startTime) * 1000);
-
-            $location = ($service instanceof Service) ? $service->getLocation() : null;
-            $target   = $location
-                ? $location->getEncryption() . '://' . $location->getHost() . ':' . $location->getPort()
-                : 'unknown host';
-
-            // stream_socket_client errors are suppressed with @ in gricob — recover them
-            $phpError = error_get_last();
-            $detail   = $e->getMessage() !== '' ? $e->getMessage() : ($phpError['message'] ?? '');
-
-            if ($detail === '' && $location !== null) {
-                $host = $location->getHost();
-                if ($host !== '' && gethostbyname($host) === $host) {
-                    $detail = "hostname '{$host}' could not be resolved";
-                } else {
-                    $detail = 'connection refused or timed out — check port and encryption settings';
-                }
-            } elseif ($detail === '') {
-                $detail = 'no details — check host, port, and encryption settings';
-            }
-
             return [
                 'success' => false,
-                'message' => sprintf(
+                'message' => 'Test failed: ' . $e->getMessage(),
-                    'Connection to %s failed (%s): %s',
-                    $target,
-                    (new \ReflectionClass($e))->getShortName(),
-                    $detail,
-                ),
             ];
         }
     }

lib/Providers/Service.php

@@ -19,6 +19,7 @@ use KTXF\Mail\Service\ServiceCollectionMutableInterface;
 use KTXF\Mail\Service\ServiceEntityMutableInterface;
 use KTXF\Mail\Service\ServiceConfigurableInterface;
 use KTXF\Mail\Service\ServiceMutableInterface;
+use KTXF\Mail\Service\DownloadResult;
 use KTXF\Resource\Provider\ResourceServiceIdentityInterface;
 use KTXF\Resource\Provider\ResourceServiceLocationInterface;
 use KTXF\Resource\Delta\Delta;
@@ -67,7 +68,10 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
             self::CAPABILITY_COLLECTION_FILTER_ROLE => 's:32:1:1',
             self::CAPABILITY_COLLECTION_FILTER_SUBSCRIBED => 'b:0:1:1',
         ],
-        self::CAPABILITY_COLLECTION_LIST_SORT   => [],
+        self::CAPABILITY_COLLECTION_LIST_SORT   => [
+            self::CAPABILITY_COLLECTION_SORT_LABEL,
+            self::CAPABILITY_COLLECTION_SORT_RANK,
+        ],
         self::CAPABILITY_COLLECTION_EXTANT => true,
         self::CAPABILITY_COLLECTION_FETCH  => true,
         self::CAPABILITY_COLLECTION_CREATE => true,
@@ -85,10 +89,19 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
             self::CAPABILITY_ENTITY_FILTER_SIZE_MIN => 'i:0:16:16',
             self::CAPABILITY_ENTITY_FILTER_SIZE_MAX => 'i:0:32:32',
         ],
-        self::CAPABILITY_ENTITY_LIST_SORT   => [],
+        self::CAPABILITY_ENTITY_LIST_SORT   => [
-        self::CAPABILITY_ENTITY_LIST_RANGE  => ['tally' => ['absolute', 'relative']],
+            self::CAPABILITY_ENTITY_SORT_FROM,
-        self::CAPABILITY_ENTITY_EXTANT     => true,
+            self::CAPABILITY_ENTITY_SORT_TO,
+            self::CAPABILITY_ENTITY_SORT_SUBJECT,
+            self::CAPABILITY_ENTITY_SORT_DATE_RECEIVED,
+            self::CAPABILITY_ENTITY_SORT_DATE_SENT,
+            self::CAPABILITY_ENTITY_SORT_SIZE,
+        ],
+        self::CAPABILITY_ENTITY_LIST_RANGE  => [
+            'tally' => ['absolute', 'relative']
+        ],
         self::CAPABILITY_ENTITY_FETCH      => true,
+        self::CAPABILITY_ENTITY_EXTANT     => true,
         self::CAPABILITY_ENTITY_CREATE     => false,
         self::CAPABILITY_ENTITY_MODIFY     => false,
         self::CAPABILITY_ENTITY_PATCH      => true,
@@ -101,8 +114,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
 
     public function __construct() {}
 
-    // ── Lazy initialisation ───────────────────────────────────────────────────
-
     private function initialize(): void
     {
         if (!isset($this->mailService)) {
@@ -111,16 +122,14 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         }
     }
 
-    // ── Store (MongoDB persistence) ───────────────────────────────────────────
-
     public function toStore(): array
     {
         return array_filter([
             'tid' => $this->serviceTenantId,
             'uid' => $this->serviceUserId,
             'sid' => $this->serviceIdentifier,
-            'label'             => $this->serviceLabel,
             'enabled' => $this->serviceEnabled,
+            'label' => $this->serviceLabel,
             'primaryAddress' => $this->primaryAddress,
             'secondaryAddresses'=> $this->secondaryAddresses,
             'location' => $this->location?->toStore(),
@@ -156,8 +165,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $this;
     }
 
-    // ── JSON ──────────────────────────────────────────────────────────────────
-
     public function jsonSerialize(): array
     {
         return array_filter([
@@ -181,12 +188,12 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
             $data = json_decode($data, true, 512, JSON_THROW_ON_ERROR);
         }
 
-        if (isset($data[self::JSON_PROPERTY_LABEL])) {
-            $this->setLabel($data[self::JSON_PROPERTY_LABEL]);
-        }
         if (isset($data[self::JSON_PROPERTY_ENABLED])) {
             $this->setEnabled($data[self::JSON_PROPERTY_ENABLED]);
         }
+        if (isset($data[self::JSON_PROPERTY_LABEL])) {
+            $this->setLabel($data[self::JSON_PROPERTY_LABEL]);
+        }
         if (isset($data[self::JSON_PROPERTY_LOCATION])) {
             $this->setLocation($this->freshLocation(null, $data[self::JSON_PROPERTY_LOCATION]));
         }
@@ -209,8 +216,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $this;
     }
 
-    // ── ServiceBaseInterface ──────────────────────────────────────────────────
-
     public function capable(string $value): bool
     {
         return isset($this->serviceAbilities[$value]);
@@ -231,8 +236,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $this->serviceIdentifier;
     }
 
-    // ── ServiceMutableInterface ───────────────────────────────────────────────
-
     public function getLabel(): ?string
     {
         return $this->serviceLabel;
@@ -295,8 +298,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         
     }
 
-    // ── ServiceConfigurableInterface ──────────────────────────────────────────
-
     public function getLocation(): ServiceLocation
     {
         return $this->location;
@@ -355,8 +356,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $this;
     }
 
-    // ── Collection operations ─────────────────────────────────────────────────
-
     public function collectionList(string|int|null $location, ?IFilter $filter = null, ?ISort $sort = null): array
     {
         $this->initialize();
@@ -398,7 +397,7 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $list;
     }
 
-    public function collectionFetch(string|int $identifier): ?CollectionBaseInterface
+    public function collectionFetch(string|int $identifier): ?CollectionResource
     {
         $this->initialize();
         
@@ -530,8 +529,6 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $collection;
     }
 
-    // ── Entity operations ─────────────────────────────────────────────────────
-
     public function entityListBulk(string|int $collection, ?IFilter $filter = null, ?ISort $sort = null, ?IRange $range = null, ?array $properties = null): array
     {
         return iterator_to_array($this->entityListStream((string) $collection, $filter, $sort, $range), true);
@@ -789,6 +786,16 @@ class Service implements ServiceBaseInterface, ServiceMutableInterface, ServiceC
         return $list;
     }
 
+    public function entityDownload(EntityIdentifier $target, array|null $part): DownloadResult {
+        $this->initialize();
+
+        $collection = $target->collection();
+        $uid        = (int) $target->entity();
+        $partId     = isset($part['partId']) ? (string) $part['partId'] : null;
+
+        return $this->mailService->entityDownload($collection, $uid, $partId);
+    }
+
     private function groupEntitiesByCollection(EntityIdentifier ...$identifiers): array
     {
         $list = [];

lib/Service/Remote/RemoteMailService.php

@@ -13,6 +13,7 @@ use DateTimeImmutable;
 use Generator;
 use KTXM\ProviderImap\Client\Client;
 use KTXM\ProviderImap\Client\Command\FetchManyCommand;
+use KTXM\ProviderImap\Client\Command\FetchOneCommand;
 use KTXM\ProviderImap\Client\Command\ExpungeCommand;
 use KTXM\ProviderImap\Client\Command\ListCommand;
 use KTXM\ProviderImap\Client\Command\SearchCommand;
@@ -45,6 +46,7 @@ use KTXF\Resource\Range\IRangeTally;
 use KTXF\Resource\Range\RangeAnchorType;
 use KTXF\Resource\Range\RangeTally;
 use KTXF\Resource\Sort\ISort;
+use KTXF\Mail\Service\DownloadResult;
 use KTXM\ProviderImap\Providers\CollectionResource;
 use KTXM\ProviderImap\Providers\EntityResource;
 
@@ -295,6 +297,116 @@ class RemoteMailService
         }
     }
 
+    /**
+     * Stream the raw bytes of a message or a specific MIME part without buffering.
+     *
+     * When $partId is given, first fetches BODYSTRUCTURE to determine the
+     * correct filename and MIME type, then starts the streaming body fetch.
+     *
+     * @param string      $collection  Mailbox name
+     * @param int         $uid         Message UID
+     * @param string|null $partId      MIME section (e.g. '1', '1.2'); null = full RFC 822
+     */
+    public function entityDownload(string $collection, int $uid, ?string $partId = null): DownloadResult
+    {
+        $this->client->perform(new SelectCommand($collection, true));
+
+        $encoding = null;
+
+        if ($partId === null) {
+            $filename = 'message.eml';
+            $mimeType = 'message/rfc822';
+        } else {
+            // Fetch BODYSTRUCTURE first to determine metadata (no body bytes transferred)
+            $message = $this->client->perform(new FetchOneCommand(
+                FetchTarget::uid(SequenceSet::items($uid)),
+                FetchOptions::of('BODYSTRUCTURE'),
+            ));
+            $bodyStructure = $message->bodyStructure();
+            $part          = $bodyStructure !== null ? $this->findBodyPart($bodyStructure, $partId) : null;
+            $mimeType      = $part?->mimeType() ?? 'application/octet-stream';
+            $partData      = $part?->toArray() ?? [];
+            $filename      = isset($partData['name']) && $partData['name'] !== ''
+                ? $partData['name']
+                : "attachment-{$partId}";
+            $encoding      = $part?->encoding();
+        }
+
+        // Start download stream
+        $stream = $this->decodeStream(
+            $this->client->download(FetchTarget::uid(SequenceSet::items($uid)), $partId ?? ''),
+            $encoding
+        );
+
+        return new DownloadResult($filename, $mimeType, $stream);
+    }
+
+    private function findBodyPart(MessagePart $root, string $partId): ?MessagePart
+    {
+        if ($root->partId() === $partId) {
+            return $root;
+        }
+        foreach ($root->parts() as $child) {
+            $found = $this->findBodyPart($child, $partId);
+            if ($found !== null) {
+                return $found;
+            }
+        }
+        return null;
+    }
+
+    /**
+     * Wraps a raw IMAP body stream with a transfer-encoding decoder.
+     *
+     * IMAP BODY[n] literals are delivered in the transfer encoding declared
+     * by BODYSTRUCTURE (typically base64 or quoted-printable for attachments).
+     * 7bit / 8bit / binary sections pass through unchanged.
+     */
+    private function decodeStream(\Generator $stream, ?string $encoding): \Generator
+    {
+        return match (strtolower($encoding ?? '')) {
+            'base64'           => $this->decodeBase64Stream($stream),
+            'quoted-printable' => $this->decodeQpStream($stream),
+            default            => $stream,
+        };
+    }
+
+    private function decodeBase64Stream(\Generator $source): \Generator
+    {
+        $buffer = '';
+        foreach ($source as $chunk) {
+            // IMAP folds base64 at 76 chars with CRLF — strip all whitespace
+            $buffer .= preg_replace('/\s+/', '', $chunk);
+            // Decode complete 4-character groups; keep any partial tail
+            $remainder = strlen($buffer) % 4;
+            $complete  = strlen($buffer) - $remainder;
+            if ($complete > 0) {
+                yield base64_decode(substr($buffer, 0, $complete), true);
+                $buffer = substr($buffer, $complete);
+            }
+        }
+        // Flush remainder (handles padded or stripped trailing '=')
+        if ($buffer !== '') {
+            yield base64_decode($buffer, true);
+        }
+    }
+
+    private function decodeQpStream(\Generator $source): \Generator
+    {
+        // Buffer until we have complete lines so soft-line-breaks are intact
+        $buffer = '';
+        foreach ($source as $chunk) {
+            $buffer .= $chunk;
+            while (($pos = strpos($buffer, "\n")) !== false) {
+                yield quoted_printable_decode(substr($buffer, 0, $pos + 1));
+                $buffer = substr($buffer, $pos + 1);
+            }
+        }
+        if ($buffer !== '') {
+            yield quoted_printable_decode($buffer);
+        }
+    }
+
     /**
      * Append a raw RFC 822 message to a mailbox and return the assigned UID.
      *