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Fixes for link-metadata feature #14

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Merged
Potherca merged 9 commits into from
Jan 16, 2022
Merged

Fixes for link-metadata feature #14

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e3358fd
Add check to mark `.meta` files as Turtle.
Potherca Jan 16, 2022
03c7005
Fix bug caused by missing error case.
Potherca Jan 16, 2022
9713b1c
Fix bug caused by URI not being passed to RDF parser.
Potherca Jan 16, 2022
50515c3
Change logic so that .meta parse failing does not error out.
Potherca Jan 16, 2022
420d7c4
Add check for sub-folder resources.
Potherca Jan 16, 2022
1718800
Add check for relative filepath.
Potherca Jan 16, 2022
9fa3f7c
Add logic to remove Link Metadata entry from meta file on file change.
Potherca Jan 16, 2022
dfde5ea
Add TODO markers for various concerns.
Potherca Jan 16, 2022
14a1cc5
Fix typo in comment.
Potherca Jan 16, 2022
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104 changes: 95 additions & 9 deletions src/Server.php
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Original file line number Diff line number Diff line change
Expand Up @@ -98,6 +98,7 @@ final public function __construct(Filesystem $filesystem, Response $response, Gr
$this->filesystem = $filesystem;
$this->graph = $graph ?? new Graph();
$this->response = $response;
// @TODO: Mention \EasyRdf_Namespace::set('lm', 'https://purl.org/pdsinterop/link-metadata#');
}

final public function respondToRequest(Request $request): Response
Expand Down Expand Up @@ -280,6 +281,7 @@ private function handleSparqlUpdate(Response $response, string $path, $contents)

try {
// Assuming this is in our native format, turtle
// @CHECKME: Does the Graph Parse here also need an URI?
$graph->parse($data, "turtle");
// FIXME: Adding this base will allow us to parse <> entries; , $this->baseUrl . $this->basePath . $path), but that breaks the build.
// FIXME: Use enums from namespace Pdsinterop\Rdf\Enum\Format instead of 'turtle'?
Expand All @@ -294,12 +296,14 @@ private function handleSparqlUpdate(Response $response, string $path, $contents)
switch($command) {
case "INSERT":
// insert $triple(s) into $graph
// @CHECKME: Does the Graph Parse here also need an URI?
$graph->parse($triples, "turtle"); // FIXME: The triples here are in sparql format, not in turtle;

break;
case "DELETE":
// delete $triples from $graph
$deleteGraph = $this->getGraph();
// @CHECKME: Does the Graph Parse here also need an URI?
$deleteGraph->parse($triples, "turtle"); // FIXME: The triples here are in sparql format, not in turtle;
$resources = $deleteGraph->resources();
foreach ($resources as $resource) {
Expand Down Expand Up @@ -339,6 +343,7 @@ private function handleSparqlUpdate(Response $response, string $path, $contents)
$response = $response->withStatus($success ? 201 : 500);

if ($success) {
$this->removeLinkFromMetaFileFor($path);
$this->sendWebsocketUpdate($path);
}
} catch (EasyRdf_Exception $exception) {
Expand Down Expand Up @@ -385,6 +390,7 @@ private function handleCreateRequest(Response $response, string $path, $contents
}

if ($success) {
$this->removeLinkFromMetaFileFor($path);
$response = $response->withHeader("Location", $this->baseUrl . $path);
$response = $response->withStatus(201);
$this->sendWebsocketUpdate($path);
Expand Down Expand Up @@ -420,6 +426,7 @@ private function handleCreateDirectoryRequest(Response $response, string $path):
$success = $filesystem->createDir($path);
$response = $response->withStatus($success ? 201 : 500);
if ($success) {
$this->removeLinkFromMetaFileFor($path);
$this->sendWebsocketUpdate($path);
}
}
Expand Down Expand Up @@ -507,6 +514,7 @@ private function handleUpdateRequest(Response $response, string $path, string $c
$success = $filesystem->update($path, $contents);
$response = $response->withStatus($success ? 201 : 500);
if ($success) {
$this->removeLinkFromMetaFileFor($path);
$this->sendWebsocketUpdate($path);
}
}
Expand Down Expand Up @@ -559,10 +567,8 @@ private function handleReadRequest(Response $response, string $path, $contents,
/*/ The file does exist and no link-metadata is present /*/
$response = $this->addLinkRelationHeaders($response, $path, $mime);

if (preg_match('/.ttl$/', $path)) {
$mimetype = "text/turtle"; // FIXME: teach flysystem that .ttl means text/turtle
} elseif (preg_match('/.acl$/', $path)) {
$mimetype = "text/turtle"; // FIXME: teach flysystem that .acl files also want text/turtle
if (preg_match('/\.(acl|meta|ttl)$/', $path)) {
$mimetype = "text/turtle"; // FIXME: teach flysystem that .acl/.meta/.ttl means text/turtle
} else {
$mimetype = $filesystem->asMime($mime)->getMimetype($path);
}
Expand All @@ -572,6 +578,11 @@ private function handleReadRequest(Response $response, string $path, $contents,
if ($contents !== false) {
$response->getBody()->write($contents);
$response = $response->withHeader("Content-type", $mimetype)->withStatus(200);
} else {
/*/ The file does exist in another format and no link-metadata is present /*/
$message = vsprintf(self::ERROR_PATH_DOES_NOT_EXIST, [$path]);
$response->getBody()->write($message);
$response = $response->withStatus(404);
}
} else {
/*/ The file does exist in another format and no link-metadata is present /*/
Expand Down Expand Up @@ -694,6 +705,7 @@ private function addLinkRelationHeaders(Response $response, string $path, $mime=
{
// @FIXME: If a `.meta` file is requested, it must have header `Link: </path/to/resource>; rel="describes"`

//@CHECKME: Should the ACL link header be added here or in/by the Auth server?
if ($this->hasAcl($path, $mime)) {
$value = sprintf('<%s>; rel="acl"', $this->getAclPath($path, $mime));
$response = $response->withAddedHeader('Link', $value);
Expand Down Expand Up @@ -815,23 +827,34 @@ private function parseLinkedMetadata(string $path)
$describedByPath = $this->filesystem->getMetadata($path)['describedby'] ?? '';
$describedByContents = $this->filesystem->read($describedByPath);
} catch (FileNotFoundException $e) {
// @CHECKME: If, for whatever reason, the file is not present after all... Do we care here?
// If, for whatever reason, the file is not present after all, the resource should still be returned (or a 404)
// @CHECKME: Should the upstream add a message to the header or something?
return $linkMeta;
}

$graph = $this->getGraph();

try {
$graph->parse($describedByContents);
$graph->parse($describedByContents, null, '/'.$describedByPath);
} catch (EasyRdf_Exception $exception) {
throw Exception::create(self::ERROR_CAN_NOT_PARSE_METADATA, [$path]);
// If the metadata can not be parsed, the resource should still be returned (or a 404)
// @CHECKME: Should the upstream add a message to the header or something?
return $linkMeta;
}

$toRdfPhp = $graph->toRdfPhp();

$rdfPaths = array_keys($toRdfPhp);
$foundPath = $this->findPath($rdfPaths, $path);

// If the requested path is a sub folder or file, it also needs te be handled
foreach ($rdfPaths as $rdfPath) {
if (strpos($rdfPath, $path) !== false) {
$foundPath = $rdfPath;
break;
}
}

if (isset($toRdfPhp[$foundPath])) {
$filteredRdfData = array_filter($toRdfPhp[$foundPath], static function ($key) {
$uris = implode('|', [
Expand All @@ -855,12 +878,18 @@ private function parseLinkedMetadata(string $path)
$value = array_pop($linkMetaValue);
$url = $value['value'] ?? null;

if (strpos($foundPath, './') === 0) {
// Filepath is relative to the meta file
$path = $foundPath;
}

if ($path !== $foundPath) {
// Change the path from the request to the redirect (or not found) path
$url = substr_replace($path,
$url,
strpos($path, $foundPath),
strlen($foundPath));
strlen($foundPath))
;
}

$linkMeta = [
Expand All @@ -885,12 +914,69 @@ private function findPath(array $rdfPaths, string $path)
// @FIXME: We have no way of knowing if the file is a directory or a file.
// This means that, unless we make a trialing slash `/` required,
// (using the example for `forget.ttl`) forget.ttl/foo.txt will
// also work although semantically is should not
// also work although semantically it should not
$path = $rdfPath;
break;
}
}

return $path;
}

private function removeLinkFromMetaFileFor($path): bool
{
$result = false;

if ($this->hasDescribedBy($path)) {
$describedByPath = $this->getDescribedByPath($path);

$graph = $this->getGraph();

try {
$contents = $this->filesystem->read($describedByPath);
$graph->parse($contents, 'turtle', '/'.$describedByPath);
} catch (\Throwable $e) {
return false;
}

// A resource might be added for a folder but written to a file,
// or vice-versa. In both cases, the _other_ entry also needs to be
// removed. And depending on the RDF entry, the resource might have
// a leading slash or not, so that also needs to be checked.
$normalizedPath = trim($path, '/');
$resourcePaths = array_unique([
$normalizedPath,
$normalizedPath . '/',
'/' . $normalizedPath,
'/' . $normalizedPath . '/',
]);

// @CHECKME: If an entry for a sub-folder is present but then a file is written,
// removing the folder, should the sub-folder entry also be removed?

$changed = false;
foreach ($resourcePaths as $resourcePath) {
$resource = $graph->resource($resourcePath);

$predicates = $resource->propertyUris();
foreach ($predicates as $predicate) {
if (strpos($predicate, 'https://purl.org/pdsinterop/link-metadata#') === 0) {
$changed = true;
$graph->deleteSingleProperty($resource, $predicate);
}
}
}

if ($changed) {
$changedContents = $graph->serialise('turtle');
try {
$result = $this->filesystem->update($describedByPath, $changedContents);
} catch (FileNotFoundException $exception) {
// $result is already false;
}
}
}

return $result;
}
}