使用PHP从Neo4j数据库导出json文件

Question

For that, I used the following code:

$result = $client->sendCypherQuery('MATCH (n) RETURN n')->getResult();
$nodes = [];
foreach ($result->getNodes() as $node) {
    $nodes[] = [
        'id' => $node->getId(),
        'labels' => $node->getLabels(),
        'properties' => $node->getProperties()
    ];
}

var_dump(json_encode($nodes));

But I get the following error:

Fatal error: Call to a member function getNodes() on a non-object in C:\\wamp\\www\\PhpProjectNeo4j1\\index.php

Answer 1

You are trying to call a function on an object which is empty or does not exists. First print the result of the returned query.

Probably the query does not return any result, but first you need to connect to the neo4j database :

Here is an example of how you can do it:

https://github.com/neo4j-examples/movies-php-neoclient/blob/fe5fd9222945ca8e9efc4ab3cac6b743f2ff8b24/index.php

$client = ClientBuilder::create()
    ->addConnection('default', $cnx['scheme'], $cnx['host'], $cnx['port'], true, $cnx['user'], $cnx['pass'])
    ->setAutoFormatResponse(true)
    ->setDefaultTimeout(20)
    ->build();

$result = $client->sendCypherQuery('MATCH (n) RETURN n')->getResult();
var_dump($result);    

A common way is to test the returned result emptiness before traversing the array.

if (!empty($result)) {
    foreach ($result->getNodes() as $node) {
        $nodes[] = [
            'id' => $node->getId(),
            'labels' => $node->getLabels(),
            'properties' => $node->getProperties()
        ];
    }
}