Config

Client Certificate used for mutual TLS.

A ClientCertificateProvider can be configure for scenarios where the ClientCertificate might change over time.

The maximum amount of time to wait to acquire a connection from the pool (to either create a new connection or borrow an existing one).

Default: 60000 (1 minute)

Specify the maximum time in milliseconds the connection can be idle without needing to perform a liveness check on acquire from the pool.

Pooled connections that have been idle in the pool for longer than this timeout will be tested before they are used again, to ensure they are still live. If this option is set too low, an additional network call will be incurred when acquiring a connection, which causes a performance hit.

If this is set high, you may receive sessions that are backed by no longer live connections, which will lead to exceptions in your application. Assuming the database is running, these exceptions will go away if you retry acquiring sessions.

Hence, this parameter tunes a balance between the likelihood of your application seeing connection problems, and performance.

You normally should not need to tune this parameter. No connection liveliness check is done by default. Value 0 means connections will always be tested for validity and negative values mean connections will never be tested.

Default: undefined (Disabled)

Specify socket connection timeout in milliseconds.

Negative and zero values result in no timeout being applied. Connection establishment will be then bound by the timeout configured on the operating system level.

Default: 30000 (30 seconds)

Make this driver always return native JavaScript numbers for integer values, instead of the dedicated Integer class.

Values that do not fit in native number bit range will be represented as Number.NEGATIVE_INFINITY or Number.POSITIVE_INFINITY.

Warning: ResultSummary It is not always safe to enable this setting when JavaScript applications are not the only ones interacting with the database. Stored numbers might in such case be not representable by native Number type and thus the driver will return lossy values. This might also happen when data was initially imported using neo4j import tool and contained numbers larger than Number.MAX_SAFE_INTEGER. Driver will then return positive infinity, which is lossy.

Default: false

Default value for this option is false because native JavaScript numbers might result in loss of precision in the general case.

Encryption level

Specify the logging configuration for the driver. Object should have two properties level and logger.

Property level represents the logging level which should be one of: 'error', 'warn', 'info' or 'debug'. This property is optional and its default value is 'info'. Levels have priorities: 'error': 0, 'warn': 1, 'info': 2, 'debug': 3. Enabling a certain level also enables all levels with lower priority. For example: 'error', 'warn' and 'info' will be logged when 'info' level is configured.

Property logger represents the logging function which will be invoked for every log call with an acceptable level. The function should take two string arguments level and message. The function should not execute any blocking or long-running operations because it is often executed on a hot path.

No logging is done by default. See neo4j.logging object that contains predefined logging implementations.

See:

• logging

The maximum allowed lifetime for a pooled connection in milliseconds.

Pooled connections older than this threshold will be closed and removed from the pool. Such discarding happens during connection acquisition so that new session is never backed by an old connection. Setting this option to a low value will cause a high connection churn and might result in a performance hit. It is recommended to set maximum lifetime to a slightly smaller value than the one configured in network equipment (load balancer, proxy, firewall, etc. can also limit maximum connection lifetime). No maximum lifetime limit is imposed by default. Zero and negative values result in lifetime not being checked.

Default: 60 * 60 * 1000 (1 hour)

The maximum total number of connections allowed to be managed by the connection pool, per host.

This includes both in-use and idle connections.

Default: 100

Specify the maximum time in milliseconds transactions are allowed to retry via Session#executeRead and Session#executeWrite functions.

These functions will retry the given unit of work on ServiceUnavailable, SessionExpired and transient errors with exponential backoff using an initial delay of 1 second.

Default: 30000 (30 seconds)

Configure filter for Notification objects returned in ResultSummary#notifications.

See SessionConfig#notificationFilter for usage instructions.

Specify a custom server address resolver function used by the routing driver to resolve the initial address used to create the driver.

Such resolution happens:

• during the very first rediscovery when driver is created

• when all the known routers from the current routing table have failed and driver needs to fallback to the initial address

  In NodeJS environment driver defaults to performing a DNS resolution of the initial address using 'dns' module. In browser environment driver uses the initial address as-is. Value should be a function that takes a single string argument - the initial address. It should return an array of new addresses. Address is a string of shape '<host>:<port>'. Provided function can return either a Promise resolved with an array of addresses or array of addresses directly.

Specify if telemetry collection is disabled.

By default, the driver will send anonymous usage statistics to the server it connects to if the server requests those. By setting telemetryDisabled=true, the driver will not send any telemetry data.

The driver transmits the following information:

Every time one of the following APIs is used to execute a query (for the first time), the server is informed of this (without any further information like arguments, client identifiers, etc.):

• Driver#executeQuery
• Session#run
• Session#beginTransaction
• Session#executeRead
• Session#executeWrite
• Session#writeTransaction
• Session#readTransaction
• The reactive counterparts of methods above.

Metrics are only collected when enabled both in server and driver instances.

Default: false

Trust strategy to use if encryption is enabled.

There is no mode to disable trust other than disabling encryption altogether. The reason for this is that if you don't know who you are talking to, it is easy for an attacker to hijack your encrypted connection, rendering encryption pointless.

TRUST_SYSTEM_CA_SIGNED_CERTIFICATES is the default choice. For NodeJS environments, this means that you trust whatever certificates are in the default trusted certificate store of the underlying system. For Browser environments, the trusted certificate store is usually managed by the browser. Refer to your system or browser documentation if you want to explicitly add a certificate as trusted.

TRUST_CUSTOM_CA_SIGNED_CERTIFICATES is another option for trust verification - whenever we establish an encrypted connection, we ensure the host is using an encryption certificate that is in, or is signed by, a certificate given as trusted through configuration. This option is only available for NodeJS environments.

TRUST_ALL_CERTIFICATES means that you trust everything without any verifications steps carried out. This option is only available for NodeJS environments and should not be used on production systems.

List of one or more paths to trusted encryption certificates.

This only works in the NodeJS bundle, and only matters if you use "TRUST_CUSTOM_CA_SIGNED_CERTIFICATES".

The certificate files should be in regular X.509 PEM format.

For instance, ['./trusted.pem']

See:

• Config#trust

Make this driver always return native Javascript BigInt for integer values, instead of the dedicated Integer class or Number.

Warning: BigInt doesn't implement the method toJSON. To serialize it as json, it's needed to add a custom implementation of the toJSON on the BigInt.prototype. See https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt#use_within_json.

Default: false (for backwards compatibility)

Optionally override the default user agent name.

Default: 'neo4j-javascript/<version>'