Configuring the Nuance Text Processing Engine service

The Nuance Text Processing Engine (NTpE), is the normalization and tokenization (or lexical analysis) engine. NTpE applies transformation rules and formats output for display or for further processing by semantic engines.

Note: NTpE is packaged with a self-signed certificate and pre-configured to enable secure connections using TLS/SSL. You can use the self-signed certificates for testing and development, but for a secure production environment you need to acquire a certificate signed by a Certificate Authority (CA), and a PEM-formatted private key. Then configure the properties described below under SSL settings (WSS).

Management Station displays commonly-used properties on the Settings tab, and the following tables shows some of these properties. (Management Station does not display less-common parameters, but you can add them to the display at any time. For a complete list, see Speech product parameters.)

General settings

Service property

Description

Data type

Default

port

Port on which NTpE listens for incoming WebSocket requests.

INT 9092

Linguistic model settings

Use these properties for any linguistic models used by your application.

Service property

Description

Data type

Default

maxNumberOfModelInMemory

Maximum number of application models that can be loaded in the process memory.

Determine this number from the number of models and the amount of available RAM. Each model requires approximately 100-150 MB of RAM.

INT 100

preloadDataPacks

Name of one or more data packs. For example: 

[ndp-eng-USA-GEN-3.7.0]

To specify multiple data packs, use a comma-separated list.

STRING  

traceLogLevel

Trace log level.

Note: Do not change unless instructed by Nuance.

STRING error

cleanupIntervalInMinutes

Specifies how often NTpE cleans up downloaded and installed unused application models. The interval is expressed in minutes.

INT 30

clientValidation : maxDrift

Specifies the drift tolerance (in seconds) between client and server hosts for security verification purposes. Based on difference in UUID timestamps, with a valid range of 1-120 seconds and default value of 2 minutes.

INT 120

Logging settings

Service property

Description

Data type

Default

log : level

Logging level for the NTpE session: error, warn, info, verbose, debug, or silly.

The Management Station default logging level is STATUS, and it overrides this default value.

STRING error

log : logFileDir

Path to the log file directory

STRING ./logs

log : fileName

Filename of the log file.

STRING service_

log : maxSize

Maximum log file size in bytes.

INT 5242880

log : maxFiles

Maximum number of log files.

INT 5

Licensing setting

Service property

Description

Data type

Default

Licensing setting

licensePath

Port and IP address of the Nuance License Manager, using the format:

port@ip_address

STRING 27000@localhost

Resource Manager settings

Service property

Description

Data type

Default

resourceManager : enabled

Enables NTpE to publish its capabilities to the Resource Manager during startup.

BOOLEAN  

resourceManager : urls

IP address (or hostname) and port (usually 9001) of the Nuance Resource Manager.

STRING

resourceManager : ntpeHost

IP address or hostname of the machine running NTpE (this machine). This property is used by Resource Manager to identify an NTpE resource

STRING  

resourceManager : retryInterval

Time to wait before attempting to reconnect to Resource Manager. Default is 5 seconds.

INT 5000

HTTPS client settings

Use these properties to control how NTpE behaves as an HTTPS client. For example, to send its digital certificate and private key to NLE to download application linguistic models.

Service property

Description

Data type

Default

httpsClient : requestCert

Requests and verifies a certificate from clients that try to connect to via HTTPS.

BOOLEAN false

httpsClient : rejectUnauthorized

When the service acts as a client, this property requires servers to be authorized by valid certificates.

BOOLEAN false

httpsClient : caCertificates

When httpClient : rejectUnauthorized is true, list of certificates to validate the certificates of an HTTPS resource.

STRING  

SSL settings (WSS)

Service property

Description

Data type

Default

https: enabled

Enables SSL/TLS communications.

BOOLEAN true

https: keyFile

Path and filename of a private key.

STRING ./keys/server.key

https: passphrase

The encrypted passphrase for the service's private keyfile.

Optional. When you acquire a TLS certificate and private key, run the startEngine command-line tool to obfuscate your TLS passphrase. Then copy/paste the output as the value of this parameter. See Securing connections with SSL/TLS.

STRING  

https : certFile

Path and filename of the signed certificate file for NTpE.

STRING ./keys/server.crt

https : requestCert

Requests and verifies a certificate from clients that try to connect to via HTTPS.

BOOLEAN false

https : rejectUnauthorized

When the service acts as a client, this property requires servers to be authorized by valid certificates.

BOOLEAN false