Configuration properties

You can add or edit PI Web API configuration properties using PI System Explorer. Alternatively, you can send a PUT request with the information to the system/configuration/{key} endpoint. See PUT in the PI Web API Reference online help.

The following list presents a compilation and explanation of the properties that can be configured for the PI Web API.

AFCacheMaxObjects

• Description

  The maximum number of objects that the AF SDK keeps in its cache at any one time. Set to 0 for no cache.

• AF Attribute Value Type

  Int32

• Default

  10000

AFCacheRefreshHoldoffTime

• Description

  Defers the parallel instance refresh time for the specified time to prevent extra refresh calls.

• AF Attribute Value Type

  Int32

• Unit

  Milliseconds

• Default

  60000

  Note: Beginning with PI Web API 2021, this setting is no longer honored when the cache-control header is set to no-cache. If using this setting is desired, use a time-based cache directive. For example, set the cache-control header to max-age=0.

AFCacheTime

• Description

  The length of time (in seconds) that AF SDK objects will be kept in the cache. Set to 0 for no cache.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  120

AFSearchCacheInterval

• Description

  The amount of time (in seconds) until the search's cached items are automatically refreshed. AFSearch automatic refresh is disabled if this value is 0.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  0

AFSearchCacheTimeout

• Description

  Timeout to clean up the cached search in the server if it has not been used. Set to 0 to disable cache.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  600

AFSearchPageSize

• Description

  The page size used for retrieving objects from the AF server.

• AF Attribute Value Type

  Int32

• Default

  1000

AllowUnrecognizedAssetServers

• Description

  Allow requests to discover unrecognized Asset Servers. Discovered servers are visible to all users, not just the user that discovered them.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

AllowUnrecognizedDataArchives

• Description

  Allow requests to discover unrecognized Data Archives. Discovered archives are visible to all users, not just the user that discovered them.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

AuthenticationMethods

• Description

  List of available authentication methods.

  Bearer is used for Claims-based authentication. All Bearer properties are related to Claims configuration.

• AF Attribute Value Type

  String Array

• Default

  Kerberos

• Options

  • Anonymous

  • Basic

  • Kerberos

  • Bearer

BearerIssuer

• Description

  The URL of the Identity Provider.

• AF Attribute Value Type

  String

BearerOpenIdConfigurationRefreshInterval

• Description

  The refresh interval (in minutes) of the OpenIdConfiguration cache. Default value is 5 days.

• AF Attribute Value Type

  Int32

• Unit

  Minutes

• Default

  7200

CacheInstanceExpirationInterval

• Description

  Cache instance expires if cache has been stale for this period of time. A number of seconds, accurate to the nearest millisecond.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  900

CacheInstanceRefreshInterval

• Description

  Cached values are updated after this time period elapses per instance. The time period is measured in seconds, accurate to the nearest millisecond.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  300

CacheInstanceUpdateInterval

• Description

  The interval at which cached values are updated with new data from the server. Interval is measured in seconds, accurate to the nearest millisecond.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  5

CacheInstanceUpdateHoldoffTime

• Description

  The minimum time, measured in seconds (accurate to the nearest millisecond) between updates of cached values, if they are long-running.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  2

ChannelPollingInterval

• Description

  How often (in milliseconds) each channel will poll PI/AF for updates to send to the client.

• AF Attribute Value Type

  Int32

• Unit

  Milliseconds

• Default

  1000

ConnectionPreference

• Description

  Defines the connection preference to when connecting to an AFCollective or PICollective.

• AF Attribute Value Type

  String

• Default

  Any

• Options

  • PreferPrimary

  • RequirePrimary

  • Any

CorsExposedHeaders

• Description

  A comma-separated list of HTTP header keys the client is allowed to expose.

  Note: All headers are returned but the client is responsible for exposing only those specified in this property as well as a few other defaults defined by the CORS standard.

• AF Attribute Value Type

  String

• Default

  Allow,Content-Encoding,Content-Length,Date,Location

CorsHeaders

• Description

  A comma-separated list of HTTP header keys that are allowed for cross-domain requests.

• AF Attribute Value Type

  String

CorsMethods

• Description

  A comma-separated list of HTTP methods (verbs) that are allowed for cross-domain requests.

• AF Attribute Value Type

  String

• Default

  GET,OPTIONS

CorsOrigins

• Description

  A comma-separated list of domains from which CORS requests may originate.

• AF Attribute Value Type

  String

CorsSupportsCredentials

• Description

  Support for including authentication information along with a cross-origin request and response.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

CustomHeaders

• Description

  Headers that are applied in addition to the responses that are sent by PI Web API. These custom headers are applied to all responses, including 400 - and 500 - range status codes.

• AF Attribute Value Type

  String Array

• Default

  null

CustomHeadersEnabled

• Description

  Enables Custom Headers.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

DataArchiveQueryLimit

• Description

  The maximum number of simultaneous concurrent queries against Data Archives.

• AF Attribute Value Type

  Int32

• Default

  200

DebugMode

• Description

  Enables PI Web API debug mode.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

DisableWrites

• Description

  Disable PI Web API writes to PI AF.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

DisableConfigurationAdminRestriction

• Description

  Allows non-administrative users to view specific system configuration endpoints. When this feature is disabled, administrative privileges are necessary to access these endpoints. This applies exclusively to GET operations. For details on the system configuration endpoints, see Protected resources.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

EnableBuiltInHelp

• Description

  When set to true, the local built-in help system is enabled.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

EnableCSRFDefense

• Description

  When set to true, this configuration works with Cors settings to enable Cross-Site Request Forgery (CSRF) defense. Refer to the following GitHub cheat sheet on Cross-Site Request Forgery.

• AF Attribute Value Type

  Boolean

• Default

  true

• Options

  • true

  • false

IgnoreCacheControlForBulkRequests

• Description

  By default, cache-control headers are not allowed for bulk requests (streamsets) to prevent redundant, expensive requests. For more information, see Cache management.

• AF Attribute Value Type

  Boolean

• Default

  false

• Options

  • true

  • false

MaxAccepts

• Description

  Max number of HTTP requests in queue (application level).

• AF Attribute Value Type

  Int32

• Default

  Environment dependent

MaxPointSearchResultPageLimit

• Description

  Maximum number of items that can be returned in a single paginated PI Point search result.

• AF Attribute Value Type

  Int64

• Default

  1000

MaxRequests

• Description

  Maximum number of active requests that can be processed.

• AF Attribute Value Type

  Int32

• Default

  2,147,483,647

MaxRequestContentLength

• Description

  Maximum number of bytes in the content of an HTTP request (roughly equivalent to the number of characters being sent, including spaces). The default value is 4 MB, displayed in bytes. Should use powers of 2.

• AF Attribute Value Type

  Int64

• Unit

  Bytes

• Default

  4,194,304

MaxRequestQueueLength

• Description

  Maximum number of HTTP requests that can be queued in http.sys (kernel level).

• AF Attribute Value Type

  Int32

• Default

  1000

MaxReturnedItemsPerCall

• Description

  Each web request returns a single item or collection of items; this property limits the maximum number of returned items; it affects the Stream and StreamSet controllers, as well as any action for any controller that contains a maxCount URL parameter.

• AF Attribute Value Type

  Int32

• Default

  150000

OmfCreateMode

• Description

  Indicates how to treat duplicate values from OMF messages in the Data Archive. For more information on the available options, see the AF SDK reference topic AFUpdateOption Enumeration.

• AF Attribute Value Type

  String

• Default

  Insert

• Options

  • Replace

    Note: We do not recommend using this mode because it skips compression.

  • Insert

  • NoReplace

PerformanceMetricsEnabled

• Description

  Allows access to performance metrics retrieval endpoints when true, denies access when false.

• AF Attribute Value Type

  Boolean

• Default

  true

PISystemProxyDisconnectTimeout

• Description

  The amount of time, in milliseconds, to allow a connection to the PI System to be disconnected before timing out. Default is set by AF SDK AFGlobalSettings.PISystemProxyDisconnectTimeout.

• AF Attribute Value Type

  Int32

• Unit

  Milliseconds

• Default

  null

PISystemProxyPoolSize

• Description

  The number of proxies in the pool of connections to the PI System. Default is set by AF SDK AFGlobalSettings.PISystemProxyPoolSize.

• AF Attribute Value Type

  Int32

• Default

  null

PreflightMaxAge

• Description

  The maximum time that a CORS preflight response should be cached. Set to -1 to never send an Access-Control-Max-Age header in the preflight response. Set to 0 to instruct the client to never cache the preflight response. Maximum allowed is 600.

• AF Attribute Value Type

  Int32

• Default

  -1

RateLimitDuration

• Description

  A duration of time, in seconds, in which a client (IP address) is limited to a specific number of requests.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  1

RateLimitMaxRequests

• Description

  Maximum number of requests per client (IP address) over a specified duration of time.

  Note: To apply changes after modifying the default value, restart PI Web API to see the updates immediately. Alternatively, keep the session inactive, refraining from making any PI Web API request, for at least two minutes for the changes to take effect.

• AF Attribute Value Type

  Int32

• Default

  1000

RateLimitSearchDuration

• Description

  A period of time (in seconds) in which you are limited to a specific number of search requests.

• AF Attribute Value Type

  Int32

• Unit

  Seconds

• Default

  1

RateLimitSearchMaxRequests

• Description

  Maximum number of search requests per client (IP address) over a specified duration of time. The Rate Limit per IP equals RateLimitSearchMaxRequests/RateLimitSearchDuration

• AF Attribute Value Type

  Int32

• Default

  50

ResponseBufferSize

• Description

  The size of the buffer for the building of the responses.

• AF Attribute Value Type

  Int32

• Default

  65536

StrictTransportSecurityMaxAge

• Description

  The time (in seconds) that the browser should remember that a site is only to be accessed using HTTPS.

• AF Attribute Value Type

  Int32

• Default

  86400

VerbosityLevel

• Description

  Indicates the verbosity level that should be used when logging events.

• AF Attribute Value Type

  String

• Default

  Concise

• Options

  • Concise

  • Verbose

WebIDType

• Description

  Indicates the format in which WebIDs should be returned.

• AF Attribute Value Type

  String

• Default

  Full

• Options

  • Full

  • IDOnly

  • PathOnly

  • LocalIDOnly

  • DefaultIDOnly

WebIDVersion

• Description

  Indicates the version in which WebIDs should be returned. When WebID 1.0 is used, some resource types will be unsupported (e.g., Notification Rules).

• AF Attribute Value Type

  Int32

• Default

  1

• Options

  • 0 (WebID 1.0)

  • 1 (WebID 2.0)

XFrameOptions

• Description

  Indicates under which circumstances a browser is able to render a page from the PI Web API in a <frame>, <iframe>, or <object> tag. If empty, protection is disabled. See the MDN web docs article, X-Frame-Options, for more information.

• AF Attribute Value Type

  String

• Default

  SAMEORIGIN

• Options

  • DENY

  • SAMEORIGIN

  • ALLOW-FROM uri

  • Empty String