ServerSentEvent Classic ASP Reference Documentation

ServerSentEvent

Current Version: 11.6.0

Chilkat.ServerSentEvent

Parse server-sent event text into event name, data, ID, and retry fields.

Chilkat.ServerSentEvent is a small helper class for parsing Server-Sent Events formatted text. Given a multi-line event block, it extracts the event name, data payload, id value, and retry interval into simple read-only properties. It is useful when an application receives event-stream text and needs to work with the structured event fields instead of manually parsing the raw lines.

Load event text

Use LoadEvent to parse a complete multi-line Server-Sent Event block.

Read event name

Inspect EventName to determine the event type supplied by the server, if an event: field is present.

Read event data

Use Data to obtain the event payload, such as JSON text from a streaming API or real-time service.

Track event IDs

Read LastEventId when the event includes an id: field that identifies the event or stream position.

Handle retry hints

Use Retry to read the server-provided retry interval when a retry: field is included.

Diagnostics

Check LastErrorText if event text cannot be parsed or if a parsing result is unexpected.

Relationship to Chilkat.WebSocket: ServerSentEvent does not manage a WebSocket connection or parse WebSocket frames. Instead, it can be used after Chilkat.WebSocket receives a text message whose payload is formatted as a Server-Sent Event. Read the WebSocket text frame, pass the event text to LoadEvent, then use EventName, Data, LastEventId, and Retry to process the event.
Common pattern: Receive or otherwise obtain a complete Server-Sent Event text block, call LoadEvent, then inspect EventName to route the event and Data to process the payload. Use LastEventId and Retry when the stream provides reconnection or event-position information.

Object Creation

set serverSentEvent = Server.CreateObject("Chilkat.ServerSentEvent")

' ... use serverSentEvent ...

set serverSentEvent = Nothing

Classic ASP creates Chilkat objects with Server.CreateObject. The registered Chilkat ActiveX must match the bitness of the IIS application pool: a pool with Enable 32-Bit Applications set to True needs the 32-bit ActiveX, otherwise the 64-bit ActiveX. To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as Server.CreateObject("Chilkat.ServerSentEvent.11") for Chilkat v11.*.*.

VBScript requires set when assigning an object, so the signatures on this page show set x = obj.Method(...) for methods that return a Chilkat object; test the result with Is Nothing, since a method that fails to return an object returns Nothing. A method with no return value is called as a statement without parentheses (obj.Method arg1, arg2). Boolean properties, arguments and return values are integers in the ActiveX: pass 1 or 0, and test success with = 1. Byte arrays are Variant arrays and can be sent with Response.BinaryWrite. Asynchronous (*Async) methods and event callbacks are not used from Classic ASP.

Properties

Data
serverSentEvent.Data ' String (read-only)
Introduced in version 9.5.0.58

The data for the server-side event. (If the data field was empty, then this will be empty.)

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DebugLogFilePath
serverSentEvent.DebugLogFilePath ' String

If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.

Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.

Possible causes of hangs include:

  • A timeout property set to 0, indicating an infinite timeout.
  • A hang occurring within an event callback in the application code.
  • An internal bug in the Chilkat code causing the hang.

More Information and Examples
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EventName
serverSentEvent.EventName ' String (read-only)
Introduced in version 9.5.0.58

The name of the server-side event. (If the event field was not present, then this will be empty.)

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LastBinaryResult
serverSentEvent.LastBinaryResult ' Variant (read-only)

This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.

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LastErrorHtml
serverSentEvent.LastErrorHtml ' String (read-only)

Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorText
serverSentEvent.LastErrorText ' String (read-only)

Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastErrorXml
serverSentEvent.LastErrorXml ' String (read-only)

Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.

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LastEventId
serverSentEvent.LastEventId ' String (read-only)
Introduced in version 9.5.0.58

The content of the id field, if present.

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LastMethodSuccess
serverSentEvent.LastMethodSuccess ' Long

Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.

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LastStringResult
serverSentEvent.LastStringResult ' String (read-only)

In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.

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LastStringResultLen
serverSentEvent.LastStringResultLen ' Long (read-only)

The length, in characters, of the string contained in the LastStringResult property.

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Retry
serverSentEvent.Retry ' Long (read-only)
Introduced in version 9.5.0.58

The integer value of the retry field, if it exists; otherwise, 0.

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VerboseLogging
serverSentEvent.VerboseLogging ' Long

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
serverSentEvent.Version ' String (read-only)

Version of the component/library, such as "10.1.0"

More Information and Examples
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Methods

LoadEvent
success = serverSentEvent.LoadEvent(eventText) ' Long (1/0)
Introduced in version 9.5.0.58

Loads the multi-line event text into this object. For example, the eventText for a Firebase event might look like this:

event: put
data: {"path": "/c", "data": {"foo": true, "bar": false}}

Returns 1 for success, 0 for failure.

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