ServerSentEvent Delphi DLL Reference Documentation
ServerSentEvent
Current Version: 11.5.0
Chilkat.ServerSentEvent
Use
Inspect
Use
Read
Use
Check 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
LoadEvent to parse a complete multi-line
Server-Sent Event block.
Read event name
EventName to determine the event type supplied by
the server, if an event: field is present.
Read event data
Data to obtain the event payload, such as JSON text from
a streaming API or real-time service.
Track event IDs
LastEventId when the event includes an
id: field that identifies the event or stream position.
Handle retry hints
Retry to read the server-provided retry interval when a
retry: field is included.
Diagnostics
LastErrorText if event text cannot be parsed or if a
parsing result is unexpected.
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.
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.
Create/Dispose
var myObject: HCkServerSentEvent; begin myObject := CkServerSentEvent_Create(); // ... CkServerSentEvent_Dispose(myObject); end;
Creates an instance of the HCkServerSentEvent object and returns a handle (i.e. a Pointer). The handle is passed in the 1st argument for the functions listed on this page.
Objects created by calling CkServerSentEvent_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function.
Properties
Data
function CkServerSentEvent__data(objHandle: HCkServerSentEvent): PWideChar; stdcall;
The data for the server-side event. (If the data field was empty, then this will be empty.)
See the notes about PWideChar memory ownership and validity.
topDebugLogFilePath
procedure CkServerSentEvent_putDebugLogFilePath(objHandle: HCkServerSentEvent; newPropVal: PWideChar); stdcall;
function CkServerSentEvent__debugLogFilePath(objHandle: HCkServerSentEvent): PWideChar; stdcall;
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.
See the notes about PWideChar memory ownership and validity.
EventName
function CkServerSentEvent__eventName(objHandle: HCkServerSentEvent): PWideChar; stdcall;
The name of the server-side event. (If the event field was not present, then this will be empty.)
See the notes about PWideChar memory ownership and validity.
topLastErrorHtml
function CkServerSentEvent__lastErrorHtml(objHandle: HCkServerSentEvent): PWideChar; stdcall;
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.
See the notes about PWideChar memory ownership and validity.
topLastErrorText
function CkServerSentEvent__lastErrorText(objHandle: HCkServerSentEvent): PWideChar; stdcall;
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.
See the notes about PWideChar memory ownership and validity.
LastErrorXml
function CkServerSentEvent__lastErrorXml(objHandle: HCkServerSentEvent): PWideChar; stdcall;
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.
See the notes about PWideChar memory ownership and validity.
topLastEventId
function CkServerSentEvent__lastEventId(objHandle: HCkServerSentEvent): PWideChar; stdcall;
The content of the id field, if present.
See the notes about PWideChar memory ownership and validity.
topLastMethodSuccess
procedure CkServerSentEvent_putLastMethodSuccess(objHandle: HCkServerSentEvent; newPropVal: wordbool); stdcall;
Indicates the success or failure of the most recent method call: True means success, False 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.
Retry
The integer value of the retry field, if it exists; otherwise, 0.
VerboseLogging
procedure CkServerSentEvent_putVerboseLogging(objHandle: HCkServerSentEvent; newPropVal: wordbool); stdcall;
If set to True, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is False. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.
Version
function CkServerSentEvent__version(objHandle: HCkServerSentEvent): PWideChar; stdcall;
Version of the component/library, such as "10.1.0"
See the notes about PWideChar memory ownership and validity.
Methods
LoadEvent
eventText: PWideChar): wordbool; stdcall;
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 True for success, False for failure.