ServerSentEvent Chilkat2 Perl Reference Documentation
Chilkat2::ServerSentEvent
Current Version: 11.7.0
Markdown version of this page for AI tools (v 11.7.0) · all AI docs
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.
Object Creation
use Chilkat2;
my $serverSentEvent = Chilkat2::ServerSentEvent->new;
# or set properties (and RaiseError) at creation:
# my $serverSentEvent = Chilkat2::ServerSentEvent->new(VerboseLogging => 1, RaiseError => 1);Creates the object. The optional pairs set writable properties (and RaiseError) in order, as if set one by one; an unknown or read-only name croaks. use Chilkat2; loads every class; the Chilkat2/ServerSentEvent.pm file holds only this class's documentation (perldoc Chilkat2::ServerSentEvent).
Perl frees the object when its last reference goes (undef $serverSentEvent, or the variable going out of scope); there is nothing to close. Objects returned by methods are independent and freed the same way. The class may be subclassed (use parent -norequire, 'Chilkat2::ServerSentEvent';): an object is a blessed hash reference whose hash is free for the subclass's own fields.
When false (the default), a method that fails returns false (or undef), and the reason is in LastErrorText. When true, it dies with a Chilkat2::Error instead, as DBI does with its RaiseError. Objects returned by a method inherit the value of the object that returned them.
Errors
A Chilkat2::Error stringifies to the failed call's full LastErrorText, and has the methods text, class ('Chilkat2::ServerSentEvent'), method (the method name) and object. Methods that look something up and find nothing return undef without dying (each such method says so), methods that answer a question (HasMember, IsUnlocked, ...) return a plain boolean, and property reads and writes never fail for Chilkat reasons.
Misuse always croaks, with your file and line, whatever RaiseError is: a wrong number of arguments, a reference or undef where a string or number is expected, an object of the wrong class, an out-of-range integer, a string containing a NUL character, a wide character in a byte string, or a write to a read-only property.
Strings are Perl character strings in both directions (length, regexes and :encoding layers see characters); binary data (BinData) is a byte string. Unlocking: call Chilkat2::Global->new->UnlockBundle('...') once at startup.
Properties
Data
my $strVal = $serverSentEvent->Data;
The data for the server-side event. (If the data field was empty, then this will be empty.)
DebugLogFilePath
my $strVal = $serverSentEvent->DebugLogFilePath;
$serverSentEvent->DebugLogFilePath($strVal);
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.
EventName
my $strVal = $serverSentEvent->EventName;
The name of the server-side event. (If the event field was not present, then this will be empty.)
LastErrorHtml
my $strVal = $serverSentEvent->LastErrorHtml;
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.
topLastErrorText
my $strVal = $serverSentEvent->LastErrorText;
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.
LastErrorXml
my $strVal = $serverSentEvent->LastErrorXml;
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.
topLastEventId
my $strVal = $serverSentEvent->LastEventId;
The content of the id field, if present.
LastMethodSuccess
my $boolVal = $serverSentEvent->LastMethodSuccess;
$serverSentEvent->LastMethodSuccess($boolVal);
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.
Retry
my $intVal = $serverSentEvent->Retry;
The integer value of the retry field, if it exists; otherwise, 0.
VerboseLogging
my $boolVal = $serverSentEvent->VerboseLogging;
$serverSentEvent->VerboseLogging($boolVal);
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.
Version
my $strVal = $serverSentEvent->Version;
Methods
LoadEvent
# $success is true or false
my $success = $serverSentEvent->LoadEvent($eventText);
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 on success, false on failure; LastErrorText says why. With RaiseError on, a failure dies with a Chilkat2::Error instead (it stringifies to the LastErrorText); the object remains usable either way.