Crate printer_event_handler 

Printer Event Handler

A cross-platform printer status monitoring library for Windows and Linux systems. This library provides functionality to query printer status, monitor printer events, and track printer state changes using platform-specific backends:

• Windows: WMI (Windows Management Instrumentation) with complete Win32_Printer support
  • PrinterStatus (current, values 1-7): Other, Unknown, Idle, Printing, Warmup, StoppedPrinting, Offline
  • PrinterState (.NET PrintQueueStatus flags): Processing (16384), Printing (1024), Offline (128), etc.
  • All 12 DetectedErrorState values (0-11): NoError, NoPaper, Jammed, ServiceRequested, etc.
• Linux: CUPS (Common Unix Printing System) with basic status detection

.NET PrintQueueStatus Flags

The PrinterState property uses .NET PrintQueueStatus bitwise flags. These flags can be combined, and our implementation uses priority-based parsing to select the most significant state.

Name	Value	Description
None	0	Status is not specified
Paused	1	The print queue is paused
Error	2	The printer cannot print due to an error condition
PendingDeletion	4	The print queue is deleting a print job
PaperJam	8	The paper in the printer is jammed
PaperOut	16	The printer does not have, or is out of, the type of paper needed for the current print job
ManualFeed	32	The printer is waiting for a user to place print media in the manual feed bin
PaperProblem	64	The paper in the printer is causing an unspecified error condition
Offline	128	The printer is offline
IOActive	256	The printer is exchanging data with the print server
Busy	512	The printer is busy
Printing	1024	The device is printing
OutputBinFull	2048	The printer’s output bin is full
NotAvailable	4096	Status information is unavailable
Waiting	8192	The printer is waiting for a print job
Processing	16384	The device is doing some kind of work, which need not be printing if the device also sets Printing
Initializing	32768	The device is in the process of initialization
WarmingUp	65536	The device is warming up
TonerLow	131072	The device is low on toner
NoToner	262144	The device has no toner
PagePunt	524288	The device cannot print the current page
UserInterventionRequired	1048576	The device needs user intervention
OutOfMemory	2097152	The device is out of memory
DoorOpen	4194304	A door on the device is open
ServerUnknown	8388608	Status is unknown
PowerSave	16777216	The device is in power save mode

Reference: Microsoft .NET PrintQueueStatus

DetectedErrorState Values

The DetectedErrorState property indicates specific error conditions on the printer.

Name	Value	Description
Unknown	0	The error state is unknown
Other	1	An error other than those listed below
No Error	2	The printer is functioning normally
Low Paper	3	The printer is low on paper
No Paper	4	The printer is out of paper
Low Toner	5	The printer is low on toner or ink
No Toner	6	The printer is out of toner or ink
Door Open	7	A door or cover on the printer is open
Jammed	8	Paper is jammed in the printer
Offline	9	The printer is offline
Service Requested	10	The printer requires service or maintenance
Output Bin Full	11	The printer’s output bin is full

Reference: Microsoft Win32_Printer DetectedErrorState

Features

• Comprehensive Windows support - Full Win32_Printer coverage per Microsoft documentation
• Cross-platform support (Windows and Linux)
• Real-time monitoring - Query all printers on the system
• Status change detection - Monitor specific printers for status changes
• Async/await support with Tokio
• Detailed status information - PrinterStatus (current) + PrinterState (.NET flags) and 11 error states
• Platform-specific backends with unified API

Example

use printer_event_handler::{PrinterMonitor, PrinterError, MonitorableProperty};

#[tokio::main]
async fn main() -> Result<(), PrinterError> {
    let monitor = PrinterMonitor::new().await?;
     
    // List all printers with complete WMI information
    let printers = monitor.list_printers().await?;
    for printer in printers {
        println!("Printer: {}", printer.name());
        println!("Status: {}", printer.status_description());
        println!("Offline: {}", printer.is_offline());
         
        // Access raw WMI data
        if let Some(code) = printer.printer_status_code() {
            println!("  PrinterStatus: {} ({})", code,
                printer.printer_status_description().unwrap_or("Unknown"));
        }
         
        if let Some(status) = printer.wmi_status() {
            println!("  WMI Status: {}", status);
        }
    }
     
    // Monitor specific property changes with type safety
    monitor.monitor_property("HP LaserJet", MonitorableProperty::IsOffline, 60000, |change| {
        println!("Offline status changed: {}", change.description());
    }).await?;
     
    Ok(())
}

Re-exports

pub use error::PrinterError;

pub use monitor::MonitorableProperty;

pub use monitor::PrinterMonitor;

pub use printer::ErrorState;

pub use printer::Printer;

pub use printer::PrinterChanges;

pub use printer::PrinterState;

pub use printer::PrinterStatus;

pub use printer::PropertyChange;

Modules

backend

error

monitor

printer

Structs

CancellationToken

A token which can be used to signal a cancellation request to one or more tasks.

Type Aliases

Result

Result type used throughout the library