Great job getting the bare printer setup working—let's fix the driver association part. The key here is understanding how CUPS maps drivers to printers, which relies on PPD (PostScript Printer Description) files. Here's how to nail this with IPP requests:

Core Concepts #

CUPS uses PPD files to define printer capabilities and driver behavior. When adding a printer, you have three reliable ways to link a driver:

1. Directly reference an existing, CUPS-recognized PPD (best for consistency)
2. Upload a custom PPD file (for proprietary or niche printers)
3. Use the printer make/model string (let CUPS auto-select the matching PPD, but less reliable for custom drivers)

Step-by-Step Implementation #

1. Validate Your PPD First #

Before sending the IPP request, confirm your target PPD is compatible:

• Run lpinfo -m in your terminal to list all PPDs CUPS currently recognizes. Look for the exact string corresponding to your printer's driver (e.g., hp/hp-laserjet-p2015.ppd).
• If using a custom PPD, ensure it's formatted correctly (valid PostScript, CUPS-compliant).

2. Build the IPP Request with Driver Attributes #

Here's how to structure your request using CUPS' C API (adjust based on your language/library):

Option A: Reference a Pre-Recognized PPD

Use the ppd-name attribute with the exact string from lpinfo -m:

ipp_t *request = ippNewRequest(CUPS_ADD_PRINTER);

// Basic printer attributes (required for CUPS to process the request)
ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "printer-uri", NULL, "ipp://localhost/printers/MyNewPrinter");
ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_NAME, "requesting-user-name", NULL, "root");
ippAddString(request, IPP_TAG_PRINTER, IPP_TAG_NAME, "printer-info", NULL, "My Office Printer");
ippAddString(request, IPP_TAG_PRINTER, IPP_TAG_TEXT, "printer-location", NULL, "Third Floor");

// Critical driver association attribute
ippAddString(request, IPP_TAG_PRINTER, IPP_TAG_NAME, "ppd-name", NULL, "hp/hp-laserjet-p2015.ppd");

// Set printer type (adjust flags based on your printer: local/network, color/mono, etc.)
ippAddInteger(request, IPP_TAG_PRINTER, IPP_TAG_ENUM, "printer-type", 1, PRINTER_TYPE_LOCAL | PRINTER_TYPE_PRINT);

// Send the request
http_t *http = httpConnectEncrypt("localhost", ippPort(), 0);
ipp_t *response = ippDoRequest(http, request, "/admin/");

Option B: Upload a Custom PPD File

If you have a custom PPD not in CUPS' default library, use the ppd-file attribute to upload it directly:

// Add this to your existing request instead of `ppd-name`
ippAddFile(request, IPP_TAG_PRINTER, "ppd-file", "/path/to/MyCustomDriver.ppd", NULL);

CUPS will automatically process and store this PPD for the new printer.

Option C: Use Make/Model for Auto-Matching

If you prefer letting CUPS pick the driver, use the printer-make-and-model attribute with the exact string from lpinfo -m (not just a generic "HP LaserJet"):

ippAddString(request, IPP_TAG_PRINTER, IPP_TAG_TEXT, "printer-make-and-model", NULL, "HP LaserJet P2015");

Note: This is less reliable if multiple PPDs match the model, or if CUPS doesn't have the driver in its library.

Common Pitfalls to Avoid #

• Using physical file paths for ppd-name: CUPS expects the logical name from lpinfo -m, not /etc/cups/ppd/MyPrinter.ppd.
• Missing basic attributes: CUPS may reject requests that don't include printer-info, printer-location, or printer-type.
• Permissions issues: If using a local PPD file, ensure it's owned by root:lp with permissions 644 so CUPS can access it.
• Incorrect IPP operation code: Make sure you're using CUPS_ADD_PRINTER (not CUPS_MODIFY_PRINTER unless updating an existing printer).

Verify the Setup #

After sending the request, confirm the driver is associated correctly:

• Run lpstat -p MyNewPrinter -l and check for the PPD line.
• Access the CUPS web interface (http://localhost:631) to view the printer's details and confirm the driver is listed.

内容的提问来源于stack exchange，提问作者hmtinc