Regarding the addition of printers (devices) to the Papple-based printer application using IPP calls.

[Kaushik1216]

Hello Everyone!

I'm working on a GSoC '24 project, with one of the main goals being to add printers (devices) to the printer application through IPP calls.

Steps:

Using device ID information, I make an IPP call to the printer application to retrieve the appropriate driver.
Using the driver and additional information, I then make a call to the printer application to add the printer.
Below are the implementations of both IPP calls.

I believe I might be using incorrect options for the IPP calls. Could anyone help me troubleshoot this? I have debugged the code but am not getting meaningful error messages.

code
gboolean
cph_cups_printer_add (CphCups *cups,
const char *printer_name,
const char *printer_uri,
const char *ppd_file,
const char *info,
const char *location)
{

    ipp_t		        *request,		
	                *response;		
    ipp_attribute_t         *attr;		
    http_t	                *http;			
    int                     timeout_param = CUPS_TIMEOUT_DEFAULT;

    http = httpConnect2("kaushik.local", 8001, NULL, AF_UNSPEC,
                       HTTP_ENCRYPTION_IF_REQUESTED, 1, 30000, NULL);

    request = ippNewRequest(IPP_OP_PAPPL_FIND_DRIVERS);
    ippAddString(request, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_URI), "system-uri", NULL, "ipp://localhost/ipp/system");
    // I will pass here correct device id for devices
    //ippAddString(request, IPP_TAG_OPERATION, IPP_CONST_TAG(IPP_TAG_TEXT), "smi55357-device-id", NULL, "MFG:HP;CMD:PJL,PML,DW-PCL;MDL:HP LaserJet Tank MFP 260x;CLS:PRINTER;DES:HP LaserJet Tank MFP 2606dn;MEM:MEM=308MB;PRN:381U0A;S:0300000000000000000000000000000000;COMMENT:RES=600x2;LEDMDIS:USB#ff#04#01;CID:HPLJPCLMSMV2;MCT:MF;MCL:FL;MCV:4.2;");
    response = cupsDoRequest(http, request, "/ipp/system");

    attr = ippFindAttribute(response, "smi55357-driver-col", IPP_TAG_BEGIN_COLLECTION);
    const char *driver = NULL;

    if (attr != NULL) {
        driver = ippGetString(attr, 0, NULL);
    }

    request = ippNewRequest(IPP_OP_CREATE_PRINTER);

    ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "system-uri", NULL, "ipp://localhost/ipp/system");
    ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_KEYWORD, "printer-service-type", NULL, "print");
    ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_KEYWORD, "smi55357-driver", NULL, driver);
    ippAddString(request, IPP_TAG_OPERATION, IPP_TAG_URI, "smi55357-device-uri", NULL, printer_uri);
    ippAddString(request, IPP_TAG_PRINTER, IPP_TAG_NAME, "printer-name", NULL, printer_name);

    response = cupsDoRequest(http, request, "/ipp/system");

    gboolean status = FALSE;
    if (cupsLastError() != IPP_STATUS_OK) {
            status = false;
    }
    ippDelete(response);
    httpClose(http);

    return status;

}

[michaelrsweet]

It would be helpful to know what errors you are getting, meaningful or not. Calling cupsLastErrorString() will at least give you the human-readable error message from the printer application, as will looking at the logs from the printer application...

One thing of note in the included code - connecting to the mDNS hostname will almost certainly result in a remote network connection (even on the same machine) which will fail since remote admin is disabled by default in printer applications (for what should be obvious security reasons...)