How can I access ink levels of printers programmatically?

Question

Okay, this is a Windows specific question.

I need to be able to access the ink levels of a printer connected to a computer. Possibly direct connection, or a network conn

Answer 1

An alternative approach could be using ipp. While most of the printers I tried support both, I found one which only worked with ipp and one that only worked for me with snmp.

Simple approach with ipptool:

• Create file colors.ipp:

{
    VERSION 2.0
    OPERATION Get-Printer-Attributes

    GROUP operation-attributes-tag
    ATTR charset "attributes-charset" "utf-8"
    ATTR naturalLanguage "attributes-natural-language" "en"
    ATTR uri "printer-uri" $uri
    ATTR name "requesting-user-name" "John Doe"
    ATTR keyword "requested-attributes" "marker-colors","marker-high-levels","marker-levels","marker-low-levels","marker-names","marker-types"
}

• Run:

ipptool -v -t ipp://192.168.2.126/ipp/print colors.ipp

• The response:

"colors.ipp":
    Get-Printer-Attributes:
        attributes-charset (charset) = utf-8
        attributes-natural-language (naturalLanguage) = en
        printer-uri (uri) = ipp://192.168.2.126/ipp/print
        requesting-user-name (nameWithoutLanguage) = John Doe
        requested-attributes (1setOf keyword) = marker-colors,marker-high-levels,marker-levels,marker-low-levels,marker-names,marker-types
    colors                                                               [PASS]
        RECEIVED: 507 bytes in response
        status-code = successful-ok (successful-ok)
        attributes-charset (charset) = utf-8
        attributes-natural-language (naturalLanguage) = en-us
        marker-colors (1setOf nameWithoutLanguage) = #00FFFF,#FF00FF,#FFFF00,#000000,none
        marker-high-levels (1setOf integer) = 100,100,100,100,100
        marker-levels (1setOf integer) = 6,6,6,6,100
        marker-low-levels (1setOf integer) = 5,5,5,5,5
        marker-names (1setOf nameWithoutLanguage) = Cyan Toner,Magenta Toner,Yellow Toner,Black Toner,Waste Toner Box
        marker-types (1setOf keyword) = toner,toner,toner,toner,waste-toner

marker-levels has current toner/ink levels, marker-high-levels are maximus (so far I've only seen 100s here), marker-names describe meaning of each field (tip: for colors you may want to strip everything after first space, many printers include cartridge types in this field).

Note: the above is with cups 2.3.1. With 2.2.1 I had to specify the keywords as one string instead ("marker-colors,marker-h....). Or it can be left altogether, then all keywords are returned.

More on available attributes (may differ between printers): https://www.cups.org/doc/spec-ipp.html
More on executing ipp calls (including python examples): https://www.pwg.org/ipp/ippguide.html