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QMI and MBIM in Python, Javascript…

This is what introspection looks like

The libqmi and libmbim libraries are every day getting more popular to control your QMI or MBIM based devices. One of the things I’ve noticed, though, is that lots of users are writing applications in e.g. Python but then running qmicli or mbimcli commands, and parsing the outputs. This approach may work, but there is absolutely no guarantee that the format of the output printed by the command line programs will be kept stable across new releases. And also, the way these operations are performed may be suboptimal (e.g. allocating QMI clients for each operation, instead of reusing them).

Since the new stable libqmi 1.26 and libmbim 1.24 releases, these libraries integrate GObject Introspection support for all their types, and that provides a much better integration within Python applications (or really, any other language supported by GObject Introspection).

The only drawback of using the libraries in this way, if you’re already using and parsing command line interface commands, is that you would need to go deep into how the protocol works in order to use them.

For example, in order to run a DMS Get Capabilities operation, you would need to create a Qmi.Device first, open it, then allocate a Qmi.Client for the DMS service, then run the Qmi.Client.get_capabilities() operation, receive and process the response with Qmi.Client.get_capabilities_finish(), and parse the result with the per-TLV reader method, e.g. output.get_info() to process the Info TLV. Once the client is no longer needed, it would need to be explicitly released before exiting. A full example doing just this is provided in the libqmi sources.

In the case of MBIM operations, there is no need for the extra step of allocating a per-service client, but instead, the user should be more aware of the actual types of messages being transferred, in order to use the correct parsing operations. For example, in order to query device capabilities you would need to create a Mbim.Device first, open it, create a message to query the device capabilities, send the message, receive and process the response, check whether an error is reported, and if it isn’t, fully parse it. A full example doing just this is provided in the libmbim sources.

Of course, all these low level operations can also be done through the qmi-proxy or mbim-proxy, so that ModemManager or other programs can be running at the same time, all sharing access to the same QMI or MBIM ports.

P.S.: not a true Python or GObject Introspection expert here, so please report any issue found or improvements that could be done 😀

And special thanks to Vladimir Podshivalov who is the one that started the hard work of setting everything up in libqmi. Thank you!



Help wanted in ModemManager/NetworkManager development!

If you have free time, and experience with gtk-doc documentation or man pages, ModemManager developers will thank you [1] if you help writing the new libmm-common, libmm-glib and mmcli documentation:
[MM 0.6] Documentation

If you have free time, basic GLib/GIO development knowledge, and a broadband modem (either USB dongle or internal) to play with, ModemManager developers will thank you [2] if you port any of the missing plugins to the new codebase in the 06-api branch:
[MM 0.6] Plugins

If you have free time, NetworkManager installed [3] and basic GLib/GIO development knowledge, ModemManager developers will thank you [4] if you help providing support for the new ModemManager1 interface in NetworkManager:
[MM 0.6] NM integration

[1] You’ll get one beer for free if we ever meet.
[2] You’ll get two beers for free if we ever meet.
[3] This already leaves out Jose, Luca and Alfred.
[4] You’ll get three! beers for free if we ever meet.

Knight’s Tour brute force algorithm example

(From Wikipedia) The Knight’s Tour is a mathematical problem involving a knight on a chessboard. The knight is placed on the empty board and, moving according to the rules of chess, must visit each square exactly once. A knight’s tour is called a closed tour if the knight ends on a square attacking the square from which it began (so that it may tour the board again immediately with the same path). Otherwise the tour is open.

Just developed my brute-force algorithm implementation, using GLib and based on a simple recursive function.

Download and try it here!

As an example of result, this is the open Knight’s Tour found by the algorithm in a 5×5 board, starting from position [0,0]:

And this one, the first Knight’s Tour found by the algorithm in a 8×8 board, starting from position [0,0]:

Both examples above show open Knight’s Tours.