Cotel provides a desktop GUI for exploration of CoAP messaging, and includes these features:
Cotel runs as a native executable. We have created an AppImage based installer for Linux, available from the repository Releases page.
Of course you also may build and run from source. See Development below. We have not attempted to build for Windows or OSX.
Cotel uses libcoap for CoAP messaging, and Dear ImGui for its UI library.
The AppImage installer for Linux is a single file. Simply mark it executable and run it. AppImage is designed to be agnostic to a user's particular distro. It's also possible to integrate Cotel into the desktop environment. See the AppImage Running page for details.
See Cotel's user guide for details on how to use it.
Required elements:
| Name | Notes |
|---|---|
| libcoap | Use commit 1739507 of the library, from 2020-08. At time of writing, v4.2.1 from 2019-11 is the most recent tag, but we need the more recent commit. |
| Nim | Use v1.4.2 of the language, or higher. See install page. |
| imgui | Nim module for GUI. Use v1.78 or higher. We currently build with v1.79. Also requires the shared library for cimgui. See details below. |
| parsetoml | Nim module to read TOML configuration file. v0.5.0 |
| tempfile | Nim module to create temporary directory for logging. v0.1.7 |
You must build libcoap from source for development, using either autotools or CMake. See BUILDING. libcoap supports several TLS libraries. We have tested only with TinyDTLS, which may be installed as a submodule of libcoap, as described in the build instructions.
The core of Cotel is written in Nim. It generates C code internally, which it then compiles to generate the executable. For Nim I find it easiest to install from the choosenim utility, as described on the Nim install page. For Nim modules, I use the Nimble installer, which is bundled with Nim.
imgui is the Nim binding module for the Dear ImGui GUI library. See the imgui module README.md for installation.
In addition, you must compile the cimgui shared library, which provides a C interface to Dear ImGui, which itself is written in C++. The imgui module includes the required source. Simply run make in the imgui module src/imgui/private/cimgui directory.
Finally, make the cimgui library visible to the generated Cotel executable -- via either copy/symlink to the same directory or with ldconfig.
To build Cotel, execute the command below from the top level directory. The compiled executable will be available in the build/bin directory.
$ nim build src/gui/main
Install the generated cotel executable, the cotel.conf configuration file, and the cimgui.so shared library into a directory. Start Cotel in development mode with:
$ ./cotel --dev
In development mode, all resources are in the startup directory. cotel.conf is generated with reasonable property defaults, but please review the Local Setup view for specifics.
If you'd like to make improvements to Cotel, see the architecture document to get started.