[Ovmsdev] Simple TCP client
Michael Balzer
dexter at expeedo.de
Tue Aug 25 04:39:41 HKT 2020
Soko,
the webserver REST API provides a simple command execution endpoint you
can use to execute Javascript code as well.
See:
-
https://docs.openvehicles.com/en/latest/components/ovms_webserver/docs/index.html#authorization
The scripting system has a simple metrics getter and JSON encoder.
See:
-
https://docs.openvehicles.com/en/latest/userguide/scripting.html#ovmsmetrics
- https://docs.openvehicles.com/en/latest/userguide/scripting.html#json
Example executing a shell command:
- http://myovms.local/api/execute?apikey=mypassword&output=text&command=stat
Example getting a single metric value:
-
http://myovms.local/api/execute?apikey=mypassword&type=js&output=text&command=print(OvmsMetrics.Value("v.b.soc"))
Examples getting multiple metrics JSON encoded:
-
http://myovms.local/api/execute?apikey=mypassword&type=js&output=text&command=JSON.print(OvmsMetrics.GetValues("m.net."))
-
http://myovms.local/api/execute?apikey=mypassword&type=js&output=text&command=JSON.print(OvmsMetrics.GetValues(["v.c.charging","v.b.soc"]))
(URI encode as needed)
Also see the scripting documentation and the plugin examples on how to
add custom modules providing custom commands.
Of course you can also write data to files and poll those via HTTP.
That's one of the reasons the webserver provides access to the file
system. Write files in C++ as usual, see scripting object VFS for script
based file I/O.
Regards,
Michael
Am 24.08.20 um 18:01 schrieb Soko:
>
> Hi again,
>
> Before I decide how to do this I would like to explore the other way:
> My home automation is polling the data from OVMS.
>
> I have had a look to the HTTP API. But it seems this is an API for the
> server on the internet and not for OVMS itself, correct?
>
> Next option: My home automation does a simple HTTP-GET to OVMS and
> reads data like this.
> Is there a way to read metrics like this?
> I have found the config->webserver site. I could point it to an own
> dir like /store/data. Now I could write/update one file there from my
> vehicle-module called "current" with all the data I need. Then simply
> to a http-get to 192.168.4.1/current and I get the data of the file.
> Is it easy - and most important: allowed - to write/update into a file
> in OVMS.
>
> thanks heaps for the input
>
> Soko
>
> On 24.08.2020 01:46, Mark Webb-Johnson wrote:
>> The vehicle module is definitely the wrong place to do this.
>>
>> If you really want to implement in C++, I suggest you look at the
>> ovms_server_v3 module. You could use that as a template for what you
>> need. It should periodically read from the metrics, and send what you
>> need to your home automation.
>>
>> You should also consider a javascript plugin to do this. That would
>> probably be simpler and easier to update (without firmware changes).
>> If it is a common home automation system, you could write it as a
>> plugin and share for others with the same system.
>>
>> Regards, Mark
>>
>>> On 24 Aug 2020, at 12:00 AM, Soko <ovms at soko.cc
>>> <mailto:ovms at soko.cc>> wrote:
>>>
>>> Hi Mark,
>>>
>>> I have my own home automation running at home. I want to push the
>>> current values (SoC, odometer, ...) once my car is in the driveway
>>> and OVMS is booked into my WiFi. My home automation has a TCP server
>>> running were I process the data further.
>>>
>>> I don't want to the OVMS Server functionality as I'm not a Linux
>>> guy, don't want the data in the internet and no SIM use on the OVMS.
>>>
>>> So does the canlog_tcpclient.cpp take care of the concurrency etc.
>>> correctly? I will do the same in my code. Or should I start a
>>> separate task from the vehicle task for every push?
>>>
>>> thx
>>> Soko
>>>
>>> On 23 August 2020 16:37:46 CEST, Mark Webb-Johnson
>>> <mark at webb-johnson.net <mailto:mark at webb-johnson.net>> wrote:
>>>
>>> What are you trying to do?
>>>
>>> From a design point of view, it seems strange to have an outgoing tcp connection from a vehicle module. Those modules need to be very responsive and realtime.
>>>
>>> Mongoose is the correct approach. But take care, because most of the work is done in the network (not vehicle) task, so you need to deal with mutex and other concurrency issues.
>>>
>>> Regards, Mark
>>>
>>> On 23 Aug 2020, at 7:54 PM, Soko <ovms at soko.cc
>>> <mailto:ovms at soko.cc>> wrote: Hey everyone, I'm trying to
>>> send a simple tcp msg to a remote tcp-server. I've looked
>>> into the FreeRTOS example
>>> (esp-idf\examples\protocols\sockets\tcp_client\) which works
>>> (kinda) but OVMS behaves weirdly when I do it like that.
>>> Thomas pointed me to mongoose... So is this the way to go? I
>>> would take canlog_tcpclient.cpp as a model... Ohh... and is
>>> it OK if I send my tcp msg in the vehcile task? Mongoose
>>> should take care of unforeseen errors so the task shouldn't
>>> block, right? thx Soko
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Michael Balzer * Helkenberger Weg 9 * D-58256 Ennepetal
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