Hi All,

To the point: What is the best way to handle Shell when it doesn't return data or something else goes wrong?

I am adding current weather and forecasts to my movies/streaming app…totally unnecessary but I'm gonna do it anyways  
I have previously used openweathermap although I have never tried to integrate into a Gambas. Openweathermap is now charging for access to the api and I'm not going to pay    :x
A few days ago I found openmeteo and it's free (at least until it's not), and I have been learning how to use the api and I am now working to integrate into a form using Shell. The api is fast but it does seem to just not respond sometimes and I don't know why….that also sometimes happens when using a browser too. When it does not respond with JSON data it makes the form unresponsive/locked up. I do not get the message box Error at all, it will hang until I stop it from the IDE. I do have error handling plus I added a Print to help me see what is going on. When it's not returning data I get this in the IDE console:
Google doesn't give me anything on that error.
Here's how I'm getting the data: (from Gambas One member SteveDee's website that I stumbled onto and added my own error handling)

I haven't tested below, just a little re-code to make sure if you get no result returned is taken care of and using a special manner (learned from master Benoit himself when I had an issue with Shell) of using Exec, that usually does the job. Just give it a try, I wrote it right here so typo's might have occured.
If I have time I will try it myself, but a bit to busy ATM.

OpenWeatherMap is still free. The URLs are
Current Weather Forecast

(Click to enlarge)

gbWilly said

I haven't tested below, just a little re-code to make sure if you get no result returned is taken care of and using a special manner (learned from master Benoit himself when I had an issue with Shell) of using Exec, that usually does the job. Just give it a try, I wrote it right here so typo's might have occured.

Code (gambas)

1. Dim Result As String
2. Dim collJson As Collection
3. Dim sCommand As String
4.  
5. sCommand = "curl 'https://api.open-meteo.com/v1/forecast?latitude=45.633331&longitude=-122.599998&timezone=America%2FLos_Angeles&current=temperature_2m&current=precipitation,rain,weather_code,showers,snowfall,wind_speed_10m&precipitation_unit=inch&temperature_unit=fahrenheit'"
6.  
7. Try Exec [System.Shell, "-c", sCommand] To Result
8. If Error Or Len(Result) = 0 Then
9.   Message.Info("Error or empty result returned")
10. Else
11.   collJson = Json.decode(Result, True)
12.   'Print "Temp: ", collJson["current"]["temperature_2m"]
13.   label1.Text = collJson["current"]["time"]
14.   label3.Text = collJson["current"]["temperature_2m"] & " F"
15.   weathercode.Value = collJson["current"]["weather_code"]
16.   label5.Text = "Wind Speed: " & collJson["current"]["wind_speed_10m"]
17.   label6.Text = "Precipitation: " & collJson["current"]["precipitation"]
18.   'there's more code here that deals with what weather_code is returned
19. Endif
20.  
21.  

If I have time I will try it myself, but a bit to busy ATM.

Thanks gbWilly, I will test here shortly.

thatbruce said

OpenWeatherMap is still free. The URLs are
Current Weather

Code (gambas)

1. https://api.openweathermap.org/data/2.5/weather?lat=&1&lon=&2&appid=&3&units=&4&lang=&5

Forecast

Code (gambas)

1. https://api.openweathermap.org/data/2.5/forecast?lat=&1&lon=&2&appid=&3&units=&4&lang=&5

Current Weather_001.png

Well yes technically it's still free but for 3.0 it seems you have to subscribe and give payment details even if you don't go over a limit which appears to be 1000 calls a day…I'm still not giving them my CC number    I started looking elsewhere because a php script using openweathermap 2.5 I have suddenly stopped giving me high and low temps in the forecast. I haven't touched that script in years so I'm still trying to figure out what's wrong with it. I'm looking at it now but since I have now spent a couple days with open-meteo, I'll stick with it unless it causes problems. Nevertheless, I'd love to learn a better way to handle the Shell when it doesn't do what you're expecting. Thanks Bruce!

EDIT: And how long before they cutoff access to 2.5? Who knows. I'll just continue with openmeteo.

gbWilly said

I haven't tested below, just a little re-code to make sure if you get no result returned is taken care of and using a special manner (learned from master Benoit himself when I had an issue with Shell) of using Exec, that usually does the job. Just give it a try, I wrote it right here so typo's might have occured.

Code (gambas)

1. Dim Result As String
2. Dim collJson As Collection
3. Dim sCommand As String
4.  
5. sCommand = "curl 'https://api.open-meteo.com/v1/forecast?latitude=45.633331&longitude=-122.599998&timezone=America%2FLos_Angeles&current=temperature_2m&current=precipitation,rain,weather_code,showers,snowfall,wind_speed_10m&precipitation_unit=inch&temperature_unit=fahrenheit'"
6.  
7. Try Exec [System.Shell, "-c", sCommand] To Result
8. If Error Or Len(Result) = 0 Then
9.   Message.Info("Error or empty result returned")
10. Else
11.   collJson = Json.decode(Result, True)
12.   'Print "Temp: ", collJson["current"]["temperature_2m"]
13.   label1.Text = collJson["current"]["time"]
14.   label3.Text = collJson["current"]["temperature_2m"] & " F"
15.   weathercode.Value = collJson["current"]["weather_code"]
16.   label5.Text = "Wind Speed: " & collJson["current"]["wind_speed_10m"]
17.   label6.Text = "Precipitation: " & collJson["current"]["precipitation"]
18.   'there's more code here that deals with what weather_code is returned
19. Endif
20.  
21.  

If I have time I will try it myself, but a bit to busy ATM.

Working so far. I'm testing over and over until it does it's thing where is doesn't respond with data…I'll post back when that happens.

rj71 said

Working so far. I'm testing over and over until it does it's thing where is doesn't respond with data…I'll post back when that happens.

Nice…  

rj71 said

gbWilly said

I haven't tested below, just a little re-code to make sure if you get no result returned is taken care of and using a special manner (learned from master Benoit himself when I had an issue with Shell) of using Exec, that usually does the job. Just give it a try, I wrote it right here so typo's might have occured.

Code (gambas)

1. Dim Result As String
2. Dim collJson As Collection
3. Dim sCommand As String
4.  
5. sCommand = "curl 'https://api.open-meteo.com/v1/forecast?latitude=45.633331&longitude=-122.599998&timezone=America%2FLos_Angeles&current=temperature_2m&current=precipitation,rain,weather_code,showers,snowfall,wind_speed_10m&precipitation_unit=inch&temperature_unit=fahrenheit'"
6.  
7. Try Exec [System.Shell, "-c", sCommand] To Result
8. If Error Or Len(Result) = 0 Then
9.   Message.Info("Error or empty result returned")
10. Else
11.   collJson = Json.decode(Result, True)
12.   'Print "Temp: ", collJson["current"]["temperature_2m"]
13.   label1.Text = collJson["current"]["time"]
14.   label3.Text = collJson["current"]["temperature_2m"] & " F"
15.   weathercode.Value = collJson["current"]["weather_code"]
16.   label5.Text = "Wind Speed: " & collJson["current"]["wind_speed_10m"]
17.   label6.Text = "Precipitation: " & collJson["current"]["precipitation"]
18.   'there's more code here that deals with what weather_code is returned
19. Endif
20.  
21.  

If I have time I will try it myself, but a bit to busy ATM.

Working so far. I'm testing over and over until it does it's thing where is doesn't respond with data…I'll post back when that happens.

Just happened about 2/10 times I tested. Same result, form freezes and your error message did not show. I got that error again in the console: (JSONCollection 0x5590da9747d8)

 It does seem I'm getting (JSONCollection 0x5590da9747d8) in the console even if it is successful and returns data. My bad on that…I didn't notice it.

rj71 said

Just happened about 2/10 times I tested. Same result, form freezes and your error message did not show. I got that error again in the console: (JSONCollection 0x5590da9747d8)

Try this:
It should give you some status on the error happening (I hope.. )

Warning Not tested in IDE, but typed here as is…
…while waiting for my oldie to be finished installing.

gbWilly said

rj71 said

Just happened about 2/10 times I tested. Same result, form freezes and your error message did not show. I got that error again in the console: (JSONCollection 0x5590da9747d8)

Try this:

Code (gambas)

1. Private $hProcess As Process
2. Private $sOut As String
3. Private $bError As Boolean
4.  
5. Public Sub GetData()
6.  
7.   Dim Result As String
8.   Dim collJson As Collection
9.   Dim sCommand As String
10.  
11.   sCommand = "curl 'https://api.open-meteo.com/v1/forecast?latitude=45.633331&longitude=-122.599998&timezone=America%2FLos_Angeles&current=temperature_2m&current=precipitation,rain,weather_code,showers,snowfall,wind_speed_10m&precipitation_unit=inch&temperature_unit=fahrenheit'"
12.  
13.   $hProcess = Exec [System.Shell, "-c", sCommand] Wait For Input As "_Process"
14.  
15.   If Not $bError Then
16.     collJson = Json.decode($sOut, True)
17.     'Print "Temp: ", collJson["current"]["temperature_2m"]
18.     label1.Text = collJson["current"]["time"]
19.     label3.Text = collJson["current"]["temperature_2m"] & " F"
20.     weathercode.Value = collJson["current"]["weather_code"]
21.     label5.Text = "Wind Speed: " & collJson["current"]["wind_speed_10m"]
22.     label6.Text = "Precipitation: " & collJson["current"]["precipitation"]
23.     'there's more code here that deals with what weather_code is returned
24.   Else
25.     Message.Error($sOut)
26.   Endif
27.  
28. End
29.  
30. Public Sub _Process_Read()
31.  
32.   Dim sLine As String
33.  
34.   sLine = Read #Last, Lof(Last)
35.   If Not IsNull(Trim(sLine)) Then
36.     $sOut &= Trim(sLine) & "\n"
37.   Endif
38.  
39. End
40.  
41. Public Sub _Process_Error(MyError As String)
42.  
43.   $sOut &= MyError
44.   If Not IsNull($hProcess) Then
45.     $hProcess.Kill
46.   Endif
47.  $bError = True
48.  
49. End
50.  
51. Public Sub _Process_Kill()
52.    
53.   Debug "\n--End of process--\n"
54.  
55. End
56.  

It should give you some status on the error happening (I hope.. )

Warning Not tested in IDE, but typed here as is…
…while waiting for my oldie to be finished installing.

Thanks gbWilly, I'll have to try it tomorrow though. My gf wants to go out for a really early dinner to her favorite place. I'll check back in tomorrow!

I don't get the command using sh -c , why not just use the command?

I'd do it like this…


I know using To implies Wait but i like to also use Wait as i think i have found it not working as expected with just To

or better still, do not use the curl command with Exec but use the gambas component gb.net.curl and HttpClient.Download()

A simple trick more relevant to your original question is to use 2>&1 with Shell

Shell "command 2>&1" Wait To Result
or..
That diverts any stderr messages to stdout (your Result String)

There should be some kind of short-key for that!!!!!!! It really helps on the occasion and a "friendly reminder" of that GAbash syntax would be soooooo helpful.
(If I had a beer for every time that I've typed I'd be slightly more than immoderately diagonal.)

Yes, I know, I'm adding it to my IDE shortcuts now.  :?