This try catches the exception:
try die X::AdHoc;
say "Got to the end";
The output shows that the program continues:
Got to the end
If I attempt it with shell and a command that doesn't exit with 0, the try doesn't catch it:
try shell('/usr/bin/false');
say "Got to the end";
The output doesn't look like an exception:
The spawned command '/usr/bin/false' exited unsuccessfully (exit code: 1)
in block <unit> at ... line ...
What's going on that this makes it through the try?
The answer is really provided by Jonathan Worthington:
https://irclog.perlgeek.de/perl6-dev/2017-04-04#i_14372945
In short, shell() returns a Proc object. The moment that object is sunk, it will throw the exception that it has internally if running the program failed.
$ 6 'dd shell("/usr/bin/false")'
Proc.new(in => IO::Pipe, out => IO::Pipe, err => IO::Pipe, exitcode => 1, signal => 0, command => ["/usr/bin/false"])
So, what you need to do is catch the Proc object in a variable, to prevent it from being sunk:
$ 6 'my $result = shell("/usr/bin/false"); say "Got to the end"'
Got to the end
And then you can use $result.exitcode to see whether it was successful or not.
I've been trying to pattern for the case where a user types in an invalid directory:
# let dir = Unix.opendir "adfalf";;
Exception: Unix.Unix_error (Unix.ENOENT, "opendir", "adfalf").
My function is as follows:
let files_of_dir d =
try
let dir = Unix.opendir d in
...
with
Unix_error (uerr, ucommand, dir) -> raise Not_found
Except I keep getting the compilation error:
Error: This variant pattern is expected to have type exn
The constructor Unix_error does not belong to type exn
I don't understand what I'm doing wrong w/ the pattern matching. If anyone could help me on this it would be greatly appreciated!
Some Other Notes:
I've been compiling my code using the following command on terminal:
ocamlbuild filename.byte
You need to say Unix.Unix_error, not just Unix_error. Note that this is what appears in your sample session.
I am calling a R script from Scala by using scala.sys.process. This script takes a command line argument in JSON format and processes it. I am using rjson's fromJSON function to store the JSON in a list.
This works very fine when I execute the R script from the command line:
$ ./dfChargerFlink.R '{"Id":"1","value":"ABC"}'
But when I call it from scala, I get the following error:
Error in fromJSON(commandArgs(1)) : unexpected character '''
Execution halted
This is the code I am using:
val shellCommand = "./dfChargerFlink.R '"+arg+"'"
return shellCommand !!
where arg is the JSON string.
You can notice that I have appended " ' " to both the sides of the JSON string as if I don't, I get this error:
Error in fromJSON(commandArgs(1)) : unclosed string
Execution halted
How can this be solved? Is it some bug?
I can't seem to catch an exception when using json.loads even though I specifically call it out. I largely see this when trying to stress my server with lots of client connection sending data very quickly. See my error below:
(I've replaced my IP address with X's in the error code)
EX: Unterminated string starting at: line 1 column 49 (char 48) Data:
'{"ap-hdop":0.55,"rtcmin":"38","ap-latdec":3.134,"a' error: uncaptured
python exception, closing channel
(:Unterminated string
starting at: line 1 column 49 (char 48)
[//faraday_server_handler.py|collect_incoming_data|34]
[/usr/lib/python2.7/json/init.py|loads|338]
[/usr/lib/python2.7/json/decoder.py|decode|366]
[/usr/lib/python2.7/json/decoder.py|raw_decode|382])
I understand this that the code fails because I simply miss a double quotes on the line:
'{"ap-hdop":0.55,"rtcmin":"38","ap-latdec":3.134,"a'
This line is usually a LOT longer so that "a.... was supposed to keep going and complete it's quotes.
Here's my relevant code:
def collect_incoming_data(self, data):
"""Read an incoming message from the client, place JSON message data into buffer"""
#self.logger.debug('collect_fing_data() -> (%d bytes)\n"""%s"""', len(data), data)
try:
loaded_data = json.loads(data)
except ValueError, ex:
self.handle_error()
type,value,traceback = sys.exc_info()
print type
#print "Collect Incoming Data: " . time.strftime("%Y-%m-%d %H:%M:%S",time.gmtime())
print "EX: ", ex
print "Data: ",repr(data)
Any ideas? I scoured the internet to see if I can find this issue, but I appear to be setting up to capture the exception which everyone else having this issue with loads seems to suggest to do.
EDIT 3/1/2016 - Evening
Commenting out my exception handle_error() let me see more of the error:
except ValueError, ex:
self.handle_error()
type,value,traceback = sys.exc_info()
print type
#print "Collect Incoming Data: " . time.strftime("%Y-%m-%d %H:%M:%S",time.gmtime())
print "EX: ", ex
print "Data: ",repr(data)
Below is my new error, I've commented out personal data. It's apparent that the issue I really have now is in-fact the unterminated string
EX: Unterminated string starting at:
line 1 column 49 (char 48) Data:
'{"ap-hdop":0.55,"rtcmin":"31","ap-latdec":XX.XXX,"a' EX: No JSON object could be decoded Data:
'p-latdeg":34,"adc6":2006,"adc7":2007,"adc4":2004,"adc5":2005,"adc2":2002,"adc3":2003,"adc0":2000,"adc1":2001,"gpio-0":30,"gpio-1":50,"gpio-2":70,"speed":5.0,"adc8":2008,"rtcday":"01","longdeg":118,"longdec":XX.XXX,"altitude":31.0,"ap-speed":0.0,"ap-pdop":0.77,"lat-dir":"N","long-dir":"W","hdop":0.01,"ap-rf":0,"alt-units":"M","rtcdow":"2","callsign":"XXXXX","ap-callsign":"XXXXX","id":1,"ap-id":1,"rtcyear":"2016","rtcmon":"03","ap-vdop":0.66,"ap-lat-dir":"N","vdop":0.02,"rtchour":"22","latdec":XX.XXX,"latdeg":34,"ap-longdeg":118,"ap-longdec":XX.XXX,"rtcsec":"15","ap-altitude":86.0,"ap-long-dir":"W","pdop":0.01,"ap-alt-units":"M","faraday-port":0}'
OK my original question was answered which was "Why am I not catching the ValueError exception even though I am providing code to do just that?"
#tadhg McDonald-jensen was correct with his comment to remove my call to handle_error().
I still have some other issues but they are a different question. Thanks!
I am using the R package rjson to download weather data from Wunderground.com. Often I leave the program to run and there are no problems, with the data being collected fine. However, often the program stops running and I get the following error message:
Error in fromJSON(paste(raw.data, collapse = "")) : unclosed string
In addition: Warning message:
In readLines(conn, n = -1L, ok = TRUE) :
incomplete final line found on 'http://api.wunderground.com/api/[my_API_code]/history_20121214pws:1/q/pws:IBIRMING7.json'
Does anyone know what this means, and how I can avoid it since it stops my program from collecting data as I would like?
Many thanks,
Ben
I can recreate your error message using the rjson package.
Here's an example that works.
rjson::fromJSON('{"x":"a string"}')
# $x
# [1] "a string"
If we omit a double quote from the value of x, then we get the error message.
rjson::fromJSON('{"x":"a string}')
# Error in rjson::fromJSON("{\"x\":\"a string}") : unclosed string
The RJSONIO package behaves slightly differently. Rather than throwing an error, it silently returns a NULL value.
RJSONIO::fromJSON('{"x":"a string}')
# $x
# NULL