topic Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output in Python Questions

arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

MaximeDemers — Sat, 11 Dec 2021 09:31:55 GMT

I have a geoservice that get some text stored from a table in order to return a json string to a javascript client. However, the arcpy.SetParameter() seems to have problem to returns the escaped new lines character (\\n)

my_dict = {"key1" : "test is a string with\nsome escaped characters\nsuch newlines"} 
my_json = json.dumps(my_dict)
print(my_json)
>>> '{"key1": "test is a string with\\nsome escaped characters\\nsuch newlines"}'

arcpy.SetParameter(0, my_json)

in the javascript console the response is the following which is not a valid json:

{"key1" : "test is a string with
some escaped characters
such newlines"}

Is there a solution?

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

DanPatterson_Retired — Mon, 19 Dec 2016 20:41:59 GMT

does the parameter that you are setting normally accept multiline input? perhaps setparameter removes what isn't needed or required

raw formatting doesn't work either I suspect either

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

MaximeDemers — Tue, 20 Dec 2016 12:51:52 GMT

Hi Dan,

It seems its an issue with the SetParameter(). I can't find any solution for this case. Is this should be reported to Esri support?

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

DanPatterson_Retired — Tue, 20 Dec 2016 12:56:38 GMT

Well I can't figure it out... so it either something we are missing or something wrong.

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JoshuaBixby — Tue, 20 Dec 2016 16:29:01 GMT

Did you try raw formatting the string like Dan suggested? If so, what were the results?

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

MaximeDemers — Sat, 11 Dec 2021 09:31:58 GMT

Using raw strings does not help.

my_dict = {"key1" : r"test is a string with\nsome escaped characters\nsuch newlines"} 
my_json = json.dumps(my_dict)
print(my_json)
>>> '{"key1": "test is a string with\\\\nsome escaped characters\\\\nsuch newlines"}'

arcpy.SetParameter(0, my_json)


Same problem with the json in the javascript console:
{"key1" : "test is a string with
some escaped characters
such newlines"}

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JamesCrandall — Wed, 21 Dec 2016 13:57:35 GMT

my_dict = {"key1" : "test is a string with\\nsome escaped characters\\nsuch newlines"} ‍

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JoshuaBixby — Wed, 21 Dec 2016 14:07:42 GMT

It will be interesting if escaping the new lines works. I won't be totally surprised if it doesn't. There are at least a couple geoprocessing tools that refuse to work properly with Python new lines. I usually find a workaround, but I am not sure what that would be in this case.

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

MaximeDemers — Wed, 21 Dec 2016 14:10:01 GMT

@James Crandall : This is not working.

@Joshua Bixby : The work around I have found is to replace the \\n with other characters, for instance <br> before passing it into the SetParameter() and then in the javavscript I replace back the <br> with \n. Off course that's not really satisfying to proceed this way.

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JoshuaBixby — Wed, 21 Dec 2016 14:15:14 GMT

Kludgy, but it seems to work for you. I would open an Esri Support case to log a bug, which this seems to be, but whether stuff like this gets fixed or not is a total crap shoot from my experience.

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JamesCrandall — Wed, 21 Dec 2016 14:24:24 GMT

Not sure if this is correct for the .dumps() but try setting strict param:

my_json = json.dumps(my_dict, strict=False)‍

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

MaximeDemers — Wed, 21 Dec 2016 14:29:55 GMT

@James Crandall : There is no such parameter in json.dumps(), at least in python 2.7

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JamesCrandall — Sat, 11 Dec 2021 09:32:02 GMT

Turn the dictionary into a string, then try to load that with the strict param:

my_dict = '{"key1" : "test is a string with\\nsome escaped characters\\nsuch newlines"}'
my_jsonloads = json.loads(my_dict, strict=False)
my_json = json.dumps(my_jsonloads)
print(my_json)‍‍‍‍‍‍‍‍

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

DanPatterson_Retired — Sat, 11 Dec 2021 09:32:05 GMT

>>> import json
>>> dir(json)
['JSONDecodeError', 'JSONDecoder', 'JSONEncoder', '__all__', '__author__', 
'__builtins__', '__cached__', '__doc__', '__file__', '__loader__', '__name__', 
'__package__', '__path__', '__spec__', '__version__', '_default_decoder', 
'_default_encoder', 'decoder', 'dump', 'dumps', 'encoder', 'load', 'loads',
 'scanner']

>>> # above in python 3.5
>>> 
>>> # now over to old-school
>>> import json
>>> dir(json)
['JSONDecoder', 'JSONEncoder', '__all__', '__author__', '__builtins__', 
'__doc__', '__file__', '__name__', '__package__', '__path__', '__version__', 
'_default_decoder', '_default_encoder', 'decoder', 'dump', 'dumps', 'encoder',
 'load', 'loads', 'scanner']
>>> # above in python 2.7
‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

JamesCrandall — Wed, 21 Dec 2016 18:18:08 GMT

FYI: this still produces the OP's result.

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

KevinHibma — Thu, 05 Jan 2017 22:13:27 GMT

I'm late to this, but if the goal is to simply remove the escaped chars, try:

re.sub(r"\s", " ", my_dict['key1'])

>> 'test is a string with some escaped characters such newlines'

From the comment: string - Python - Why does str.strip() automatically removes all the escape characters? - Stack Overflow

Re: arcpy.SetParameter() - Problem passing escaped string as geoprocessing service output

MaximeDemers — Thu, 19 Jan 2017 18:35:06 GMT

Thank you, but the aim is to keep the the newlines. Removing it is not wanted.