topic Re: How to check if in an Edit Session using python and arcpy in Python Questions

How to check if in an Edit Session using python and arcpy

VishalShah2 — Sat, 11 Dec 2021 16:13:48 GMT

I am currently working on a tool that uses the updateCursor function but the tool needs to be in an edit session to use. However some who may use the tool may end up not being in an edit session before running the tool and get an error. Rather than come ask me every time about the error, I'd like to implement an if statement in the script in the beginning that checks if the user is currently in an edit session, if they are then run tool. if not, a dialogue box explaining they need to be in an edit session and ask if they want the script to turn editor on. Formatted as such:

#if edit session is on:
    #run tool
#elif edit session is off:
    #dialogue box explaining user has to be in edit session and asking if they want the script to turn editor on (Yes or no option):
        #if yes:
            #run tool
        #if no:
            #quit‍‍‍‍‍‍‍‍

I am trying to do this without using the work done by Mark Cederholm as referenced in this post: How do I access ArcObjects from Python?, and code examples provided by Matt Wilkie in his "Snippits.py" file.

Re: How to check if in an Edit Session using python and arcpy

DanPatterson_Retired — Wed, 08 Mar 2017 21:26:27 GMT

Did you read up on the Editor in the help? It would be best to run your functionality from a tool in arctoolbox, to ensure or validate that you are in an edit session than relying on the user getting into an edit session manually

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Sat, 11 Dec 2021 16:13:50 GMT

Dan, I was thinking along the lines of the format I have below. This way users wouldn't have to turn editor on manually but just have to simply click yes or no. Would this work?

if isEditing == True:
    run tool
elif isEditing == False:
    dialogue box pops up informing user to be in edit session and ask if they want script to turn it on for them:
        if yes:
            arcpy.startEditing()
        elif no:
            quit‍‍‍‍‍‍‍‍

Re: How to check if in an Edit Session using python and arcpy

DanPatterson_Retired — Sat, 11 Dec 2021 16:13:53 GMT

I would just bail .... totally untested of course.

# -*- coding: UTF-8 -*-
import sys
import os
import arcpy

#edit_me = sys.argv[1]
fc = r"C:\GIS\array_projects\data\Pro_base.gdb\Line"
workspace = os.path.dirname(fc)
edit = arcpy.da.Editor(workspace)
if edit.isEditing:
    print("you are in an edit session")
else:
    print("you aren't in an edit session")
    sys.exit‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How to check if in an Edit Session using python and arcpy

JoshuaBixby — Thu, 09 Mar 2017 16:40:32 GMT

Good idea, unfortunately it doesn't seem to work. I just tested a file and enterprise geodatabase, and arcpy.da.Editor appears to only be aware of itself, i.e., isEditing() only returns True if the instantiated editor object starts an edit session.

Re: How to check if in an Edit Session using python and arcpy

JoshuaBixby — Thu, 09 Mar 2017 16:42:21 GMT

If an edit session doesn't exist, when exactly does the user see the error? Right away, or is it after the tool has ran for a while? What is the function or method call that is generating the error? What specifically is the error?

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Thu, 09 Mar 2017 16:50:46 GMT

Hi Joshua, so the error pops up milliseconds to like 2 seconds after you start running the tool. The tool is a custom export tool that has the function updateCursor function, which updates the fields to a particular value rather than leaving the blank fields as null values. The error states that updateCursor can not be used outside of the edit session and the rest of the tool does not run. Hence why I want to create this check to see if edit session is active and if not, to provide a prompt for the user that enables the user to select 'Yes' or 'No' to allow the script to turn an edit session on and then run the tool.

Re: How to check if in an Edit Session using python and arcpy

IanMurray — Thu, 09 Mar 2017 16:56:38 GMT

Yea we ran into this question a couple weeks ago where the Map Document and the arcpy Editor object aren't aware of each others editting status and their isn't a way to pythonicly check if an edit session is going on in the map document without using ArcObjects. I pointed them to the below post but I'm not sure if they got anywhere with it or not.

https://community.esri.com/thread/190456-arcpydaeditor-setup-for-tool

http://gis.stackexchange.com/questions/61708/checking-via-arcpy-if-arcmap-is-in-edit-session

Re: How to check if in an Edit Session using python and arcpy

JoshuaBixby — Thu, 09 Mar 2017 17:14:35 GMT

iamurray‌ provided some good links, I suggest you read over them.

Given the tools generates an error anywhere from "milliseconds to like 2 seconds," which is pretty quick (it isn't like it runs for tens of minutes and then errors out), I would go with a try except block. Python handles EAFP (easier to ask forgiveness than permission) much better than other languages, so generating exceptions and handling them isn't seen as a big deal. Unlike some of the code examples in the StackExchange thread that Ian referenced, you really don't want to trap all exceptions with a generic except clause. It is better to trap the specific exception relating to edit sessions because you want other errors to still propagate through to the user.

Re: How to check if in an Edit Session using python and arcpy

IanMurray — Thu, 09 Mar 2017 17:27:43 GMT

I wonder if instead of trying to check if an edit session is going on, just check if a LOCK file is present for that workspace the file you are hoping to edit is in for the file in question. A file GDB creates a LOCK file of the same name regardless of whether it is being editted within an ArcMap Edit Session or using an Editor Object(FeatureClassName.ed.lock). Its not perfect since obviously more than one person can be accessing the dataset and create a lock on it, but at least you can check if the data is being editted at all.

Just spitballing here.

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Thu, 09 Mar 2017 17:33:25 GMT

I've never worked with exceptions before so I was wondering if you have an example of what it may look like and the formatting of the script so I may try that out.

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Thu, 09 Mar 2017 17:57:53 GMT

Joshua, so it's actually a Runtime Error that says "Objects in this class cannot be updated outside an edit session [lists the feature class]." Then it says "Failed to execute (ToolName)." So there wasn't an error code you get and so I'm wondering if using exceptions would work then?

Re: How to check if in an Edit Session using python and arcpy

JoshuaBixby — Sat, 11 Dec 2021 16:13:56 GMT

Something along the lines of:

fc = # path to feature class
fields = # list of fields

try:
    with arcpy.da.UpdateCursor(fc, fields) as cur:
        for row in cur:
            # functional code
except RuntimeError as err:
    if "cannot be updated outside an edit session" in err.message:
        arcpy.AddMessage("No edit session exists")
    else:
        raise err‍‍‍‍‍‍‍‍‍‍‍‍
‍‍‍‍‍‍‍‍‍‍‍‍

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Sat, 11 Dec 2021 16:13:58 GMT

So I believe doing it this way may actually work in a sense to get the Message Box using the python add-ins module. However, one issue I am having is doing the check to see which value from the message box the user selected. This is the first thing that happens when the user selects to use this tool. This is an add-in portion of the tool. Any help on figuring out how to call on the value in the Message Box will be helpful. The mb_type here is 4 so that the message box type is yes/no. Other mb_types and information about python add-ins can be found here. So my issue is figuring out how to see if the Message Box value the user selected was a yes or a no.

import arcpy
import pythonaddins
import os

toolPath = r'path to toolboox.tbx'
workspace = 'some workspace'
editor = arcpy.da.Editor(workspace)


if editor.isEditing == 'true':
    pythonaddins.GPToolDialog(toolPath, 'CustomExportTool')
elif editor.isEditing == 'false': 
    pythonaddins.MessageBox("You must be in an edit session to run the Custom Export Tool. If you wish to turn an edit session on, please click 'yes'. If you do not wish to turn an edit session on, please click 'no'.", "Turn Editor On?", 4)
        if MessageBox == 'yes':
            editor.startEditing(False, False)
            pythonaddins.GPToolDialog(toolPath, 'CustomExportTool')
        elif MessageBox == 'no':
            quit‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How to check if in an Edit Session using python and arcpy

JoshuaBixby — Fri, 10 Mar 2017 17:23:26 GMT

The message box function returns a string, so provide a variable for the return string to get stored in:

msg = pythonaddins.MessageBox("You must be in an edit session to run the Custom Export Tool. If you wish to turn an edit session on, please click 'yes'. If you do not wish to turn an edit session on, please click 'no'.", "Turn Editor On?", 4)‍

Then check the value stored in the variable.

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Fri, 10 Mar 2017 17:37:20 GMT

And would you define this variable at the beginning or where would you implement that variable in the code I have?

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Fri, 10 Mar 2017 20:03:53 GMT

Hey Joshua

I just tried what you suggested but the Message Box did not pop up and so the value could not be stored. Any solutions on fixing this?

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Sat, 11 Dec 2021 16:14:01 GMT

Joshua is this what you had in mind?

import arcpy
import pythonaddins
import os

toolPath = r'path to toolboox.tbx'
workspace = 'some workspace'
editor = arcpy.da.Editor(workspace)


if editor.isEditing == 'true':
    pythonaddins.GPToolDialog(toolPath, 'CustomExportTool')
elif editor.isEditing == 'false': 
    pythonaddins.MessageBox("You must be in an edit session to run the Custom Export Tool. If you wish to turn an edit session on, please click 'yes'. If you do not wish to turn an edit session on, please click 'no'.", "Turn Editor On?", 4)
    msg = pythonaddins.MessageBox("You must be in an edit session to run the Custom Export Tool. If you wish to turn an edit session on, please click 'yes'. If you do not wish to turn an edit session on, please click 'no'.", "Turn Editor On?", 4)
        if msg == 'yes':
            editor.startEditing(False, False)
            pythonaddins.GPToolDialog(toolPath, 'CustomExportTool')
        elif msg == 'no':
            quit‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

Re: How to check if in an Edit Session using python and arcpy

JoshuaBixby — Sat, 11 Mar 2017 15:45:36 GMT

Several comments:

As has been discussed throughout this thread, calling isEditing will always return False unless an edit session was started by calling startEditing because the Editor is only aware of itself, i.e., it can't tell if another edit session is already open on a workspace.
Even if the Editor was aware of more than itself, the code still wouldn't work because what is returned from calling isEditing are Python booleans, not strings. The code would have to read: if editor.isEditing == True: or simply if editor.isEditing: . The same goes for how you are checking for false.
When checking the return value from the MessageBox, string comparisons are case sensitive. Neither of the conditions as written will ever be met because what is returned is 'Yes' or 'No' .

Re: How to check if in an Edit Session using python and arcpy

VishalShah2 — Sat, 11 Dec 2021 16:14:04 GMT

Joshua, I am currently working on another tool where setting the user input equal to a variable is crucial. Is this the right way to do it in terms of setting the variable equal to something the user can do an input and then a conditional to check on what they input?

if editor.isEditing == True:
    pythonaddins.GPToolDialog(toolPath, 'CustomExportTool')
elif editor.isEditing == False: 
    pythonaddins.MessageBox("", "", 4)
    msg = pythonaddins.MessageBox("", "", 4)
        if msg == 'Yes':‍‍‍‍‍‍