Exporting attachments and ignoring attributes that don't have attachments using ArcPy?

Question

I'm using the following python script to export photo attachments:

from arcpy import da
import os

attachTable = arcpy.GetParameterAsText(0)
origTable = arcpy.GetParameterAsText(1)
nameField = arcpy.GetParameterAsText(2)
fileLocation = arcpy.GetParameterAsText(3)
with da.SearchCursor(attachTable,['DATA','ATT_NAME','REL_GLOBALID']) as attachCursor:
    for attRow in attachCursor:
        binaryRep = attRow[0]
        fileName = attRow[1]
        relID = attRow[2]

with da.SearchCursor(origTable,['GlobalID', nameField]) as originCursor:
    for origRow in originCursor:
        origID = origRow[0]
        origName = origRow[1]
        if origID == relID:
            break
        open(fileLocation + os.sep + origName + ".jpg", 'wb').write(binaryRep.tobytes())
        del origRow

I get this error after running it:

Runtime error

Traceback (most recent call last): File "", line 7, in IOError: [Errno 2] No such file or directory: u'W:\work\dry_creek_exp\images\Hwy 20/Crowley Rd (turn left).jpg'

... I believe this file doesn't exist because I didn't have a photo attached to it. My question is, does anyone know of a way to get python to ignore these files that don't have attachments?? I hoping when I save this code as a script and run it on bigger projects that it will help the run time.

Answer 1

You can add some additional nested if conditions to check for values before the open method. Also you do not have to del the row object because you are using the with loop:

with da.SearchCursor(attachTable,['DATA','ATT_NAME','REL_GLOBALID']) as attachCursor:
    for attRow in attachCursor:
        if attRow[0]:
            binaryRep = attRow[0]
            if attRow[1]:
                fileName = attRow[1]
                if attRow[2]:
                    relID = attRow[2]

with da.SearchCursor(origTable,['GlobalID', nameField]) as originCursor:
    for origRow in originCursor:
        if origRow[0]:
            origID = origRow[0]
            if origRow[1]:
                origName = origRow[1]
                    if origID <> relID:
                        open(fileLocation + os.sep + origName + ".jpg", 'wb').write(binaryRep.tobytes())

Currently your cursor logic is going through the entire attachTable then cursoring through the origTable. With this structure you may be overwriting the binaryRep, fileName, and relID variables with only the last instance/record found that have these values. You may need to nest the second cursor within the first cursor after the relID = attRow[2] statement to reference all found values within the attachTable.