Python-function to extract absolute path

Hi

I'm not quite sure I'm understanding your use-case, but have you tried using something like:

It seems to work for me.

David

Hi

I've written the following two helper functions to accomplish exactly this:

import re
import os.path
 
def expand_fme_macros(input):
    # Expands all FME macro values in input string
    matches = re.findall("\$\((\w+)\)", input)
    for group in matches:
        input = input.replace("$(%s)" % group, FME_MacroValues[group])
    return input
 
def get_fully_qualified_path(input):
    # Expands input string into an absolute path
    input = os.path.abspath(expand_fme_macros(input))
    dir = os.path.dirname(input)
    if not dir:
        input = os.path.join(FME_MacroValues['FME_MF_DIR'], input)
    return os.path.abspath(input)

Use expand_fme_macros() for strings in general, and get_fully_qualified_path() for path and file names.

Usage, given that the parameter value "FME_MF_DIR" = "c:\my_data_dir\"

• expand_fme_macros("The value of FME_MF_DIR is $(FME_MF_DIR)") returns "The value of FME_MF_DIR is c:\my_data_dir\"
• get_fully_qualified_path("my_data.mdb") returns "c:\my_data_dir\my_data.mdb"
• get_fully_qualified_path("temp\my_data.mdb") returns "c:\my_data_dir\temp\my_data.mdb"
• get_fully_qualified_path("temp\..\my_data.mdb") returns "c:\my_data_dir\my_data.mdb"
• get_fully_qualified_path("d:\another\dir\my_data.mdb") returns "d:\another\dir\my_data.mdb"

This works for any value found in FME_MacroValues, notably:

• FME internal parameters, such as FME_MF_DIR, FME_JOB_ID, FME_DATA_REPOSITORY, FME_SERVER_NAME, etc.
• Published parameters
• Private parameters

Hope this helps.

David

Thanks, quite an elegant solution for replacing every parameter-like value surrounded by $( ). Will probably use your findall and .replace("$(%s)") to tidy-up at least the double reg-ex and list-indices in my code.

Still leaves the clear sign more people are dealing with this matter using regex-wizardry.

Makes me a bit uneasy, as there might be a real value which meets the regex, but is no FME-parameter, making the workspace barf at a "key not found" error or something alike when searching the fme.macroValue dictionary.

Would like Safe software to take that code-responsibility. Found the cause of this problem this afternoon, cooked up above code, but have to get used to it a little before I trust it in a high-load production environment.

Kind regards,

Martin

edit: Made my reply vegetarian by having 'values meet' in stead of 'meat'.

Feels like we should include @david_r 's functions in the Python FME API. I'll discuss with the appropriate authorities.

I agree that expand_fme_macros() could use some error checking:

def expand_fme_macros(input):
    # Expands all FME macro values in input string
    matches = re.findall("\$\((\w+)\)", input)
    for group in matches:
        try:
            input = input.replace("$(%s)" % group, FME_MacroValues[group])
        except:
            pass
    return input
 

This way it'll just silently ignore any unknown macros $(...)

David

The authorities like it. PR filed as 68362.

Hi,

Perhaps I am missing something here, but when I run the following in a Startup Python Script:

The output I get is:

What build of FME is being run that doesn't auto-evaluate the $(FME_MF_DIR)?

Thanks,

Yes, I've also noticed that, FME tries to be pretty clever about macros in hard coded strings in your code.

But if you read a string containing an FME macro from e.g. a configuration file, it does not get expanded automatically. That is a potential use case for the function above.

Thanks for the clarification David!

Hi, I tried to implement @david_r solution into a Pythoncaller, sadly the resulting workspace won't run and complains about undefined macro %s. I needed the solution since I read a parameter set containing FME Parameter references and use one of them to pass to a FeatureReader (for windows paths) as a filename. If I pass one of the parameter file strings, it complains that it cannot find the file, all though the file verily exist..

This has been released as part of FME 2017.0 . Visit http://www.safe.com/downloads to download it and give it a spin.