File exists check
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It would be good if we could get the result of whether a file exists in G Code.
For example could M36 be changed to return an error code 1 or 2 if the file isn't found?
At present it returns the error state as part of the JSON response but returns and error state of zero even if the file isn't found. -
I've added this to the work list.
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@dc42 Has it been decided what firmware version this will be in? Thanks!
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@donstauffer I believe it will be in 3.3
exists name -> bool Yields true if 'name' is a valid variable or object model element name and is not null (available in RRF 3.3beta3 and later). Especially useful for testing whether a particular parameter has been provided when a file macro was called.
https://duet3d.dozuki.com/Wiki/GCode_Meta_Commands#Section_Functions
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@phaedrux This is about files, not variables.
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@donstauffer ah, my mistake.
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@phaedrux I found a very awkward workaround: M471 is the only code I know of which returns a result that tells you something about the existence of a file. Unfortunately, it does that when potentially deleting the file in question. I didn't want that, so I had to set up a system of dummy "semaphor" files created in parallel with the file I was interested in, which fortunately my macros created, so it could keep the semaphors consistent with the actual file status.
But all that turned what would have been about a half page of code with a file exists capability into about 2 pages.
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@dc42 would have to comment on whether it's been implemented yet for sure.
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As a work around you can use M38.
M38: Compute SHA1 hash of target file
Example:
M38 gcodes/myfile.gUsed to compute a hash of a file on the SD card and returns a hexadecimal string which is the SHA1 of the file. If the file cannot be found, then the string "Cannot find file" is returned instead.
