CODEWITHSUNDEEP
autodesk-forge
C3pLus
C3pLus

Reputation: 93

Autodesk Forge download object, but cannot tell if it is a Revit model or zip file

I was downloading Revit models from BIM360 team hub via ForgeAPI using the following uri.

https://developer.api.autodesk.com/oss/v2/buckets/:bucketKey/objects/:objectName

All my objectName ended with .rvt. So I downloaded and saved them as rvt file. However I noticed that some of the files cannot be opened by Revit. They are actually not rvt files but zip files. So I have to change the extension to .zip and unzip the file to get real 'rvt` files.

My Problem is that not all files is zip file. I cannot tell from the API because the URI I request is always ended with .rvt.

Upvotes: 1

Views: 204

Answers (1)

Jeremy Tammik
Jeremy Tammik

Reputation: 8294

Every Unix OS provides the file command, a standard utility program for recognising the type of data contained in a computer file:

https://en.wikipedia.org/wiki/File_(command)

A zip file is directly recognised and reported like this:

$ file test_dataset.zip
test_dataset.zip: Zip archive data, at least v2.0 to extract

A Revit RVT model is a Windows compound document file, so it generates the following output:

$ file little_house_2021.rvt
little_house_2021.rvt: Composite Document File V2 Document, Cannot read section info

Hence you can use the same algorithm as file does to distinguish between RVT and ZIP files.

Afaik, file just looks at the first couple of bytes in the given file.

The Python programming language offers similar utilities; try an Internet search for distinguish file type python; the first hits explain How to check type of files without extensions in Python and point to the filetype Python project.

Other programming languages can provide similar functionality.

Upvotes: 2

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