Azure Functions Temp storage

Question

When I try to save a file to the Temp storage in Azure Functions directory (D:\home\data\temp\response.pdf), I get the following error. Why can't I write to this directory?

mscorlib: Exception has been thrown by the target of an invocation. System: An exception occurred during a WebClient request. mscorlib: ***Could not find a part of the path 'D:\home\data\temp\response.pdf'.*** 2017-09-19T07:05:24.353 Function completed (Failure, Id=3aa4b740-ba8a-465c-ad7c-75b38fa2a472, Duration=334ms) 2017-09-19T07:06:31  No new trace in the past 1 min(s). 

Answer 1

I recommend using System.IO.Path.GetTempPath() as this will always give us a valid path for any given system.

Additionally, functions may execute multiple times simultaneously for a given instance, so it's best to ensure we have a unique path for each execution. Here's a simple example:

var tempPath = Path.Combine(Path.GetTempPath(), Guid.NewGuid().ToString()); 

Alternately, we can use System.IO.Path.GetTempFileName() which will additionally create the file before returning the full path and unique filename.

Answer 2

I find a better choice. You can use System.IO.Path.GetTempFileName() this create a %userprofile%\Local\Temp\tmpE128.tmp file