make an MSBuild Copy Task only copy if the source is newer regardless of size

Question

I'm currently using an msbuild file to copy some files to the public documents folder when my EXE is compiled. My current script includes this:

<Target Name="DeployToPublicDocuments"
              Inputs="@(DeploymentItems)"
              Outputs="$(PublicDocumentsFolder)%(Path)\%(DeploymentItems.RecursiveDir)%(DeploymentItems.Filename)%(DeploymentItems.Extension)">
        <Copy SourceFiles="%(DeploymentItems.FullPath)"
            DestinationFiles="$(PublicDocumentsFolder)%(Path)\%(DeploymentItems.RecursiveDir)%(DeploymentItems.Filename)%(DeploymentItems.Extension)"
                Condition="!Exists('$(PublicDocumentsFolder)%(Path)\%(DeploymentItems.RecursiveDir)%(DeploymentItems.Filename)%(DeploymentItems.Extension)')" />

This code only copies if the destination doesn't exist. However, I want to replace the destination if my source is newer. How do I modify my script to make that happen? I see the SkipUnchangedFiles flag, but it also compares file size to determine if the destination should be overwritten. That is not what I want.

Scroll

How are you determining when it is newer? The reason I ask is because if someone modifies the destination by hand, the destination is now newer based on modified time. The only other time to use is created time and that would only work if you delete the source before creating it. – Garvin

I'm using the Modification Date for determining what is newer. As long as the destination is newer than the source, I don't want to overwrite it. – Scroll

Answer 1

Your copy's conditional can be changed as follows:

    <Copy SourceFiles="%(DeploymentItems.FullPath)"
        DestinationFiles="$(PublicDocumentsFolder)%(Path)\%(RecursiveDir)%(Filename)%(DeploymentItems.Extension)"
            Condition="%(Filename)!='' AND (!Exists('$(PublicDocumentsFolder)%(Path)\%(RecursiveDir)%(Filename)%(DeploymentItems.Extension)') OR $([System.DateTime]::Parse('%(ModifiedTime)').Ticks) &gt; $([System.IO.File]::GetLastWriteTime('$(PublicDocumentsFolder)%(Path)\%(RecursiveDir)%(Filename)%(DeploymentItems.Extension)').Ticks))" />

%(ModifiedTime) = Modified Datetime of the source file

$([System.IO.File]::GetLastWriteTime($(PublicDocumentsFolder)%(Path)\%(RecursiveDir)%(Filename)%(DeploymentItems.Extension))) = Modified Datetime of the destination file, if it exists

Let me know if this works or not, did not test.

Garvin

I ran your code and got this: A numeric comparison was attempted on "%(ModifiedTime)" that evaluates to "2013-05-22 15:53:21.5210339" instead of a number – Scroll

It looks like I got it working with this enhancement: $([System.DateTime]::Parse('%(ModifiedTime)').Ticks) – Scroll

One more minor edit: you need to specify .Ticks on the end of the second DateTime clause as well. – Scroll

Answer 2

I think you may have misread the docs:

SkipUnchangedFiles

If true, skips the copying of files that are unchanged between the source and destination. The Copy task considers files to be unchanged if they have the same size and the same last modified time.

http://msdn.microsoft.com/en-us/library/vstudio/3e54c37h.aspx

Hortensiahorter

So if someone modifies a destination file by hand, I don't want that file overwritten until the source is newer than it. SkipUnchangedFiles doesn't achieve that, true? – Scroll

@Scroll I think I may have misread your question! Understand what you want now. Perfectly reasonable, but I don't know how to do it. – Hortensiahorter