how to replace string in file using msbuild?

Question

I want to replace a string such "how r u" in file test.xml with a string "i am fine" in another file xy.xml.using regular expression in ms build.

ie i have to read string from one file(xy.xml) and replace it in another file test.xml. so please provide necessary steps to solve this issue with example

Answer 1

EDIT: This answer is obsolete. Use solution below...

Use ReadLinesFromFile task to get replacement string from the xy.xml file. Check this

Then use value from xy.xml as a replacement string for FileUpdate task. Check this

And put it all together ;)

Answer 2

An updated to answer from James

  <UsingTask TaskName="ReplaceTextInFiles" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.$(VsBuildTaskBinarySuffix).dll">
<ParameterGroup>
  <MatchExpression ParameterType="System.String" Required="true" />
  <ReplacementExpression ParameterType="System.String" Required="true" />
  <InputFile ParameterType="Microsoft.Build.Framework.ITaskItem" Required="true" />      
  <IsTextReplaced ParameterType="System.Boolean"  Output="True"/>
</ParameterGroup>
<Task>
  <Reference Include="System.Core" />
  <Using Namespace="System" />
  <Using Namespace="System.IO" />
  <Using Namespace="System.Text.RegularExpressions" />
  <Code Type="Fragment" Language="cs">
    <![CDATA[
      bool isMatchFound = false;
      string filecontent = "";
      string path = InputFile.ItemSpec;

      Log.LogMessage(MessageImportance.High, "[ReplaceTextInFiles]: Match= " + MatchExpression);
      Log.LogMessage(MessageImportance.High, "[ReplaceTextInFiles]: Replace= " + ReplacementExpression);

      IsTextReplaced = false;
      using(StreamReader rdr = new StreamReader(path))
      {
        filecontent = rdr.ReadToEnd();
        if (Regex.Match(filecontent, MatchExpression).Success)
        {
          filecontent = Regex.Replace(filecontent, MatchExpression, ReplacementExpression);
          isMatchFound = true;            
        }
      }

      if(isMatchFound){
        using(StreamWriter wrtr = new StreamWriter(path))
        {
          wrtr.Write(filecontent);
          IsTextReplaced = true;
          Log.LogMessage(MessageImportance.Normal, "[ReplaceTextInFiles]: Replaced text in file:" + path);
        }
      }       
    ]]>
  </Code>
</Task>

Answer 3

If you prefer not using third party (community) binaries, nor embedding code into your msbuild project, I'd suggest creating a simple task library which implements File.WriteAllText and can later host other tasks :

using System.IO;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;

public class FileWriteAllText : Task
{
    [Required]
    public string Path { get; set; }
    [Required]
    public string Contents { get; set; }

    public override bool Execute()
    {
        File.WriteAllText(Path, Contents);
        return true;
    }
}

Then you can replace, append, etc. in msbuild :

<UsingTask TaskName="FileWriteAllText" AssemblyFile="MyTasks.dll" />
<FileWriteAllText Path="test.xml"
     Contents="$([System.Text.RegularExpressions.Regex]::Replace(
         $([System.IO.File]::ReadAllText('test.xml')), 'how r u', 'i am fine'))" />

Answer 4

The answer from @csharptest.net is good, but it doesn't work on DotNetCore. I would have added this as a comment, but I don't have enough reputation.

On DotNetCore you have to update:

• Task Factory to "RoslynCodeTaskFactory"
• Task Assembly to "$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll"
• Remove the reference to "System.Core"
• The consuming Target has to specify the "AfterTargets" attribute as "Build"

Everything else should be the same:

<Project Sdk="Microsoft.NET.Sdk.Web">
  ...

  <UsingTask
    TaskName="ReplaceFileText"
    TaskFactory="RoslynCodeTaskFactory"
    AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.Core.dll">
    <ParameterGroup>
      <InputFilename ParameterType="System.String" Required="true" />
      <OutputFilename ParameterType="System.String" Required="true" />
      <MatchExpression ParameterType="System.String" Required="true" />
      <ReplacementText ParameterType="System.String" Required="true" />
    </ParameterGroup>
    <Task>
      <Using Namespace="System"/>
      <Using Namespace="System.IO"/>
      <Using Namespace="System.Text.RegularExpressions" />
      <Code Type="Fragment" Language="cs">
        <![CDATA[  
          File.WriteAllText(
            OutputFilename,
            Regex.Replace(File.ReadAllText(InputFilename), MatchExpression, ReplacementText)
            );
        ]]>
      </Code>
    </Task>
  </UsingTask>

  <Target Name="AfterBuildStep" AfterTargets="Build">
    <ReplaceFileText
       InputFilename="$(OutputPath)File.exe.config" 
       OutputFilename="$(OutputPath)File.exe.config" 
       MatchExpression="\$version\$" 
       ReplacementText="1.0.0.2" />
  </Target>
</Project>

Answer 5

I ran the both replacements against same file that sits on a Unix drive and used the unc path to it \server\path...:

<ReplaceFileText
  InputFilename="$(fileToUpdate)"
  OutputFilename="$(fileToUpdate)"
  MatchExpression="15.0.0"
  ReplacementText="15.3.1"/>


<FileUpdate Files="$(fileToUpdate2)"
            Regex="15.0.0"
            ReplacementText="15.3.1" />

and the cs custom action above does not add the bom; however the FileUpdate did:

%head -2 branding.h branding2.h
==> branding.h <==
#/* branding.h
#** This file captures common branding strings in a format usable by both sed and C-preprocessor.

==> branding2.h <==
#/* branding.h
#** This file captures common branding strings in a format usable by both sed and C-preprocessor.

Thanks csharptest.net - I was doing doing exec's with perl subtitute commands for unix builds.

Answer 6

This is no longer required... you can now inject C# into the project/build file...

Define a custom task and parameters as follows:

<UsingTask TaskName="ReplaceFileText" TaskFactory="CodeTaskFactory" AssemblyFile="$(MSBuildToolsPath)\Microsoft.Build.Tasks.v4.0.dll">
  <ParameterGroup>
    <InputFilename ParameterType="System.String" Required="true" />
    <OutputFilename ParameterType="System.String" Required="true" />
    <MatchExpression ParameterType="System.String" Required="true" />
    <ReplacementText ParameterType="System.String" Required="true" />
  </ParameterGroup>
  <Task>
    <Reference Include="System.Core" />
    <Using Namespace="System" />
    <Using Namespace="System.IO" />
    <Using Namespace="System.Text.RegularExpressions" />
    <Code Type="Fragment" Language="cs">
      <![CDATA[
            File.WriteAllText(
                OutputFilename,
                Regex.Replace(File.ReadAllText(InputFilename), MatchExpression, ReplacementText)
                );
          ]]>
    </Code>
  </Task>
</UsingTask>

Then simply call it like any other MSBuild task

<Target Name="AfterBuild">
  <ReplaceFileText 
    InputFilename="$(OutputPath)File.exe.config" 
    OutputFilename="$(OutputPath)File.exe.config" 
    MatchExpression="\$version\$" 
    ReplacementText="1.0.0.2" />
</Target>

The above example replaces "$version$" with "1.0.0.2" in the "File.exe.config" located in the output directory.

Answer 7

There is very simple approach to just replace string in a file:

  <Target Name="Replace" AfterTargets="CoreCompile">
      <PropertyGroup>
          <InputFile>c:\input.txt</InputFile>
          <OutputFile>c:\output.txt</OutputFile>
      </PropertyGroup>
      <WriteLinesToFile
          File="$(OutputFile)"
          Lines="$([System.IO.File]::ReadAllText($(InputFile)).Replace('from','to'))"
          Overwrite="true"
          Encoding="Unicode"/>
  </Target>

See https://learn.microsoft.com/en-us/visualstudio/msbuild/property-functions?view=vs-2019 to explore inlinable C# code. [System.Text.RegularExpressions.Regex] included into the list.