# How to enable “skip duplicate” NuGet feature?

## post by flibustier7seas on Aug 5, 2024

Hi everyone,

I’ve been using the “dotnet nuget push” command with the “–skip-duplicate” flag. As I understand it, if the NuGet package already exists in the repository, it should return a “Conflict” (409) HTTP status code. However, I’m encountering an issue where my Nexus NuGet Hosted Repository returns a “Bad Request” (400) status code instead.

```sh
dotnet nuget push ".\Published\MyPackage.0.1.0.nupkg" -s http://my-nexus.local/repository/nuget/index.json -k <api-key> --skip-duplicate

# warn : You are running the 'push' operation with an 'HTTP' source, 'http://my-nexus.local/repository/nuget/index.json'. Non-HTTPS access will be removed in a future version. Consider migrating to an 'HTTPS' source.
# Pushing MyPackage.0.1.0.nupkg to 'http://my-nexus.local/repository/nuget'...
# warn : You are running the 'push' operation with an 'HTTP' source, 'http://my-nexus.local/repository/nuget/'. Non-HTTPS access will be removed in a future version. Consider migrating to an 'HTTPS' source.
#   PUT http://my-nexus.local/repository/nuget/
#   BadRequest http://my-nexus.local/repository/nuget/ 92ms
# error: Response status code does not indicate success: 400 (Bad Request).
#
#
# Usage: dotnet nuget push [arguments] [options]
#
# Arguments:
#   [root]  Specify the path to the package and your API key to push the package to the server.
#
# Options:
#   -h|--help                      Show help information
#   --force-english-output         Forces the application to run using an invariant, English-based culture.
#   -s|--source <source>           Package source (URL, UNC/folder path or package source name) to use. Defaults to DefaultPushSource if specified in NuGet.Config.
#   -ss|--symbol-source <source>   Symbol server URL to use.
#   -t|--timeout <timeout>         Timeout for pushing to a server in seconds. Defaults to 300 seconds (5 minutes).
#   -k|--api-key <apiKey>          The API key for the server.
#   -sk|--symbol-api-key <apiKey>  The API key for the symbol server.
#   -d|--disable-buffering         Disable buffering when pushing to an HTTP(S) server to decrease memory usage.
#   -n|--no-symbols                If a symbols package exists, it will not be pushed to a symbols server.
#   --no-service-endpoint          Does not append "api/v2/package" to the source URL.
#   --interactive                  Allow the command to block and require manual action for operations like authentication.
#   --skip-duplicate               If a package and version already exists, skip it and continue with the next package in the push, if any.
#
```

```http
HTTP/1.1 400 Bad Request
...
<error xmlns="http://schemas.microsoft.com/ado/2007/08/dataservices/metadata">
  <code>400</code>
  <message xml:lang="en-US">Repository does not allow updating assets: nuget</message>
</error>
```

Has anyone else faced this issue or can anyone provide guidance on how to resolve this so that the correct status code is returned?

Thanks in advance for your help!

## post by flibustier7seas on Apr 7, 2025

It seems that Nexus doesn’t fully implement the NuGet API, because the “Push a package” method should return 409 when a package with the provided ID and version already exists, but the Nexus API returns 400 instead.

Links:
- [Push and Delete, NuGet API \| Microsoft Learn](https://learn.microsoft.com/en-us/nuget/api/package-publish-resource#push-a-package)
- [NuGet publish duplicate package fails with 400 instead of 409 · Issue #463 · sonatype/nexus-public · GitHub](https://github.com/sonatype/nexus-public/issues/463)