update_service.rb

require_relative "base_service"

module Files
  class UpdateService < Files::BaseService
    def execute
      allowed = ::Gitlab::GitAccess.new(current_user, project).can_push_to_branch?(ref)

      unless allowed
        return error("You are not allowed to push into this branch")
      end

      unless repository.branch_names.include?(ref)
        return error("You can only create files if you are on top of a branch")
      end

      blob = repository.blob_at_branch(ref, path)

      unless blob
        return error("You can only edit text files")
      end

      content =
        if params[:encoding] == 'base64'
          Base64.decode64(params[:content])
        else
          params[:content]
        end

      sha = repository.commit_file(
        current_user,
        path,
        content,
        params[:commit_message],
        params[:new_branch] || ref
      )

      after_commit(sha)
      success
    rescue Gitlab::Satellite::CheckoutFailed => ex
      error("Your changes could not be committed because ref '#{ref}' could not be checked out", 400)
    rescue Gitlab::Satellite::CommitFailed => ex
      error("Your changes could not be committed. Maybe there was nothing to commit?", 409)
    rescue Gitlab::Satellite::PushFailed => ex
      error("Your changes could not be committed. Maybe the file was changed by another process?", 409)
    end
  end
end