Converting raw text into polished, SEO‑friendly content is a daily challenge for many .NET developers building content‑rich web applications. GroupDocs.Rewriter Cloud SDK for .NET provides a powerful API that rewrites sentences while preserving meaning. This step-by-Step guide to Integrate with ASP.NET Core MVC shows you how to set up the library, configure credentials, implement the rewriting logic in a controller, and render the results in a Razor view.

The Use Case Requirements

Enterprises that generate user‑generated articles, product descriptions, or marketing copy often need to improve readability without manual editing. The requirements for such a scenario include:

  • Real‑time text rewriting directly from a web form.
  • Secure handling of API credentials on the server side.
  • Seamless integration with the existing ASP.NET Core MVC pipeline.

Using generic string‑manipulation code quickly becomes error‑prone and does not scale, which is why a dedicated document rewriting library is essential.

Choosing GroupDocs.Rewriter Cloud SDK for .NET for the Job

GroupDocs.Rewriter Cloud SDK for .NET offers a REST‑based API that supports multiple languages, customizable rewrite modes, and high‑performance processing. Its key capabilities that match the use case are:

  • RewriteModeEnum.Rewrite - produces a natural‑language rewrite of the input text.
  • DI‑friendly client - can be registered as a singleton in the ASP.NET Core service container.
  • Strong typing and async support - fits naturally into modern .NET asynchronous patterns.

The step-by-Step guide to Integrate with ASP.NET Core MVC demonstrates how these capabilities map to the requirements. For detailed API information, see the official documentation and the API reference.

Implementing Step‑by‑Step Guide to Integrate with ASP.NET Core MVC

This step-by-Step guide to Integrate with ASP.NET Core MVC will walk you through each required configuration step.

Install the SDK Package

Add the NuGet package to your project.

dotnet add package GroupDocs.Rewriter-Cloud

You can also download the binaries from the download page.

Add Configuration for Rewriter Credentials

Place your AppSid and AppKey in the configuration. The snippet below adds them in‑memory for simplicity.

builder.Configuration.AddInMemoryCollection(new[]
{
    new KeyValuePair<string,string>("GroupDocsRewriter:AppSid", "YOUR_APP_SID"),
    new KeyValuePair<string,string>("GroupDocsRewriter:AppKey", "YOUR_APP_KEY")
});

Register the Rewriter API Client in DI

The SDK client is registered as a singleton so it can be injected into controllers.

builder.Services.Configure<RewriterSettings>(builder.Configuration.GetSection("GroupDocsRewriter"));

builder.Services.AddSingleton<IRewriterApi>(sp =>
{
    var settings = sp.GetRequiredService<IOptions<RewriterSettings>>().Value;
    var config = new Configuration
    {
        AppSid = settings.AppSid,
        AppKey = settings.AppKey
    };
    return new RewriterApi(config);
});

Create the MVC Controller and View Model

The controller receives the original text, calls the Rewriter API, and returns the rewritten result.

public class RewriterController : Controller
{
    private readonly IRewriterApi _rewriterApi;

    public RewriterController(IRewriterApi rewriterApi)
    {
        _rewriterApi = rewriterApi;
    }

    [HttpGet]
    public IActionResult Index()
    {
        return View(new RewriterViewModel());
    }

    [HttpPost]
    public async Task<IActionResult> Index(RewriterViewModel model)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }

        var rewriteRequest = new RewriteRequest
        {
            Text = model.InputText,
            Language = "en",
            TargetLanguage = "en",
            RewriteMode = RewriteModeEnum.Rewrite
        };

        RewriteResponse response = await _rewriterApi.RewriteAsync(rewriteRequest);
        model.OutputText = response?.Result?.Text ?? string.Empty;

        return View(model);
    }
}

The accompanying view model holds the input and output strings.

public class RewriterViewModel
{
    [Required]
    [Display(Name = "Original Text")]
    public string InputText { get; set; } = string.Empty;

    [Display(Name = "Rewritten Text")]
    public string OutputText { get; set; } = string.Empty;
}

Build the Razor View for Text Input and Output

The Razor page presents a simple form and displays the rewritten text when available.

@model RewriterViewModel
@{
    ViewData["Title"] = "Text Rewriter";
}
<h2>@ViewData["Title"]</h2>

<form asp-action="Index" method="post" class="form-horizontal">
    <div class="form-group">
        <label asp-for="InputText" class="control-label"></label>
        <textarea asp-for="InputText" class="form-control" rows="6"></textarea>
        <span asp-validation-for="InputText" class="text-danger"></span>
    </div>
    <div class="form-group">
        <button type="submit" class="btn btn-primary">Rewrite</button>
    </div>
</form>

@if (!string.IsNullOrWhiteSpace(Model.OutputText))
{
    <hr />
    <h4>Rewritten Text</h4>
    <textarea class="form-control" rows="6" readonly>@Model.OutputText</textarea>
}

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

Full Working Example for Document Rewriting in ASP.NET Core MVC

The example below contains the complete source files needed to run the solution.

// ---------------------------------------------------
// Program.cs
// ---------------------------------------------------
using Microsoft.AspNetCore.Builder;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Options;
using GroupDocs.Rewriter.Cloud.Sdk.Api;
using GroupDocs.Rewriter.Cloud.Sdk.Client;
using GroupDocs.Rewriter.Cloud.Sdk.Model.Requests;
using GroupDocs.Rewriter.Cloud.Sdk.Model;
using System.Threading.Tasks;

var builder = WebApplication.CreateBuilder(args);

// Add configuration for GroupDocs Rewriter credentials
builder.Configuration.AddInMemoryCollection(new[]
{
    new KeyValuePair<string,string>("GroupDocsRewriter:AppSid", "YOUR_APP_SID"),
    new KeyValuePair<string,string>("GroupDocsRewriter:AppKey", "YOUR_APP_KEY")
});

builder.Services.Configure<RewriterSettings>(builder.Configuration.GetSection("GroupDocsRewriter"));

// Register GroupDocs Rewriter API client in DI
builder.Services.AddSingleton<IRewriterApi>(sp =>
{
    var settings = sp.GetRequiredService<IOptions<RewriterSettings>>().Value;
    var config = new Configuration
    {
        AppSid = settings.AppSid,
        AppKey = settings.AppKey
    };
    return new RewriterApi(config);
});

builder.Services.AddControllersWithViews();

var app = builder.Build();

if (!app.Environment.IsDevelopment())
{
    app.UseExceptionHandler("/Home/Error");
}
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();

app.MapControllerRoute(
    name: "default",
    pattern: "{controller=Rewriter}/{action=Index}/{id?}");

app.Run();

// ---------------------------------------------------
// RewriterSettings.cs
// ---------------------------------------------------
public class RewriterSettings
{
    public string AppSid { get; set; } = string.Empty;
    public string AppKey { get; set; } = string.Empty;
}

// ---------------------------------------------------
// Models/RewriterViewModel.cs
// ---------------------------------------------------
using System.ComponentModel.DataAnnotations;

public class RewriterViewModel
{
    [Required]
    [Display(Name = "Original Text")]
    public string InputText { get; set; } = string.Empty;

    [Display(Name = "Rewritten Text")]
    public string OutputText { get; set; } = string.Empty;
}

// ---------------------------------------------------
// Controllers/RewriterController.cs
// ---------------------------------------------------
using Microsoft.AspNetCore.Mvc;
using System.Threading.Tasks;

public class RewriterController : Controller
{
    private readonly IRewriterApi _rewriterApi;

    public RewriterController(IRewriterApi rewriterApi)
    {
        _rewriterApi = rewriterApi;
    }

    [HttpGet]
    public IActionResult Index()
    {
        return View(new RewriterViewModel());
    }

    [HttpPost]
    public async Task<IActionResult> Index(RewriterViewModel model)
    {
        if (!ModelState.IsValid)
        {
            return View(model);
        }

        // Build request for the Rewriter API
        var rewriteRequest = new RewriteRequest
        {
            Text = model.InputText,
            Language = "en",               // source language
            TargetLanguage = "en",         // target language (same for rewriting)
            RewriteMode = RewriteModeEnum.Rewrite // choose rewrite mode
        };

        // Call the API
        RewriteResponse response = await _rewriterApi.RewriteAsync(rewriteRequest);

        // Populate the view model with the rewritten text
        model.OutputText = response?.Result?.Text ?? string.Empty;

        return View(model);
    }
}

// ---------------------------------------------------
// Views/Rewriter/Index.cshtml
// ---------------------------------------------------
@model RewriterViewModel
@{
    ViewData["Title"] = "Text Rewriter";
}
<h2>@ViewData["Title"]</h2>

<form asp-action="Index" method="post" class="form-horizontal">
    <div class="form-group">
        <label asp-for="InputText" class="control-label"></label>
        <textarea asp-for="InputText" class="form-control" rows="6"></textarea>
        <span asp-validation-for="InputText" class="text-danger"></span>
    </div>
    <div class="form-group">
        <button type="submit" class="btn btn-primary">Rewrite</button>
    </div>
</form>

@if (!string.IsNullOrWhiteSpace(Model.OutputText))
{
    <hr />
    <h4>Rewritten Text</h4>
    <textarea class="form-control" rows="6" readonly>@Model.OutputText</textarea>
}

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

Note: This code example demonstrates the core functionality. Before using it in your project, make sure to update any file paths and configuration values to match your actual environment, verify that all required dependencies are properly installed, and test thoroughly in your development environment. If you encounter any issues, please refer to the official documentation or reach out to the support team for assistance.

Executing Document Rewriting Via REST API Using cURL

Below is a quick cURL workflow that performs the same rewrite operation via the GroupDocs Rewriter REST endpoints.

Authenticate and Get Access Token

curl -X POST "https://api.groupdocs.cloud/v1/auth/token" \
     -H "Content-Type: application/json" \
     -d '{"client_id":"YOUR_CLIENT_ID","client_secret":"YOUR_CLIENT_SECRET"}'

The response returns an access_token that you will use in subsequent calls.

Upload the Source Text (optional for large files)

curl -X POST "https://api.groupdocs.cloud/v1/storage/file/upload" \
     -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
     -F "file=@input.txt"

Execute the Rewrite Operation

curl -X POST "https://api.groupdocs.cloud/v1/rewriter/rewrite" \
     -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
     -H "Content-Type: application/json" \
     -d '{
           "text": "Your original text goes here.",
           "language": "en",
           "targetLanguage": "en",
           "rewriteMode": "Rewrite"
         }'

The JSON response contains the rewritten text in the result.text field.

Download the Result (if you stored it as a file)

curl -X GET "https://api.groupdocs.cloud/v1/storage/file/download?path=output.txt" \
     -H "Authorization: Bearer YOUR_ACCESS_TOKEN" \
     -o rewritten.txt

For more details on request parameters and response formats, see the official API documentation.

Final Thoughts

Integrating the GroupDocs.Rewriter Cloud SDK for .NET into an ASP.NET Core MVC project is straightforward once you follow this step-by-Step guide to Integrate with ASP.NET Core MVC. The library handles the heavy lifting of natural‑language rewriting, letting you focus on UI and business logic. Remember to secure your AppSid and AppKey, use the temporary license for evaluation, and upgrade to a full license for production workloads. With the code and cURL examples in hand, you can now add intelligent text rewriting to any .NET web application.

FAQs

How does the step-by-Step guide to Integrate with ASP.NET Core MVC handle error responses from the API?
The controller example checks ModelState.IsValid before calling the API and captures the RewriteResponse. If the API returns an error, the response object will be null, and the view will simply show an empty output. For detailed error handling, consult the official documentation.

Can I rewrite documents other than plain text, such as DOCX or PDF, using the same approach?
Yes. The Rewriter API accepts raw text extracted from supported formats. You can first use GroupDocs.Parser or GroupDocs.Conversion to extract text, then pass it to the rewrite endpoint. Both SDKs are listed in the GroupDocs product family.

Is it possible to run the rewrite operation asynchronously in a high‑traffic web site?
Absolutely. The controller uses await _rewriterApi.RewriteAsync(...), which is fully asynchronous and scales with ASP.NET Core’s async pipeline. This fits the pattern demonstrated in the step-by-Step guide to Integrate with ASP.NET Core MVC.

Where can I obtain a temporary license for testing?
A temporary license is available from the temporary license page. It lets you evaluate the SDK without committing to a purchase.

Further Reading