File Uploads

Overview

The file upload system in MvcCore Utilidades provides a robust way to handle file uploads with automatic path mapping and URL generation. It uses the UploadFilesController combined with the HelperPathProvider helper class to manage file storage across different folders.

Key Components

UploadFilesController

The main controller for handling file upload operations. Namespace: MvcCoreUtilidades.Controllers Dependencies:

HelperPathProvider - Injected via constructor for path mapping

HelperPathProvider

Helper class that provides path mapping functionality for different folder types. Namespace: MvcNetCoreUtilidades.Helpers Dependencies:

IWebHostEnvironment - For accessing web root path
IServer - For generating full URLs with server addresses

Configuration

Add the HelperPathProvider as a singleton service in Program.cs:

builder.Services.AddSingleton<HelperPathProvider>();

Create folder structure

Ensure the following folders exist in your wwwroot directory:

images/ - For image uploads
uploads/ - For general file uploads
facturas/ - For invoice documents
temp/ - For temporary files

Folder Enumeration

The system uses an enum to define available folders:

public enum Folders
{
    Images,
    facturas,
    Uploads,
    Temporal
}

HelperPathProvider Methods

MapPath

Generates the physical file system path for a file.

FileName

string

required

The name of the file to map

folder

Folders

required

The folder enumeration value (Images, facturas, Uploads, or Temporal)

Returns: string - The full physical path to the file

public string MapPath(string FileName, Folders folder)

Example:

string path = helper.MapPath("photo.jpg", Folders.Images);
// Result: /path/to/wwwroot/images/photo.jpg

MapUrlPath

Generates the full URL path for accessing a file.

fileName

string

required

The name of the file to map

folder

Folders

required

The folder enumeration value

Returns: string - The full URL to access the file

public string MapUrlPath(string fileName, Folders folder)

Example:

string urlPath = helper.MapUrlPath("photo.jpg", Folders.Images);
// Result: https://localhost:5001/images/photo.jpg

Controller Actions

SubirFile (GET)

Displays the file upload form.

public IActionResult SubirFile()
{
    return View();
}

SubirFile (POST)

Handles file upload with asynchronous streaming.

fichero

IFormFile

required

The uploaded file from the form

[HttpPost]
public async Task<IActionResult> SubirFile(IFormFile fichero)

Process:

Extracts the file name from IFormFile
Maps the physical path using HelperPathProvider.MapPath()
Maps the URL path using HelperPathProvider.MapUrlPath()
Creates a file stream and copies the uploaded file asynchronously
Returns success message and URL path

Complete Upload Example

Controller
View (Razor)
Program.cs

using Microsoft.AspNetCore.Mvc;
using MvcNetCoreUtilidades.Helpers;

namespace MvcCoreUtilidades.Controllers
{
    public class UploadFilesController : Controller
    {
        private HelperPathProvider helper;

        public UploadFilesController(HelperPathProvider helper)
        {
            this.helper = helper;
        }

        [HttpPost]
        public async Task<IActionResult> SubirFile(IFormFile fichero)
        {
            string fileName = fichero.FileName;
            
            // Get physical path
            string path = this.helper.MapPath(fileName, Folders.Images);
            
            // Get URL path
            string urlPath = this.helper.MapUrlPath(fileName, Folders.Images);
            
            // Upload file using Stream
            using (Stream stream = new FileStream(path, FileMode.Create))
            {
                await fichero.CopyToAsync(stream);
            }
            
            ViewData["MENSAJE"] = "Fichero subido a " + path;
            ViewData["URLPATH"] = urlPath;
            return View();
        }
    }
}

@{
    ViewData["Title"] = "Subir Archivo";
}

<h2>Upload File</h2>

<form method="post" enctype="multipart/form-data">
    <div class="form-group">
        <label>Select File:</label>
        <input type="file" name="fichero" class="form-control" required />
    </div>
    <button type="submit" class="btn btn-primary">Upload</button>
</form>

@if (ViewData["MENSAJE"] != null)
{
    <div class="alert alert-success mt-3">
        @ViewData["MENSAJE"]
    </div>
    <div class="mt-3">
        <strong>URL:</strong> @ViewData["URLPATH"]
    </div>
}

using MvcNetCoreUtilidades.Helpers;

var builder = WebApplication.CreateBuilder(args);

builder.Services.AddControllersWithViews();

// Register HelperPathProvider as singleton
builder.Services.AddSingleton<HelperPathProvider>();

var app = builder.Build();

app.UseStaticFiles();
app.UseRouting();

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

app.Run();

Usage Patterns

Upload to Different Folders

// Upload invoice
string invoicePath = helper.MapPath("invoice.pdf", Folders.facturas);

// Upload general file
string uploadPath = helper.MapPath("document.docx", Folders.Uploads);

// Upload temporary file
string tempPath = helper.MapPath("temp_file.tmp", Folders.Temporal);

Get URL for Display

// After uploading an image
string imageUrl = helper.MapUrlPath("photo.jpg", Folders.Images);
ViewData["ImageUrl"] = imageUrl;

// In the view:
// <img src="@ViewData["ImageUrl"]" alt="Uploaded photo" />

Best Practices

File Name Sanitization: Always validate and sanitize file names before uploading to prevent path traversal attacks.

File Size Limits: Configure maximum file size limits in your web server and application settings to prevent denial of service attacks.

Validate File Extensions

[HttpPost]
public async Task<IActionResult> SubirFile(IFormFile fichero)
{
    var allowedExtensions = new[] { ".jpg", ".jpeg", ".png", ".gif" };
    var extension = Path.GetExtension(fichero.FileName).ToLowerInvariant();
    
    if (!allowedExtensions.Contains(extension))
    {
        ModelState.AddModelError("", "Invalid file type");
        return View();
    }
    
    // Proceed with upload...
}

Generate Unique File Names

[HttpPost]
public async Task<IActionResult> SubirFile(IFormFile fichero)
{
    var extension = Path.GetExtension(fichero.FileName);
    var uniqueFileName = $"{Guid.NewGuid()}{extension}";
    
    string path = this.helper.MapPath(uniqueFileName, Folders.Images);
    
    using (Stream stream = new FileStream(path, FileMode.Create))
    {
        await fichero.CopyToAsync(stream);
    }
    
    return View();
}

Error Handling

[HttpPost]
public async Task<IActionResult> SubirFile(IFormFile fichero)
{
    try
    {
        if (fichero == null || fichero.Length == 0)
        {
            ViewData["ERROR"] = "Please select a valid file";
            return View();
        }
        
        string fileName = fichero.FileName;
        string path = this.helper.MapPath(fileName, Folders.Images);
        string urlPath = this.helper.MapUrlPath(fileName, Folders.Images);
        
        using (Stream stream = new FileStream(path, FileMode.Create))
        {
            await fichero.CopyToAsync(stream);
        }
        
        ViewData["MENSAJE"] = "File uploaded successfully";
        ViewData["URLPATH"] = urlPath;
    }
    catch (Exception ex)
    {
        ViewData["ERROR"] = $"Upload failed: {ex.Message}";
    }
    
    return View();
}

Source Reference

UploadFilesController: Controllers/UploadFilesController.cs:6
HelperPathProvider: Helpers/HelperPathProvider.cs:11
MapPath method: Helpers/HelperPathProvider.cs:21
MapUrlPath method: Helpers/HelperPathProvider.cs:46

Getting Started

Core Utilities

Examples

Overview

Key Components

UploadFilesController

HelperPathProvider

Configuration

Folder Enumeration

HelperPathProvider Methods

MapPath

MapUrlPath

Controller Actions

SubirFile (GET)

SubirFile (POST)

Complete Upload Example

Usage Patterns

Upload to Different Folders

Get URL for Display

Best Practices

Validate File Extensions

Generate Unique File Names

Error Handling

Source Reference

Build docs developers (and LLMs) love

Getting Started

Core Utilities

Examples

​Overview

​Key Components

​UploadFilesController

​HelperPathProvider

​Configuration

​Folder Enumeration

​HelperPathProvider Methods

​MapPath

​MapUrlPath

​Controller Actions

​SubirFile (GET)

​SubirFile (POST)

​Complete Upload Example

​Usage Patterns

​Upload to Different Folders

​Get URL for Display

​Best Practices

​Validate File Extensions

​Generate Unique File Names

​Error Handling

​Source Reference

Build docs developers (and LLMs) love

Overview

Key Components

UploadFilesController

HelperPathProvider

Configuration

Folder Enumeration

HelperPathProvider Methods

MapPath

MapUrlPath

Controller Actions

SubirFile (GET)

SubirFile (POST)

Complete Upload Example

Usage Patterns

Upload to Different Folders

Get URL for Display

Best Practices

Validate File Extensions

Generate Unique File Names

Error Handling

Source Reference